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Is the Normal Shoulder Rotation Strength Ratio Altered in Elite Swimmers?
Abstract
Introduction:
It is commonly believed that the shoulder external rotation (ER) to internal rotation (IR) strength ratio is decreased in swimmers due to predominant IR loading during the pull-through (propulsive) phase which predisposes to shoulder pain. However, the evidence supporting this hypothesis is inconclusive. Therefore, the aim of this study was to examine shoulder rotation strength parameters in elite swimmers and investigate potential associations with shoulder pain.
Methods:
Sixty-eight (40 male; age = 19.9±3.2 years) elite swimmers provided demographic and shoulder pain history data prior to measurement of shoulder rotation strength. Mixed model analyses were used to examine differences in shoulder IR and ER strength normalised to body weight (BW) and the shoulder rotation strength ratio. A multinomial logistic regression model was utilised to examine associations between shoulder rotation strength parameters and shoulder pain.
Results:
Mean shoulder IR strength (BW) was approximately 0.29 for male swimmers and 0.26 for females. Mean shoulder ER strength (BW) was approximately 0.19 for male swimmers and 0.18 for females. The shoulder ER: IR strength ratio was approximately 0.70 bilaterally for all swimmers. There were no significant differences between dominant and non-dominant shoulders in IR or ER strength normalized to body weight (p≥0.547). There were no associations between any shoulder strength parameters and shoulder pain (r=0.032, p=0.107).
Conclusion:
Despite the high IR loading, optimal swimming technique does not alter the normal ER:IR strength ratio at the shoulder. Elite swimmers who report current or a history of shoulder pain demonstrate normal shoulder rotation strength ratios. The finding of symmetrical shoulder rotation strength points to side-to-side strength comparisons as a valuable clinical tool in managing swimmers with unilateral shoulder pain.
... According to the first author's main affiliation, most studies are from Australia (14 -20.3%), followed by Brazil (10 -16.7%), followed by France and USA with seven studies each (11.7%). Seventeen (28.3%) studies reported some funding (3,6,17,19,23,29,38,49,(51)(52)(53)(54)57,65,66,76,77). ...
... Twenty-one studies that measured asymmetries during dry-land tests used statistical tests (e.g., t-test, Wilcoxon, ANOVA, Mann-Whitney, or multiple regression) to analyze the between-limbs differences (Table 1). Twelve studies reported no significant side-to-side differences (p > 0.05) (6, 16,17,32,39,45,47,49,50,72,75,85), while nine showed a significant difference (p < 0.05) in at least one tested variable (21,43,56,59,60,63,67,83,84). The specific metrics that presented significant inter-limb differences included: triceps electromyographic activity (reported as a % of maximal voluntary load), shoulder medial and lateral rotation (°), subacromial bursa thickness (mm), scapula-humeral rhythm ratio (°), shoulder extension peak of torque (N.m), shoulder external rotation (°), shoulder isolated and composite internal rotation (°), shoulder total arc of motion (°), power output (W), scapula lateral displacement (cm), scapula retraction peak force (N), and scapula protraction/retraction ratio (N). ...
The objectives of the present review were to: (a) map the studies analyzing bilateral asymmetries in specific (in-water tests) and non-specific (dry-land tests) swimming contexts and (b) investigate the effects of inter-limb asymmetries on swimming performance. Searches were systematically conducted on four databases. Out of 768 studies examined, 60 were eligible for the final selection (https://osf.io/46gya). Twenty-eight studies analyzed asymmetries during in-water tests, with asymmetry values ranging from 2.7 to 60.0%, and most studies (n = 18) reported significant between-limb differences (p < 0.05). Asymmetries were also analyzed during dry-land tests in 24 studies, with asymmetry values ranging from 1.1 to 16.6%. Interestingly, most of these studies (n = 12) did not verify any significant between-limb differences (p > 0.05). Eight studies measured asymmetries in both contexts and reported asymmetry values from-24.1 to 17.4%, with four studies finding significant differences between body sides (p < 0.05). Seven of the 60 studies selected investigated the relationship between asymmetries and swimming performance, with five reporting no meaningful associations with swimming performance. In conclusion, significant asymmetries in swimming are more evident during in-water than during dry-land tests. In addition, the few studies investigating asymmetries' influence on swimming performance reported that asymmetries rarely impact swimming performance.
... A reduced muscle strength of shoulder external and internal rotation has been recognized as a contributor to shoulder pain, and commonly presented in elite swimmers (Bak & Magnusson, 1997;Boettcher et al., 2020;Hegedus et al., 2012). In spite of that, evidence on the relationship between symptomatic swimmers' shoulder strength and supraspinatus tendon structural abnormality was lacking. ...
Shoulder pain is common among elite swimmers due to the tremendous stress over shoulders during swimming. Supraspinatus muscle is one of the major prime movers and stabilizers of shoulder and is highly susceptible to overloading and tendinopathy. An understanding of the relationship between supraspinatus tendon and pain; and between supraspinatus tendon and strength would assist health care practitioners for developing training regime. The objectives of this study are to evaluate 1) the association between structural abnormality of supraspinatus tendon and shoulder pain and 2) the association between structural abnormality of supraspinatus tendon and shoulder strength. We hypothesized that structural abnormality of supraspinatus tendons positively associated with shoulder pain and negatively associated with shoulder muscle strength among elite swimmers. 44 elite swimmers were recruited from the Hong Kong China Swimming Association. Supraspinatus tendon condition was evaluated using diagnostic ultrasound imaging and shoulder internal and external rotation strength was evaluated by the isokinetic dynamometer. Pearson’s R was used to study the correlation between shoulder pain and supraspinatus tendon condition and to evaluate the association between isokinetic strength of shoulders and supraspinatus tendon condition. 82 shoulders had supraspinatus tendinopathy or tendon tear (93.18%). However, there was no statistically significant association between structural abnormality of supraspinatus tendon and shoulder pain. The results showed that there was no association between supraspinatus tendon abnormality and shoulder pain and there was a significant correlation between left maximal supraspinatus tendon thickness (LMSTT) and left external rotation/ concentric (LER/Con) and left external rotation/ eccentric (LER/Ecc) shoulder strength (p < 0.05) while internal rotation/ external rotation (IR/ER) ratio can also be a significant predicator on LMSTT >6mm (R2 = 0.462, F = 7.016, df = 1, p = 0.038). Structural change of supraspinatus tendon was not associated with shoulder pain, but could be a predictor on MSTT >6mm in elite swimmers.
Purpose:
To examine the longitudinal relationships between shoulder internal and external rotation (IR and ER) strength, maturity status, and swim performance (aim 1). To determine whether maturity status mediated (partially/fully) the relationship between shoulder IR/ER strength and performance in age-group swimmers (aim 2).
Methods:
Using a repeated-measures design, anthropometrics, maturity status, shoulder IR/ER strength, and 200-m front-crawl velocity were assessed over 3 competition seasons in N = 82 Australian male competitive swimmers (10-15 y). For aim 1, linear mixed models examined longitudinal relationships between assessed variables. For aim 2, causal mediation analyses examined proportional (in)direct contributions of maturity status between shoulder IR strength and swim performance.
Results:
For aim 1, linear mixed models identified a significant relationship between shoulder IR strength and swim performance over time (F1,341.25 = 16.66, P < .001, marginal R2 = .13, conditional R2 = .91). However, maturity status was influential (ΔAkaike information criterion = -75.8, χ2 = 19.98, P < .001), suggesting removal of the shoulder IR strength-swim velocity relationship (F1,214.1 = 0.02, P = .88). For aim 2, mediation analyses identified maturity status as fully mediating the shoulder IR strength-swim velocity relationship (92.30%, P < .001).
Conclusions:
Shoulder IR and ER strength did not account for variance in longitudinal age-group swim performance independent of maturity status. Interindividual differences in maturity status fully explained the relationship between shoulder IR/ER strength and swim performance. For practitioners, findings promote the need to account for maturation status and question the rationale for upper-limb strength assessment during maturational years.
Context:
Overhead athletes place tremendous demands on the shoulder complex, which result in adaptive kinematics but potential susceptibility to injury. This study aimed to compare shoulder glenohumeral range of motion (ROM) and rotator muscles strength in bilateral and unilateral overhead sports.
Design:
Cross-sectional study; secondary care.
Methods:
Forty-two elite athletes (17.7 [4.5] y; 42.9% female), including 18 swimmers and 24 badminton players, were included. Preseason glenohumeral rotation ROM and isokinetic shoulder internal and external rotator muscles strength was tested (60°·s-1). Bilateral (nondominant:dominant) and agonist:antagonist (external rotator:internal rotator) conventional and functional deceleration ratios (eccentric to concentric) were calculated. The impact of sport and number of competitive years on shoulder ROM and strength was tested.
Results:
Badminton players had greater glenohumeral internal rotation deficit, total ROM deficit, and lower bilateral strength ratio than swimmers (P < .050). Rotational strength was positively associated with the competitive years, but greater in swimmers (P < .050) and on the internal rotator (P < .001). The functional deceleration ratio was negatively associated with the competitive years on the dominant side in swimmers and for both sides in badminton.
Conclusions:
Unilateral overhead athletes had greater ROM and rotational strength asymmetries than bilateral athletes. Interestingly, the functional deceleration ratio was lower over time on the dominant shoulder for both sports, but, surprisingly, also on the nondominant shoulder in badminton, potentially creating a greater risk for shoulder injuries.
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Swimming is a popular activity with numerous health benefits.
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Swimming involves complex biomechanical movements that, especially if performed incorrectly, can lead to musculoskeletal injuries.
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The shoulder is the most commonly affected joint, although lower-extremity and spine injuries have also been reported.
Objectives
To establish muscle-strength and -balance profiles for shoulder external rotation (ER) and internal rotation (IR) in master’s swimmers.
Design
Cross-sectional study.
Setting
Laboratory.
Participants
Six male and seven female master’s swimmers and a matched control group.
Measurements
Concentric and eccentric ER and IR shoulder movements were recorded (Kin-Com™ isokinetic dynamometer). Peak-torque values, concentric ER:IR ratios, eccentric ER:IR (conventional) ratios, and eccentric ER:concentric IR (functional) ratios were examined between groups.
Results
Mean peak-torque values ranged from 21.23 to 37.69 N · m for the swimmers, which, although 15% to 27% greater than those of the controls, were not statistically different. Conventional (0.78:0.86) and functional (1.06:1.17) ratios did not differ between groups.
Conclusions
These data will contribute to the development of guidelines for assessing shoulder-muscle strength in Master’s swimmers.
Swimming is one of the most popular recreational and competitive sporting activities. In the 2013/2014 swimming season, 9630 men and 12,333 women were registered with the National Collegiate Athletics Association in the USA. The repetitive nature of the swimming stroke and demanding training programs of its athletes raises a number of concerns regarding incidence and severity of injuries that a swimmer might experience during a competitive season. A number of risk factors have previously been identified but the level of evidence from individual studies, as well as the level of certainty that these factors predispose a swimmer to pain and injury, to our knowledge has yet to be critically evaluated in a systematic review. Therefore, the primary objective of this review is to conduct a systematic review to critically assess the published evidence for risk factors that may predispose a swimmer to shoulder pain and injury. Three electronic databases, ScienceDirect, PubMed and SpringerLink, were searched using keywords "(Injury OR pain) AND (Swim*)" and "(Shoulder) AND (Swim*)". Based on the inclusion and exclusion criteria, 2731 unique titles were identified and were analyzed to a final 29 articles. Only articles with a level of evidence of I, II and III were included according to robust study design and data analysis. The level of certainty for each risk factor was determined. No studies were determined to have a high level of certainty, clinical joint laxity and instability, internal/external rotation, previous history of pain and injury and competitive level were determined to have a moderate level of certainty. All other risk factors were evaluated as having a low level of certainty. Although several risk factors were identified from the reviewed studies, prospective cohort studies, larger sample sizes, consistent and robust measures of risk should be employed in future research.
During the repeated execution of the swimming strokes, the shoulder adductor and internal rotator muscles have a tendency to become proportionally stronger when compared to their antagonist group. This can lead to muscle imbalances. The aim of this study was to examine the effects of a compensatory training programme on the strength and balance of shoulder rotator muscles in young swimmers. A randomized controlled trial design was used. Forty male swimmers took part in the study and were randomly divided into two groups: an experimental group (n = 20) and a training group (n = 20). A control group (n = 16) of young sedentary male students was also evaluated. The experimental group subjects participated in a 16-week shoulder-strength programme with Thera-Band® elastic bands; the training group was restricted to aquatic training. Peak torque of shoulder internal rotator and external rotator (ER) was measured at baseline and after 16 weeks. Concentric action at 1.04 rad s−1 (3 reps) and 3.14 rad s−1 (20 reps) was measured using an isokinetic dynamometer. The strength- training programme led to an improvement of the ER strength and shoulder rotator balance in the experimental group (data from both shoulders at 1.04 rad s−1). Moreover, concentric action at 3.14 rad s−1 presented significant differences only for the dominant shoulder. Findings suggest that the prescribed shoulder-strengthening exercises could be a useful training option for young competitive swimmers. They can produce an increase in absolute strength values and greater muscle balance in shoulder rotators.
The continuous execution of swimming techniques may cause muscle imbalances in shoulder rotators leading to injury. However, there is a lack of published research studies on this topic. The aim of this study was to analyze the influence of a competitive swim period on the shoulder rotator–cuff balance in young swimmers. A randomized controlled pretest–posttest design was used, with two measurements performed during the first macrocycle of the swimming season (baseline and 16 weeks). Twenty-seven young male swimmers (experimental group) and 22 male students who were not involved in swim training (control group) with the same characteristics were evaluated. Peak torque of shoulder internal and external rotators was assessed. Concentric action at 1.04 rad s!1 (3 repetitions) and 3.14 rad s!1 (20 repetitions) was measured using an isokinetic dynamometer (Biodex System 3). External/internal rotators strength ratios were also obtained. For both protocols, there were significant training effects on internal rotator strength and external/internal rotator ratios (p à .05). This trend was the same for both shoulders. Within-group analysis showed significant changes from baseline to 16 weeks for internal rotators strength and unilateral ratios of the experimental group. Swimmers’ internal rotator strength levels increased significantly. In contrast, a significant decrease of the unilateral ratios was observed. Findings suggest that a competitive swim macrocycle leads to an increase in muscular imbalances in the shoulder rotators of young competitive swimmers. Swimming coaches should consider implementing a compensatory strength-training program.
It is common clinical practice to assess muscle strength during examination of patients following shoulder injury or surgery. Strength comparisons are often made between the patient's injured and uninjured shoulders, with the uninjured side used as a reference without regard to upper extremity dominance. Despite the importance of strength measurements, little is known about expected normal baselines of the uninjured shoulder. The purpose of this study was to report normative values for isometric shoulder strength for physically active college-age men and women without history of shoulder injury.
University students-546 males (18.8 ± 1.0 years, 75.3 ± 12.2 kg) and 73 females (18.7 ± 0.9 years, 62.6 ± 7.0 kg)-underwent thorough shoulder evaluations by an orthopaedic surgeon and completed bilateral isometric strength measurements with a handheld dynamometer. Variables measured included internal rotation, external rotation, abduction, supine internal rotation and external rotation at 45°, and lower trapezius in prone flexion.
Significant differences were found between the dominant and nondominant shoulder for internal rotation, internal rotation at 45°, abduction, and prone flexion in males and in internal rotation at 45° and prone flexion for females (P ≤ 0.01).
Context:
The prevalence of shoulder pain in the competitive swimming population has been reported to be as high as 91%. Female collegiate swimmers have a reported shoulder-injury rate 3 times greater than their male counterparts. There has been little information on how to best prevent shoulder pain in this population. The purpose of this study was to examine if differences exist in shoulder range of motion, upper-extremity strength, core endurance, and pectoralis minor length in NCAA Division I female swimmers with and without shoulder pain and disability.
Methods:
NCAA Division I females (N = 37) currently swimming completed a brief survey that included the pain subscale of the Penn Shoulder Score (PSS) and the sports/performing arts module of the Disabilities of the Arm, Shoulder, and Hand (DASH) Outcome Measure. Passive range of motion for shoulder internal rotation (IR) and external rotation (ER) at 90° abduction was measured using a digital inclinometer. Strength was measured using a handheld dynamometer for scapular depression and adduction, scapular adduction, IR, and ER. Core endurance was assessed using the side-bridge and prone-bridge tests. Pectoralis minor muscle length was assessed in both a resting and a stretched position using the PALM palpation meter. All measures were taken on the dominant and nondominant arms.
Results:
Participants were classified as positive for pain and disability if the following 2 criteria were met: The DASH sports module score was >6/20 points and the PSS strenuous pain score was ≥4/10. If these criteria were not met, participants were classified as negative for pain and disability. Significant differences were found between the 2 groups on the dominant side for pectoralis muscle length at rest (P = .003) and stretch (P = .029).
Conclusions:
The results provide preliminary evidence regarding an association between a decrease in pectoralis minor length and shoulder pain and disability in Division I female swimmers.
Context
Changes in strength over the course of a swim season could predispose the shoulder to strength imbalances and lead to injury.
Objective
To examine isometric shoulder internal- (IR) and external-rotator (ER) strength in high school swimmers over a 12-week competitive season.
Design
Three 3 × 2 × 2 ANOVAs with repeated measures were used to determine significant main effects for IR, ER, and IR:ER strength ratio.
Participants
27 (14 female, 13 male) high school varsity swimmers.
Main Outcome Measures
IR and ER strength during preseason, midseason, and postseason.
Results
Significant increases in IR strength in both groups were revealed for all test sessions. ER strength significantly improved in both males and females from preseason to midseason and from preseason to postseason. IR:ER ratio revealed a significant increase from preseason to postseason.
Conclusions
Increases in IR strength without equal gains in ER strength were revealed and could contribute to future shoulder pathologies in competitive swimmers
Considering that some studies suggest that shoulder rotators muscle imbal-ances are related to joint pain and injury, and that there are no normative data for young swimmers, the aim of this study was: i) to describe the muscle balance, fatigue and isokinetic strength prole of the shoulder rotators in young swimmers; ii) to compare the results between swimmers and a group of young non-practitioners; iii) to contribute to the acquisition of normative data of unilateral ratios of shoulder rotators. We evaluated the shoulder rotators concentric strength and unilateral ratios (ratio between torque of external and internal rotators) of 60 swimmers (age: 14.55 ± 0.5 years old; body mass: 61.16 ± 7.08 kg) and 60 non-practitioners (age: 14.62 ± 0.49 years old; body mass: 60.22 ± 10.01 kg). e evaluation was performed in the sitting position (90° abduction and elbow exion) at 60º.s -1 and 180º.s -1 angular speeds using an isokinetic dynamometer (Biodex System 3). e results of the fatigue ratios revealed no dierences between the groups. Swimmers showed unilateral ratios of 73.39 ± 17.26% in the dominant limb (DL) and 77.89 ± 15,23% in the non-dominant limb (NDL) for assessments at 60º.s-1 . At 180º.s -1 , ratios were 74.77± 13.99% for DL and 70.11 ± 14.57% for NDL. Swimmers presented greater muscle imbalance, and diered from non-practitioners in the ability to produce power with the internal rotators, which was signicantly higher in the former group.
The purpose of this study was to analyse the effects of a competitive swim season on the strength, balance and endurance of shoulder rotator cuff muscles in young swimmers. A repeated-measures design was used with three measurements performed during the swim season. A swimmers group (n = 20) of young males with no dry-land training and a sedentary group (n=16) of male students with the same characteristics (age, body mass, height and maturational state) were evaluated. In both groups, the peak torque of shoulder internal (IR) and external (ER) rotators was assessed during preseason, midseason (16 weeks), and postseason (32 weeks). Concentric action at 60°[BULLET OPERATOR]s and 180°[BULLET OPERATOR]s was measured using an isokinetic dynamometer. The ER/IR strength ratios and endurance ratios were also obtained. At 60°[BULLET OPERATOR]s, there were significant training effects in the IR strength and ER/IR ratio on both shoulders. This trend was the same throughout the competitive season. The same trend was present at 180°[BULLET OPERATOR]s since the training effects are seen primarily in IR and ER/IR ratios. With respect to endurance ratios, within-group data were similar in ER and IR for both shoulders, with no significant differences between moments. However, between-group differences occurred mostly in the IR. Results suggest that a competitive swim season favours the increase of muscular imbalances in the shoulder rotators of young competitive swimmers, mainly due to increased levels of IR strength and endurance that are proportionally larger than those of their antagonists. A compensatory strength training program should be considered.
This study was supported in part by the School of Health Related Professions Research and Development Fund, University of Pittsburgh, Pittsburgh, PA A common complaint of competitive swimmers is shoulder pain. The purposes of this study were to: 1) provide normative data on shoulder flexibility in swimmers, 2) determine if a correlation exists between flexibility and shoulder pain, and 3) determine the correlation between strength and endurance ratios to shoulder pain. The subjects were 28 Division I collegiate swimmers and four club swimmers. Shoulder flexibility measurements were obtained bilaterally using a universal goniometer. Strength and endurance ratios were obtained bilaterally using the Cybex II(R) isokinetic dynamometer and the Upper Body Exercise Table(R). The swimmers completed a questionnaire that included a shoulder pain performance scale. The Pearson product moment correlation coefficient and multiple regression (R) analysis were the applied statistics. The results demonstrated that no significant correlation (p > 0.001) existed between shoulder flexibility, strength ratios, and shoulder pain. There was a significant (p </= 0.001) negative Pearson's correlation between endurance ratios of external rotation, abduction, and shoulder pain in competitive swimmers. A multiple R of 0.78 was obtained for the combination of external rotation and abduction endurance ratios to shoulder pain, which was significant (p </= 0.001). Clinical implications suggest that when evaluating swimmers, clinicians need to be aware of the importance of assessing the endurance ratios of the shoulder abductors and the external rotators at faster speeds. With decreased endurance ratios, competitive swimmers may be more likely to develop shoulder pain. J Orthop Sports Phys Ther 1992;16(6):262-268.
The purpose of this study was to profile shoulder, trunk, and thigh strength and shoulder range of motion in competitive Masters' level swimmers and to see if these variables were related to swimming performance. Twenty-four Masters' level swimmers (13 men and 11 women) were tested for isometric trunk flexion and extension, isokinetic knee extension and flexion, shoulder abduction, internal rotation, external rotation, and supraspinatus muscle strength; shoulder internal and external rotation range of motion; and 50-yard swimming time. Strength scores were adjusted for weight. The men were significantly stronger than the women in trunk extension and flexion. Shoulder range of motion, shoulder abduction strength, and thigh strength were equal for both the men and the women. The men were stronger than the women in internal and external shoulder rotation. Conversely, the women tested were significantly stronger than the men in the supraspinatus muscle test. The men were significantly faster than the women in the 50-yard swim. Inverse relationships existed between swimming time and trunk flexion, trunk extension, and shoulder internal rotation strength. Trunk flexion strength remained the only significant predictive variable of swimming time in a multiple regression analysis.
Objectives:
Optimal shoulder rotation range of motion (ROM) for swimming is unknown. The primary aim of this study was to examine shoulder rotation ROM in elite swimmers, including the influence of humeral torsion on rotation ROM, in order to establish optimal shoulder rotation parameters for swimming. In addition, we examined the relationship between rotation ROM and shoulder pain.
Design:
Descriptive cohort study.
Methods:
Seventy elite Australian swimmers provided shoulder pain history data prior to measurement of humeral torsion and passive and active shoulder rotation ROM. Repeated measure analyses of variance were used to investigate within and between participant differences for all variables. Associations between humeral torsion and rotation ROM were investigated using Pearson's correlation coefficient. Multiple regression analysis was utilised to examine the associations between rotation ROM and shoulder pain.
Results:
Average humeral torsion angles of 27±10° (dominant side) and 31±10° (non-dominant side) were demonstrated in this elite swimming cohort. In general, increased humeral torsion was positively associated with increased internal rotation (IR) and decreased external rotation (ER) ROM. There were significant differences in both IR and ER ROM measured passively and actively (F2,136≥93.1, p<0.001) with passive ROM greater than active ROM (p<0.001) and active IR ROM measured in supine greater than measured in prone (p<0.001). There were no associations between any rotation ROM variables and current or history of shoulder pain (r(2)=0.058; p=0.46).
Conclusions:
Humeral torsion angle and passive shoulder IR ROM were similar while passive ER ROM was greater in elite swimmers compared to reported normal population values.
Shoulder pain is the most common musculoskeletal complaint in swimming athletes, affecting a majority of participants over their competitive lifetimes. Muscle fatigue and imbalance associated with upper extremity endurance training, as well as unique biomechanical demands and related changes in range of motion, are all thought to be contributors to the development of shoulder pathology in the swimmer. The commonly used term of “swimmer’s shoulder” encompasses a complex spectrum of interrelated pathologies involving scapular dyskinesis, impingement, rotator cuff tendinopathy, labral injury, and changes in glenohumeral motion and stability. Multiple risk factors have been characterized in the literature regarding the development of these conditions in swimmers, including years of experience, level of competition, increased training intensity, and faulty stroke mechanics. Treatment includes an emphasis on early recognition and rest, as well as physical therapy to specifically address muscular weakness and imbalances, particularly of the scapular stabilizers and rotator cuff.
Background:
Shoulder pain is a common problem in competitive swimmers, but the structural alterations in elite-level competitive swimmers are not well known.
Hypothesis:
Adaptive changes are common in the rotator cuff, bursa, labrum, and capsule in elite swimmers, and such abnormalities are related to factors concerning training and correlate with symptoms.
Study design:
Cross-sectional study; Level of evidence, 3.
Methods:
The study population was the 2008 United States Olympic swimming team. All athletes completed standardized scales on shoulder pain and function and provided data on their training history and history of shoulder pain or injuries. Each athlete also underwent a comprehensive physical examination of both shoulders, followed by an evaluation of the rotator cuff, biceps, and bursa using ultrasound with dynamic images to assess for subcoracoid impingement and subacromial impingement.
Results:
A history of shoulder pain was reported by 29 of 42 (66%) athletes. Morphological changes consistent with tendinosis were common in the biceps (33/46 shoulders; 72%) and supraspinatus/infraspinatus (44/46 shoulders; 96%). Subcoracoid impingement was seen in 17 of 46 shoulders (37%), with subacromial impingement seen in 34 of 41 shoulders (83%). There was an increased odds ratio (OR) for biceps tendinosis in older swimmers (OR, 1.92; 95% CI, 1.23-3.00; P = .004) and in swimmers who had missed a competition because of shoulder pain (OR, 9.76; 95% CI, 1.13-84.3; P = .038). There was an increased OR for rotator cuff tendinosis in swimmers who reported worse scores for pain with activities (OR, 0.10; 95% CI, 0.01-0.78; P = .028) and in those with a positive sulcus sign (OR, 33.2; 95% CI, 3.09-355; P = .004). There was an increased OR for impingement in swimmers with a positive sulcus sign (OR, 5.40; 95% CI, 0.80-36.3; P = .083), worse pain scores (OR, 0.44; 95% CI, 0.22-0.87; P = .019), and a partial rotator cuff tear (OR, 31.2; 95% CI, 3.58-272; P = .002).
Conclusion:
We found a high prevalence of rotator cuff and biceps tendinopathy, which was associated with increased symptoms. Tendinosis was also more common in swimmers with a positive sulcus sign, suggesting a role for shoulder laxity.
Objectives:
To investigate inter and intra-rater reliability of hand held (HHD) and externally fixed (EFD) dynamometry for shoulder internal (IR) and external rotation (ER) strength and their correlation to isokinetic testing.
Design:
Within participant, inter and intra-rater reliability study.
Participants:
Twenty active, healthy male and female participants underwent testing by two examiners.
Outcome measures:
Intra-class coefficients (ICC), percentage standard error of measurement (%SEM), and percentage minimal detectable change (%MDC) were calculated for inter-rater, intra-day and intra-rater, inter-week reliability. Maximum and average of three repetitions were compared to the isokinetic results at three speeds (60°/sec, 180°/sec, 240°/sec) for both concentric and eccentric contractions.
Results:
Inter and intra-tester values demonstrated good to high agreement (HHD, ICC range = 0.89-0.97, %SEM = 4.80-8.60%, %MDC = 13.29-23.70%; EFD, ICC = 0.88-0.96, %SEM = 6.60-11.00%, %MDC = 18.40-30.04%). HHD and EFD showed moderate to very strong correlations to the isokinetic testing (HHD, r = 0.45-0.86; EFD, r = 0.49-0.83).
Conclusions:
The results of this study indicate that both EFD and HHD are suitable for clinical practice and research. Hand-held dynamometry is preferred due to its higher intra- and inter-rater reliability and smaller MDC and lower SEM.
The common problem of shoulder pain in swimmers is caused by instability of the glenohumeral joint. The instability stems from demands placed on the shoulder that allow for increased performance but simultaneously reduce the humeral head's ability to remain centered in the glenoid. These demands include: 1) the beneficial effects of increased shoulder range of motion; 2) the beneficial effects of increased internal rotation and adduction strength; and 3) the beneficial effects of prolonged, fatiguing, shoulder-intensive training. Treatment is aimed at increasing stability by modifying these demands and reducing the inflammation, which can lead to scarring and perpetuation of pain.
Although flexion is a common component of the routine clinical assessment of the shoulder the muscle recruitment patterns during this movement are not clearly understood making valid interpretation of potential muscle dysfunction problematic. The purpose of this study was to comprehensively examine shoulder muscle activity during flexion in order to compare the activity levels and recruitment patterns of shoulder flexor, scapular lateral rotator and rotator cuff muscles. Electromyographic (EMG) data were recorded from 12 shoulder muscles sites in 15 volunteers. Flexion was performed in standing in the sagittal plane at no load, 20%, and 60% of each subject's maximum load. EMG data were normalized to maximum values obtained during maximum voluntary contractions. Results indicated that anterior deltoid, pectoralis major, supraspinatus, infraspinatus, serratus anterior, upper, and lower trapezius were activated at similar moderate levels. However, subscapularis was activated at low levels and significantly lower than supraspinatus and infraspinatus. Similar activity patterns across time were demonstrated in the muscles that produce flexion torque, laterally rotate the scapula, as well as supraspinatus and infraspinatus, and did not change as flexion load increased. The onset of activity in supraspinatus and anterior deltoid occurred at the same time and prior to movement of the limb at all loads with infraspinatus activity also occurring prior to movement onset at the medium and high load conditions only. Posterior rotator cuff muscles appear to be counterbalancing anterior translational forces produced during flexion and it would appear that supraspinatus is one of the muscles that consistently "initiates" flexion.
A recent study has shown that posterior rotator cuff (RC) muscles are recruited at significantly higher levels than the anterior RC during shoulder flexion. It was proposed that the mechanism whereby the posterior RC muscles were providing shoulder stability during flexion was to counterbalance potential anterior humeral head translation caused by flexion torque producing muscles. This hypothesis implies that anterior RC activity should be higher than posterior RC activity during extension to prevent posterior humeral head translation. As the normal recruitment pattern of the RC during extension has not been established, the purpose of this study was to examine this hypothesis by comparing shoulder muscle activation levels and recruitment patterns during flexion and extension exercises. Electromyographic (EMG) activity was recorded from 9 shoulder muscles in 15 volunteers. Flexion and extension exercises were performed in prone at 20%, 50%, and 70% of each participant's maximal load. A repeated measures ANOVA was used to determine differences between exercises, muscles and loads, while Pearson's correlation analysis was used to relate mean EMG patterns. During extension subscapularis and latissimus dorsi were activated at higher levels than during flexion; during flexion, supraspinatus, infraspinatus, deltoid, trapezius, and serratus anterior were more highly activated than during extension. In addition, the pattern of activity in each muscle did not vary with load. These results support the hypothesis that during flexion and extension the RC muscles are recruited in a direction specific manner to prevent potential antero-posterior humeral head translation caused by torque producing muscles.
The authors conclude that swimmer's shoulder is a result of repetitive arm motion in the position of abduction, forward flexion, and internal rotation. This produces impingement in the vulnerable avascular region of the supraspinatus and biceps tendons. Local treatment includes ice, ultrasound, isokinetic strengthening activities, and transcutaneous stimulation. Oral anti-inflammatory medication may be helpful in the short term. Surgical relief measures include coraco-acromial ligament division and anterior acromioplasty. The apprehension shoulder in swimming is produced by subluxation of the shoulder anteriorly and may be relieved by a change in the style of the turn as well as surgical intervention, buttressing the anterior capsule of the shoulder. Breast stroker's knee is a result of inflammation of the tibial collateral ligament which is stressed by the knee going from flexion to extension with a valgus stress and external rotation. Local remedies include ice, ultrasound, and rest. Inflammation of the extensor tendons along the dorsum of the foot is common in the flutter and backstroke kick, and is relieved by local measures and perhaps the judicious use of steroid injection.
Torque production was assessed in the shoulders of competitive men and women swimmers for the motions of abduction, adduction, and external and internal rotation. Testing was performed on the Cybex II dynamometer and the results were compared to controls. In addition, the ratios of torque development for adduction:abduction and external rotation:internal rotation were evaluated. The results demonstrated a statistically significant increase in torque production in swimmers for most motions tested. Statistically significant ratio shifts were also noted. The ratio of adduction:abduction increased and that for external rotation:internal rotation decreased. We think these shifts in the torque ratios in swimmers' shoulders resulted from sport-specific repetitive activity that emphasizes adduction and internal rotation.
Shoulder pain is the most common orthopaedic problem in competitive swimming. In a group of 137 of this country's best swimmers, 58 had had symptoms of "swimmer's shoulder." Population characteristics of this group indicated that symptoms increased with the caliber of the athlete, were slightly more common in men, and were related to sprint rather than distance swimming. The use of hand-paddle training exacerbated symptoms, which were more common during the early and middle season. Consideration of shoulder mechanics in swimming reveals that freestyle, butterfly, and backstroke require similar motions; a swimmer using any of these strokes is susceptible to developing shoulder pain. Swimmer's shoulder represents chronic irritation of the humeral head and rotator cuff on the coracoacromial arch during abduction of the shoulder, the so-called impingement syndrome. Treatment included stretching, rest, ice therapy, oral antiinflammatory agents, judicious use of injectable steroids, and surgery as a last resort.
The prevalence of shoulder pain in United States competitive swimmers has not been extensively surveyed but is perceived as common. To evaluate this concern, a questionnaire survey was conducted on 1262 United States swimmers: 993 age group, 198 senior development, and 71 national team athletes. We sought to identify the incidence of interfering shoulder pain in this population and how it is influenced by various training tasks. The prevalence of current shoulder pain in these groups varied between 10% (age group) to 26% (national team) and increased with time in the sport. In those athletes with a painful shoulder, weight training, use of hand paddles, kickboard use, stretching, and various resistance activities aggravated the painful shoulder. This survey has identified that interfering shoulder pain is present in a substantial number of competitive swimmers.
The objective was to study prevalence and underlying pathology of "swimmer's shoulder". Twenty-two competitive swimmers of national "D-Kader" (elite development swimmers) were evaluated by means of questionnaire, clinical examination and isokinetic testing of external rotation and internal rotation. At the examination current interfering pain necessitating a cessation or reduction of practice was found in 5 (23%) athletes. At isokinetic testing 8 (36%) athletes complained of shoulder pain. Any history of pain was seen in 14 (64%) swimmers. A positive impingement sign was noted in 11 (50%) athletes. Apprehension sign which is indicative of anterior instability was found in 11 (50%) swimmers. Clinical equivalents of dysfunction of scapulothoracic muscles such as scapular winging (5 athletes) and shoulder protraction (12 athletes) were noted. For comparison of results of isokinetic testing a control group of non-swimmers was selected matching the group of swimmers exactly in terms of age, sex and dominant side. External rotation/internal rotation ratio of peak torque and total work at 60 deg/sec and 180 deg/sec was significantly lower in swimmers than in controls. The ratio was independent of sex, dominant side, history of pain and pain at examination. During internal rotation competitive swimmers produced significantly higher peak torques and total work than controls. There was no significant difference in external rotation. In conclusion there are several different abnormalities of function contributing to the pathology of "swimmer's shoulder":--Laxity of anterior-inferior capsuloligamentous structures with atruamatic anterior instability due to repetitive overload.--Impingement with rotator cuff tendinitis.--Muscular imbalance of the rotator cuff muscles and scapulothoracic dysfunction.
To evaluate differences in shoulder strength and range of motion between painful and pain-free shoulders we examined two matched groups of athletes. Fifteen competitive swimmers were allocated to two groups. Group 1 consisted of seven swimmers with unilateral shoulder pain related to swimming (Neer and Welsh phase I to II). The control group (Group 2) consisted of eight swimmers with no present or previous history of shoulder pain. Concentric and eccentric internal rotational torques were reduced in painful shoulders in between-group comparisons as well as in side-to-side comparisons. The decrease in internal rotational torque resulted in significantly greater concentric and eccentric external-to-internal rotational strength ratios of the painful shoulder in Group 1 swimmers compared with the controls. Furthermore, the functional ratio (eccentric external rotation:concentric internal rotation) was significantly greater in the painful shoulder in both between-group and side-to-side comparisons. Both groups of swimmers exhibited increased external range of motion and reduced internal range of motion compared with normalized data, but no between-group or side-to-side differences were detected. Our findings suggest that prevention or rehabilitation of swimmer's shoulder might not solely involve strengthening of the external rotators of the shoulder joint. Attention might also be drawn toward correction of a possible deficit in internal rotational strength. Changes in shoulder range of motion seem unrelated to the occurrence of shoulder pain.
Treatment of shoulder pain includes the following: 1. Avoid all painful activities. 2. A 2-week course of nonsteroidal anti-inflammatory medication and ice. 3. Decreased anterior capsule stretching and increased posterior capsule stretching. 4. Increased rotator cuff exercise with emphasis on external rotators. 5. Scapular-positioning muscle exercises and increasing body roll. Shoulder pain can be prevented by the following: 1. Avoid all painful activities, and notify coach of shoulder pain immediately. 2. Do not use nonsteroidal anti-inflammatory medications or ice on a chronic basis. 3. Spend equal time stretching the posterior and anterior capsules. 4. Perform general rotator cuff exercises. 5. Perform scapular-positioning muscle exercises, with emphasis on body roll. [figure: see text] Shoulder pain in swimmers is common and can be debilitating. Most of the pain is caused by instability, which stems from swimming-specific demands that increase performance but decrease shoulder stability. These sport-specific demands are (1) increased shoulder range of motion, (2) increased internal rotation and adduction strength, and (3) prolonged, fatiguing, shoulder-intensive training. Instability leads to [figure: see text] inflammation and pain and can become a self-perpetuating process. Treatment consists of patient education, cessation of all activities that cause pain, activity modifications to increase shoulder stability, and pharmacologic treatment of the inflammation. In patients who do not improve using this regimen, surgery can be of benefit, either to reduce capsular laxity or to remove chronic inflammation and scar tissue. The patient must be aware of the risk of decreased performance.