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Do changes in hand grip strength correlate with shoulder rotator cuff function?
Abstract
Background:
Shoulder pain as a result of rotator cuff pathology is one of the most common musculoskeletal complaints presenting within primary care. Assessment of hand grip strength has been proposed as an indicator of rotator cuff function. This experimental study assessed the relationship between grip strength and shoulder lateral rotator muscle strength in a number of different shoulder positions, aiming to investigate whether such a relationship existed and whether grip strength could be used as a functional assessment tool for the posterior cuff.
Methods:
Twenty-seven healthy, physically active, volunteers (19 males, eight females) with no history of shoulder, upper limb or neck injury comprised the study group. The mean (SD) age was 19.8 (5.7) years (range 18 years to 23 years). Grip strength (measured with hand grip dynamometer) and lateral rotator strength (measured with a hand held dynamometer) was measured at neutral, 90° abduction, and 90° abduction with 90° external rotation.
Results:
The correlation between grip strength and shoulder lateral rotation strength ranged between r = 0.91 (r (2 )= 0.84) and r = 0.72 (r (2 )= 0.52) across all positions.
Conclusions:
A strong correlation between grip strength and lateral rotator strength was shown at all positions for both left and right hands, suggesting that assessment of grip strength could be used as a rotator cuff monitor of recruitment function.
... 9 Based on the above, weakness of the scapular and glenohumeral muscles is one of the main impairments in patients with SIS. [10][11][12][13] Indeed, in these patients, the greatest impairment in muscle strength has been reported in the lateral rotator muscles of the shoulder (i.e., infraspinatus and teres minor, supraspinatus), 11,12 leading to imbalance in the function of the rotator cuff muscles and alterations in the glenohumeral kinematics. 11 Additionally, positive correlations between shoulder muscle strength, grip strength and upper limb function have been reported in previous studies. ...
... 11 Additionally, positive correlations between shoulder muscle strength, grip strength and upper limb function have been reported in previous studies. 10,13 Due to the shoulder muscle imbalance that commonly exists in patients with SIS, the entire upper limb kinetic chain is affected, negatively impacting energy transfer through the upper limb as well as grip function. 10 Therefore, shoulder rehabilitation programs should focus on the prescription of exercises to improve lateral rotation and handgrip strength deficits in these patients. ...
... 10,13 Due to the shoulder muscle imbalance that commonly exists in patients with SIS, the entire upper limb kinetic chain is affected, negatively impacting energy transfer through the upper limb as well as grip function. 10 Therefore, shoulder rehabilitation programs should focus on the prescription of exercises to improve lateral rotation and handgrip strength deficits in these patients. ...
Background
Weakness of the rotator cuff has been reported in patients with subacromial impingement syndrome (SIS). A novel therapeutic approach proposes adding exercises for the core musculature to aid in functional recovery in these patients.
Purpose
The aim of this study was to assess the short-term effects of adding a core exercise program to supervised physiotherapy on improve lateral rotator strength and functional outcomes in patients with SIS.
Study Design
A pre–post single-group study.
Methods
A total of 47 participants with SIS were recruited. All patients were treated with five weeks of supervised physiotherapy plus a core exercise program. The primary outcomes were isometric lateral rotator strength and grip strength, measured with a dynamometer. Secondary outcomes included muscular endurance assessed with the Closed Kinetic Chain Upper Extremity Stability Test (CKCUEST), shoulder function with the Constant-Murley (CM) questionnaire, and pain intensity reported using the Visual Analog Scale (VAS). Need a brief statement of statistical approach.
Results
At end of the five week intervention, isometric lateral rotator strength showed an increase of 9.2 kg ( d = 2.1; p < 0.001) and grip strength an increase of 10.6 kg ( d = 2.4; p < 0.001). The CKCUEST showed an increase of 5.6 repetitions ( d = 3.7; p < 0.001), the CM questionnaire showed an increase of 30.3 points ( d = 4.9; p < 0.001) and the VAS showed a decrease of 3.9 cm ( d = 6.0; p < 0.001). All outcomes showed large effect sizes and statistically significant differences.
Conclusion
In the short term, adding a core exercise program to supervised physiotherapy showed statistically and clinically significant differences in lateral rotator strength and functional outcomes in patients with SIS.
Level of Evidence
Level 3
... Completion of QuickDASH and FABQ questionnaires. [16,17]. Active range of motion provides an objective measure of functional mobility that directly impacts daily activities. ...
... Grip strength: Measured using the "JAMAR" Hydraulic Hand Dynamometer (5030J1, Preston Corporation, NJ, USA) to estimate upper extremity strength [16]. Measurements were taken in a seated position with a neutral shoulder, 90 • elbow flexion, and a neutral wrist [17]. The average of three 5 s hold repetitions was used in the analysis [17]. ...
... Measurements were taken in a seated position with a neutral shoulder, 90 • elbow flexion, and a neutral wrist [17]. The average of three 5 s hold repetitions was used in the analysis [17]. ...
Featured Application
The ULSPT, in particular, shows promise as a functional power test for adults with RCRSP. It provides a continuous measure of shoulder function that correlates with established clinical measures. Further research with larger samples is needed to fully elucidate the clinical utility of both tests and determine if one test may suffice for comprehensive assessment.
Abstract
Background: Rotator cuff-related shoulder pain (RCRSP) is a common musculoskeletal condition characterized by pain, functional disability, reduced mobility, and weakness. There is a need for valid functional tests that can measure shoulder strength and power without exacerbating pain. The Seated Medicine Ball Throw (SMBT) and Unilateral Shot-Put Test (ULSPT) are throwing tests that use a weighted ball in a seated position, measuring throwing distance (m). This study aimed to evaluate the feasibility, discriminative validity, and convergent validity of these tests in individuals with RCRSP. Methods: This cross-sectional study included 64 participants: 30 with RCRSP and 34 asymptomatic controls. Participants completed the QuickDASH and Fear-Avoidance Beliefs Questionnaire (FABQ). Pain was assessed using a 10 cm visual analog scale (VAS) at multiple time points. The SMBT and ULSPT were performed using a 2 kg ball, with throwing distance calculated as the average of three trials. Active shoulder range of motion (AROM) and grip strength were also measured. A two-way mixed-model repeated-measures ANOVA was conducted to examine group effects, with post hoc analyses performed where relevant. Pearson correlations explored associations among outcome measures. Results: The RCRSP group presented with persistent moderate shoulder pain (mean duration = 6.33 ± 5.7 months, VAS = 5.03 ± 1.99 cm, QuickDASH = 26.2 ± 10.54). Pain did not significantly increase after throwing (VAS change = 0.5 ± 1.6 cm, P = 0.4), supporting the tests’ feasibility. ULSPT demonstrated significant differences between the RCRSP and control groups for both symptomatic (2.03 ± 0.81 m) and asymptomatic shoulders (2.04 ± 0.8 m) compared with controls (2.51 ± 0.93 m, P < 0.01). SMBT showed a trend toward group differences (P = 0.05). RCRSP participants showed reduced AROM (166.2 ± 10° vs. 175.1 ± 8.2°) but similar grip strength compared to controls. ULSPT strongly correlated with SMBT (r = 0.92–0.94, P < 0.0001). Both throwing tests correlated moderately with grip strength (r = 0.61–0.81, P < 0.05) and showed mild to moderate correlations with disability, pain, and fear-avoidance measures (r = 0.26–0.48, P < 0.05). Conclusions: The ULSPT demonstrated good discriminative validity in differentiating individuals with RCRSP from controls, while the SMBT showed a trend toward discrimination. Both tests were feasible to administer without significantly exacerbating pain. The strong correlation between ULSPT and SMBT, along with their associations with established measures, supports their potential as functional assessments of upper extremity performance in RCRSP.
... Horsely et al (2016) found a strong correlation between handgrip strength and lateral rotator strength when both variables were measured with the arm in three different positions: neutral (relaxed); 90 degrees abduction; and 90 degrees abduction with 90 degrees of external rotation of both the left and right shoulder respectively. This implies that grip strength, when measured with the arm in a neutral position, could be used to monitor the various stages of the rehabilitation process, especially in patients experiencing pain (Horsley et al, 2016). However, the findings of Horsley et al (2016), and those of others (Sporrong et al, 1995;1996;Mandalidis and O'Brien, 2010), are only related to individuals with healthy asymptomatic shoulders. ...
... This implies that grip strength, when measured with the arm in a neutral position, could be used to monitor the various stages of the rehabilitation process, especially in patients experiencing pain (Horsley et al, 2016). However, the findings of Horsley et al (2016), and those of others (Sporrong et al, 1995;1996;Mandalidis and O'Brien, 2010), are only related to individuals with healthy asymptomatic shoulders. The question whether a similar association exists in individuals with pathological shoulders remains unanswered. ...
... Physicians and orthopedic surgeons referred individuals with shoulder pain to the physiotherapy department, who were then invited to participate in this study. A priori estimation of the sample size of 30 was derived, with a power of 0.9 and an alpha level of 0.05 (Horsley et al, 2016). ...
Background/Aims
Shoulder pain is reported to be the third most common musculoskeletal disorder. Rotator cuff muscles play an important role in stabilising the shoulder and decreasing pain. Assessment of handgrip strength has been proposed as an indicator of rotator cuff function in healthy individuals, but not in those experiencing shoulder pain. The aim of this study was to assess the relationship between handgrip strength and shoulder rotator cuff strength in patients experiencing shoulder pain as a result of pathology or surgical intervention. A secondary aim was to identify any association between the duration of shoulder pain and handgrip strength and shoulder rotator cuff strength.
Methods
A total of 32 patients with shoulder pain (19 men, 13 women) were evaluated. The mean age was 52.88 (± 15.66) years, with a mean duration of shoulder pain of 13.44 (± 10.22) weeks. Handgrip strength was measured using the standard Jamar hydraulic hand dynamometer, and individual isometric rotator cuff strength was measured using the Baseline push-pull dynamometer.
Results
Correlation was found between handgrip strength and the abductor (r=0.58), external rotator (r=0.57), and internal rotator strength (r=0.59). A linear regression model was used to derive the equations for the association. No significant (P>0.05) correlation was found between the duration of pain and the handgrip strength or rotator cuff strength.
Conclusions
The strength of the correlation found indicates that handgrip strength can be used for assessment and within a rehabilitation programme to monitor rotator cuff function in patients with shoulder pain or post-surgical rehabilitation. The strength of rotator cuff muscles can be predicted by the equations derived from the regression model relating to grip strength assessment.
... Essentially, shoulder movements are used to position and move the hand during fine tasks. Due to the muscle imbalance that exists in patients with SAIS, handgrip strength is concomitantly affected, and the positive correlation between handgrip and shoulder muscle strength has been demonstrated in previous studies [24][25][26][27][28]. Although strengthening the handgrip is an essential aspect of SAIS treatment [23][24][25][26][27][28], no previous studies have investigated the effects of including handgrip-strengthening exercises in treatment programs for patients with SAIS. ...
... Due to the muscle imbalance that exists in patients with SAIS, handgrip strength is concomitantly affected, and the positive correlation between handgrip and shoulder muscle strength has been demonstrated in previous studies [24][25][26][27][28]. Although strengthening the handgrip is an essential aspect of SAIS treatment [23][24][25][26][27][28], no previous studies have investigated the effects of including handgrip-strengthening exercises in treatment programs for patients with SAIS. ...
... Handgripstrengthening exercises (HGSE) were performed under therapeutic supervision in addition with the standardized conventional intervention for the patients with primary SAIS in experimental group as previously mentioned in the literature [24,25,32,33]. An adjustable heavy-grip handgripper (El-Falah Sports House Co., China) was used to perform 10 repetitions at repetition maximum as shown in Figure 2. Patients were asked to perform the exercises in a standing position with their back against a wall, arm at either 30, 60, or 90°of abduction, and with 90°external rotations as in Figures 2(a)-2(d). ...
Background:
Impingement syndrome was shown to be associated with shoulder pain in 44-70% of patients worldwide. It usually occurs due to imbalance and insufficient activation of the rotator cuff (RC) muscles.
Aim:
This study explores the relative effects of handgrip-strengthening exercises on shoulder function, pain, strength, and active range of motion as part of the treatment program for the patients with primary subacromial impingement syndrome.
Materials and methods:
A total of 58 patients aged 18-50 years with primary subacromial impingement syndrome were randomly enrolled to participate in this single-blind randomized clinical trial. Out of them, only forty patients have eligibly matched the inclusion criteria and randomly assigned to one of two groups to undergo a standardized therapeutic program consisting of two sessions a week for 8 weeks. The control group prescribed ultrasound therapy, ice, and stretching exercises, while the experimental group followed the same program with the addition of handgrip-strengthening exercises (HGSE). Both patients of conventional therapy (control) and handgrip-strengthening exercises (experimental group) were advised to adhere also to stretching and HGSE exercises once a day at home for eight weeks. The outcomes were the shoulder function, pain intensity, muscle strength, and active range of motion of the shoulder joint.
Results:
Patients treated with conventional interventions plus handgrip-strengthening exercises showed the significant improvement over time in shoulder pain and function, strength of rotator cuff muscles, and pain-free range of motion forward flexion, abduction, and external and internal rotation through eight weeks in the experimental group compared to control patient group treated with conventional interventions. In addition, patients of both control and experimental groups showed no significant difference in the adherence to respective home-based stretching and HGSE exercises once a day at home for eight weeks.
Conclusions:
Adding handgrip-strengthening exercises to conventional intervention increases the efficacy of treatment for patients with primary subacromial impingement syndrome in terms of shoulder function, pain, muscle strength, and active range of motion.
... The handgrip is a physiology-related variable that can be affected by a wide range of factors such as age, gender, and body mass index (BMI) [11]. It is frequently used in rehabilitation centers to compare patient grip strength with normative data or to compare the force generated by dominant and nondominant arms [12]. The handgrip is evaluated not only as an element of hand function but also as an objective index of upper limb functional integrity [11]. ...
... Mandalidis and O'Brien [18] concluded that the isometric grip strength could be used to monitor the isokinetic strength of shoulder stabilizers in eighteen collegiate-level male athletes. In 27 subjects, Horsley et al. [12] suggested using handgrip strength as a monitor for rotator cuff recruitment function. Sathya et al. [11] studied 75 intercollegiate cricket players and concluded that grip strength testing could be used as a predictor for shoulder power. ...
... If they were willing to participate and fully understood what was involved, they were asked to sign the written informed consent form. The raw data were taken for healthy participants (N = 27, mean age 19.8 ± 5.7 years, range 18 to 23 years) from the study by Horsley et al. [12] and compared to the data collected in this study. ...
Aim
To investigate if there is a correlation between grip strength (GS) and rotator cuff (RC) strength in patients with atraumatic shoulder instability (ASI) and to compare the relationship between these two measures with that previously published for a healthy population. Moreover, to determine if testing GS could be incorporated as a surrogate clinical assessment for RC strength in these patients.
Methods
A total of 20 subjects with ASI were included. Out of the 20 patients, eight presented with bilateral instability, which constituted a total of 28 atraumatic unstable shoulders ( N = 28). GS was measured using a Jamar hand-dynamometer. External rotation (ER) and internal rotation (IR) strength was tested in inner and outer ranges using a hand-held dynamometer (HHD). Pearson’s correlation test was computed to investigate the relationship. Multiple linear regression was conducted to predict GS based on RC strength.
Results
Significant and strong positive correlations were found between GS and inner-range IR ( r = 0.764, P < 0.001), inner-range ER ( r = 0.611, P = 0.001), outer-range IR ( r = 0.817, P < 0.001), and outer-range ER ( r = 0.736, P < 0.001). A significant regression equation was found ( F (4, 23) = 13.254, P < 0.001), with an R ² of 0.697 indicating that RC strength explained 69.7% of the variance in GS.
Conclusions
The results support the hypothesis showing that GS is strongly associated with RC strength in ASI patients. The simplicity of handgrip testing allows it to be used in clinical scenarios where sophisticated assessment tools are not available. GS is a convenient means to monitor patient progress during shoulder rehabilitation programs.
... Furthermore, this test is useful to monitor upper limbs fatigue and the risk of suffering shoulder injuries. 16 Despite the great importance of monitoring the objective fatigue measures (i.e., CMJ and HG), the subjective perception of effort of the athlete should be taken into account. In this line, Rate of Perceived Effort (RPE) Scale is a valid tool to monitor subjective perceived fatigue. ...
... An optimal warm-up that improves the strength of the muscles that stabilize the different joints of the upper limb, can improve the speed of hitting 27 as well as prepare the different tissues for competitive practice. 16 In our study, it was shown that an optimal warm-up was not carried out by high-level players, not achieving the protective role of the warm-up 28 due to the higher values offered by the athletes at the end of the matches compared to the prematch values. In relation to neuromuscular performance in lower limbs, CMJ was assessed. ...
Background: Padel is a sport that requires a combination of physical and technical skills. Fatigue is a major modulator of padel players' performance. The aim of this study was to analyze the changes in neuromuscular performance and perceived effort among high-level padel players.
Methods: Countermovement jump and handgrip strength of 58 participants (men: N.=38 age = 28.3±7.05 years, height = 178.9±8.41 cm; body mass = 75.25±8.2 kg. women: N.=21, age = 23.07±4.6 years, height = 163.86±10.34 cm; body mass = 59.9±6.13 kg) were assessed pre- and post-match in 43 official matches during the Padel Master 2021 of the Andalusian Padel Federation. Additionally, the Rating of Perceived Exertion (RPE) Scale was used to assess players' subjective perception of effort after each match.
Results: Players experienced significant increases in postmatch jump height, with no changes in handgrip strength. Moreover, changes in jump height were greater in male players after the match when compared to their female counterparts, but the match duration was not determinant when comparing CMJ or handgrip between 2-sets and 3-sets matches. Finally, players reported a higher RPE after longer matches, but perceived effort was not different between sexes.
Conclusions: These findings suggest that the internal load generated during competitive padel matches is insufficient to cause a declination in performance of the studied variables. It is also concluded that players' warm-up routines could be optimized to enhance neuromuscular performance at the start of matches.
... In orthopedic research, grip strength predicts surgical and functional outcomes in patients undergoing spine and hip fracture surgery [21][22][23]. Furthermore, numerous studies have demonstrated the correlation between grip strength and rotator cuff function [24][25][26][27]; Manske et al. investigated this correlation in patients with RCT and reported positive correlations between grip strength of the affected side and ipsilateral shoulder abduction and external rotation strength [27]. ...
... Our findings suggest the predictive role of these three parameters for early postoperative shoulder function; higher baseline grip strength predicts more favorable functional recovery after ARCR, whereas a higher total suture anchor number and BMI may predict less favorable early postoperative shoulder function. Numerous studies have reported a positive correlation between grip strength and rotator cuff function [24][25][26][27] between grip strength and several measures of shoulder function [27]. According to their findings, grip strength of the affected side was significantly and positively correlated with the strength of ipsilateral shoulder external rotation and abduction, although no significant correlations were observed between grip strength and patientreported functional scores [27]. ...
Background
Rotator cuff tears (RCTs) are a common musculoskeletal disorder, and arthroscopic rotator cuff repair (ARCR) is widely performed for tendon repair. Handgrip strength correlates with rotator cuff function; however, whether preoperative grip strength can predict functional outcomes in patients undergoing ARCR remains unknown. This study aimed to investigate the correlation between preoperative grip strength and postoperative shoulder function following ARCR.
Methods
A total of 52 patients with full-thickness repairable RCTs were prospectively enrolled. Baseline parameters, namely patient characteristics and intraoperative findings, were included for analysis. Postoperative shoulder functional outcomes were assessed using the Quick Disabilities of the Arm, Shoulder, and Hand (QDASH) questionnaire and Constant–Murley scores (CMSs). Patients were followed up and evaluated at three and six months after ARCR. The effects of baseline parameters on postoperative outcomes were measured using generalized estimating equations.
Results
At three and six months postoperatively, all clinical outcomes evaluated exhibited significant improvement from baseline following ARCR. Within 6 months postoperatively, higher preoperative grip strength was significantly correlated with higher CMSs (β = 0.470, p = 0.022), whereas increased numbers of total suture anchors were significantly correlated with decreased CMSs (β = − 4.361, p = 0.03). Higher body mass index was significantly correlated with higher postoperative QDASH scores (β = 1.561, p = 0.03) during follow-up.
Conclusions
Higher baseline grip strength predicts more favorable postoperative shoulder function following ARCR. A preoperative grip strength test in orthopedic clinics may serve as a predictor for postoperative shoulder functional recovery in patients undergoing ARCR.
... Considering the post-op period, the total MCMS, pain, daily activities, ROM, and strength of participants with RC surgery were lower than those of healthy participants, which supports the literature. 25 , it is possible that grip strength has decreased due to the redistribution of force in the RC muscles following an injury. Because the simultaneous activation of proximal and distal arm muscles is required during gripping, this may have led to the individual's inability to perform activities of daily living such as grasping objects of different weights. ...
... Horsley et al25 reported that a strong correlation between grip strength and RC strength was observed in all positions for both the left and right hands. However, Manske et al 18 interestingly reported that there was no relationship between grip strength and RC dysfunction in individuals with rotator cuff tears. ...
Objective: The aims of this study were (a) to compare shoulder functional performance, shoulder functionality, grip strength, and scapular endurance between individuals with rotator cuff repair (RCr) and healthy controls, and (b) to investigate the impact of these factors on shoulder performance. Methods: In this study, a study group (n = 32) of individuals with RCr and a control group (n = 32) of healthy individuals were included. The study group comprised individuals who underwent surgical repair for full-thickness rotator cuff (RC) ruptures (excluding massive size) and completed at least 24 weeks of postoperative follow-up. Shoulder performance and functionality, grip strength, and scapular endurance were evaluated by the Functional Impairment Test-Hand-andNe ck/Sh oulde r/Arm (FIT-HaNSA), the Modified Constant-Murley Score (MCMS), the Jamar hand dynamometer, and the Scapular Muscle Endurance Test, respectively. These factors affecting the performance of the shoulder were examined by regression analysis. Results: Functional Impairment Test-Head and Neck, Shoulder, Arm, the MCMS, and the Jamar score were lower in the study group (P < .05). Scapular endurance was similar in both groups (P > .05). Functional Impairment Test-Head and Neck, Shoulder, Arm was correlated with the MCMS, the Jamar score, and the scapular endurance , respectively (r: 0.455 / 0.727 / 0.438; P < .05). A regression analysis was run to determine the variables affecting shoulder performance. The values of pain, strength, total score of MCMS, scapular endurance, and Jamar score explained 14.8%, 29.5%, 27.3%, 18.9%, and 30.8% of shoulder performance, respectively (P < .05). Conclusion: The functional performance of the shoulder was lower in individuals with RCr compared to healthy individuals. The most significant variables affecting shoulder performance were upper limb strength, shoulder functionality, scapular muscle endurance, and the pain sub-parameter of MCMS, according to the rates of influence, respectively.
... In addition, shoulder injuries can impair sensory-motor control and limit force transfer to the upper extremity, causing physical disability or functional impairment related to the performance of activities of daily living (ADLs) or negatively impacting hand function [21,22]. Patients suffering from SIS often experience decreased handgrip strength, and grip strength can be used as an indicator to monitor rotator cuff function [23,24]. The function of the upper extremities is essential for most activities of daily living. ...
... Through this training, the ability of the rotator cuff and surrounding muscles to control the humeral head can be improved. Increased shoulder joint stability due to enhanced control of the rotator cuff may also affect hand function [21][22][23][24]. Our results showed an improvement in grip strength in the CGH group. ...
Subacromial impingement syndrome (SIS) is one of the most common causes of shoulder pain in adults and is caused by muscle imbalance around the shoulder joint, which is referred to as secondary SIS. Centralization of the glenohumeral joint (CGH), one of the intervention methods for this, targets strengthening the control ability of the rotator cuff. Dynamic humeral centering (DHC) targets the learning of selective contractile function of the pectoralis major and latissimus dorsi as depressors of the humeral head. This study aims to determine the short-term effects of CGH and DHC on pain, disability, and grip strength in patients with secondary SIS. Forty-eight patients with secondary SIS participated in the study and were randomly allocated into three groups (CGH group (n = 16), DHC group (n = 16), and simple exercise group (n = 16)) and received the intervention for 50 min. The Constant–Murley score was used to assess shoulder pain and disability (primary outcome), and a hand-held dynamometer was used to assess grip strength (secondary outcome). Measurements were performed before the intervention and one day after the intervention. The results showed that the Constant–Murley score improved in the CGH and DHC groups. In addition, pain and disability (range of motion scores) improved in both the CGH and DHC groups. Improvements in disability (shoulder strength) and grip strength were seen only in the CGH group. Both CGH and DHC can be used as methods for short-term pain release and disability recovery in secondary SIS. In particular, CGH appears to be more effective in the short-term improvement in shoulder strength and grip strength.
... Finally, rotator cuff strength was measured using a portable dynamometer (EH101, TNI Commerce, China). With the participant sitting down, hand grip strength was measured three times in 90º abduction and 90º external rotation and the mean was used for analysis ( Figure 2) [29]. The correlation between grip strength and shoulder lateral rotation strength ranged between r＝0.91 and r＝0.72 [29]. ...
... With the participant sitting down, hand grip strength was measured three times in 90º abduction and 90º external rotation and the mean was used for analysis ( Figure 2) [29]. The correlation between grip strength and shoulder lateral rotation strength ranged between r＝0.91 and r＝0.72 [29]. ...
... The muscle strength of the rotator cuff was highly correlated with grip strength, evaluated using a dynamometer (R = 0.91). [38] Grip strength was measured using a dynamometer (TKK-5401, Japan). TKK is the most ideal dynamometer with a low error value compared with other models. ...
... Moreover, this finding is supported by the results of a previous study, in which grip strength was highly correlated with rotator cuff strength. [38] Although muscle stiffness did not show significant immediate changes (P > .05), it showed significant postintervention changes in the supraspinatus (95% CI, -67.455 to -26.345) and infraspinatus (P = .045). In a study by Marusiak et al [57] using Myoton, increased muscle stiffness in patients with Parkinson disease compared to that in healthy participants did not necessarily indicate positive changes. ...
Rotator cuff tear is a common cause of shoulder pain and disability. Arthroscopic rotator cuff repair (ARCR) is performed to treat a torn tendon. Postoperative joint immobilization is essential, but it is a problem that needs to be addressed in the rehabilitation process. This study aimed to evaluate the effects of radial extracorporeal shock wave therapy (rESWT) in patients who underwent ARCR and required active movement after the immobilization period. This study was an open-label, prospective, single-arm trial of 30 inpatients aged >18 years who underwent ARCR. A total of 6 rESWT sessions, along with the conventional rehabilitation program for ARCR patients, were provided at the hospital’s sports rehabilitation center for 2 weeks. The application sites of rESWT are periscapular muscles (supraspinatus, infraspinatus, teres minor, and rhomboid). Evaluations were conducted 3 time points—baseline, immediately after the first session of rESWT, and after 2 weeks of intervention. The outcome measures were the numeric pain rating scale for pain, and shoulder flexion, scaption flexion, abduction, horizontal adduction, external rotation, and internal rotation for shoulder range of motion. For shoulder function, disabilities of the arm, shoulder and hand, shoulder pain and disability index, and simple shoulder test were used, and muscle strength was expressed by grip strength. supraspinatus and infraspinatus evaluated thickness, tone, and stiffness. The muscle strength (95% CI, –3.554 to –0.073) and supraspinatus tone (P = .017) showed significant changes immediately after the first session of rESWT. Further, there was significant improvement in ROM (P < .01); shoulder function (P < .01); and muscle strength (95% CI, –3.561 to –0.625), supraspinatus stiffness (95% CI, –67.455 to –26.345), and infraspinatus stiffness (P = .045) after 2 weeks of intervention. However, muscle thickness and tone were significantly improved only in supraspinatus (P = .044, P = .040). Rehabilitation with radial extracorporeal shock wave therapy additionally applied to the periscapular muscles in patients who started active movement in rehabilitation after arthroscopic rotator cuff repair is effective for shoulder function and muscle properties (muscle strength, thickness, tone, and stiffness). However, a randomized controlled trial is needed to further assess the effects of radial extracorporeal shock wave therapy alone.
... The reports of HGS and pain are ambiguous. While some reports suggest that HGS decreases with pain sensations in neck, [14] back, [9] and shoulder regions, [15] other reports suggest positive or no association. [16][17][18] HGS is affected by pain and fatigue thus encompassing the major outcomes in the physiological cost of schoolbag carriage. ...
... Increase in HGS of right hand was found to be simultaneous with the occurrence of shoulder pain (Phi coefficient = 0.21, P = 0.030), conforming to prior reports. [15,28] The same relationship had an OR of 2.515. The odds of having low HGS is reportedly higher among the individuals not performing aerobic physical activity (OR = 1.415). ...
BACKGROUND: Heavy schoolbag carriage induces pain and fatigue in children. It can alter the handgrip strength (HGS) in children – an important parameter given that most activities in school curriculum require hand dexterity. The purpose of this study is to explore if and how schoolbag carriage influence HGS in children.
MATERIALS AND METHODS: Twenty-five healthy male participants (10–15 years) walked without schoolbag (0% load of bodyweight) or with schoolbags (weighing 4%, 8%, 12%, or 16% of their bodyweight) for 20 min on plane surface at preferred pace. The number of steps taken during walk was measured using pedometer. HGS was measured before and after each walk using dynamometer. The heart rate during walk was measured using Polar HR monitor. Pain occurrence in the entire body was mapped.
RESULTS: HGS averaged for both hand decreased from 17.8 (±6.72) kg to 17.3 (±6.28) kg after 20-min walk (P = 0.033, paired sample t-test). The adopted speed and heart rate was higher when carrying a schoolbag but it portrayed no significant association with HGS. Occurrence of shoulder pain significantly associated with increasing in HGS of right hand after walking (Phi coefficient = 0.21[P = 0.030]). If shoulder pain was perceived during walk, there was a 2.5 times higher likelihood that the participants' HGS for right hand increased (odd's ratio = 2.515, 95% confidence interval = 1.086–5.825).
CONCLUSION: Schoolbag carriage reduces HGS in children. Therefore, performing upper body conditioning exercises may help ameliorate the ill effects of heavy backpack carriage.
... Poor ergonomics, repetitive use, and overuse of the wrist and hand can lead to carpal tunnel syndrome, which damages the peripheral nerve fibres and even introduces maladaptive reorganization in the central nervous system [14,15]. Grip strength assessment is typically used following hand surgery or injuries to examine both functional recovery and clinical outcomes [16], or to monitor shoulder rotator cuff function [17]. ...
Background
Pinch and grip strengths are vital indicators of upper limb function, musculoskeletal health, and general health. While most research has focused on older individuals, it is crucial to build normative data for younger populations. This cross-sectional study was conducted to determine the normative values for lateral pinch strength (LPS) and hand grip strength (HGS) in healthy adult Singaporeans.
Methods
The study recruited 500 healthy individuals without any serious general illnesses and upper limb pain, aged 21–80 years. LPS and HGS were measured using a standardized JAMAR hand dynamometer. Age, gender, hand dominance, and participant demographics were recorded. Normative values were then established for different age groups and hand dominance. A machine learning approach was employed to determine the most relevant variables for dominant LPS and HGS in our data, respectively.
Results
Our data showed that HGS and LPS peaked between 40–44 years of age in women. In men, average HGS peaked between 35–39 years and LPS peaked between 50–54 years. Compared to the non-dominant side, dominant HGS was 6.86% and 6.23% higher in women and men, respectively. The difference between dominant and non-dominant LPS in men and women was 6.96% and 9.18%, respectively. Age was strongly associated with hand strength for older participants, but not for younger ones. Height, weight, and age were important for predicting dominant HGS and LPS, and gait speed for HGS only.
Conclusions
Our data align with past results, but the normative values are comparatively lower than the consolidated Western norms. Compared to the non-dominant hand, the strength of the dominant hand is significantly higher. No statistical difference between the right- and left-handed participants in terms of dominant HGS and dominant LPS. The results can be valuable for researchers and healthcare providers working with young and older adults.
... [17][18][19] Pitching velocity and grip strength are both associated with pitching performance and are potential variables that can be used to objectively assess in real-time, alongside pitch count, the decline in upper limb muscle strength while pitching during a game. 20 21 Moreover, grip strength has been found to be associated with shoulder rotator cuff strength, 20 important muscles involved in the pitching motion. 21 In fact, a recent study by Erickson et al 22 highlighted the need for further knowledge regarding the changes in grip strength between innings to determine if acute changes in grip strength play a role in injury and if a threshold can be established to make decisions about removing a player from a game. ...
Background/aim
In baseball pitching, neuromuscular fatigue and its manifestations on muscle strength, muscle soreness and pain perception affect pitching performance. The purpose of this study was to quantify the evolution of grip strength, muscle soreness and pain threshold perception and pitching velocity in baseball pitchers throughout a simulated 75-pitch game.
Methods
30 high-level amateur male baseball pitchers were recruited. Repeated measure analysis of covariance with age as a covariate (p<0.05) was used to identify significant differences across blocks of pitches for grip strength, muscle soreness, pain threshold perception and pitching velocity.
Results
Dominant arm grip strength (55.67±12.32 kg to 48.62±12.25 kg ; −12.66%) and pitching velocity (119.87±8.00 km/hour to 118.75±6.90 km/hour ; −0.93%) declined while muscle soreness perception increased in dominant arm forearm flexors (1.65±1.16 to 4.19±2.02 ; 25.38%), biceps (1.81±1.39 to 4.31±1.85 ; 25%) and non-dominant arm forearm flexors (1.38±1.10 to 2.12±1.63 ; 7.31%) across the pitching blocks (p<0.05).
Conclusion
In summary, a pitch count of 75 fastball pitches triggered an acute decline in grip strength combined with an increase in muscle soreness perception of the throwing arm in baseball pitchers.
... There are also some studies focusing on association between grip and global muscle strength or isokinetic muscle function [35][36][37]. Horsley et al. found a strong correlation between grip strength and lateral rotator strength, suggesting that assessment of grip strength could be used as a rotator cuff monitor of recruitment function [38]. The hand grip-measuring device is very simple to use, useful for testing hand function and capacity and widely used to test comprehensive muscle strength at upper extremity. ...
Introduction. Swimming is an athletic discipline that largely involves the upper limbs. Due to the driving and propulsive function, there is a heavy involvement of almost all muscles of the arm. Painful shoulder syndrome (PSS) is considered to be one of the main causes of interference with an effective and correct movement of the underwater stroke, which is a fundamental element of functionality in this discipline. The aim of this study was to evaluate whether PSS affects upper limb function in competitive swimmers. Material and methods. Thirty-two swimmers aged 17–24 years with at least 2nd sport class participated in the study. The swimmers were divided into two groups: group I – the experimental group, with subjects reporting pain in the shoulder area, and group II – the control group (sub-jects without pain in the shoulder area). Isokinetic tests at 60°/s, 180°/s, and 300°/s, hand grip strength tests, and upper limb power measurements on a swim er-gometer were performed. The standard visual analogue pain scale (VAS) was used to assess the severity of pain. Results. There were significant relationships between hand grip and pulling force. Hand grip also strongly correlated with peak torque in all considered limb movements. The other examined parameters did not show statistical significance. Conclusions. Despite the significant results of the study component, there was no significant in-fluence of painful shoulder syndrome on performance levels.
... Ancak TMB olan bireylerde omuz ve servikal bölgedeki postural değişimleri inceleyen çalışmalar mevcuttur (Ferão ve Traebert, 2017). H.Ü. Sağlık Bilimleri Fakültesi Dergisi Cilt: 8 (Horsley, Herrington, Hoyle, Prescott, Bellamy, 2016). Ancak yapılan çalışmalarda sadece üst ekstremitenin etkilenimi vurgulanmış, boyun eklem hareket açıklığı ile temporomandibular eklem etkilenimleri araştırmalara dahil edilmemiştir (Nascimento, Polese, Faria, Teixeira-Salmela, 2012 (Tashjian, Deloach, Porucznik, Powell ,2009). ...
Amaç: Omuz ağrılı bireylerde skapular diskinezi, kavrama kuvveti, servikal bölge hareketliliği ve temporomandibular eklem bozukluğu arasındaki ilişkiyi incelemektir. Gereç ve Yöntem: Çalışmaya omuz problemi olan 40 birey (28 kadın,12 erkek) alındı. Çalışmaya katılan tüm bireylerin sosyodemografik verileri kaydedildi. Bireylerin skapular diskinezileri, Skapular Yardım Testi (SYT) ile, boyun normal eklem hareketi gonyometrik ölçümlerle, kavrama kuvveti el dinamometresi ile, Temporomandibular eklem bozukluğu (TMB) Fonseca Anamnestik Anketi ile değerlendirildi. Bulgular: Omuz ağrısı olan bireylerde skapular diskinezinin varlığı ile kavrama kuvvetinin (r=0.366, p=0.020), etkilenmiş taraf omuz yönünde boyun rotasyonunun (r=0.401, p=0.010) ve lateral fleksiyonunun (r=-0.358, p=0.023), sağlam taraf omuz yönünde boyun rotasyonunun azaldığı (r=0.145, p> 0.05), Fonseca Anamnestik Anketi (r=-0.501, p=0.001) sonuçlarının arttığı belirlendi. Sonuç: Çalışmamızda omuz ağrısının skapular diskinezi ile boyun hareketleri, temporomandibular eklem ve kavrama kuvvetiyle ilişkili olduğu belirlenmiştir. Omuz ağrısı olan bireylerin değerlendirmeleri ve tedavileri sırasında boyun, skapula, temporomandibular eklem ile kavrama kuvveti etkilenimi olabileceği de düşünülmelidir.
... The most predominant occur in the lower limbs because of overuse and/or altered biomechanics during running, and the risk of suffering them can be predicted by conducting some simple field tests such as one-leg standing test [11], navicular drop test [12], Jack's test [13], and active straight leg raise test [14]. But, upper extremities injuries can also be present in this sports modality because of the suspension obstacles, so the assessment of scapular kinematics [15] and isometric hand grip strength could be interesting [16,17]. ...
Obstacle course races (OCR) have experienced significant growth in recent years, with millions of participants worldwide. However, there is limited research on the specific physiological demands and injury prevention strategies required for these events. This study aimed to analyze the physiological responses and injury risks in participants of a 5 km (Sprint) and 13 km (Super) OCR. Sixty-eight participants were assessed for cortical arousal, leg strength, isometric handgrip strength, blood lactate, heart rate, blood oxygen saturation, body temperature, urine composition, spirometry values, hamstring flexibility, lower limb stability, foot biomechanics, and scapular kinematics, one hour before and immediately after the races. The results showed a significant decrease in leg strength (Sprint: r = −0.56, p < 0.01; Super: r = −0.54, p = 0.01) and urine pH (Sprint: r = −0.70, p = 0.03; Super: r = −0.67, p = 0.01) in both distances, with increases in urine colour, protein, and glucose (Sprint: p < 0.04). In the 13 km race, lower limb stability decreased significantly post-race (r = −0.53, p = 0.01). Positive correlations were found between performance and pre-race handgrip strength (Sprint: r = 0.71, p = 0.001; Super: r = 0.72, p = 0.01) and spirometry values (FVC, FEF 25–75%, FEV1) (Sprint: r = 0.52, p = 0.031; Super: r = 0.48, p = 0.035). Thermoregulation capacity, reflected in a higher pre-race body temperature and lower post-race body temperature, also correlated with improved performance (r = 0.49, p = 0.046). Injury risk increased post-race, with a significant decline in lower limb stability (p < 0.05). These findings highlight the importance of targeted training programs, focusing on grip strength, leg strength, respiratory muscle training, and hydration strategies to optimize performance and reduce injury risk in OCR athletes.
... In addition, Anwer et al. stated that flexion, abduction, and rotation ROMs were most significantly associated with the severity of pain and physical disability in patients with shoulder dysfunction [50]. The hand grip strength has been proposed as an indicator of rotator cuff function [51]. Considering all these relationships, it is not surprising that, in the KT group, where improvements in all the pain scores were observed, there were also favorable improvements in the function, ROM, and grip strength. ...
Background and Objectives: Rotator cuff tendonitis (RCT) is one of the most common shoulder pathologies. It causes pain, limits shoulder joint movements, and impairs function. Despite various treatment methods, there are currently no specific guidelines regarding the most effective intervention for RCT. To the best of our knowledge, no studies have compared the effects of Kinesio taping (KT) and cold therapy (CT) on individuals with RCT. To this end, this study aimed to investigate and compare the short-term effects of KT and CT on pain relief and upper extremity functionality in individuals with RCT. Materials and Methods: One hundred and fourteen individuals were assessed for eligibility. Fifty-two individuals with RCT who met the inclusion criteria and agreed to participate were randomly allocated into either the KT or the CT group. A standardized home exercise program was given to all the participants. Their pain intensity, upper extremity function, shoulder range of motion (ROM), and grip strength were evaluated initially and after the three days of KT or CT applications. Results: All the assessment values significantly improved in the KT group. In the CT group, only the pain scores (except for the numerical rating scale (NRS) pain score during activity) were significantly improved in the CT group at the end of the third day of application compared to the initial values (p < 0.05). For all the measurement outcomes, the effects of time × group interactions were statistically significant (p < 0.05) in favor of the KT group, except for the resting pain (p = 0.688). Conclusions: The findings suggest that KT and CT could be used as adjunctive modalities to exercise for resting and night pain relief in patients with RCT. KT also had positive effects on the activity pain, function, ROM, and grip strength. The use of KT along with an exercise program could be a more effective therapeutic choice than the use of CT for improving night pain, activity pain, and upper extremity function during the short-term rehabilitation of RCT patients.
... Handgrip strength was positively correlated with shoulder function (Horsley, Herrington, Hoyle, Prescott, & Bellamy, 2016). It was assessed using the Jamar analogue hand dynamometer in kilograms according to the recommendation of the American Society of Hand Therapists (Fess, 1992). ...
Physiotherapy is a physically demanding profession. Health and skill-related physical fitness should be emphasized in physiotherapy students for both the personal benefit on their own health and injury prevention and for the sustainability of their ability to meet job demands. This study aims to assess levels of health and skill-related physical fitness in undergraduate physiotherapy students in Jordan. A cross sectional study of 109 physiotherapy students; 23 males aged 19.57 (1.44) years and 86 females aged 20.02 (2.61) years. The following health and skill-related physical fitness components were assessed: body mass index (BMI), modified sit and reach, partial curl-up, push-ups, vertical jump, 20-m shuttle run, handgrip strength, 4x10 shuttle run, and star excursion balance tests. Most of the students had normal BMI (65.1%) but levels of physical fitness were mainly poor and below average except for hamstring flexibility which was excellent. Lack of normative data on agility and dynamic balance in healthy adults who are not athletes limited determining their level in our students. The results mainly demonstrated poor levels of health-related physical fitness of Jordanian physiotherapy students, which could have a significant effect on their performance and increase their risk of injury. Dynamic balance and agility results are presented for the first time in healthy adults (not athletes) which could be used in future research. It is suggested to encourage commitment towards lifestyle modification and health behaviour and increase awareness of the physical demands of the profession.
... Studies have indicated that grip strength is associated with overall upper extremity strength and function. 18 In this study, we observed that grip strength and upper extremity muscle strength were notably low before arthroscopic surgery and increased during recovery post-surgery. ...
... 25 Also this study's findings go in parallel with those of Horsley et al who showed that there was a strong correlation between grip strength and lateral rotator strength which was shown at all positions for both left and right hands, suggesting that assessment of grip strength could be used as a rotator cuff monitor of recruitment function. 26 As the results of the experimental group in this study are better than those of the other group, this reflected the useful effects of adding shoulder stabilizer training in regaining hand function and achieving optimum functional level at ADL. ...
Background
Hand injuries are common and could have an impact on all upper limb functions. Engaging shoulder muscle training during the rehabilitation protocol postoperatively could have a significant impact on regaining all upper limb function. The purpose of this study was to assess the effect of adding shoulder stabilization exercise to hand rehabilitation postoperatively.
Methods
Forty patients were randomly assigned to 2 equal groups. Group A received a standard physical therapy program plus shoulder exercise protocol and group B received only a standard physical therapy protocol for hand rehabilitation. Outcome measures were pain intensity; grip strength; Arabic modified Disabilities of the Arm, Shoulder, and Hand (QuickDASH) questionnaire; and range of motion (ROM). All outcome measures were assessed before and after treatment.
Results
Statistical analysis revealed that both groups, the experimental and control, showed significant improvement in all outcome measures, but experimental group A showed significant improvement than the control group B posttreatment for hand grip strength, ROM, and QuickDASH questioners ( P < .001).
Conclusion
Adding shoulder stabilizer muscle training to the hand rehabilitation protocol postoperatively has a significant impact on hand function outcomes.
... 11 The literature frequently reports an association between rotator cuff muscle impairment and impaired hand function. 12 It is also hypothesized that rotator cuff strength decreases in individuals following unilateral hand or wrist disorder. 10,13,14 Varied pieces of evidence 2,11,[15][16][17] in the literature highlight the association between impaired shoulder girdle musculature and dysfunctions of the wrist and hand. ...
INTRODUCTION: Gripping activity is an essential daily activity at home and at the workplace, where lifting and holding loads with a relatively static grip using isometric contraction is often required. Muscle strength and endurance in the proximal aspect of the upper extremities influence hand function, and individuals with reduced strength and endurance are more prone to developing work-related musculoskeletal disorders. Good grip endurance might be influenced by the stabilization provided by shoulder muscles. This study aims to determine the correlation between hand grip endurance and scapula muscle endurance among young asymptomatic individuals. METHOD:The sample size for this study is n = 62, based on previous studies. Healthy individuals of both genders, aged between 18 and 25 years, were included. An objective assessment of grip endurance was performed using a hydraulic hand dynamometer, while scapular endurance was evaluated using the scapular muscle test. RESULTS: Data analysis was performed using SPSS version 20. There were significant positive correlations between scapular endurance measures and the hand grip endurance on both sides (Pearson correlation test, r = 0.612 (p < 0.001) and r = 0.524 (p < 0.001), respectively, for non-dominant and dominant hand grip endurance). FINAL CONSIDERATIONS: The preliminary findings of this study support the notion that scapular muscle endurance is related to hand grip endurance, suggesting that scapular endurance training may be an effective adjunct in the rehabilitation process for upper extremity functions.
... Studies have indicated that grip strength is associated with overall upper extremity strength and function. 18 In this study, we observed that grip strength and upper extremity muscle strength were notably low before arthroscopic surgery and increased during recovery post-surgery. ...
Aim We aimed to examine the effect of kinesiophobia on functional capacity, disease activity, quality of life and spatiotemporal parameters of patients with AS by comparing AS patients with healthy controls.
Material and method Our study included 46 patients with ankylosing spondylitis (AS) and 45 healthy controls (HC). Bath Ankylosing Spondylitis Metrology Index (BASMI), Bath Ankylosing Spondylitis Functional Index (BASFI), Ankylosing Spondylitis Quality of Life Scale (ASQoL), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Tampa Kinesiophobia Scale (TKS) scores, Timed Up and Go (TUG) test, maximum plantar pressure and spatiotemporal parameters (total weight transfer, step cycle duration, double-support phase, swing phase, step length, foot angle and cadence) were evaluated.
Results Ninety-one individuals (46 AS, 45 HC) (age/sex/BMI) were included in our study. Statistically significant differences were seen between AS and HC groups in TUG, cadence, TKS, maximum pressure, step cycle duration, swing phase, step length, double-support phase, and foot angle measurements (p<0.05). Significant positive correlations existed between TKS and BASMI, BASDAI, BASFI, ASoQ, TUG and foot angle (p<0.05) in AS. Substantial negative correlations were found between TKS and maximum pressure, cadence and swing phase values (p<0.05) in AS.
Conclusion Our study is the first in the literature to measure spatiotemporal parameters between patients with AS and HC and evaluate their relationship with kinesiophobia, which was done to the best of our knowledge. We found that patients with AS changed their gait phases by developing a unique pattern and created a more cautious and safe gait model to provide balance and stability. Our study revealed a statistically significant relationship between kinesiophobia and disease activity, functional status, quality of life, cadence, maximum plantar pressure, swing phase, and foot angle. The detailed data we obtained in our study will shed light on gait analysis and research on kinesiophobia in patients with AS. Kinesiophobia should be evaluated in routine gait rehabilitation protocols applied to individuals with AS, and treatment protocols for kinesiophobia should be added if necessary.
... Grip strength (GS) has been used as a measure of physical function 1 associated with upper limb and total muscle strength, frailty, sarcopenia and cardiovascular outcomes. [2][3][4] The utility of GS data obtained in healthy populations as a predictor for mortality risk, type 2 diabetes, length of hospital stay and post-surgical complications has also been demonstrated. [5][6][7][8] Grip strength measurement tools can also be used to assess GS, establish baselines and monitor progress throughout rehabilitation. ...
Introduction
Digital dynamometers to assess grip strength are becoming more common in research and clinical settings. The aim of the study was to assess validity and reliability of the K-force dynamometer compared to the Jamar dynamometer. We also aimed to assess differences over the course of three measurements.
Methods
Twenty-seven healthy participants were included. Three trials with the K-force and Jamar dynamometers were completed. Testing order was randomised. Intraclass correlation coefficients (ICCs) with absolute agreement assessed reliability and validity. Standard error of the measurement (SEM) and minimal detectable change (MDC 95 ) were calculated. Concurrent validity was assessed using Pearson’s correlations and ICCs. Differences between the three repetitions were assessed using one-way repeated measures ANOVAs.
Results
Both the K-force and the Jamar presented excellent intra-rater reliability with ICCs ranging from 0.96 to 0.97. The SEM ranged from 1.7 to 2 kg and the MDC from 4.7 to 5.7 kg for both dynamometers. The concurrent validity of the K-force was high ( r ≥ 0.89). However, the K-force underestimated the grip strength by 4.5–8.5 kg. There was no change in grip strength with either dynamometer over the course of three trials.
Conclusions
The K-force is reliable, but it underestimates grip strength by 4.5–8.5 kg compared to the Jamar dynamometer. K-force can be used to monitor progress over time but cannot be used to compare results against normative data. The use of a single measurement when assessing grip strength is sufficient when assessing healthy subjects.
... To involve the shoulder joint, the second position is with the shoulder abducted at 90°and externally rotated at 90°, elbow flexed at 90° and forearm in neutral. 25 Patients will start with their unaffected controls with their right sides. In each position, two maximal attempts will be recorded after two submaximal familiarisation trials. ...
Introduction
To date, there is no valid single test or battery of tests for informing return-to-play (RTP) decisions following an acute shoulder injury. The purpose of this exploratory study is to evaluate a diagnostic test battery based on a Delphi consensus at the time of unrestricted return to team training after acute shoulder injury.
Methods and analysis
Data for this prospective multicentre cohort study are collected at two measurement time points: when the respective physician clears the patient for RTP (t1) and 12 months after RTP (t2). The study participants are 18–35 years old athletes participating at a professional level in the following team sports: handball, basketball, ice hockey, soccer, volleyball and American football. Maximum comparability will be ensured via uninjured matched pair teammates. To assess the subjective assessment of shoulder functioning and the athlete’s readiness to RTP, patient-reported outcome measures (Western Ontario Shoulder Instability Index, Quick-Disabilities of the Arm, Shoulder and Hand, Psychological Readiness of Injured Athlete to Return to Sport and Shoulder Instability-Return to Sport after Injury) will be completed. After a medical check-up with a range of motion and anthropometric measurements as well as clinical tests, the participants will perform a structured warm-up protocol. The functional tests comprise handgrip strength, upper quarter Y-balance test, isometric strength, closed kinetic chain upper extremity stability test, wall hop test, functional throwing performance index and the unilateral seated shot put test and isokinetic tests.
Ethics and dissemination
The results of this study will be disseminated through peer-reviewed publications and scientific presentations at national and international conferences. Ethical approval was obtained through the Institutional Review Board of Martin-Luther-University Halle-Wittenberg (reference number: 2022–016).
Trial registration number
DRKS00028265.
... Se registraron los siguientes datos demográficos: edad, sexo, miembro superior dominante (determinado por la mano con la cual escribe) (20), actividad física y frecuencia de la actividad física según cantidad de horas semanales. ...
Objetivos: Determinar la confiabilidad interobservador de la evaluación de la fuerza muscular de rotadores de hombro mediante el dinamómetro handgrip (HG). Materiales y métodos: Se incluyeron 21 participantes voluntarios sanos. Se analizó la confiabilidad entre la primera y segunda medición realizada por 2 diferentes operadores para la rotación externa e interna, tanto del miembro dominante como del no dominante. Se utilizó el Coeficientede Correlación Intraclase (CCI) con sus respectivos intervalos de confianza al 95%. Para determinar el umbral de cambio real en la fuerza de HG cuando diferentes valuadoresregistran las mediciones, se calculó el mínimo cambio detectable (MCD) Resultados: Se observó una excelente confiabilidad entre evaluador para la rotación externa dominante y no dominante (CCI= 0.80 [IC95% 0.58 - 0.92] y CCI 0.80 [IC95%= 0.56 - 0.91], respectivamente). La confiabilidad interevaluador para la rotación interna dominante resultó regular(CCI: 0.56 [IC95% 0.18 - 0.80] y para la no dominante buena (CCI:0.61 [IC95% 0.25 - 0.82]). Conclusión: El estudio mostró que la confiabilidad interobservador de la herramienta HG para medir fuerza de hombro es excelente para los rotadores externos y de regular a buena para los rotadores internos.
... The strength of the fingers when holding something is known as grip strength and it is an important index in the evaluation of the motor function of the hand 17 . Since grip strength is strongly positive correlated with muscular strength 18 , grip strength can be used to evaluate changes in muscular strength effectively. Grip strength has been used in a lot of studies because of its simple measurement 19,20 Grip strength is not simply the force generated by the fingers and wrist joint, it is also intimately connected with the muscular strength of forearm and shoulder joints. ...
Background: Proximal joint stability is required to perform distal movements. Good grip strength might require adequate shoulder stability which will be dependent upon its musculature. Purpose: To find the relation of hand grip strength with scapular muscle strength in breast cancer survivors post modified radical mastectomy (MRM). Methodology: An observational cross sectional study was conducted in a tertiary care hospital. A total of 33 breast cancer survivors who underwent MRM before 6 months or more were included. Their affected side hand grip strength along with serratus anterior muscle strength and strength of upper, middle and lower fibers of trapezius was measured using hand held dynamometer. Results: Karl pearson’s correlation coefficient was used to find the correlation between hand grip strength and scapular muscle strength. Strong positive correlation was found between hand grip strength and serratus anterior muscle (r = 0.848) as well as lower trapezius (r = 0.868) strength. Whereas moderate positive correlation was found between hand grip strength and upper trapezius (r = 0.665) as well as middle trapezius (r = 0.444) muscle strength which was statistically significant (p<0.05). Conclusion: Hand grip strength was significantly correlated with the scapular muscle strength in breast cancer survivors post MRM. Keywords: Breast cancer survivors, hand grip strength, hand held dynamometer, Modified Radical Mastectomy, Scapular muscle.
... In terms of grip strength, participants in the EB group gained significantly more strength than the control group. We postulated that this could be a result of the increased shoulder strength because the shoulder-wrist complex is linked by a synergistic pattern (Dounskaia et al., 2020), and research has suggested a positive correlation between grip strength and shoulder strength (Horsley et al., 2016;Mandalidis and O'Brien, 2010;Nascimento et al., 2012). For this reason, we inferred that the increase in grip strength in the EB group may be related to increased shoulder strength. ...
An elongation band (EB) is used to improve the physical strength of older adults. However, the evidence of its effect on the upper limb is a deficiency. This study investigated the effectiveness of EB exercises on upper limb function in the elderly. Participants were divided into two groups: EB (n=16) and control (n=14). The EB group performed exercises in a sitting position using an EB while the control group performed active stretching exercises without bands. The exercise regimen consisted of four shoulder joint movements. Each group performed the exercise for 20 min per day, 5 days per week over a period of 2 months. Measurements included upper limb muscle strength, shoulder joint range of motion, and grip strength. Measurements were performed at baseline, and 1 and 2 months after the intervention. Analysis of covariance was used to compare differences between the groups. The EB group demonstrated significant increases in muscle strength (upper trapezius, deltoid, middle trapezius muscle), shoulder joint range of motion (right shoulder flexion, internal rotation, external rotation, left shoulder joint extension), and grip strength. In conclusion, EB exercises increased upper limb muscle strength, shoulder joint range of motion, and grip strength in older adults.
... Considering that the reported MCID of SST was 2 points in the shoulder function [28], a reduction of 4 points in follow-up compared to baseline is a clinically meaningful result. The fact that grip strength was confirmed by muscle strength was highly correlated with rotator cuff strength [29]. Therefore, the 13kg increase in grip strength indirectly means the improvement of the rotator cuff strength. ...
... The difference could be explained by the fact that their subjects were not practicing any sport. Horsley, et al., (2016) also found a strong correlation between dynamometry and the shoulder muscular strength (r = 0.72). ...
This paper aims to examine the effects of proprioceptive training upon upper limbs force in the case of female weightlifters. 10 weightlifters from CSS N. Rotaru in Constanța, Romania, took part in an experiment specially designed for this purpose. The experimental group was assigned a proprioceptive training programme of 15 minutes two times per week, for a period of 20 weeks. The tests administered for the assessment of their upper limbs force were push-ups, push-ups on the Bosu ball, and dynamometry testing. Data analysis shows that no significant differences between the experimental group and the control group are visible at the initial test (p> 0.05). In the final evaluation, however, the experimental group obtained better scores than the control group in all tests. These findings indicate that the proprioceptive programme proposed has lead to the enhancement of female weightlifters’ muscular force. In conclusion, the programme is an efficient training tool that can be integrated with the sportswomen’s exercise routine.
... The strength of the fingers when holding something is known as grip strength and it is an important index in the evaluation of the motor function of the hand (14). Since grip strength is strongly positively correlated with muscular strength (15), grip strength can be used to evaluate changes in muscular strength effectively and economically. Grip strength has been used in a lot of studies because of its simple measurement (16,17) Grip strength is not simply the force generated by the fingers and wrist joint, it is also intimately connected with the muscular strength of forearm, and the brachial and shoulder joints18. ...
The human hand is designed to perform various kinds of skilled movements in the daily activities. Such activities are termed as 'Prehension Activities'. Grip strength has been used to assess general strength in order to determine work capacity, to determine the extent of injury and disease processes and progress of rehabilitation. To perform distal movements it is important to have proximal joint stability. The hand being the distal component, a good grip might require adequate shoulder stability which will be dependent upon its musculature. Hence this study was conducted to find out if there exists a correlation between these two. Aim: To find out if there is a correlation between grip strength and scapular muscles Methodology: Grip strength assessment was done using dynamometer and scapular muscle strength was assessed using Micro-FET. Results: Pearson's correlation coefficient was calculated for the correlation between grip strength and scapular muscle strength Conclusion: There is the statistically significant correlation between grip strength and scapular muscle strength
... Hand grip strength is considered as a monitor for the strength of the shoulder stabilizer muscles. A strong correlation was reported between hand grip strength and rotator cuff strength of the glenohumeral joint, in all the positions of the left and right hands [24]. ...
Objective: To investigate the additive effects of instrument assisted soft tissue mobilization to the conventional physical therapy program on handgrip strength, upper limb functions, and pain in patients with subacromial impingement syndrome. Design: A single-blinded, randomized controlled study. Setting:Outpatient physical therapy clinic, Cairo University Hospitals. Subjects: Sixty patients, 25 to 40 years old, with subacromial impingement syndrome, were randomly assigned either into one of two groups: study or control. Intervention: The study group received the conventional physical therapy for subacromial impingement syndrome plus instrument assisted soft tissue mobilization (IASTM), while the control group received only the conventional physical therapy. Interventions were conducted three times per week for four weeks. Outcome measures: Hand grip strength, upper limb functions, andpainwere evaluated at the beginning of the study and after two, and four weeks of interventions. Results:There were statistically significant differences in hand grip strength, upper limb functions, and pain in both groups after 2 and 4 weeks from intervention in favor of the study group (p< 0.05). After 4 weeks from intervention, M±SD for HG, DASH, and VAS were 31.28±5.19 kg, 7.18±3.44, and 15.0±5.72 mm in the study group, and 21.48±6.87 kg, 16.69±6.67, and 30.67±6.91 mm in the control group, respectively. Conclusions: Instrument assisted soft tissue mobilization combined with the conventional physical therapy program was more beneficial in improving hand grip strength, upper limb functions, and pain than the conventional physicaltherapy alone. It could be used as a useful adjunctive therapy in management of patients with subacromial impingement syndrome.
... The underlying mechanism of elastic resistance exercises and close chain exercises appears to involve distal and proximal muscle recruitment to increase proximal stability. The distal stabilizing mechanism may trigger a proximal activation (Supraspinatus and Infraspinatus muscles) in response to the distal strength requirements because thus could maintain the humeral axis of rotation to muscles with a higher arm like the deltoid muscle, that can act elevating the arm efficiently stimulating the recruitment of Supraspinatus and Infraspinatus muscles [13][14][15][16]. Previously, it has been shown a positive correlation between hand gripping activity and rotator cuff muscle activity [17]. ...
Purpose: It is unknown whether the effect of increased distal stabilization can trigger the onset of the Supraspinatus and Infraspinatus muscles, and if handgrip strength levels can elicit early proximal shoulder stabilization. Hence, we aimed to compare the electromyography activation of the Supraspinatus and Infraspinatus muscles during the abduction motion with handgrip strength in different levels (0%, 30%, and 60%) of maximal voluntary isometric contraction (MVIC).
Methods: Twenty participants were submitted to abduction shoulder movement with three different handgrip strengths (0%, 30%, and 60%) using electromyography. The onset of Supraspinatus and Infraspinatus muscles was measured. A Friedman's test was used to compare handgrip conditions and the onset between muscles. Then, multiple comparisons were performed. All alpha error was set to 5%.
Results: There was an anticipated onset for Supraspinatus muscle at 0% of the MVIC (-0.554 [-0.657 to -0.497] ms vs. -0.098 [-0.264 to 0.108] ms, p < 0.001), at 30% of the MVIC (-0.560 [-0.628 to -0.521] ms vs. -0.125 [-0.243 to -0.031] ms, p < 0.001), and at 60% of the MVIC (-0.543 [-0.573 to -0.514] ms vs. -0.215 [-0.325 to -0.017] ms, p = 0.001).
Conclusion: Shoulder abduction with handgrip triggers the onset of the Supraspinatus and Infraspinatus muscles. The Supraspinatus muscle elicits an anticipated onset. Two stabilizing strategies are suggested; the internal rotation instability capable be induced by the deltoid muscles (abduction movement) and from the wrist flexor-pronator muscles (handgrip). Both tasks are counteracted and anticipated by the action of the Supraspinatus and Infraspinatus muscles.
... We also observed a significant and moderate correlation between hand grip strength and upper extremity dysfunction. It is known that hand grip strength is correlated with different functional disorders of the upper extremity, such as rheumatoid arthritis, carpal tunnel syndrome, lateral epicondylalgia, stroke, traumatic injuries and neuromuscular diseases, and it is also strongly related to general health status [22,40]. The sample of our study presented only one worker with upper extremity dysfunction related to rheumatoid arthritis, which was asymptomatic. ...
Abstract Background Upper extremity musculoskeletal disorders negatively affect ability to perform activities of daily living, self-care and work. Therefore, outcome measurements that address muscle strength, fatigue resistance, functionality and work physical capacity must be defined to assess and plan specific actions to minimize them. Objective To investigate the association of upper extremity muscle strength with upper extremity fatigue resistance, work ability and upper extremity dysfunction in a sample of workers from a tertiary hospital. Methods Shoulder and elbow isokinetic strength were assessed by Biodex System 4™, isometric hand grip by JAMAR™, upper extremity fatigue resistance by Functional Impairment Test Hand and Neck/Shoulder/Arm (FIT-HaNSA), ability to work by the Work Ability Index and upper extremity dysfunction by the Quick-Disabilities of the Arm, Shoulder and Hand QuickDASH-Br questionnaire. The Nordic questionnaire and Numeric Pain Rating Scale (NPRS) were used for pain description. The associations were analysed by Spearman’s correlation coefficient (rho) (p
... Kavrama kuvveti el ve önkolun izometrik gücünü test ederek üst ekstremite kuvveti hakkında çıkarımlar yapılmasını sağlamaktadır (12). Tenis oyuncularında kavrama kuvveti servis atma, forehand ve backhand vuruşları için oldukça önemli bir parametredir; bu sebeple kavrama kuvvetinin değerlendirmesi performans açısından belirleyici olarak görülmektedir (13,14). ...
Amaç: Tenis oyuncularında omuz performansı ile ilişkili birçok faktör bulunmaktadır. Bu çalışmanın amacı, adolesan tenis oyuncularının üst ekstremite performans parametreleri ile omuz rotator kas kuvveti arasındaki ilişkiyi incelemekti.Yöntem: Çalışmaya 10 ile 18 yaş arası 31 adolesan tenis oyuncusu dahil edildi. Üst ekstremite performansını belirlemede sağlık topu fırlatma, kapalı kinetik zincir üst ekstremite stabilite testi ve kavrama kuvveti testi kullanıldı. Omuz rotator izokinetik kas kuvveti ISOMED 2000 (D&R GmbH, Almanya) sistemi ile değerlendirildi. İstatistiksel analizde doğrusal regresyon analizi kullanıldı.Sonuçlar: Sağlık topu fırlatma mesafesi ile 60°/s açısal hızda internal rotator (İR) tepe tork (TT) (r=0,535, p=0,002) ve eksternal rotator (ER) TT (r=0,421, p=0,018) değerleri arasında pozitif yönde orta düzeyde ilişki bulundu. Kavrama kuvveti ile 60°/s İR-TT (r=0,647, p=0,001) ve ER-TT (r=0,645, p=0,001) değerleri arasında güçlü düzeyde ilişki bulundu. Kapalı kinetik zincir üst ekstremite stabilite test sonuçları ile 60°/s ER TT arasında ilişki saptandı (r=0,391, p=0,029).Tartışma: Çalışmanın sonucunda; adolesan tenis oyuncularında omuz rotator kas kuvveti artıkça omuz performansının arttığı görüldü. Tenis oyuncularında performansı etkileyen faktörlerin adolesan dönemde saptanması, performansı arttırmak ve koruyucu yönde önlemler almak için oldukça önemlidir.
... The most popular of them are assessing overall strength to compare muscle function across populations and evaluate progression of wasting conditions, like sarcopenia, or even identify potential deficits [1,2]. Handgrip dynamometers are also used as functional assessment tools to measure the strength of different muscles, directly related with a pathological condition, like rotator cuff strength [3]. Regarding the rehabilitation process, handgrip dynamometers are mainly used for evaluation purposes, such as tracking overall progress through rehabilitation [4] or testing the effect of a specific rehabilitation protocol targeting a problem related to grip strength like shoulder impingement syndrome [5]. ...
Background: Handheld dynamometers are used for diagnosis and rehabilitation at several pathologies. Grip force is essential for a person’s quality of life. Most dynamometers are not equipped with rehabilitation or training protocols, although the bibliography highlights this need. Objective: To compare the validity and reliability of Jamar and K-Force Grip dynamometers in patients with shoulder impingement syndrome and healthy people. Methods: Concurrent validity was assessed using known weights. Forty-four (44) patients and 69 healthy adults performed three maximum repetitions in random order with each hand, at each instrument. Reliability was evaluated using ICCs for each instrument separately, and between the two instruments. The differences between the two dynamometers were evaluated using repeated t-tests. Results: Concurrent validity of the two instruments did not reveal fix or proportional bias. Analyses for reliability yield high correlation coefficients for both groups with the lower one being between the two instruments r = 0.90, p < 0.05, (0.72–0.91) for the healthy group. T-tests showed that all participants had lower force values when using the K-Force Grip (p < 0.05). Conclusion: Both dynamometers were reliable in measuring hand grip strength for both groups. K-Force Grip was reliable and valid with respect to Jamar that was used as a benchmark. The different handle dimensions between the two dynamometers may be the reason for the different force values.
... 7 Each test (ER and IR) was performed 3 times for each arm, with the results reported in newtons, and the mean was used for final analysis. 15 Variables included in the study were dominant and nondominant ER and IR shoulder strength, the ratio of dominant and nondominant ER to IR shoulder strength, and the difference between dominant and nondominant ER and IR shoulder strength. 7 Biomechanical Analysis 3-D motion data were collected using the 40 reflective marker set required for PitchTrak (Motion Analysis Corporation) and a 16-camera motion analysis system (Motion Analysis Corporation). ...
Background
Scapular assessment is important in examining overhead athletes, but there is inconsistency in scapular clinical assessment and its relation to pathology.
Purpose
To determine the relationship between clinical scapular assessment and biomechanical scapula resting position, shoulder strength, and pitching shoulder kinematics and kinetics.
Study Design
Descriptive laboratory study.
Methods
Two clinicians performed scapular assessments and graded the scapula as presence or absence of scapular dyskinesis. Shoulder external rotation (ER) and internal rotation (IR) strength were collected. The 3-dimensional biomechanics of the scapula resting position (upward/downward rotation, IR/ER, and anterior/posterior tilt) were assessed while participants stood at rest, and pitching kinematics (maximum shoulder ER, shoulder abduction, shoulder horizontal abduction, shoulder rotation velocity) and kinetics (maximum shoulder distraction force) were assessed when participants pitched off the portable pitching mound that was engineered to meet major league specifications.
Results
A total of 33 high school baseball pitchers (age, 16.3 ± 1.2 years; height, 184.0 ± 6.9 cm; weight, 76.8 ± 20.8 kg; hand dominance: left, 9 [27%]; right, 24 [73%]; pitch velocity, 34.7 ± 2.3 m/s) participated in this study. Of them, 15 participants had scapular dyskinesis, and 18 had normal scapulothoracic rhythm. No differences were observed for upward/downward rotation or anterior/posterior tilt, shoulder ER, shoulder abduction, or shoulder distraction force, based on the presence of scapular dyskinesis. Pitchers with scapular dyskinesis demonstrated significantly greater scapular resting IR position (effect size [ES], 0.80; 95% CI, 0.06 to 1.54; P = .020), greater nondominant shoulder ER to IR strength ratio (ES, 0.49; 95% CI, –0.02 to 1.00; P = .018), and decreased shoulder rotation velocity (ES, 14.66; 95% CI: 12.06 to 17.25; P = .016). Pitchers with greater anterior tilt demonstrated greater shoulder rotation velocity ( r = –0.48; P = .006).
Conclusion
Pitchers with scapular dyskinesis had greater scapular IR, greater nondominant shoulder ER to IR strength ratio, and reduced shoulder rotation velocity.
Clinical Relevance
Scapular assessment may be more influenced by differential IR than upward rotation or anterior tilt. Scapular dyskinesis has no competitive performance advantage among amateur athletes. Greater understanding is needed to decipher the critical threshold between beneficial and maladaptive scapular movement patterns.
... It has been suggested that gripping has an effect on rotator cuff activity, but the extent to which this is the case is unclear. It has been shown that gripping causes a significant increase in infraspinatus and supraspinatus activity (Horsley et al., 2016). These findings have been replicated in another study which found that this effect is increased in overhead activities (Sporrong et al., 1996) which would translate into the Y and I positions. ...
Objectives
To determine the concurrent validity of a sphygmomanometer for assessing shoulder strength in the I, Y and T positions during the athletic shoulder test (ASH test). Force platforms were used as the gold standard measurement tool for this purpose.
Design
Shoulder strength was assessed using force platforms and a sphygmomanometer, both placed on the floor and the participant positioned prone. One rater assessed strength, taking three measurements in each of the I, Y and T positions, using the sphygmomanometer and force platforms. Concurrent validity was calculated using the force platforms as the gold standard device.
Setting
Data was collected within the treatment room of an amateur rugby club.
Participants
Twenty male amateur rugby players (25.15 years old ± 3.27 years) were recruited for this study.
Main outcome measures
Peak force across the shoulder girdle was assessed using the force platforms and sphygmomanometer which provided values in Newtons (N) and millimetres of mercury (mmHg) respectively.
Results
Results showed high concurrent validity (Pearsons r = 0.76–0.81) between the sphygmomanometer and the force platform. Coefficient of determination (r² = 0.59–0.67) showed the sphygmomanometer to have a valid predictive model in the I, Y and T positions.
Conclusions
The sphygmomanometer is suitable for monitoring force transfer across the shoulder during the ASH test, and is able to quantify peak force in mmHg. The sphygmomanometer enables coaches and clinicians to accurately quantify force production across the shoulder girdle in order to screen and monitor players at a low cost.
... 3 Finally, the HGF provides an objective indicator of the functional status of the upper limb and has also been proposed as an indirect assessment of posterior cuff function. 16 Considering that training intensity is an important component of training loads, 9 it is important to understand the effects of training intensity on these physical qualities. ...
Context: Shoulder pain is the main cause of missed or modified training in competitive swimmers. Shoulder musculo-skeletal maladaptations occur to some extent as a consequence of training loads during swimming that may increase the risk of shoulder injury. Further evidence is needed to understand the training intensities at which these maladaptations occur.
Objective: To determine the acute effect of training intensity on the shoulder musculoskeletal physical qualities associated with shoulder injury in competitive swimmers.
Design: Cross-sectional study. Setting: Indoor swimming pool. Patients or Other Participants: Sixteen asymptomatic national-and regional-level swimmers (7 females, 9 males; age = 14.6 6 3.9 years, height = 160.5 6 12.7 cm, mass = 55.3 6 12.5 kg).
Main Outcome Measure(s): Bilateral active shoulder-rotation range of motion (ROM), joint position sense, latissimus dorsi length, combined elevation test, and shoulder-rotation isometric peak torque and handgrip peak force normalized to body weight were measured before and immediately after low-and high-intensity swim-training sessions. The intensity of the sessions was determined by the distance swum over or at the pace threshold and confirmed by the swimmer's rating of perceived exertion.
Results: After the high-intensity training session, shoulder external-rotation ROM (dominant side: P < .001, change = -7.8°; d = 1.10; nondominant side: P = .002, change = -6.5°, d = 1.02), internal-rotator isometric peak torque (dominant side: P < .001, change = -11.4%, d = 0.42; nondominant side: P = .03, change = -6.6%, d = 0.20), and external-rotator isometric peak torque (dominant side: P = .004, change = -8.7%, d = 0.27; nondominant side: P = .02, change = -7.6%, d = 0.25) were reduced. No changes were found in any of the outcome measures after the low-intensity session.
Conclusions: Shoulder active external-rotation ROM and rotation isometric peak torque were decreased immediately after a high-intensity training session, possibly increasing the risk of injury during subsequent training. Monitoring these variables may help practitioners adjust and manage training loads to decrease the risk of shoulder injury.
OBJECTIVE: To measure the change in acromiohumeral distance during clinician-applied and self-applied manual shoulder joint mobilization. We hypothesized that the acromiohumeral distance would be significantly greater with clinician-applied manual joint mobilizations (MJM) than with self-applied joint mobilization.
DESIGN: Within-subject, repeated measures design
METHODS: Nineteen healthy adults (mean age: 22.9 ± 1.2 years) participated. A traction force of 15% body weight was applied during MJM and self-applied joint mobilization (SJM). Acromiohumeral distance was measured via ultrasound imaging at rest (baseline) and during the two test conditions (2 trials each) to quantify inferior accessory motion. The transducer was placed at the anterolateral border of the acromion and the subacromial space was clearly visualized for acromiohumeral distance measurements.
RESULTS: The ICC for acromiohumeral distance measurements ranged from 0.876 to 0.963. Changes in acromiohumeral distance during MJM (3.90 ± 0.51mm) were significantly greater than SJM (1.68 ± 0.49mm, p<0.001). AHD changes between sexes: MJM (female: 3.16 ± 0.58mm, male: 5.15 ± 0.90mm, p=0.060); SJM (female: 0.88 ± 0.51 mm, male 3.05 ± 0.90mm, p=0.029).
CONCLUSIONS: Our acromiohumeral distance measurement methodology had excellent test-retest reliability. There was significantly more inferior humeral accessory motion with MJM than SJM. The acromiohumeral distance was 132% greater during MJM and was unchanged or less than resting baseline measurements in almost a third of participants during SJM.
Background:
Systemic disorders including diabetes mellitus, obesity, and depression affect the outcomes of reverse shoulder arthroplasty (RSA). Sarcopenia (a general skeletal muscle disorder) is common in elderly people, but its effect on patients after RSA is not clear. We hypothesized that the preoperative sarcopenia indices of grip strength and general skeletal muscle mass would correlate with the clinical outcomes of RSA METHODS: Grip strength and general skeletal muscle mass were measured in patients scheduled (between 2016 and 2021) for primary RSA to treat cuff tear arthropathy, an unrepairable cuff tear, or osteoarthritis with a large cuff tear. Before surgery, grip strength was measured using a hydraulic dynamometer and general skeletal muscle mass was calculated from the appendicular relative skeletal muscle mass index (aRSMI) using dual-energy X-ray absorptiometry. In all, 58 patients were included; the minimal follow-up duration was 12 months. The postoperative clinical results (pain, active range of motion, shoulder strength, and functional scores) were evaluated during scheduled outpatient visits. We calculated correlations between the preoperative sarcopenia indices, and the clinical results at the final follow-up.
Results:
The mean preoperative grip strength and aRSMI were 21.6 ± 4.0 kg and 5.98 ± 0.84 kg/m2 in females, and 30.6 ± 7.5 kg and 7.21 ± 0.94 kg/m2 in males, respectively; the grip strength and aRSMI were not associated with each other (P = 0.083). Ten females (25%) and 10 males (56%) met the criteria for sarcopenia. The postoperative abduction shoulder strength and Constant-Murley shoulder score increased significantly with higher preoperative grip strength (R = 0.420 and P = 0.001; and R = 0.497 and P < 0.001, respectively) and the American Shoulder and Elbow Surgeons Score was related to the preoperative aRSMI (R = 0.320, P = 0.039).
Conclusions:
The shoulder strength and functional score after RSA correlated positively with the preoperative grip strength. Measuring grip strength before RSA allows the surgeon to predict shoulder strength after RSA.
Introduction:
The purpose of this study was to investigate the relationships between supraspinatus atrophy on magnetic resonance imaging (MRI) and other objective parameters in patients with rotator cuff tears. It was hypothesized that high-grade supraspinatus fatty infiltration would be correlated negatively with handgrip strength, shoulder strength, and patient-reported outcome measures (PROMs).
Methods:
Patients with MRI-proven rotator cuff tears treated by a single sports medicine fellowship-trained orthopaedist at a single institution underwent comprehensive preoperative evaluation including bilateral handgrip and shoulder strength measurements with dynamometers and multiple online questionnaires from the Surgical Outcomes SystemTM (Arthrex, Naples, FL). Available shoulder MRIs were reviewed to grade supraspinatus fatty infiltration severity according to the 5-tier Goutallier system and an alternate 3-tier classification scheme. Difference analysis and Spearman (rho) rank order correlation were applied to the collected data to define the relationships between supraspinatus fatty infiltration and key variables including handgrip strength, shoulder strength, and scores derived from the shoulder PROMs.
Results:
Ninety of the 121 patients enrolled in the study had shoulder MRIs available for review. There was no correlation found between supraspinatus fatty infiltration and handgrip strength, shoulder abduction strength, or any of the seven common shoulder PROM scores evaluated. There was statistically significant, albeit weak, correlation between MRI-derived fatty infiltration and shoulder external rotation strength.
Conclusions:
Contrary to the hypothesis, high-grade supraspinatus fatty infiltration is largely unrelated to and should not be considered predictive of handgrip strength, shoulder strength, or common shoulder PROM scores.
The attraction, engagement, and retention of new players
to a sport is an important effort to undertake by governing
sport bodies. With the growth of so many sport involvement
opportunities, engaging new tennis players, specifically, and
retaining them can be a challenge. A unique phenomenon
occurred in 2020 wherein an influx of four million new
tennis players in the United States occurred through little to
no formal efforts on the part of the tennis industry due to
the impacts of the worldwide COVID-19 pandemic.
Background: Basketball is a contact pivot sport. Basketball moves are generally individual actions used by players in basketball to pass by defenders to gain a clean pass to a teammate to score points. Stability, mobility and strength are the 3 main components to determine the athlete's performance among the professional basketball players. There are limited studies and effective method of evaluation on field test that assess upper body stability, mobility and strength. This study aims to assess the relationship between upper extremity dynamic balance and hand grip strength in professional basketball players. Materials and Methods: Convenience sampling technique was used to include 20 Professional basketball player's age between (18-28) years. After initial assessment of age, height, playing hours per day per week and upper limb length measurement. Upper extremity dynamic balance using Upper Quadrant Balance Test (UQ-YBT) and Hand Grip Strength (HGS) using Jamar hand held dynamometer were measured. Results: Karl Pearson's correlation was used to measure the relationship between hand grip strength and upper extremity dynamic balance. Moderate positive correlation was found between Left-HGS and Left-UQYBT(r=+0.479), Right-HGS and Right-UQYBT(r=+0.556), (p>0.05). Conclusion: This study conclude that, the tests are interrelated and also can be use to assess equal component of upper extremity ability. This observation may provide professional basketball trainer and physical therapist with a reliable and easy quick-to-administrate to evaluate upper extremity stability, mobility and strength in a clinical setting.
Background. There is evidence that yoga practice can improve cardiovascular endurance, and that physically fit individuals have better psychomotor functioning, however, to the best of our knowledge, no information is available regarding yoga effects in population aged 60 years and older.
The aim of the study was to test the hypothesis that 10 weeks of yoga practice would improve
physical fitness and psychomotor coordination in older adults.
Methods. Thirty-three older adults aged 66.9 ± 6.0 years were randomly assigned to the control group and the experimental group, which had 90-min yoga practice twice a week, for 10 weeks. Attendance and adherence ratios, and changes in cardiovascular endurance, flexibility, grip strength, and psychomotor coordination were assessed.
Results. Attendance of the experimental group subjects in yoga practice was 96.4 ± 4.1%. Yoga practice increased (p < 0.05) hand grip strength, flexibility in hips, thighs and spine, and decreased (p < 0.05) the distance from target in the psychomotor task, whereas no changes in peak oxygen consumption were observed.
Conclusion. Nevertheless, regular 10-week yoga practice had no effect on cardiovascular endurance, but it produced beneficial changes in muscular strength, flexibility and psychomotor coordination for older adults.
Keywords: aging, cardiovascular endurance, strength, flexibility, exercise.
Hand grip strength (HGS) is a useful, functional measure of the integrity of upper extremity, however many studies examined it from selected positions (supine, sitting, standing), with no emphasis on other derived positions that are used in a clinical setting. The objective was to evaluate HGS in different body positions that are used in a clinical setting by using a standard protocol. A convenience sample of 40 healthy male participants was recruited for this study, with no history of psychiatric or neurological dysfunction, or upper extremity orthopedic dysfunction. Grip strength was measured in the dominant hand with Jamar Plus+ digital hand dynamometer in five positions: supine, prone, side-lying, sitting and standing. The HGS value in the prone position was significantly lower than that in standing position (p = 0.043) and the sitting position (p = 0.013). However, no statistical difference was found in HGS among supine, prone, side-lying positions. Grip strength correlated moderately with age (r = 0.643). This study provides a useful evaluation of grip strength in different positions. Using identical upper extremity positions, grip strength is variable among different body positions. Grip strength is equivalent when tested from the supine, side-lying or prone, thus position can be adjusted according to the patient's condition. Finally, Age is one of the important determinants of the hand grip evaluation, particularly when standing position is used.
We examined 4 shoulder muscles-the supraspina-tus, infraspinatus, the middle portion of the deltoid and the descending part of the trapezius-with electromyography (EMG) in abducted and flexed arm positions, in 9 healthy subjects. the subjects were asked to produce a static handgrip force of 30% and 50% of maximal voluntary contraction (MVC) in 8 different arm positions. in all positions, the subjects held a dynamometer in the hand. the myoelectric activity in the shoulder muscles with only the dynamometer in the hand was compared to the EMG activity when static contractions were added. There was an association between static handgrip and shoulder muscle activity, as revealed by EMG. the EMG activity increased in the supraspinatus muscle in humeral flexion from and above 60° and in 120° abduction. in the infraspinatus muscle, the changes were less; a significant increase, however, was noticed in flexion. in the deltoid muscle there was a tendency towards increased activity in positions lower than 90°, in the higher arm positions, the activity decreased. There was no significant alteration regarding the EMG activity of the trapezius.
Our findings imply that high static handgrip force, particularly in elevated arm positions, increases the load on some shoulder muscles. the stabilizing muscles (the rotator cuff) were more influenced than the motor muscles by hand activity. Handgrip activity is important to evaluate while assessing shoulder load in manual work and in clinical evaluations of patients with shoulder pain.
Tennis is a popular sport with tens of millions of players participating worldwide. This popularity was one factor leading to the reappearance of tennis as a medal sport at the 1988 Summer Olympics in Seoul, South Korea. The volume of play, combined with the physical demands of the sports, can lead to injuries of the musculoskeletal system. Overall, injury incidence and prevalence in tennis has been reported in a number of investigations. The sport creates specific demands on the musculoskeletal system, with acute injuries, such as ankle sprains, being more frequent in the lower extremity while chronic overuse injuries, such as lateral epicondylitis, are more common in the upper extremity in the recreational player and shoulder pain more common in the high-level player. This review discusses the epidemiology of injuries frequently experienced in tennis players and examines some of these injuries' correlation with the development of osteoarthritis. In addition, player-specific factors, such as age, sex, volume of play, skill level, racquet properties and grip positions as well as the effect of playing surface on the incidence and prevalence of injury is reported. Finally, recommendations on standardisation of future epidemiological studies on tennis injuries are made in order to be able to more easily compare results of future investigations.
The purpose of this meta-analysis was to consolidate the results of studies presenting normative values for grip strength obtained with the Jamar dynamometer in accordance with the recommendations of the American Society of Hand Therapists. Relevant data from 12 sources (3317 subjects) were employed. Means and 95% confidence intervals are presented for the left and right sides of men and women in 12 age groups (20–24, 25–29, 30–34, 35–39, 40–44, 45–49, 50–54, 55–59, 60–64, 65–69, 70–74, 75+ years). The consolidated grip strength reference values offer a better standard for comparison than provided by any single study alone. Limitations in the meta-analysis notwithstanding, the lower limit of the 95% confidence interval can serve as a reasonable threshold for establishing grip strength impairment among adults.
The subacromial impingement syndrome (SIS) is the most common diagnosed disorder of the shoulder in primary health care, but its aetiology is unclear. Conservative treatment regimes focus at reduction of subacromial inflammatory reactions or pathologic scapulohumeral motion patterns (intrinsic aetiology). Long-lasting symptoms are often treated with surgery, which is focused at enlarging the subacromial space by resection of the anterior part of the acromion (based on extrinsic aetiology). Despite that acromionplasty is in the top-10 of orthopaedic surgical procedures, there is no consensus on its indications and reported results are variable (successful in 48-90%). We hypothesize that the aetiology of SIS, i.e. an increase in subacromial pressure or decrease of subacromial space, is multi-factorial. SIS can be the consequence of pathologic scapulohumeral motion patterns leading to humerus cranialisation, anatomical variations of the scapula and the humerus (e.g. hooked acromion), a subacromial inflammatory reaction (e.g. due to overuse or micro-trauma), or adjoining pathology (e.g. osteoarthritis in the acromion-clavicular-joint with subacromial osteophytes).We believe patients should be treated according to their predominant etiological mechanism(s). Therefore, the objective of our study is to identify and discriminate etiological mechanisms occurring in SIS patients, in order to develop tailored diagnostic and therapeutic strategies.
In this cross-sectional descriptive study, applied clinical and experimental methods to identify intrinsic and extrinsic etiologic mechanisms comprise: MRI-arthrography (eligibility criteria, cuff status, 3D-segmented bony contours); 3D-motion tracking (scapulohumeral rhythm, arm range of motion, dynamic subacromial volume assessment by combining the 3D bony contours and 3D-kinematics); EMG (adductor co-activation) and dynamometry instrumented shoulder radiographs during arm tasks (force and muscle activation controlled acromiohumeral translation assessments); Clinical phenotyping (Constant Score, DASH, WORC, and SF-36 scores).
By relating anatomic properties, kinematics and muscle dynamics to subacromial volume, we expect to identify one or more predominant pathophysiological mechanisms in every SIS patient. These differences in underlying mechanisms are a reflection of the variations in symptoms, clinical scores and outcomes reported in literature. More insight in these mechanisms is necessary in order to optimize future diagnostic and treatment strategies for patients with SIS symptoms.
Dutch Trial Registry (Nederlands Trial Register) NTR2283.
Clinical experience indicates that a substantial number of handball players may suffer from shoulder pain, but they continue to play despite having shoulder pain problems. The aim of this study was to evaluate the prevalence and consequences of shoulder pain problems among Norwegian female elite handball players. In the preseason of the 2007-2008 season, 179 players from all 12 teams of the Norwegian elite league went through the following tests: internal and external shoulder range of motion, apprehension, relocation test, and shooting velocity. All players completed the Fahlström questionnaire and, for players with current pain, the Western Ontario shoulder instability index questionnaire. Sixty-five (36%) players reported shoulder pain on the test day, and 40 (22%) players reported previous shoulder pain. Two thirds of the players with pain reported a gradual onset. For players with current or previous pain, 22 (36%) and 14 (36%) had missed match play, and 43 (68%) and 28 (76%) reported changing their training habits. A positive apprehension and relocation test was found among 51 (29%) of the players. In conclusion, a high proportion of female elite handball players experience shoulder pain and problems and have an unstable shoulder.
The North West Adelaide Health Study is a representative longitudinal cohort study of people originally aged 18 years and over. The aim of this study was to describe normative data for hand grip strength in a community-based Australian population. Secondary aims were to investigate the relationship between body mass index (BMI) and hand grip strength, and to compare Australian data with international hand grip strength norms.
The sample was randomly selected and recruited by telephone interview. Overall, 3 206 (81% of those recruited) participants returned to the clinic during the second stage (2004-2006) which specifically focused on the collection of information relating to musculoskeletal conditions.
Following the exclusion of 435 participants who had hand pain and/or arthritis, 1366 men and 1312 women participants provided hand grip strength measurement. The study population was relatively young, with 41.5% under 40 years; and their mean BMI was 28.1 kg/m2 (SD 5.5). Higher hand grip strength was weakly related to higher BMI in adults under the age of 30 and over the age of 70, but inversely related to higher BMI between these ages. Australian norms from this sample had amongst the lowest of the hand grip strength of the internationally published norms, except those from underweight populations.
This population demonstrated higher BMI and lower grip strength in younger participants than much of the international published, population data. A complete exploration of the relationship between BMI and hand grip strength was not fully explored as there were very few participants with BMI in the underweight range. The age and gender grip strength values are lower in younger adults than those reported in international literature.
Clinical Sports Medicine has been fully updated from the popular 2nd edition (2000). It is even more practical, now superbly illustrated, easy-to-read and packed with substantially updated and new material. There are samples of several chapters online including the whole "Pain in the Achilles region" chapter. This book describes a completely symptom-oriented approach to treating clinical problems.
Both structural and non-structural components can contribute to shoulder instability. Classification and therefore management must recognise these factors to achieve functional stability. This paper discusses a classification system proposing three types of shoulder instability recognising the structural and non-structural components and that a continuum exists between pathologies. Structural causes can be addressed with surgical intervention, but non-structural causes such as altered neuromuscular control within the rotator cuff should be addressed conservatively. The purpose of this article is to describe the types of instability and guide appropriate management, helping to avoid surgery in inappropriate cases and ensure that effective rehabilitation has been achieved.
Rehabilitation of the patient with glenohumeral impingement requires a complete understanding of the structures involved and the underlying mechanism creating the impingement response. A detailed clinical examination and comprehensive treatment programme including specific interventions to address pain, scapular dysfunction and rotator cuff weakness are recommended. The inclusion of objective testing to quantify range of motion and both muscular strength and balance in addition to the manual orthopaedic clinical tests allows clinicians to design evidence-based rehabilitation programmes as well as measure progression and patient improvement.
The influence of external factors such as arm posture, hand loading and dynamic exertion on shoulder muscle activity is needed to provide insight into the relationship between internal and external loading of the shoulder joint. Surface electromyography was collected from 8 upper extremity muscles on 16 participants who performed isometric and dynamic shoulder exertions in three shoulder planes (flexion, mid-abduction and abduction) covering four shoulder elevation angles (30 degrees , 60 degrees , 90 degrees and 120 degrees). Shoulder exertions were performed under three hand load conditions: no load, holding a 0.5 kg load and 30% grip. It was found that adding a 0.5 kg load to the hand increased shoulder muscle activity by 4% maximum voluntary excitation (MVE), across all postures and velocities. Performing a simultaneous shoulder exertion and hand grip led to posture specific redistribution of shoulder muscle activity that was consistent for both isometric and dynamic exertions. When gripping, anterior and middle deltoid activity decreased by 2% MVE, while posterior deltoid, infraspinatus and trapezius activity increased by 2% MVE and biceps brachii activity increased by 6% MVE. Increased biceps brachii activity with gripping may be an initiating factor for the changes in shoulder muscle activity. The finding that hand gripping altered muscle activation, and thus the internal loading, of the shoulder may play an important role in shoulder injury development and rehabilitation.
This study was designed to determine the effect of testing posture and elbow position on grip strength. A hand dynamometer was used to measure the grip strength of 61 subjects (26 female and 35 male) in four positions: (1) sitting with elbow in 90 degree flexion, (2) sitting with elbow in full extension, (3) standing with elbow in 90 degree flexion, and (4) standing with elbow in full extension. The four experimental conditions were randomized, and standardized instructions were followed. A two-factor (gender and treatment) repeated measures ANOVA was used to determine any significant difference in grip strength between the sexes and the experimental (treatment) conditions. The result of the ANOVA revealed a significant F-ratio for gender and treatment main effects. Scheffé post hoc analysis revealed that males had higher (p less than .01) grip strength than females at all the testing postures and elbow joint angles, and that there was a significant (p less than .05) difference between the grip strength measured in subjects sitting with the elbow in 90 degree flexion and standing with the elbow in full extension. The findings suggest the need for clinicians to maintain standard testing conditions while measuring grip strength.
The primary purpose of this study was to establish clinical norms for adults aged 20 to 75+ years on four tests of hand strength. A dynamometer was used to measure grip strength and a pinch gauge to measure tip, key, and palmar pinch. A sample of 310 male and 328 female adults, ages 20 to 94, from the seven-county Milwaukee area were tested using standardized positioning and instructions. Right hand and left hand data were stratified into 12 age groups for both sexes. This stratification provides a means of comparing the score of individual patients to that of normal subjects of the same age and sex. The highest grip strength scores occurred in the 25 to 39 age groups. For tip, key, and palmar pinch the average scores were relatively stable from 20 to 59 years, with a gradual decline from 60 to 79 years. A high correlation was seen between grip strength and age, but a low to moderate correlation between pinch strength and age. The newer pinch gauge used in this study appears to read higher than that used in a previous normative study. Comparison of the average hand strength of right-handed and left-handed subjects showed only minimal differences.
Epidemiologically-based rheumatology healthcare needs assessment requires an understanding of the incidence and prevalence of musculoskeletal disorders in the community, of the reasons why people consult in primary care, and of the proportion of people who would benefit from referral to secondary care and paramedical services. This paper reports the first phase of such a needs assessment exercise.
To estimate the relative frequency of musculoskeletal pain in different, and multiple, anatomical sites in the adult population.
Three general practices in the former Tameside and Glossop Health Authority, Greater Manchester, UK, a predominantly urban area.
Population survey.
An age and sex stratified sample of 6000 adults from the three practices was mailed a questionnaire that sought data on demographic factors, musculoskeletal symptoms (pain in the past month lasting for more than a week), and physical disability (using the modified Health Assessment Questionnaire--mHAQ). The areas of pain covered were neck, back, shoulder, elbow, hand, hip, knee, and multiple joints. The Carstairs index was used as a measure of social deprivation of the postcode sector in which the person lived.
The response rate after two reminders was 78.5%. Non-responders were more likely to live in areas of high social deprivation. People who lived in more deprived areas were also more likely to report musculoskeletal pain, especially backpain. After adjusting for social deprivation the rates of musculoskeletal pain did not differ between the practices and so their results were combined. After adjustment for social deprivation, the most common site of pain was back (23%; 95% CI 21, 25) followed by knee (19%; 95% CI 18, 21), and shoulder (16%; 95% CI 14, 17). The majority of subjects who reported pain had pain in more than one site. The prevalence of physical disability in the community rose with age. It was highest in those with multiple joint problems but was also high in those with isolated back or knee pain.
Musculoskeletal pain is common in the community. People who live in socially deprived areas have more musculoskeletal symptoms. Estimates of the overall burden of musculoskeletal pain that combine the results of site specific surveys will be too high, those that do not adjust for socioeconomic factors will be too low.
A bilateral comparison of strength and range of motion testing in professional baseball pitchers.
We studied 39 professional male baseball pitchers to determine if the shoulder used for throwing was weaker or had less passive range of motion, compared to the nondominant arm.
Shoulder muscle weakness has been proposed as a possible risk factor for developing injury. Therefore, objective quantification of the strength of glenohumeral and scapular rotator muscle groups should be studied in a population of professional baseball pitchers.
Passive internal and external range of motion was bilaterally measured at 90 degrees of abduction. Muscle strength of the following muscles was measured bilaterally with a hand-held dynamometer: external and internal glenohumeral rotators, supraspinatus, middle trapezius, lower trapezius, and serratus anterior.
Passive external rotation of the glenohumeral joint at 90 degrees of abduction on the pitching side was significantly greater than on the nonpitching side. Passive internal rotation range of motion on the nonpitching side was significantly greater than on the pitching side. The pitching arm's internal rotators, when tested in abduction, were significantly stronger than the nonpitching arm. The nonpitching arm's external rotators in the plane of the scapula, and in abduction, were significantly greater than those of the pitching arm. The pitching arm's middle and lower trapezius muscles were significantly stronger than those of the nonpitching arm.
The range of motion and strength characteristics measured in this study can assist clinicians in evaluating athletes who use overhead throwing motions.
To evaluate the interobserver reproducibility of the assessment of severity of complaints, grip strength, and pressure pain threshold in patients with lateral epicondylitis in primary care.
Two physiotherapists assessed independently, and in randomized order, the severity of complaints scored on an 11-point numeric rating scale, pain-free grip strength, maximum grip strength, and pressure pain threshold.
Primary care center in the Netherlands.
Fifty patients were assessed by both physiotherapists.
Not applicable.
Intraclass correlation coefficients (ICCs) and 95% confidence intervals (CIs) were calculated to assess interobserver reliability. The Bland and Altman method was used to assess interobserver agreement, which included calculation of the mean difference between the observers (d), the 95% CI for d, the standard deviation of the differences, and the 95% limits of agreement. Finally, the smallest detectable difference (SDD) was calculated.
The ICC for the severity of complaints was.90. The ICCs for the pain-free grip strength and maximum grip strength were.97 and.98, respectively. The pressure pain threshold showed a lower reliability (ICC=.77). The interobserver agreement for all outcome measures was good, but systematic differences in assessment between the physiotherapists were found for the maximum grip strength and pressure pain threshold. For pressure pain threshold, the SDD was clearly larger than the predefined acceptable difference of 10% of the total range of measurement.
The interobserver reliability of severity of complaints and grip strength was excellent, whereas the pressure pain threshold showed unsatisfactory reliability. Grip strength and overall assessment of the severity of complaints are useful and reliable measures for the assessment of lateral epicondylitis. Pain-free grip strength, in particular, is relatively easy to perform and has been shown to be associated with other measures of functional disability in patients with lateral epicondylitis. We, therefore, recommend the use of pain-free grip strength in both research and clinical practice.
Impingement on the tendinous portion of the rotator cuff by the coracoacromial ligament and the anterior third of the acromion is responsible for a characteristic syndrome of disability of the shoulder. A characteristic proliferative spur and ridge has been noted on the anterior lip and undersurface of the anterior process of the acromion and this area may also show erosion and eburnation. The treatment of the impingement is to remove the anterior edge and undersurface of the anterior part of the acromion with the attached coracoacromial ligament. The impingement may also involve the tendon of the long head of the biceps and if it does, it is best to decompress the tendon and remove any osteophytes which may be in its groove, but to avoid transplanting the biceps tendon if possible. Hypertrophic lipping at the acromio-clavicular joint may impinge on the supraspinatus tendon when the arm is in abduction and, if the lip is prominent, this joint should be resected. These are the principles of anterior acromioplasty.
Shoulder range of motion (ROM) and strength measurements are imperative in the clinical assessment of the patient's status and progression over time. The method and type of assessment varies among clinicians and institutions. No comprehensive study to date has examined the reliability of a variety of procedures based on different testing equipment and specific patient or shoulder position. The purpose of this study was to establish absolute and relative reliability for several procedures measuring the rotational shoulder ROM and strength into internal (IR) and external (ER) rotation strength.
Thirty healthy individuals (15 male, 15 female), with a mean age of 22.1 ± 1.4 years, were examined by 2 examiners who measured ROM with a goniometer and inclinometer and isometric strength with a hand-held dynamometer (HHD) in different patient and shoulder positions. Relative reliability was determined by intraclass correlation coefficients (ICC). Absolute reliability was quantified by standard error of measurement (SEM) and minimal detectable change (MDC). Systematic differences across trials or between testers, as well as differences among similar measurements under different testing circumstances, were analyzed with dependent t tests or repeated-measures analysis of variance in case of 2 or more than 2 conditions, respectively.
Reliability was good to excellent for IR and ER ROM and isometric strength measurements, regardless of patient or shoulder position or equipment used (ICC, 0.85-0.99). For some of the measurements, systematic differences were found across trials or between testers. The patient's position and the equipment used resulted in different outcome measures.
All procedures examined showed acceptable reliability for clinical use. However, patient position and equipment might influence the results.
Shoulder range of motion (ROM) and strength measurements are imperative in the clinical assessment of the overhead athlete in the prevention and rehabilitation of sports related shoulder injuries. The method and type of assessment varies among clinicians and institutions. Until present, no comprehensive study ever examined reliability of a variety of procedures based on different testing equipment, and specific patient or shoulder position.
To establish absolute and relative reliability for several procedures measuring the rotational shoulder ROM and strength into internal (IR) and external (ER) rotation strength.
Controlled laboratory study.
30 healthy subjects (15 male, 15 female) with a mean age of 22.1 (±1.4) years.
Subjects were examined by 2 examiners measuring ROM with a goniometer and inclinometer, and isometric strength with a Hand-Held-Dynamometer (HHD) respectively, in different patient's positions, and shoulder's positions. Relative reliability was determined by Intra-Class-Correlation coefficients (ICC). Absolute reliability was quantified by Standard-Error-of-Measurement (SEM) and Minimal-Detectable-Change (MDC). Systematic differences across trials or between testers, as well as differences among similar measurements under different testing circumstances were analyzed with dependent t-tests or ANOVA Repeated Measures (in case of 2 or more than 2 conditions respectively).
Range of motion (in degrees) and isometric muscle strength (in Newton).
Good to excellent intra- and intertester reliability was established for IR and ER ROM and isometric strength measurements, regardless of patient or shoulder position or equipment used (ICC 0.85-0.99). No systematic differences were found across trials or between testers. However patient's position, as well as equipment resulted in different outcome measures.
All procedures examined showed acceptable reliability for clinical use. However, patient position and equipment might influence the results. For sport specific measurements, ROM and strength should be measured in positions, resembling the throwing position.
The purpose of this study was to compare subjects with subacromial impingement and subjects with normal shoulders with respect to muscle activity. Fifteen subjects in each group were studied by means of fine-wire electromyography. The middle deltoid and rotator cuff muscles were evaluated during isotonic scaption from 30 to 120 degrees. Overall, the impingement group demonstrated decreased mean muscle activity in comparison with the group of normal subjects. The magnitude of diminished activity was statistically significantly different (P
Background There have been few in-depth studies of upper limb injury epidemiology in rugby union football, despite reports that they accounted for between 14% and 28% of all rugby injuries.
Objective To report on upper limb injury incidence, injury severity and to identify the risk factors associated with upper limb injuries, for example, level of play, season (years) and playing position.
Design Prospective cohort study across five rugby seasons from 2004 to 2008.
Setting Formal rugby competitions—suburban, provincial and international.
Participants 1475 adult male rugby players in Colts, Grade and Elite competitions.
Main outcome measurements An upper limb injury resulting in a missed game and its characteristics.
Results A total of 61 598 athletic exposures (AE) and 606 upper limb injuries were recorded. About 66% of the injuries were to the shoulder. The overall upper limb injury incidence rate (IIR) was 9.84 injuries/1000 AE (95% CI 9.06 to 10.62). Statistically significant associations were found between upper limb injuries and level of play; and between shoulder injuries and playing position (p<0.05). No association was found between upper limb and shoulder injuries and study year. The overall upper limb IIR decreased as the level of play increased; 10.74 upper limb injuries/1000 AE (95% CI 9.93 to 11.56) in Colts to 6.07 upper limb injuries/1000 AE (95% CI 5.46 to 6.69) in Elite.
Conclusions The upper limb IIR decreased as the level of play increased indicating that age, level of skill and playing experience may be risk factors for upper limb injury.
Purpose: This study compared bilateral rotator cuff strength in patients with a unilateral hand or wrist disorder. The purpose of this study was to document rotator cuff weakness in patients with distal upper extremity disorders.Background: The onset of shoulder pain after hand injuries is an acknowledged risk. These symptoms may be due to rotator cuff weakness and dysfunction. Patients with hand injuries use the upper extremity less, which can lead to deconditioning, rotator cuff weakness and fatigue. The prevalence of rotator cuff weakness in this population is unknown.Methods and Materials: Ipsilateral rotator cuff strength was measured in 57 patients age 18 and older (average age 42) with an injury or disorder of the hand or wrist distal to the distal radius and compared with the uninvolved side. Thirty-four patients were men and 23 were women. Fifty were right hand dominant and seven were left hand dominant. Injuries involved the dominant extremity in 33 cases and the non-dominant extremity in 24. Patients with bilateral symptoms and/or a history of significant upper extremity symptoms were excluded. Information on age, dominance, injury side, time since injury, mechanism of injury and worker's compensation status was collected. Patients were divided into acute (traumatic onset less than six weeks) and chronic (traumatic onset greater than six weeks or insidious).Rotator cuff strength was measured using a hand held dynamometer (Microfet 2; Hoggan Health Industries, Draper, UT). Measurements were done in a standardized manner for each muscle with trials and rest breaks. Specific testing postures are outlined in the article for easy comparison. Both make and break tests were performed and an independent examiner recorded measurements.Results: There was a statistically significant decrease in elevated external rotation strength (infraspinatus) for both make and break tests for the ipsilateral arm. There was also a statistically significant decrease in strength of elevation in the scapular plane (supraspinatus) for breaks tests but not for make tests. There was a statistically significant correlation between decreased strength supraspinatus make and infraspinatus break test and age. Percentage of strength loss was greater for younger patients. Neither time from injury or worker's compensation status was significant in strength loss. There was, however, an increased vulnerability for patients whose injury was in the non-dominant extremity.Discussion: The author acknowledges that despite the presence of shoulder symptoms in some patients with distal upper extremity problems, it is unclear whether there is a causal relationship. This study attempts to address the issue by documenting statistically significant ipsilateral rotator cuff weakness in patients with distal problems. Weakness was found in both the make and break tests for the infraspinatus and the break tests for the supraspinatus. Further research is required to determine if any relationship exists between shoulder pain and ipsilateral distal extremity injuries.The finding of greater vulnerability when the non-dominant injury was involved is consistent with easier substitution during activity for these extremities and the use of dominant extremity despite pain and limitations. Previous studies are cited that found no significant difference in strength between dominant and non-dominant extremities so this was not a factor in the data analysis. The issue of strength loss and time from injury requires further research and the author suggests a study that follows individual patients with acute injuries over time.Weaknesses of this study included the difficulty in totally isolating muscles for testing and errors associated with use of a hand held dynamometer. The dynamometer errors occur because the examiner breaks first. They would have affected the stronger extremity, making it appear weaker, thus decreasing the statistical significance. Since findings were statistically significant for all but the supraspinatus make tests elimination of this weakness would only strengthen the findings.This study points to the need for early and ongoing assessment of rotator cuff strength in our patients. Selective strengthening of rotator cuff muscles may be clinically important to both therapists and surgeons in treating patients with distal upper extremity problems.
This study compared the Jamar and Rolyan hydraulic dynamometers to determine their concurrent validity with known weights as well as their inter-instrument reliability and concurrent validity for measuring grip strength in a clinical setting. Thirty females and 30 males were tested on these two grip strength measurement devices using a repeated measure design. Results showed that the Jamar and Rolyan dynamometers have acceptable concurrent validity with known weights (that is, correlation coefficients were r ≥ 0.9994), excellent inter-instrument reliability (that is, intraclass correlation coefficients ranged from 0.90 to 0.97) and strong concurrent validity (that is, no significant differences between dynamometers' scores). Data indicate that Jamar and Rolyan dynamometers measure grip strength equivalently and can be used interchangeably. Thus, therapists using the Rolyan dynamometer are justified in using published normative data, which were collected with the Jamar dynamometer. Copyright © 2002 Whurr Publishers Ltd.
This study investigated the effect of shoulder, elbow positions with respect to wrist positioned in neutral and in extension in 25 males and 25 females. A hydraulic dynamometer was used to measure the grip strength in six testing positions with respect to wrist positioned in neutral and in extension. The six grip strength tests consisted of three positions in which the elbow was maintained in full extension with varying degrees of shoulder flexion (00, 900 and 1800) and other three positions where the elbow was maintained in 900 flexion combined with varying degrees of shoulder flexion (00, 900 and 1800). Only the dominant hand was tested. The highest mean grip strength score was recorded when the shoulder was positioned in 1800 of flexion with elbow in complete extension with respect to wrist being positioned in neutral (30.20 ± 8.74) and wrist in extension (25.44 ± 7.51), while the lowest mean grip strength score was recorded when shoulder was positioned in 1800 flexion with elbow 900 flexion with respect to wrist being positioned in neutral (21.92 ± 7.45) and wrist in extension (19.40 ± 6.21). Finally grip strength differed significantly for both sexes and study showed males have greater grip strength than females with respect to wrist being positioned in neutral and in extension. In essence, our study affirms that various joint positions can affect grip strength, especially elbow and shoulder joints with respect to wrist positions (neutral and extension). Clinically useful information may be derived from these findings and are valuable in evaluation and rehabilitation training of hand injured patients
The purpose of this study was to determine if the effect of visually targeted gripping on shoulder muscle activity was maintained with repeated exposures. Eleven healthy males had eight shoulder muscles monitored via surface electromyography while maintaining shoulder elevation at 90° in the scapular plane with and without a 30% grip force. Three non-gripping trials were followed by 15 gripping trials and another 3 non-gripping control trials. Gripping significantly decreased the activity of the anterior deltoid, trapezius, and latissimus dorsi over the exposure of 15 trials. Gripping also reduced variability in all muscles' activity. The changes in shoulder muscle activity are likely in response to forces being transferred through multi-articular muscles spanning from the forearm to the shoulder. Targeted gripping during shoulder elevation resulted in small but significant decreases in muscle activity and reduced variability which supports previous evidence for increased risk of upper extremity disorders in occupational settings.
Reliable electromyographic evaluation of the shoulder in common painful conditions is a major challenge due to a reduced range of movement and pain-related muscle inhibition. This study investigates the use of a hand grip task for the assessment of shoulder muscle activation.
Muscle activity and fatigue for supraspinatus and infraspinatus muscles were measured in 16 healthy controls using fine-wire electrodes during a controlled gripping task at 50% of maximum voluntary contraction, in a standardized sitting and arm position. Changes in muscle activity and fatigue were measured by the time-slope of root mean square amplitude and median frequency, respectively.
A significant positive amplitude slope (p<0.01) was found for both supraspinatus and infraspinatus, indicating that the task resulted in increasing muscle activity. Judging by the median frequency slope, there was no sign of fatigue progression.
A standardized hand grip task in a neutral position activates key rotator cuff muscles. This might provide a method for electromyographic assessment of shoulder girdle muscles which avoids problems due to pain-related limitation of movement, and might be useful in the development and monitoring of shoulder rehabilitation strategies.
People move differently in pain. Although this statement is unquestioned, the underlying mechanisms are surprisingly poorly understood. Existing theories are relatively simplistic, and although their predictions are consistent with a range of experimental and clinical observations, there are many observations that cannot be adequately explained. New theories are required. Here, we seek to consider the motor adaptation to pain from the micro (single motoneuron) to macro (coordination of whole-muscle behaviour) levels and to provide a basis for a new theory to explain the motor changes in pain.
The etiology of rotator cuff tendinopathy is multi-factorial, and has been attributed to both extrinsic and intrinsic mechanisms. Extrinsic factors that encroach upon the subacromial space and contribute to bursal side compression of the rotator cuff tendons include anatomical variants of the acromion, alterations in scapular or humeral kinematics, postural abnormalities, rotator cuff and scapular muscle performance deficits, and decreased extensibility of pectoralis minor or posterior shoulder. A unique extrinsic mechanism, internal impingement, is attributed to compression of the posterior articular surface of the tendons between the humeral head and glenoid and is not related to subacromial space narrowing. Intrinsic factors that contribute to rotator cuff tendon degradation with tensile/shear overload include alterations in biology, mechanical properties, morphology, and vascularity. The varied nature of these mechanisms indicates that rotator cuff tendinopathy is not a homogenous entity, and thus may require different treatment interventions. Treatment aimed at addressing mechanistic factors appears to be beneficial for patients with rotator cuff tendinopathy, however, not for all patients. Classification of rotator cuff tendinopathy into subgroups based on underlying mechanism may improve treatment outcomes.
The purpose of this study was to examine the relationship between hand-grip (HG) isometric strength and isokinetic moment of the shoulder musculature in 18 healthy male volunteers. HG isometric strength at 0 degrees , 90 degrees and 180 degrees of shoulder flexion and isokinetic peak and average concentric moments of the shoulder rotators and abductors and the elbow flexors at 60 degrees s(-1) were measured on both the dominant and non-dominant sides. Pearson correlation coefficients revealed statistically significant positive relationships between HG isometric strength and isokinetic moments of the shoulder external rotators (r=0.40-0.54), the shoulder abductors (r=0.42-0.71) and the elbow flexors (r=0.45-0.66) regardless of hand dominance. The positive relationships between HG isometric strength and isokinetic strength of the shoulder stabilisers was probably attributed to mechanisms providing stability to the elbow and shoulder joints either by force transmission via myotendinous and myofascial pathways or by "overflow" of muscular activity via neural circuits. The results of the present findings suggested that HG isometric strength can be used to monitor isokinetic strength of certain muscle groups contributing to the stability of the shoulder joint; however, HG strength may account only for approximately 16-50% of the variability in isokinetic strength of these muscle groups.
The purpose of this study was to examine the association between maximal isometric strength and mobility among 75-year-old men and women. All those born in 1914 and resident in the city of Jyväskylä in August 1989 comprised the study group (n = 388); 355 persons were interviewed at their homes (92%): 101 men (81% of all male residents) and 186 women (75%) participated in the laboratory strength tests. As part of the home interview the person′s mobility at home, on stairs and outdoors was assessed using a four-point scale: —1 able, 2—able with difficulty, 3—needs help, 4—unable. Poor mobility was more common among the drop-outs than among the strength-tested subjects in both sexes. Maximal isometric strength of hand grip, arm flexion, knee extension and trunk flexion and extension were measured using specially constructed dynamometers. The strength results were adjusted for body weight. The study also included a stair-mounting test and measurement of maximal walking speed. The body-weight adjusted maximal forces were consistently significantly associated with mobility. Those who claimed no problems in the mobility interview and performed better in the walking and stair-mounting tests exhibited greater maximal isometric strength. The present results indicate that maximal isometric strength tests provide useful information about physical functional capacity among elderly people. These findings also suggest that the maintenance of adequate strength could be favourable to the mobility of older persons.
The purpose of the study was to quantify age-related changes in hand grip strength and three types of pinch grip strength (key pinch, tip pinch, and palmar pinch) among male and female participants. The study included 199 healthy participants (100 females, 99 males) aged 20-79 years, who were divided into four age groups. The Baseline Hydraulic Hand Dynamometer and Baseline Hydraulic Pinch Gauge were used according to the standard procedures. For both the dominant and the nondominant hands, statistically significant differences between males and females, and between the age groups, were found using the analysis of variance. Mean hand and pinch grip strength were generally higher for the dominant hand and in males. The highest values of hand and pinch grip strength were found for males in the age group 35-49 years, and for females in age groups 20-34 and 35-49 years. Regardless of sex, the age group 65-79 years obtained the lowest values for all strength measures. The post-hoc tests showed significant differences between this and the other age groups in the majority of measures. Fewer differences were found between the younger groups. All strength measures correlated negatively with age (r = -0.29 to -0.41; P<0.01). In conclusion, these results show age-related changes in hand and pinch grip strength of the dominant and nondominant hands among male and female participants. Normative values according to the age groups are presented.
Imbalance of the internal and external rotator muscu lature of the shoulder, excess capsular laxity, and loss of capsular flexibility, have all been implicated as etio logic factors in glenohumeral instability and impinge ment syndrome; however, these assertions are based largely on qualitative clinical observations. In order to quantitatively define the requirements of adequate pro tective synergy of the internal and external rotator musculature, as well as the primary capsulolabral re straints, we prospectively evaluated 53 subjects: 15 asymptomatic volunteers, 28 patients with glenohu meral instability, and 10 patients with impingement syndrome. Range of motion was evaluated by gonio metric technique in all patients with glenohumeral insta bility and impingement. Laxity assessment was per formed and anterior, posterior, and inferior humeral head translation was graded on a scale of 0 to 3+. Isokinetic strength assessment was performed in a modified abducted position using the Biodex Clinical Data Station with test speeds of 90 and 180 deg/sec. Internal and external rotator ratios and internal and external rotator strength deficits were calculated for both peak torque and total work.
Patients with impingement demonstrated marked lim itation of shoulder motion and minimal laxity on drawer testing. Both anterior and multidirectional instability pa tients had excessive external rotation as well as in creased capsular laxity in all directions. Sixty-eight per cent of the patients with instability had significant im pingement signs in addition to apprehension and capsular laxity.
Isokinetic testing of asymptomatic subjects demon strated a 30% greater internal rotator strength in the dominant shoulder. Comparison of all three experimen tal groups demonstrated a significant difference be tween internal and external rotator ratios for both peak torque and total work.
Conclusions are that there appears to be a domi nance tendency with regard to internal rotator strength in asymptomatic individuals. Impingement syndrome and anterior instability have significant differences in both strength patterns of the rotator muscles and flex ibility and laxity of the shoulder. Isokinetic testing po tentially may be helpful in diagnostically differentiating between these two groups in cases where there is clinical overlap of signs and symptoms.
Twenty-seven college women participated in a study to evaluate the reliability and validity of four tests of hand strength: grip, palmar pinch, key pinch, and tip pinch. Standardized positioning and instructions were followed. The results showed very high inter-rater reliability. Test-retest reliability was highest in all tests when the mean of three trials was used. Lower correlations were shown when one trial or the highest score of three trials were utilized. The Jamar dynamometer by Asimow Engineering and the pinch gauge by B&L Engineering demonstrated the highest accuracy of the instruments tested.
A new electronic dynanometer was developed and used to determine hand grip function in patients with rheumatoid arthritis. Triplicate pressure-time recordings of grip for each hand were used to calculate maximum grip strength, time required to reach 95% maximum grip strength (t95), total work and maximum power output. Measurements were done on 30 women aged 32 to 74 years (mean, 53 years) who had rheumatoid arthritis and 20 healthy women aged 37 to 69 years (mean, 50 years). The values obtained for patients and healthy women showed that the dominant hand was stronger than the nondominant hand in all women. However, all tests in patients with arthritis indicated decreased function and strength, the relative decrease being greater for nondominant hands compared with dominant hands. This new approach to measurement of hand grip function may provide better discrimination in the quantitative assessment of morning stiffness and response to changes in drug therapy. The time required to achieve 95% of maximum grip strength and maximum power outputs in particular appear to be more sensitive indicators of function than the standard maximum grip strength measurement.
We examined 4 shoulder muscles--the supraspinatus, infraspinatus, the middle portion of the deltoid and the descending part of the trapezius--with electromyography (EMG) in adducted and flexed arm positions, in 9 healthy subjects. The subjects were asked to produce a static handgrip force of 30% and 50% of maximal voluntary contraction (MVC) in 8 different arm positions. In all positions, the subjects held a dynamometer in the hand. The myoelectric activity in the shoulder muscles with only the dynamometer in the hand was compared to the EMG activity when static contractions were added. There was an association between static handgrip and shoulder muscle activity, as revealed by E < G. The EMG activity increased in the supraspinatus muscle in humeral flexion from and above 60 degree in 120 degree abduction. In the infraspinatus muscle, the changes were less; a significant increase, however, was noticed in flexion. In the deltoid muscle there was a tendency towards increased activity in positions lower than 90 degree, in the higher arm positions, the activity decreased. There was no significant alteration regarding the EMG activity of the trapezius. Our findings imply that high static handgrip force, particularly in elevated arm positions, increases the load on some shoulder muscles. The stabilizing muscles (the rotator cuff) were more influenced than the motor muscles by hand activity. Handgrip activity is important to evaluate while assessing shoulder load in manual work an in clinical evaluations of patients with shoulder pain.
Four shoulder muscles (the supraspinatus, the infraspinatus, the middle portion of the deltoid and the descending part of the trapezius muscle) were examined using electromyography (EMG) in abducted and flexed arm positions, in nine subjects who had no history of illness from arm or shoulder. The subjects were asked to supply an intermittent isometric handgrip force of 30% and 50% of maximal voluntary contraction, in a total of eight different arm positions. The EMG activity with and without hand activity was compared in all positions. There was a statistically significant increase in the EMG activity in the supraspinatus muscle in humeral flexion from and above 60 degrees. In the infraspinatus muscle the changes were less; a significant decrease was however noticed in abduction. In the deltoid muscle there was a significant decrease with hand activity in flexion from and above 90 degrees. There was no statistically significant alteration regarding the EMG activity of the trapezius muscle. The result of this study implies that high demands on handgrip force, particularly while using hand tools in elevated arm positions, adds further to the already high load on some shoulder muscles. This factor should be considered in the design of manual work and in the places of work.
The effectiveness of arthroscopic surgery, supervised exercises, and placebo was compared in 125 patients with rotator cuff disease (impingement syndrome stage II) in a randomized clinical trial. The median age was 48 years, and the median duration of complications was 1 to 2 years. The treatments were arthroscopic subacromial decompression performed by 2 experienced surgeons, an exercise regimen supervised for 3 to 6 months by 1 experienced physiotherapist, or 12 sessions of detuned soft laser (placebo) for 6 weeks. The criterion for success was a Neer shoulder score > 80. Fifteen (50%) and 11 (22%) of the patients randomized to placebo and exercises, respectively, had surgery during the 2 1/2-year follow-up period and were classified as having failure with the treatments. The success rate was higher (P < .01) for patients randomized to surgery (26 of 38) and exercises (27 of 44) compared with the placebo group (7 of 28). The odds ratio for success after surgery compared with exercises was 1.5 (95% confidence interval 0.6 to 3.7; P = .49). Including all patients who underwent operation, the success rate in those not on sick leave (19 of 21) before surgery was higher compared with those on sick leave (18 of 36) (adjusted odds ratio 5.6 [1.2 to 29.2]). Similar results were observed for patients not receiving versus those receiving regular pain medication before surgery (adjusted odds ratio 4.2 [1.2 to 15.8]).
Work-related shoulder pain is an increasing problem. Work in overhead positions, which causes high pressure in the supraspinatus muscle, has been shown to increase the shoulder load. It is not known how different types of muscle activity in the shoulder affect pressure in the muscle. The aim of this study was to investigate the difference between contraction modes. This has not been done before for shoulder muscles. The results are relevant from several aspects, both clinical and experimental. Pressure in the supraspinatus muscle and torque generation in the shoulder during isokinetic concentric and eccentric activity were measured in nine healthy human subjects. Torque and arm position were measured continuously with a computerized ergonometer. The contraction velocity was 60° per second, and the range of movement was 0–120° of abduction. Electromyographic measurements were recorded with a surface electrode above the supraspinatus muscle belly. Intramuscular pressure was recorded with a microcapillary infusion technique. Peak intramuscular pressure did not differ significantly between the two modes of contraction, but the peak was reached at 115° (SD = 15°) of abduction during concentric activity and at 6° (SD = 7°) of abduction during eccentric concentric activity and 2.3 mm Hg/Nm (0.31 kPa/Nm) during eccentric activity. The peak torque occurred at 44° of abduction during concentric muscle activity and at 74° of abduction during eccentric activity. Intramuscular pressure was higher during isometric contraction than during eccentric and concentric activity, and the torque was in between the two latter contraction modes. We conclude that the supraspinatus muscle is heavily loaded not only in high arm positions during concentric contraction but also during eccentric contraction in arm positions of 0-30° of abduction.
Two-group mixed-model analysis of covariance and correlation analysis.
To determine whether differences in humeral translations exist between patients with shoulder impingement symptoms and an asymptomatic comparison group, and if so, to determine if shoulder range-of-motion (ROM) measures are associated with abnormal translations.
Abnormal translations of the humeral head are believed to reduce the available subacromial space and to contribute to the development or progression of shoulder impingement symptoms. These abnormal translations have also been theorized to be related to tightness of the posterior capsule and decreased shoulder ROM.
Three-dimensional humeral translations were tracked in symptomatic construction workers and an asymptomatic comparison group while elevating the arm in the scapular plane under no-load, 2.3-kg, and 4.6-kg hand-load conditions. Between-group comparisons were made across 3 phases of motion (30 degrees-60 degrees, 60 degrees-90 degrees, and 90 degrees-120 degrees) and the association between humeral translations and cross-body adduction and shoulder internal rotation ROM measures were determined by Pearson correlation analysis.
Persons with shoulder symptoms demonstrated small but significant changes in anterior-posterior translations of the humerus. These changes for the 90 degrees-120 degrees phase of humeral elevation were moderately negatively associated with available cross-body adduction ROM.
The identified kinematic deviations are consistent with possible reductions of the subacromial space. Further study of relationships between posterior capsule tightness, rotator cuff function, and abnormal humeral translations is warranted to better delineate underlying kinematic mechanisms that may contribute to shoulder impingement symptoms and to refine rehabilitation techniques.
Equal proximal and distal lengthening of rat extensor digitorum longus (EDL) were studied. Tibialis anterior, extensor hallucis longus, and EDL were active maximally. The connective tissues around these muscle bellies were left intact. Proximal EDL forces differed from distal forces, indicating myofascial force transmission to structures other than the tendons. Higher EDL distal force was exerted (ratio approximately 118%) after distal than after equal proximal lengthening. For proximal force, the reverse occurred (ratio approximately 157%). Passive EDL force exerted at the lengthened end was 7-10 times the force exerted at the nonlengthened end. While kept at constant length, synergists (tibialis anterior + extensor hallucis longus: active muscle force difference approximately -10%) significantly decreased in force by distal EDL lengthening, but not by proximal EDL lengthening. We conclude that force exerted at the tendon at the lengthened end of a muscle is higher because of the extra load imposed by myofascial force transmission on parts of the muscle belly. This is mediated by changes of the relative position of most parts of the lengthened muscle with respect to neighboring muscles and to compartment connective tissues. As a consequence, muscle relative position is a major codeterminant of muscle force for muscle with connectivity of its belly close to in vivo conditions.
The purpose of this study was to document bilateral rotator cuff strength in patients with unilateral hand or wrist disorders.
Fifty-seven patients who had suffered a unilateral injury or disorder isolated to their hand or wrist, distal to the distal radius, had their bilateral rotator cuff strength measured.
A statistically significant decrease in strength was found in the ipsilateral shoulder for both elevation in the plane of the scapula (supraspinatus) and for elevated external rotation (infraspinatus). Younger patients and the nondominant extremity were affected more adversely.
An increased prevalence of rotator cuff weakness is shown proximal to ipsilateral hand injuries or disorders.
Shoulder muscles contribute to both mobility and stability of the glenohumeral joint. To improve treatments for shoulder instability, we focused on the contribution of the shoulder muscles to glenohumeral joint stability in clinically relevant positions. Both computational and experimental models were used. A computational model of the glenohumeral joint quantified stability provided by active muscle forces in both mid-range and end-range glenohumeral joint positions. Compared with mid-range positions, the resultant joint force at end-range positions was more anteriorly directed, indicating that its contribution to glenohumeral joint stability was diminished. In end-range positions, simulated increases in rotator cuff muscle forces tended to improve stability whereas increases in deltoid or pectoralis major muscle forces tended to further decrease stability. To validate these results, a cadaveric model, simulating relevant shoulder muscles, was used to quantify glenohumeral joint stability. When infraspinatus muscle activity was decreased, compressive forces decreased. When pectoralis major muscle activity was increased, anteriorly directed forces increased. If anteriorly directed forces increase or compressive forces decrease, stability of the glenohumeral joint decreases. This cadaveric model was then used to evaluate the effect of placing the joint in the apprehension position of abduction, external rotation, and horizontal abduction. Consistent with the results of our computational model, apprehension positioning increased anteriorly directed forces. Knowledge gained from these models was then used to develop a cadaveric model of glenohumeral joint dislocation. Dislocation resulted from the mechanism of forcible apprehension positioning when the appropriate shoulder muscles were simulated and a passive pectoralis major muscle was included. Capsulolabral lesions resulted that were similar to those observed in vivo. Shoulder muscle forces are usually powerful stabilizers of the glenohumeral joint, especially in mid-range positions when the passive stabilizers are lax. However, muscle forces can contribute to instability as well. Certain muscle forces decrease glenohumeral joint stability in end-range positions. We found this to be the case with both active and passive pectoralis major forces. Improved understanding of the contribution of muscle forces not only toward stability but also toward instability will improve rehabilitation protocols for the shoulder and prove useful in the treatment of joint instability throughout the body.
A principal cause of subacromial impingement (SAI) is failure of the rotator cuff to center the humeral head in the glenoid during shoulder motion, counteracting the effect of the deltoid. As rehabilitation of the rotator cuff endeavors to restore balance between these muscle groups, the purpose of this companion study was to evaluate, in the symptomatic shoulders of patients with SAI, (1) the conditions of resisted isometric external rotation (ER) that optimized the contribution of the infraspinatus and (2) the load of ER at which adduction was most effective at reducing the deltoid contribution and then to compare this with the relative contribution of the infraspinatus and the posterior and middle deltoid in asymptomatic shoulders. In 14 subjects (18 shoulders) with SAI, surface electromyographic activity of the infraspinatus and the posterior and middle deltoid and pectoralis major was recorded at low, medium, and high loads of resisted isometric ER, with and without adduction. These data were normalized to find each muscle's relative contribution to the task and were compared with normalized data from subjects with healthy shoulders. In subjects with SAI, low loads of isometric ER (10%-40% maximum voluntary isometric contraction) optimized the relative contribution of the infraspinatus. Adduction with isometric ER at 10% maximum voluntary isometric contraction reduced the middle deltoid involvement. Higher loads preferentially activated the middle deltoid over the infraspinatus and may have effected unwanted humeral head superior translation, counteracting the presumed benefits of rotator cuff ER exercises. An individualized loading regimen and the use of surface electromyography may have significant implications during rotator cuff rehabilitation.
- P Brukner
- K Khan
Brukner P and Khan K. Clinical sports medicine. Sydney:
McGraw-Hill Professional, 2010.
Kinesiology: scientific basis of human motion
- K Luttgens
- H Deutsch
- N Hamilton
Luttgens K, Deutsch H and Hamilton N. Kinesiology:
scientific basis of human motion, 8th edition. Madison,
WI: Brown and Benchmark, 1992.
High prevalence of shoulder pain among elite Norwegian female handball players
- G Mycklebust
- L Haslan
- Barr R Steffan
Mycklebust G, Haslan L, Barr R and Steffan K. High
prevalence of shoulder pain among elite Norwegian
female handball players. Scand J Med Sci Sports 2013;
23: 288-94.