Article

Trunk-Rotation Flexibility in Collegiate Softball Players With or Without a History of Shoulder or Elbow Injury REPLY

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Abstract

Throwing is a whole-body motion that requires the transfer of momentum from the lower extremity to the upper extremity via the trunk. No research to date examines the association between a history of shoulder or elbow injury and trunk flexibility in overhead athletes. To determine if injury history and trunk-rotation flexibility are associated and to compare trunk-rotation flexibility measured using 3 clinical tests: half-kneeling rotation test with the bar in the back, half-kneeling rotation test with the bar in the front, and seated rotation test in softball position players with or without a history of shoulder or elbow injury. Cross-sectional design. University softball facilities. Patients or Other Participants: Sixty-five female National Collegiate Athletic Association Division I softball position players. Intervention(s): Trunk-rotation flexibility was measured with 3 clinical tests. Recent injury history was obtained using a questionnaire and verified by the certified athletic trainer. Main Outcome Measure(s): Binomial regression models were used to determine if injury history was associated with flexibility categories (high, normal, or limited tertiles) for each of the 6 (3 tests × 2 directions) trunk-rotation flexibility measures. Trunk-rotation flexibility measures from 3 clinical tests were compared between participants with and without a history of shoulder or elbow injury using analysis-of-variance models. When measured using the half-kneeling rotation test with the bar in the back and the seated rotation test, injury history and forward trunk-rotation flexibility were associated. However, no mean group differences were seen in trunk-rotation flexibility between participants with and without a history of shoulder or elbow injury. Limited forward trunk-rotation flexibility may be a risk factor for shoulder or elbow injuries. However, further study is needed to confirm the study finding.

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... 3,4 Research has identified shoulder mobility deficits, shoulder strength deficits, trunk mobility deficits, and kinetic chain considerations as a risk for future injury in baseball players. 2,5 Aragon et al 6 reported that limited trunk rotation increases the amount of load placed on the shoulder and elbow during a pitching sequence. This limited trunk mobility predisposed an individual to be up to 2.75 times more likely to sustain an injury. ...
... 10 It is clear that overuse injuries have several risk factors ranging from mobility deficits to pitch volume to consider when attempting to minimize injuries. 2,[5][6][7][8][9][10] Research results suggest that a positive relationship between training load and injury exists. 11, 12 Monitoring training load throughout a competitive season allows clinicians to objectively measure changes in performance, reveal fatigue, and minimize the risk of non-functional fatigue, illness, and injury. ...
... Trunk rotation was assessed with the participant in a half kneeling position beginning with the right leg forward in line with the left knee. 6,17 One PVC pipe is placed directly under the participant's hips in the coronal plane. Another PVC pipe is placed interlocked behind the participant's back under their elbow with their hands on their hips. ...
Article
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Background: Repetitive pitching places tremendous forces on the shoulder and elbow which can lead to upper extremity (UE) or lower extremity (LE) overuse injuries. Purpose: The purpose of this study was to evaluate pre-season physical measurements in collegiate baseball players and track in-season baseball throwing volume to determine which factors may predict throwing overuse injuries. Study design: Retrospective Cohort study. Methods: Baseline preseason mobility, strength, endurance, and perception of function were measured in 17 collegiate baseball pitchers. Participants were then followed during the course of the season to collect rate of individual exposure, estimated pitch volume, and rating of perceived exertion in order to determine if changes in workload contributed to risk of injury using an Acute-to-Chronic Workload ratio (ACWR). Results: Participants developing an injury had greater shoulder internal rotator strength (p=0.04) and grip strength in a neutral position (p=0.03). A significant relationship was identified between ACWR and UE injuries (p <0.001). Athletes with an ACWR above or below 33% were 8.3 (CI95 1.8-54.1) times more likely to suffer a throwing overuse injury occurring to the upper or lower extremity in the subsequent week. Conclusion: ACWR change in a positive or negative direction by 33% was the primary predictor of subsequent injury. This finding may assist sports medicine clinicians by using this threshold when tracking pitch volume to ensure a safe progression in workload during a baseball season to reduce the risk of sustaining overuse upper or lower extremity injuries. Level of evidence: 3b.
... Online resource 3 outlines the key data extracted for this review. Of the 44 studies included, the most frequently studied team ball sport was soccer (represented in 24 studies; 55%) , followed by basketball (represented in 14 studies, 32%) [64,65,71,73,83,[85][86][87][88][89][90][91][92][93], and volleyball (represented in 7 studies, 16%) [64,71,83,[89][90][91]94]. Other team ball sports investigated included handball [81,90,95,96], netball [97][98][99][100], softball [101][102][103], field hockey [61,65], lacrosse [61], and rugby union [104]. Almost one quarter (23%) of the studies included multiple team ball sport players in their study population. ...
... Two studies (level II) utilised an allcomplaints definition to prospectively examine any upper extremity injury [103] or overuse shoulder injuries [95]. The remaining two studies used a time-loss injury definition to investigate prospective (level II) shoulder injuries [96] or history of shoulder or elbow injuries by cross-sectional study design (level III) [101]. Both handball and softball players comprised study populations. ...
... These main findings implicate both scientists and practitioners working with female, team ball sport players, particularly due to the lack of research regarding the direct role of physical fitness and its association with sports injury in this population. Despite significant relationships demonstrating players with increased joint mobility, joint laxity, or muscular flexibility were at an increased risk of sports injury [61,73,76,78,80,95,100,101,104], no association summary conclusions with primarily moderate certainty were consistently demonstrated between flexibility and all injury categories in female, team ball sport players. The lack of association between flexibility and sports injury supports the results of several studies that have included stretching exercises in injury prevention programs, but found no significant reduction in injury rates [105][106][107]. ...
Article
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Background: Understanding the relationships between physical fitness characteristics and sports injury may assist with the development of injury minimisation programs. The purpose of this systematic review was to investigate the association between physical fitness attributes and sports injury in female, team ball sport players. Methods: Four scientific databases (MEDLINE, EMBASE, SPORTDiscus, Scopus) and reference lists of relevant research were searched for eligible studies up to September 2, 2019. Full-text articles examining the relationship between physical fitness and sports injury in female, team ball sport players were included. A modified Downs and Black checklist was used to assess methodological quality. Data synthesis determined summary conclusions based on the number of significant relationships divided by the total relationships investigated and reported as a percentage. Level of certainty was identified for summary conclusions based on level of evidence. Sub-analyses regarding competition level, age, and single injury types were also conducted. Results: A total of 44 studies were included. Data synthesis revealed no associations (low to moderate certainty) between body composition (1/9; 11%), flexibility (18-20%), and balance (2/8; 25%) and 'any injury' classification. No associations (mostly of moderate certainty) were found between flexibility (0-27%), muscular strength (0-27%), and body composition (14-33%) and various body region injury classifications, whereas mixed summary conclusions were shown for balance (0-48%). Many associations between physical fitness and sports injury were deemed 'unknown' or with an insufficient level of certainty. Sub-analyses revealed no association between strength and noncontact ACL injuries (0/5; 0%) or ankle sprains (0/12; 0%), and between flexibility and ankle sprains (1/5; 20%); however, insufficient certainty of these results exists. Clear associations were concluded between balance and lower body injuries in female, non-elite (10/16; 63%) and junior (9/12; 75%) team ball sport players, with moderate and insufficient certainty of these results, respectively. Conclusion: Limited evidence is available to demonstrate relationships between physical fitness and sports injury in female, team ball sport players. High-quality evidence investigating the multifactorial nature of sports injury, including the interactions physical fitness qualities have with other injury determinants, is needed to better understand the role of physical fitness in minimising sports injuries in female, team ball sport players. Trial registration: CRD42017077374 (PROSPERO on September 14, 2017).
... It was predicted that there would be < 5% missing questions from total answers of all participants and no floor and ceiling effects will be observed [38]. As recommended by McHorney and Tarlov, the floor and ceiling effects were considered to exist if > 15% participants have attained the minimum or maximum possible total score [38,54] [55, 3,56]. The floor and ceiling effects were measured by calculating the number of respondents who have recorded the lowest and highest score on ODI-U, respectively [38,46]. ...
... It was hypothesised that there would be a moderate positive correlation of ODI-U with VAS pain and VAS disability but a moderate negative correlation of ODI-U with all SF-36 domains [20,64,65]. If 75% of results matched with hypothesis the validity was considered to be good [56]. ...
... Excellent test re-test reliability (ICC = 0.95) was found in this study which is comparable to the [82]. On the contrary, 1-2 week interval was recommended by Deyo et al. [83] and Terwee et al. [56] to minimize the memory effects. The Bland-Altman plot showed very minimal systematic bias i.e. 0.8 points, which is comparable to the previous ODI translation studies. ...
Article
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Background: Oswestry Disability Index (ODI) is broadly used in clinical and research settings for assessing the disability level in patients with lumbar radiculopathy but it has not been translated into Urdu language according to the pre-established translation guidelines as well as the validity and reliability of ODI Urdu version has not been tested yet. The aim of this study was to translate ODI in native Urdu language (ODI-U) according to recommended guidelines and to measure its psychometric properties in Urdu speaking patients suffering from lumber radiculopathy. Methods: Out of 108 participants, 54 were healthy (who filled ODI-U) and 54 were patients of lumber radiculopathy. The patients were administered through ODI-U, visual analogue scales for disability (VAS disability), pain intensity (VAS pain) and SF-36 at baseline and after 3 days. Reliability was investigated through test-retest method, internal consistency, standard error of measurement (SEM) and smallest detectable change (SDC). ODI-U was assessed for exploratory factor analysis, construct (convergent and discriminative) validity and content validity. Alpha level < 0.05 was considered statistically significant and psychometric standards were evaluated contrary to priori hypothesis. Results: ODI-U revealed excellent test-retest reliability for total score (ICC2,1 = 0.95) and for all item (ICC2,1 = 0.72-0.98). Cronbach's alpha of 0.89 showed excellent internal consistency and moderate correlation between ODI-U total score and each item through spearman's correlation coefficient (r = 0.51-0.76). One factor structure was created, explaining 52.5% variance. There was no floor and ceiling effect of total ODI-U score. Content validity was assessed through conducting interviews with patients and incorporating expert's opinions. The discriminative validity was measured by independent sample t-test, where significant difference between healthy and patients (P < 0.001) was observed. The convergent validity was evaluated through Pearson's correlation showing moderate positive correlation of ODI-U with VAS pain (r = 0.49) and VAS disability (r = 0.51) but moderate negative correlation with all SF-36 domains (r = - 0.43to - 0.63). Conclusion: ODI-U showed adequate psychometric properties. ODI-U was found to be a reliable and a valid tool to measure the level of disability in Urdu-speaking patients with lumber radiculopathy.
... Findings from three studies (n = 82, n = 68 females) report 4-8° thoracic extension occurring during arm elevation [37][38][39] with studies reporting variable ranges and degrees of other thoracic movement. Findings are relevant to athletes engaged in overhead sporting activities 1,3 where deficiencies in thoracic extension may place more stress on other components of the kinetic chain resulting in pain, altered performance, and impact on an athlete's ability to train and compete. 1 Whilst a recent review found inconclusive evidence of a relationship between static thoracic posture and shoulder complaints, 15 functional kinetic chains are dynamic, requiring a variable mix of movement, motor control, and strength across the component parts, including the thoracic spine to enable performance of skilled functional Upper thoracic Crosbie et al. 38 Extension 2 [1,3] Lateral flexion (Ipsilateral) 3 [2,3] Rotation (Ipsilateral) 7 [5,9] Lower thoracic Crosbie et al. 38 Extension 6 [4,8] Lateral flexion (Contralateral) 3 [2,4] Rotation Crosbie et al. 38 Stewart et al. 37 Lateral flexion Ipsilateral 1 [0, 2] 2.1 ± 1.6 ...
... Findings from three studies (n = 82, n = 68 females) report 4-8° thoracic extension occurring during arm elevation [37][38][39] with studies reporting variable ranges and degrees of other thoracic movement. Findings are relevant to athletes engaged in overhead sporting activities 1,3 where deficiencies in thoracic extension may place more stress on other components of the kinetic chain resulting in pain, altered performance, and impact on an athlete's ability to train and compete. 1 Whilst a recent review found inconclusive evidence of a relationship between static thoracic posture and shoulder complaints, 15 functional kinetic chains are dynamic, requiring a variable mix of movement, motor control, and strength across the component parts, including the thoracic spine to enable performance of skilled functional Upper thoracic Crosbie et al. 38 Extension 2 [1,3] Lateral flexion (Ipsilateral) 3 [2,3] Rotation (Ipsilateral) 7 [5,9] Lower thoracic Crosbie et al. 38 Extension 6 [4,8] Lateral flexion (Contralateral) 3 [2,4] Rotation Crosbie et al. 38 Stewart et al. 37 Lateral flexion Ipsilateral 1 [0, 2] 2.1 ± 1.6 ...
Article
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Background: Knowledge of the contribution of the thoracic spine movement, a requisite for UL functional movement offers the potential for novel directions for research and management in shoulder rehabilitation. Objectives: To synthesise evidence of thoracic spine mobility during UL movement in athletes. Design: Systematic review using 3 reviewers at each stage. Key databases (Medline, CINAHL, Web of Science) were searched up to 30/6/18. Eligibility criteria: adults age 18-40 (reflecting athletic population) and studies assessing thoracic spine and UL movement. Quality assessment was evaluated using AXIS tool and GRADE for overall quality of evidence. Results: Seven studies were included (n=168, mean age 26.4 years, 33% males) with n=20 in an athlete population. Main findings: Unilateral and bilateral UL flexion resulted in 6.7-8.0 and 12.0-12.8 degree thoracic extension respectively. Unilateral and bilateral UL abduction resulted in 3.0-4.0 and 9.0-15.0 and degrees respectively. Other thoracic spine movement (lower and upper, rotation and lateral flexion) was variable across movement planes. Conclusion: There is unequivocal evidence of thoracic spine movement, mainly extension during UL movement and notably at the end of elevation across all planes. Findings support further targeted high quality research and examination of thoracic mobility, an essential link in the kinetic chain, in practice.
... To measure the ROM of trunk rotation toward the dominant side, the player positioned the dominant leg forward and the nondominant leg behind the trunk with both legs in a straight line on the floor to minimize pelvic rotation. 22 To measure the ROM of trunk rotation toward the nondominant side, the player moved the nondominant leg forward and the dominant leg behind the trunk. Next, the participant placed his front foot on the ground with the contralateral knee, tibia, and toe in contact with the floor. ...
... Next, the participant placed his front foot on the ground with the contralateral knee, tibia, and toe in contact with the floor. Previous authors 20,22 have demonstrated that the half-kneeling trunk-rotation test with the bar in both the front and back has good reliability. The bar-infront position was more reliable than the bar-in-back position. ...
Article
Context Deficient glenohumeral rotational range of motion (ROM) is a risk factor for shoulder pain. Adapted ROM of the trunk and hip in response to loss of glenohumeral ROM has been suggested, as the nature of baseball leads to ROM adaptations. Objective To compare the bilateral rotational ROM values of the trunk and glenohumeral and hip joints in adolescent baseball players with or without shoulder pain and to measure the correlation between shoulder-pain intensity and bilateral rotational ROM values for each body area. Design Cross-sectional study. Setting Research laboratory. Patients or Other Participants Ninety-five adolescent baseball players (60 with shoulder pain, 35 without shoulder pain). Main Outcome Measure(s) Bilateral trunk rotation and internal rotation, external rotation, and total rotation of the dominant and nondominant glenohumeral and hip joints. Results Glenohumeral and hip ROM did not differ between groups, and pain intensity and rotational ROM were not related in either joint. Trunk rotational ROM was greater in the pain group than in the control group (dominant side = 48.8° ± 14.2° versus 41.8° ± 11.9°, respectively; nondominant side = 45.1° ± 14.2° versus 38.9° ± 7.7°, respectively; P values < .05), although the difference was clinically small (mean differences = 7.0° ± 2.7° [95% confidence interval = 1.7, 12.4] on the dominant side, P = .01, and 6.1° ± 2.7° [95% confidence interval = 0.8, 11.5] on the nondominant side, P = .03). Positive but low correlations in all players (ρ = 0.27, P = .01) and in those with shoulder pain (ρ = 0.36, P = .001) were present between shoulder-pain intensity and trunk rotational ROM toward the dominant side. Conclusions We found no clinical relationship between shoulder pain and rotational ROM and no clinical differences in rotational ROM values between players with and those without shoulder pain.
... Some studies reported injuries in more than one sport. The women's sports covered in the eligible studies were [7,8,14,28,43,[53][54][55][56][57][58][59][60][61][62][63][64][65], softball (n = 13) [10,11,14,15,42,43,49,56,58,[60][61][62]66], field hockey (n = 23) [9-11, 14, 43-46, 53, 55, 57, 58, 61-65, 67-72] and cricket (n = 2) [47,48]. The studies represented sporting populations in the United States of America (USA) (n = 26) [7, 8, 14, 15, 28, 42-44, 49, 53, 55-66, 68-70, 73], Canada (n = 3) [46,54,67], Australia (n = 2) [47,48], United Kingdom (UK) (n = 1) [45] and South Africa (n = 1) [71]. ...
... Injury definitions varied across the studies. Eighteen studies used a combination of time-loss and medical attention definition [8,9,14,15,28,42,44,46,55,56,[59][60][61][62][63][64][65]73], nine studies used a medical attention only definition [10, 11, 47-49, 57, 58, 67, 68], four studies used a time-loss only definition [7,43,71,72], and four studies used other injury definitions [53,54,66,69]. Two studies did not include an injury definition [45,70]. ...
Article
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Background Team bat-or-stick sports, including cricket, softball and hockey, are popular among women. However, little is known about the injury profile in this population. Objective The aim was to describe the incidence, nature and anatomical location of injuries in bat-or-stick sports played by women in a competitive league. Methods This review was prospectively registered (PROSPERO CRD42015026715). CINAHL, MEDLINE, PsycINFO, PubMed, SPORTDiscus were systematically searched from January 2000 to September 2016, inclusive. Peer-reviewed original research articles reporting the incidence, nature and anatomical location of injuries sustained by women aged 18 + years in competitive bat-or-stick sports were included. Two meta-analyses based on injury incidence proportions (injury IP) and injury rates per 1000 person-days of athletic exposure (AE) were performed. ResultsA total of 37 studies satisfied the inclusion criteria, and five had low risk of bias. The weighted injury IP was 0.42 [95% confidence interval (CI) 0.39–0.45]. The weighted injury rate was 6.12 (95% CI 6.05–6.18) overall, and greater in games [15.79 (95% CI 15.65–15.93)] than in practice [3.07 (95% CI 2.99–3.15)]. The ankle was the most commonly injured anatomical location, followed by the hand (including wrist and fingers), knee and head. Soft tissue and ligament injuries were most common types of injuries. Conclusion Injury prevention in women’s sports is a novel and emerging field of research interest. This review highlights that injury incidence is high among female bat-or-stick players, but little information is known about direct causal mechanisms. This review clearly establishes the need for enhancements to injury data collection. Without this information, it will not be possible to develop evidence-based injury prevention interventions.
... To our knowledge, our study is the first to report normative data for trunk rotation tests. The tests have been used to identify risk factors or the relationship between a shoulder injury and trunk rotation flexibility in collegiate softball players (Aragon, Oyama, Oliaro, Padua, & Myers, 2012) and adolescent elite handball players (Asker et al., 2017), but no normative values have been reported. ...
Article
Objective To study normative values of range of motion (ROM), strength, and functional performance and investigate changes over 1 year in adolescent female football players. Design Cross-sectional. Participants 418 adolescent female football players aged 12–17 years. Main outcome measures The physical characteristic assessments included (1) ROM assessment of the trunk, hips, and ankles; (2) strength measures (maximal isometric and eccentric strength for the trunk, hips, and knees, and strength endurance for the neck, back, trunk and calves), and (3) functional performance (the one-leg long box jump test and the square hop test). Results Older players were stronger, but not when normalized to body weight. Only small differences in ROM regarding age were found. ROM increased over 1 year in most measurements with the largest change in hip external rotation, which increased by 6–7 degrees (Cohen's d = 0.83–0.87). Hip (d = 0.28–1.07) and knee (d = 0.38–0.53) muscle strength and the square hop test (d = 0.71–0.99) improved over 1 year. Conclusions Normative values for ROM and strength assessments of neck, back, trunk, hips, knees, calves and ankles are presented for adolescent female football players. Generally, fluctuations in ROM were small with little clinical meaning, whereas strength improved over 1 year.
... Sports, such as baseball, in which the throwing motion is performed repeatedly and the trunk is rotated to throw the ball in the throwing direction, 1,2) can lead to adaptive changes in the rotational range of motion (ROM) of the trunk and hip joints, leading to differences between the throwing and non-throwing sides. 3,4) There have been studies on the characteristics and left-right differences of shoulder rotational ROM, [5][6][7][8] but there are few detailed reports on the characteristics and left-right differences in the ROMs of the neck, trunk, and lower extremities for throwing athletes. 9) Because of increased participation in sports and the potential for sports-related injuries in young athletes, the treatment and prevention of injury has become an important topic in sports medicine. ...
Article
Objective: The rotational range of motion (ROM) in the upper extremities, trunk, and lower extremities is important for throwing motion. However, unlike for the shoulders, the differences relating to age and throwing-side in trunk and lower extremity ROMs in baseball pitchers are unknown. This study examined the effects of age and dominance on the ROMs of the trunk and upper and lower extremities. Methods: The study included 356 young baseball pitchers aged 9-17 years who participated in off-season baseball camps. The subjects comprised 155 youth pitchers (aged 9-14 years) and 201 high-school pitchers (aged 15-17 years) who were able to throw at full force without pain. The neck, shoulder, trunk, and hip rotational ROMs on the dominant and non-dominant side were measured by well-trained physical therapists. The differences between throwing sides and between age groups were examined using two-way analysis of variance. Results: Shoulder external rotation on the dominant side was greater than that on the non-dominant side. Shoulder external and internal rotational ROMs were maintained regardless of age, whereas the trunk rotational ROM significantly increased with age. Conclusions: The effects of age and dominance on ROMs of the neck, trunk, and upper and lower extremities in Japanese youth and high-school baseball pitchers were clarified. These data could be used as a specific reference and as target values for the rehabilitation of throwing injuries in young athletes.
... Participants sat upright on a chair with knees and feet together and arms across the chest (Aragon et al., 2012). Participants held a stick horizontally at the sternum just below the clavicles. ...
Article
Objectives: The primary purpose was to evaluate the reliability of the Upper Limb Rotation Test (ULRT). The secondary objective was to evaluate the relationship between the ULRT and two PPTs (SMBT and CKCUEST), trunk rotation range of motion (SRT) and shoulder rotational isometric strength. Design: Reliability study and correlation study. Setting: Laboratory. Participants: 91 healthy adults participated to establish the reliability and validity of the ULRT. Main outcome measures: We used a two-session measurement design to evaluate the reliability of the ULRT. The SMBT, CKCUEST, SAC and the SRT were performed to determine relationships with the ULRT. Results: Results showed good reliability. The SEM 95 and the MDC95 showed clinically acceptable absolute reliability values for the ULRT. A moderate correlation was found between the ULRT and CKCUEST scores. A moderate correlation was found between ULRT and SMBT scores. Conclusions: Results demonstrated good relative reliability and clinically acceptable absolute reliability values for the ULRT. Performances on the ULRT were moderately correlated with the PPTs.
... However, Veronica et al assessed spinal rotation in three different positions and suggested that position can not affect the rotation. [21,22] ...
Article
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Assessment of back function is limited due to lack of standard data set which may be used to accurately describe the range of motion of spine as there is wide disparity in the reference values for spine.The objective of present study was to establish reference values for trunk mobility in normal adults. In this cross sectional study, 137 subjects were assessed using Tape method and goniometry for trunk mobility in all planes (sagittal, frontal and transverse). The mean values by tape method and goniometry for flexion with stabilization were 6.95±0.64 cm and 74.68±5.670, (for flexion without stabilization 9.59±0.73 cm and 99.33±5.530,) for extension 4.71±0.51 cm and 26.03±3.290, for Rt. Lateral flexion 17.28±2.59 cm and 32.95±3.380, for Lt. lateral flexion 17.06±2.54 cm and 32.60±3.440, for Rt. Rotation 5.49±0.55 cm and 41.93±3.350, for Lt. rotation 5.38±0.55 cm and 41.65±3.390 respectively. The study concluded that there was no statistically significant difference for all spinal movements among the genders, except in lateral flexion (p value 0.009 & 0.008) and rotation (p value 0.023 & 0.004) where females had greater mobility than males.
... Improper trunk rotation sequences demonstrated greater maximal shoulder external rotation angle that might alter shoulder joint loading 27 . Moreover, trunk rotation was associated with a history of shoulder injury 28 . ...
Conference Paper
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Shoulder is one of the most common sites of badminton injury. Identifying risk factors of shoulder pain could better prevent shoulder injury. The purpose of this study was to identify intensity and risk factors of shoulder pain in college badminton players. Basic parameters (age, badminton experience, training hours per day, training times per week, etc.), physical fitness (hand grip strength, finger floor distance (FFD), heel buttock distance (HBD), straight leg raising (SLR), shoulder flexibility, balance, general joint laxity, shoulder and trunk joint range of motion, etc.) and intensity of shoulder pain were investigated using medical check-up among 15 male university badminton players (aged 18-21). The results showed that shoulder pain occurred in all players, and players with present shoulder pain had greater SLR degree, weaker balance ability and trunk right rotation deficit. Visual analog scale (VAS) showed moderate shoulder pain in both groups of players with present and previous shoulder pain (51.8 mm and 40.6 mm, respectively). Greater SLR, weak balance ability and asymmetric trunk rotation are risk factors of shoulder pain. Identifying players with specific risk factors may enhance the prevention of badminton injury.
... The seated rotation test (SRT) 55 was used to assess the flexibility of trunk rotation. The participant, seated on a chair with his feet together and on the ground, was asked to turn as much as possible to the right and to the left while keeping the alignment of the back and the arms crossed, and each time the degree of rotation was measured by a goniometer. ...
Article
Background: The aim of this study was to research and compare the effect of Crossfit® (CF), LesMills® (LM) and traditional resistance (TRAD) training program on short performances. Methods: Participants were assigned randomly into 3 groups and followed the training sessions allocated at the rate of 5 sessions/week for 16 weeks. A battery of tests including anthropometric and performance measures were carried out over three sessions: before training (T0), after eight weeks (T1) and sixteen weeks of training (T2). Results: Findings indicated that strength tests demonstrated a significant time effect (p<0.001, ηp 2=0.6), the results showed that CF and TRAD groups improved strength every 8 weeks while LM group only at T2, The speed test demonstrated also a significant time effect (p<0.001 , ηp 2=0.5) the results showed an improvement in speed every 8 weeks for LM, at T2 for CF and no change for TRAD, for flexibility, all tests demonstrated a main time effect (p<0.001 , ηp 2=0.46 - 0.7) CF was the best in shoulder range of motion and LM in trunk and lower limb flexibility, all power tests also demonstrated a significant time effect (p<0.001 , ηp 2=0.76 - 0.9) the improvement for all groups was every 8 weeks. Conclusions: Based on these findings, we recommend TRAD and CF as valuable trainings for strength development, LM for flexibility and all three trainings for power improvement.
... Lateral movements that precede an attack can give players the maximum chance in achieving the best outcome. Environments like beach volleyball cause different challenges with sand slowing the acceleration of the movements 1 .Volleyball requires a variety of physical attributes (speed, power, flexibility, strength and balance) and specific playing skills 5 . Therefore, participants need to train and prepare to meet at least a minimum set of physical, physiological and psychological requirements to cope with the demands of play and reduce the risk of injury 6 . ...
... The speed of the ball is correlated with the orientation of the pelvis and thorax at MER, and with pelvic orientation at BR [4]. The range of trunk rotation of baseball players that have experienced pitching-related injuries is narrower than those without such injuries [5]. Moreover, a decline of the range of rotation in the throwing direction of the neck, trunk, and the range of hip internal rotation of the lead leg might become a risk factor for pitchingrelated injuries [6]. ...
Article
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Purpose: The purpose of this study was to compare pitching motion of the professional female baseball pitchers with the male university baseball pitchers focused on the pelvic and thoracic movements. Subjects and methods: The participants were 15 healthy professional female baseball pitchers (11 right-handers and 4 left-handers; age, 21.7 ± 3.2 years; height, 162.5 ± 5.1 cm; weight, 59.0 ± 6.6 kg) and 14 healthy male university baseball pitchers (12 right-handers and 2 left-handers; age, 19.9 ± 0.8 years; height, 176.4 ± 3.0 cm; body mass, 73.1 ± 3.0 kg). Throwing motion was captured by three-dimensional motion analysis system. Kinematic data of the lead hip, pelvis, thorax, and dominant shoulder were collected and the joint angle at maximum external rotation phase and ball release phase were compared. Results: The female baseball pitchers rotated pelvis and thorax more than the male at the maximum external rotation phase and ball release phase (p < 0.05). At the same, the pelvis and thorax of the female baseball pitchers were tilted significantly closer to horizontal plane than the male (p < 0.05). The pelvis and thorax of the male baseball pitchers was tilted to non-dominant lateral side. Conclusions: The results of this study indicate that the pelvic and thoracic movements of the professional female baseball pitchers was different from male university pitchers.
... Tabla 8. Valores de referencia para la prueba de rotación de tronco104 . ...
Book
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Libro que describe el qué, el cómo y el por qué se hace lo que se hace en relación a las Ciencias Aplicadas al Deporte en el Deporte de Alto Rendimiento en Chile. Estas ciencias apoyan el proceso de preparación y competencia de los atletas chilenos, con el propósito de mejorar el rendimiento deportivo a nivel internacional.
... However, Veronica et al assessed spinal rotation in three different positions and suggested that position can not affect the rotation. [25,27] A study done to compare genders for spine mobility concluded similar results. They justified it stating young females have more arch in back than males leading to more spinning of vertebrae which gives more rotation than males. ...
Article
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Introduction: There are multiple factors which can affect spinal range of motion such as medical conditions, pelvic asymmetry age, sex, race and geographical distribution etc. Aim: The present study aims to assess the differences between genders for trunk mobility in normal adults. Material & methods: In this cross sectional study, 137 subjects (71 females and 66 males) were included for 6 months from various institutes of Sumandeep Vidyapeeth and assessed using Tape method and goniometry for trunk mobility in all planes (sagittal, frontal and transverse) for forward flexion with and without stabilization, extension, lateral flexion and rotation to both the sides and their gender specific differences were calculated using students t test. Result: The mean values by tape method and goniometry for all movements (flexion with and without stabilization, extension, lateral flexion to both the sides and rotation to both the sides) have been given in form of descriptive statistics in the table. There was no statistically significant difference for all spinal movements among the genders, except in lateral flexion (p value 0.009 & 0.008) and rotation (p value 0.023 & 0.004) where females had greater mobility than males.
... Seated trunk rotation test was used to measure the trunk flexibility in right and left side (Aragon, Oyama, Oliaro, Padua, & Myers, 2012;Johnson & Grindstaff, 2010). The subject was asked to sit on a chair with their feet together and flat on the ground, with the trunk in upright posture and arms across their chest. ...
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Background study: Flexibility in human spine has always plays an important role in dexterity and seamless ambulatory activities. When optimum range is not maintained by the trunk column, due to lack of flexibility, the posture gets affected resulting in reduce trunk rotation flexibility and mobility hence loss of complete trunk rotation. Objective: The purpose of this study is to determine the effect of Shapemaster Power Assisted Exercise Equipment (SPAEE) on trunk flexibility. Methodology: Twenty healthy individual ages between 40 to 60 years were randomly divided into control and exercise groups. Shapemaster exercise program performed two times per week for 5 weeks and 45 minutes per session. Before and after 10 sessions of Shapemaster exercise protocol, Seated trunk rotation test was used to measure trunk flexibility. Results: Repeated measurement ANOVA were used to analysis data between groups. The results of this study illustrated that after 10th sessions trunk flexibility significantly improved (F (1.0, 18) = 11.732, p < 0.003). Conclusion: In conclusion results were determined that SPAEE is safe and it did effectively enhance flexibility among individual healthy adults
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Background: An observational tennis serve analysis (OTSA) tool was developed using previously established body positions from three-dimensional kinematic motion analysis studies. These positions, defined as nodes, have been associated with efficient force production and minimal joint loading. However, the tool has yet to be examined scientifically. Purpose: The primary purpose of this investigation was to determine the inter-observer reliability for each node between two health care professionals (HCPs) that developed the OTSA, and secondarily to investigate the validity of the OTSA. Methods: Two separate studies were performed to meet these objectives. An inter-observer reliability study preceded the validity study by examining 28 videos of players serving. Two HCPs graded each video and scored the presence or absence of obtaining each node. Discriminant validity was determined in 33 tennis players using video taped records of three first serves. Serve mechanics were graded using the OSTA and categorized players into those with good ( ≥ 5) and poor ( ≤ 4) mechanics. Participants performed a series of field tests to evaluate trunk flexibility, lower extremity and trunk power, and dynamic balance. Results: The group with good mechanics demonstrated greater backward trunk flexibility (p=0.02), greater rotational power (p=0.02), and higher single leg countermovement jump (p=0.05). Reliability of the OTSA ranged from K = 0.36-1.0, with the majority of all the nodes displaying substantial reliability (K>0.61). Conclusion: This study provides HCPs with a valid and reliable field tool used to assess serve mechanics. Physical characteristics of trunk mobility and power appear to discriminate serve mechanics between players. Future intervention studies are needed to determine if improvement in physical function contribute to improved serve mechanics. Level of evidence: 3.
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Fast – pitch, windmill softball pitchers see significant volumes of throwing during a given season, exposing these athletes to substantial risk of upper extremity overuse injury.In particular, the shoulde biceps – labral complex experiences substantial stress immediately prior to the release phase of the fast - pitch cycle, with angular velocity reaching as high as 2190 deg / s and distraction forces as high as 80% of body weight.We present a case of an 18 year – old, competitive, fast – pitch softball pitcher who presented with progressive anterior shoulder pain, loss in velocity and difficulty with pitch location.
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Background The thoracic spine is critical for athletic kinetic chain functioning yet widely overlooked in terms of specific evidenced based exercise prescription. Thoracic mobility, motor control and strength are required to optimise performance in sport and minimise excessive load/stress on other components of the kinetic chain. Objective To identify and evaluate mobility, motor control, work capacity and strength thoracic exercises for use in athletes Design Systematic review involving expert reviewers at key stages: searches and screening (n=1), eligibility, evaluation, data extraction, and evaluation (n=3). Key databases and social media sources were searched to 16/8/2019. Eligible exercises were thoracic exercises to promote mobility, motor control, work capacity and strength. A narrative synthesis enabled an outcome-based classification of exercises, with level of evidence of individual sources informing overall level of evidence for each outcome (Oxford Centre for Evidence-based Medicine). Results From 2348 sources (social media, database searches and other sources), 38 exercises were included. Sources included images, video clips, & written descriptions of exercises. Exercises targeting all planes of motion were evaluated and classified according to outcome. Exercises comprised functional and non-functional exercises for mobility (n=9), work capacity (n=15), motor control (n=7) and strength (n=7). Overall level of evidence for each outcome was level 5. Conclusion This synthesis and evaluation of exercises has captured the scope of thoracic exercises used in ‘practice’. Evaluation against an expert derived outcome based classification provides practitioners with a framework to facilitate exercise prescription. Evaluation of validity and effectiveness of exercises on outcomes is now required.
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Introduction: The purpose of this review is to identify risk factors in the kinetic chain associated to the disabled
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Background Softball pitching is a ballistic, complex movement that requires an underhand windmill motion to create force and ball velocity. In addition to proper pitch biomechanics, upper and lower extremity strength and joint motion likely contribute to ball location accuracy and velocity. Yet, the number of studies reporting muscle strength and joint range of motion among softball pitchers is scarce. Objective To assess differences between throwing and non‐throwing (NT) shoulder, elbow and hip (lead and trail leg) strength and range of motion (ROM) in high school (HS) and collegiate level softball windmill pitchers. Design Cross‐Sectional study Participants Thirty‐three female softball pitchers (24 HS, 9 collegiate) were recruited from local teams. Methods Goniometric joint ROM and handheld dynamometer strength and of the bilateral shoulders, elbows and hips were measured. Main outcome measurements Goniometric joint ROM of the bilateral elbows (flexion, extension), shoulders and hips (flexion, extension, internal rotation (IR), external rotation (ER)). Handheld dynamometer strength measurements of the bilateral shoulders (flexion, extension, abduction, IR, ER) elbows (flexion, extension) and hips (flexion, extension, IR, ER, abduction). Results Across all pitchers, there was greater shoulder flexion ROM in the non‐throwing (NT) limb than in the throwing limb (p=.004). There was greater hip extension in the lead leg than trail leg. Among HS pitchers, there was greater shoulder ER (x=105.792&pm;7.11) than collegiate pitchers (x=100.1 &pm;6.92), p=.05. There was no difference in total arc of shoulder rotational motion (ER+ IR) between throwing and NT limbs across all pitchers, nor between HS and collegiate pitchers. Strength measures demonstrated greater throwing limb shoulder abduction (p=.006) and IR strength (p=.001) than the NT shoulder across all pitchers. Elbow flexion strength was significantly greater than the NT side (p= .001). No difference was noted in hip strength between lead and trail lower extremities. Conclusions Developing normative data for softball pitchers upper and lower extremity strength and range of motion may allow providers to assess players more comprehensively and identify athletes out of the expected value range. This information may help in guiding strength and conditioning programs for softball pitchers. This article is protected by copyright. All rights reserved.
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Softball is the third most popular women’s collegiate sport in the United States, with 19,680 total athletes as of the 2015–2016 season. Despite its popularity and growth in recent years, research focusing on the biomechanics of the windmill pitch and its associated shoulder injuries is relatively scarce. The incidence of shoulder injury is highest during the preseason and the beginning of the regular season. The windmill pitch can be divided into distinct phases, with the shoulder experiencing the greatest force during the delivery phase. Significant demands placed on the shoulder during the windmill pitch put pitchers at a higher risk of developing shoulder injuries than position players. Maximum shoulder compression/distraction forces during the windmill pitch have been shown to be comparable to those experienced during the baseball overhand throw, dispelling the myth that the windmill pitch is not taxing on the shoulder. Injuries associated with the high compression/distraction forces include lesions to the rotator cuff, glenoid labrum, and biceps brachii. Pitcher-specific training, cross-training, and whole-body conditioning should be incorporated into current training regimens to decrease the risk of shoulder injuries.
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The upper quarter Y-balance test is an upper extremity, closed kinetic chain assessment that requires individuals to reach in three directions while in a three-point plank position. The upper quarter Y-balance test was performed in 22 collegiate softball players (19.95 ± 1.52 years) to determine the (a) differences between throwing and nonthrowing (NT) sides and (b) influence of reach sequence. While stabilizing on the NT side, participants reached significantly further in the inferolateral direction than the throwing side (NT: 83.7 ± 12.2% arm length; throwing: 80.1 ± 10.5% arm length; p = .03; effect size = −0.57). Altering reach sequence significantly influenced medial reach ( p < .01, effect size = 0.66) and composite score ( p = .017, effect size = 1.03) when stabilizing on the NT side. Asymmetries in upper quarter Y-balance test in collegiate softball players should be interpreted cautiously, and an ordered test sequence should be consistently followed.
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Background Early pelvis rotation has been associated with decreased throwing arm kinetics and conventionally was considered a component of proper pitching form in baseball throwers. However, previous assessments of pelvis rotation style have not accounted for confounders such as playing level, anthropometric characteristics, or ball velocity and have not evaluated sufficient sample sizes. Purpose To compare kinetic and kinematic parameters based on pelvis rotation style in high school and professional pitchers. Study Design Descriptive laboratory study. Methods High school and professional baseball pitchers threw 8 to 12 fastball pitches while being evaluated using 3-dimensional motion capture (480 Hz). These pitchers were 1:1 propensity score matched by age, height, weight, handedness, and ball velocity based on early (<60°) versus late (≥60°) pelvis rotation style at foot contact. A total of 26 kinematic and 10 kinetic parameters were compared between groups. The kinematic parameters were used to conduct a linear regression between early and late pelvis rotation at foot contact. Results Pelvis rotation at foot contact was not significantly associated with ball velocity for either high school ( P = .243) or professional pitchers ( P = .075). No difference was found in elbow varus torque between high school early rotators (57.5 ± 14.9 N·m) and late rotators (51.3 ± 14.7 N·m; P = .036) and between professional early rotators (80.1 ± 11.8 N·m) and late rotators (79.0 ± 11.2 N·m; P = .663). At foot contact in high school pitchers, stride length increased by 2.1% of body height (B = −0.205; β = −0.470; P < .001), trunk rotation increased by 4.2° (B = −0.417; β = −0.488; P < .001), and trunk flexion at foot contact decreased by 4.4° (B = 0.442; β = 0.476; P < .001) with every 10° increase in pelvis rotation. At foot contact in professional pitchers, stride length increased by 2.3% of body height (B = –0.229; β = –0.478; P < .001), trunk rotation increased by 4.3° (B = –0.431; β = –0.515; P < .001), and trunk flexion decreased by 4.0° (B = 0.404; β = 0.373; P < .001) with every 10° increase in pelvis rotation. Conclusion Pelvis rotation at foot contact was associated with several kinematic parameters in both groups and may influence mechanics further along the kinetic chain. Landing open or closed was not significantly associated with throwing arm kinetics or ball velocity for both high school and professional baseball pitchers, contrary to previous thought. Clinical Relevance Coaches and players may better focus their efforts on refining other kinematic parameters for enhanced performance outcomes and safe pitching mechanics.
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Pitching motion is made up by three-dimensional whole body movement. Pelvic and trunk rotation movement is important for the prevention of throwing injuries. Throwing is not a simple rotation movement. Evaluation should reflect muscle strength, coordination, and pitching motion characteristics. We have devised throwing rotational assessment (TRA) similar to throwing as the new evaluation of total rotation angle required for throwing. The purpose of this study was to introduce the new method and to examine the characteristics of players with throwing disorders. The subjects were 76 high school baseball pitchers who participated in the medical check. Pain-induced tests were elbow hyperextension test and intra-articular shoulder impingement test. Pitchers who felt pain in either test were classified as disorder group. TRA evaluation was performed as follows. In the positions similar to the foot contact phase, rotation angles of the pelvis and trunk were measured. In the position similar to follow through phase, the distance between the middle finger and the second toe was measured. All tests were performed in the throwing and opposite direction. Twenty five pitchers were classified as disorder group. All TRA tests in healthy group were significantly higher in the throwing direction than in the opposite direction, but there was no significant difference in the disorder group. Disorder group had significantly lower average rotation angles of the pelvis and trunk in the throwing direction and rotation angle of trunk in the opposite direction than the healthy group. Restrictions on TRA reflecting the complex whole body rotation movement may be related to the throwing disorder. This evaluation is a simple method. It would be useful early detection of throwing disorder and systematic evaluation in medical check, as well as self-check in the sports field.
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During the pitching motion, velocity is generated by the upper extremity kinetic chain on internal rotation of the shoulder and trunk translational/rotational motion. This generation of power places significant forces and torques on the elbow and shoulder. Elbow valgus torque and shoulder rotational torque are theoretically linked to elbow injury. Pitchers experiencing higher levels of elbow valgus torque and shoulder external rotation torque throughout the pitching motion are more likely to suffer elbow injury than pitchers with lower levels of torque. Cohort study; Level of evidence, 3. With an established biomechanical analysis model, 23 professional baseball pitchers were videotaped during spring training games and followed prospectively for the next 3 seasons for elbow injury. A mixed statistical model using differences of least squares means and analysis of variance was used to analyze the association between elbow injury and torque levels throughout the pitching motion as well as at each major event within the pitching motion. There were overall statistical trends relating elbow injury with both higher elbow valgus torque (P = .0547) and higher shoulder external rotation torque (P = .0548) throughout the entire pitching motion. More importantly, there was an individual significant correlation of elbow injury with both higher elbow valgus torque (P = .0130) and higher shoulder external rotation torque (P = .0018) at the late cocking phase (pitching event of maximum external rotation of the shoulder). This study provides information that supports existing theories about how and why certain injuries occur during the throwing motion in baseball. The late cocking phase appears to be the critical point in the pitching motion, where higher levels of torque at the shoulder and elbow can result in increased risk of injury. Manipulation of pitching mechanics to alter these torque levels or using these measures to identify pitchers at risk may help decrease injury rates.
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Studies have shown that various biomechanical factors affect valgus extension overload during baseball pitching; yet, their relationships are not clearly defined, and factors such as trunk rotation and arm slot have not been investigated. The onset of trunk rotation, with other biomechanical variables that define sequential body motion, will significantly predict elbow valgus loading. Descriptive laboratory study. Sixty-nine adult baseball players pitched off an indoor mound during 3-dimensional motion analysis to measure whole body kinematics and kinetics at 240 Hz. Thirteen biomechanical variables were calculated and extracted for regression analysis to investigate their associations with elbow valgus load. A 2-way analysis of variance compared valgus torques between pitchers with 2 onsets of trunk rotation (before and after front-foot contact) and 2 arm slot positions (overhand and sidearm). Six biomechanical variables had significant correlations (P < .02) with elbow valgus torque-with maximum shoulder external rotation, elbow flexion at peak valgus torque, and elbow valgus loading rate accounting for 68% of its variance. Reduced elbow valgus torques were associated with increased elbow flexion (P < .01). Players who initiated trunk rotation before front-foot contact had significantly higher elbow valgus torques than did those who rotated afterward (P = .02). Fourteen pitchers displayed a sidearm delivery and had significantly higher elbow valgus torques than did those with an overhand arm slot position. Valgus torque at the elbow during baseball pitching is associated with 6 biomechanical variables of sequential body motion. A condition of late trunk rotation, reduced shoulder external rotation, and increased elbow flexion appeared to be most closely related to valgus torque. Sidearm pitchers appeared to be more susceptible than overhand pitchers to reduced elbow valgus torque. The biomechanical findings of this study offer scientific feedback for developing methods used to minimize the effects of valgus load on pitching-related elbow injuries.
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Elbow and shoulder kinetics for 26 highly skilled, healthy adult pitchers were calculated using high-speed motion analysis. Two critical instants were 1) shortly before the arm reached maximum external rotation, when 67 N-m of shoulder internal rotation torque and 64 N-m of elbow varus torque were generated, and 2) shortly after ball release, when 1090 N of shoulder compressive force was produced. Inability to generate sufficient elbow varus torque may result in medial tension, lateral compression, or posteromedial impingement injury. At the glenohumeral joint, compressive force, joint laxity, and 380 N of anterior force during arm cocking can lead to anterior glenoid labral tear. Rapid internal rotation in combination with these forces can produce a grinding injury factor on the labrum. After ball release, 400 N of posterior force, 1090 N of compressive force, and 97 N-m of horizontal abduction torque are generated at the shoulder; contribution of rotator cuff muscles in generating these loads may result in cuff tensile failure. Horizontal adduction, internal rotation, and superior translation of the abducted humerus may cause subacromial impingement. Tension in the biceps tendon, due to muscle contraction for both elbow flexion torque and shoulder compressive force, may tear the anterosuperior labrum.
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Single-group repeated measures for single rater reliability. To describe the intratester reliability for measurements of active lumbar spine mobility and pelvic inclination during standing obtained with the back range-of-motion (BROM) device. The BROM device has often been used to quantify lumbar spine active range of motion. No studies have reported the reliability of the BROM device in a clinical setting. One examiner measured all 3 planes of lumbar range of motion in 40 nonimpaired subjects. For each plane of motion, 2 BROM device measurements were made. Intraclass correlation coefficients were calculated to express the intratester reliability for each plane of motion measured. Intraclass correlation coefficients were in the range of 0.67 to 0.94 for lumbar measurements with the BROM device. Intratester reliability was fair to poor for sagittal plane measurements and pelvic inclination. Measurements obtained by the same examiner for lumbar lateral flexion and rotation with the BROM device, however, were reliable.
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Context: Professional baseball players must achieve a delicate balance between shoulder mobility and stability to attain optimal sports performance. The sport-specific demands of repetitive overhead throwing may result in an altered mobility-stability relationship.Objective: To evaluate clinical measures of shoulder mobility in professional baseball players in order to examine differences between the throwing and the nonthrowing shoulders and to describe chronic adaptations to throwing.Design: Descriptive.Setting: The athletic training room at Maryvale Baseball Park, Phoenix, AZ.Patients or Other Participants: Twenty-seven professional baseball players (20 pitchers, 7 position players; age = 20 +/- 1.6 years, height = 190.5 +/- 4.8 cm, mass = 91.6 +/- 9.6 kg) with no previous history of shoulder or elbow injury.Main Outcome Measure(s): We recorded scapular upward rotation at 4 levels of humeral elevation in the scapular plane (rest, 60 degrees , 90 degrees , 120 degrees ); posterior shoulder tightness; and passive, isolated glenohumeral joint internal and external range of motion.Results: Scapular upward rotation was significantly greater in the throwing shoulder (14.2 +/- 6.5 degrees ) than in the nonthrowing shoulder (10.6 +/- 6.1 degrees ) at 90 degrees of humeral elevation (P = .04). We observed no statistically significant difference in posterior shoulder tightness between the throwing (30.2 +/- 4.6 cm) and the nonthrowing (28.0 +/- 4.8 cm) shoulder (P = .09). In addition, the throwing shoulder exhibited a statistically significant decrease in isolated glenohumeral internal rotation (56.6 +/- 12.5 degrees ) compared with the nonthrowing shoulder (68.6 +/- 12.6 degrees ) (P = .001), with a concomitant increase in isolated glenohumeral external rotation (throwing = 108.9 +/- 9.0 degrees , nonthrowing = 101.9 +/- 5.9 degrees , P = .0014). An analysis of the total arc of motion (internal rotation + external rotation) revealed no statistically significant difference between sides (P = .15).Conclusions: The throwing shoulder exhibited significant differences in scapular and glenohumeral mobility compared with the nonthrowing shoulder. Further research is necessary to determine the relation of these adaptive changes, if any, to shoulder injury and disability.
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A significant number of time-loss injuries to the upper extremity in elite windmill softball pitchers has been documented. The number of outings and pitches thrown in 1 week for a softball pitcher is typically far in excess of those seen in baseball pitchers. Shoulder stress in professional baseball pitching has been reported to be high and has been linked to pitching injuries. Shoulder distraction has not been studied in an elite softball pitching population. The stresses on the throwing shoulder of elite windmill pitchers are similar to those found for professional baseball pitchers. Descriptive laboratory study. Three-dimensional, high-speed (120 Hz) video data were collected on rise balls from 24 elite softball pitchers during the 1996 Olympic Games. Kinematic parameters related to pitching mechanics and resultant kinetics on the throwing shoulder were calculated. Multiple linear regression analysis was used to relate shoulder stress and pitching mechanics. Shoulder distraction stress averaged 80% of body weight for the Olympic pitchers. Sixty-nine percent of the variability in shoulder distraction can be explained by a combination of 7 parameters related to pitching mechanics. Excessive distraction stress at the throwing shoulder is similar to that found in baseball pitchers, which suggests that windmill softball pitchers are at risk for overuse injuries. Normative information regarding upper extremity kinematics and kinetics for elite softball pitchers has been established.
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Alterations in glenohumeral range of motion, including increased posterior shoulder tightness and glenohumeral internal rotation deficit that exceeds the accompanying external rotation gain, are suggested contributors to throwing-related shoulder injuries such as pathologic internal impingement. Yet these contributors have not been identified in throwers with internal impingement. Throwers with pathologic internal impingement will exhibit significantly increased posterior shoulder tightness and glenohumeral internal rotation deficit without significantly increased external rotation gain. Case control study; Level of evidence, 3. Eleven throwing athletes with pathologic internal impingement diagnosed using both clinical examination and a magnetic resonance arthrogram were demographically matched with 11 control throwers who had no history of upper extremity injury. Passive glenohumeral internal and external rotation were measured bilaterally with standard goniometry at 90 degrees of humeral abduction and elbow flexion. Bilateral differences in glenohumeral range of motion were used to calculate glenohumeral internal rotation deficit and external rotation gain. Posterior shoulder tightness was quantified as the bilateral difference in passive shoulder horizontal adduction with the scapula retracted and the shoulder at 90 degrees of elevation. Comparisons were made between groups with dependent t tests (P < .05). The throwing athletes with internal impingement demonstrated significantly greater glenohumeral internal rotation deficit (P = .03) and posterior shoulder tightness (P = .03) compared with the control subjects. No significant differences were observed in external rotation gain between groups (P = .16). These findings could indicate that a tightening of the posterior elements of the shoulder (capsule, rotator cuff) may contribute to impingement. The results suggest that management should include stretching to restore flexibility to the posterior shoulder.
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Recently, an increasing number of systematic reviews have been published in which the measurement properties of health status questionnaires are compared. For a meaningful comparison, quality criteria for measurement properties are needed. Our aim was to develop quality criteria for design, methods, and outcomes of studies on the development and evaluation of health status questionnaires. Quality criteria for content validity, internal consistency, criterion validity, construct validity, reproducibility, longitudinal validity, responsiveness, floor and ceiling effects, and interpretability were derived from existing guidelines and consensus within our research group. For each measurement property a criterion was defined for a positive, negative, or indeterminate rating, depending on the design, methods, and outcomes of the validation study. Our criteria make a substantial contribution toward defining explicit quality criteria for measurement properties of health status questionnaires. Our criteria can be used in systematic reviews of health status questionnaires, to detect shortcomings and gaps in knowledge of measurement properties, and to design validation studies. The future challenge will be to refine and complete the criteria and to reach broad consensus, especially on quality criteria for good measurement properties.
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High rotational torques during baseball pitching are believed to be linked to most overuse injuries at the shoulder. This study investigated the effects of trunk rotation on shoulder rotational torques during pitching. A total of 38 pitchers from the professional, college, high school, and youth ranks were recruited for motion analysis. Professional pitchers demonstrated the least amount of rotational torque (p = .001) among skeletally mature players, while exhibiting the ability to rotate their trunks significantly later in the pitching cycle, as compared to other groups (p = .01). It was concluded that the timing of their rotation was optimized as to allow the throwing shoulder to move with decreased joint loading by conserving the momentum generated by the trunk. These results suggest that a specific pattern in throwing can be utilized to increase the efficiency of the pitch, which would allow a player to improve performance with decreased risk of overuse injury.
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To review 16 years of National Collegiate Athletic Association (NCAA) injury surveillance data for women's softball and to identify potential areas for injury prevention initiatives. The NCAA Injury Surveillance System has tracked injuries in all divisions of NCAA softball from the 1988-1989 to the 2003-2004 seasons. This report describes what was found and why the findings are important for the safety, enhancement, and continued growth of the sport. Across all divisions, preseason practice injury rates were more than double the regular-season practice injury rates (3.65 versus 1.68 injuries per 1000 athlete-exposures, rate ratio = 2.2, 95% confidence interval [CI] = 2.0, 2.4, P < .01). The rate of injury in a game was 1.6 times that in a practice (4.30 versus 2.67 injuries per 1000 athlete-exposures, rate ratio = 1.6, 95% CI = 1.5, 1.7). A total of 51.2% of game injuries resulted from "other-contact" mechanisms, whereas 55% of practice injuries resulted from noncontact mechanisms. In games, ankle ligament sprains and knee internal derangements accounted for 19% of injuries. Twenty-three percent of all game injuries were due to sliding, most of which were ankle sprains. In practices, ankle ligament sprains, quadriceps and hamstring strains, shoulder strains and tendinitis, knee internal derangements, and lower back strains (combined) accounted for 38% of injuries. Ankle ligament sprains, knee internal derangements, sliding injuries, and overuse shoulder and low back injuries were among the most common conditions in NCAA women's softball. Preventive efforts should focus on sliding technique regardless of skill level, potential equipment changes, neuromuscular training programs, position-specific throwing programs, and mechanisms of low back injury. Further research is needed on the development and effects of these preventive efforts, as well as in the area of windmill-pitching biomechanics.
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Kinematic and kinetic aspects of baseball pitching and football passing were compared. Twenty-six high school and collegiate pitchers and 26 high school and collegiate quarterbacks were analyzed using three-dimensional high-speed motion analysis. Although maximum shoulder external rotation occurred earlier for quarterbacks, maximum angular velocity of pelvis rotation, upper torso rotation, elbow extension, and shoulder internal rotation occurred earlier and achieved greater magnitude for pitchers. Quarterbacks had shorter strides and stood more erect at ball release. During arm cocking, quarterbacks demonstrated greater elbow flexion and shoulder horizontal adduction. To decelerate the arm, pitchers generated greater compressive force at the elbow and greater compressive force and adduction torque at the shoulder. These results may help explain differences in performance and injury rates between the two sports.
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A number of sporting and daily activities involve rotation of the spine. The ability to quantify motion of the spine in a clinical setting usually relies on the use of a device to measure angles (goniometer or inclinometer) or visual assessment. Standardized measurement criteria exist for measuring rotation at the cervical and lumbar spine. Little has been written regarding established methods for measuring thoracic spine rotation. Thoracic rotation may be measured in a seated position, half-kneeling position, or quadruped position. Steps should be taken to minimize motion of surrounding segments such as the shoulder and hips, which may improve measurement accuracy. Key words: inclinometer, goniometer, range of motion.
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The ability to identify pitchers at risk for injury could be valuable to a professional baseball organization. To our knowledge, there have been no prior studies examining the predictive value of preseason strength measurements. Preseason weakness of shoulder external rotators is associated with increased risk of in-season throwing-related injury in professional baseball pitchers. Cohort study (prognosis); Level of evidence, 2. Preseason shoulder strength was measured for all pitchers in a professional baseball organization over a 5-year period (2001-2005). Prone internal rotation (IR), prone external rotation (PER), seated external rotation (SER), and supraspinatus (SS) strength were tested during spring training before each season. The players were then prospectively followed throughout the season for incidence of throwing-related injury. Injuries were categorized on an ordinal scale, with no injury, injury treated conservatively, and injury resulting in surgery delineated 0, 1, and 2, respectively. Subset analyses of shoulder injuries and of players with prior surgery were also performed. The association between strength measurements and injury was analyzed using Spearman rank correlation. A statistically significant association was observed for PER strength (P = .003), SER strength (P = .048), and SS strength (P = .006) with throwing-related injury requiring surgical intervention. Supraspinatus strength was also significantly associated with incidence of any shoulder injury (P = .031). There was an association between the ratio of PER/IR strength and incidence of shoulder injury (P = .037) and some evidence for an association with overall incidence of throwing-related injury (P = .051). No associations were noted in the subgroup of players with prior surgery. Preseason weakness of external rotation and SS strength is associated with in-season throwing-related injury resulting in surgical intervention in professional baseball pitchers. Thus, preseason strength data may help identify players at risk for injury and formulate strengthening plans for prevention.
Article
Increased pitch counts have been linked to increased complaints of shoulder and elbow pain in youth baseball pitchers. Improper pitching mechanics have not been shown to adversely affect the upper extremity in youth pitchers. The correct performance of 5 biomechanical pitching parameters correlates with lower humeral internal rotation torque and elbow valgus load, as well as higher pitching efficiency, in youth and adolescent pitchers. Descriptive laboratory study. In sum, 169 baseball pitchers (aged 9-18) were analyzed using a quantitative motion analysis system and a high-speed video while throwing fastballs. The correct performance of 5 common pitching parameters was compared with each pitcher's age, humeral internal rotation torque, elbow valgus load, and calculated pitching efficiency. Motion analysis correlated with video analysis for all 5 parameters (P < .05). Youth pitchers (aged 9-13) performing 3 or more parameters correctly showed lower humeral internal rotation torque, lower elbow valgus load, and higher pitching efficiency (P < .05). Youth pitchers with better pitching mechanics generate lower humeral internal rotation torque, lower elbow valgus load, and more efficiency than do those with improper mechanics. Proper pitching mechanics may help prevent shoulder and elbow injuries in youth pitchers. The parameters described in this study may be used to improve the pitching mechanics of youth pitchers and possibly reduce shoulder and elbow pain in youth baseball pitchers.
Article
The shoulder is one of the most commonly injured body sites among athletes. Little previous research describes shoulder injury patterns in high school athletes. To describe and compare shoulder injury rates and patterns among high school athletes in 9 sports (football, soccer, basketball, baseball, and wrestling for boys and soccer, volleyball, basketball, and softball for girls). Prospective injury surveillance study. Injury data were collected from 100 nationally representative US high schools via High School Reporting Information Online. Athletes from participating high schools injured while involved in a school-sanctioned practice or competition in 1 of the above sports during the 2005-2006 and 2006-2007 school years. Shoulder injury rates, diagnoses, severity, and mechanisms. During the 2005-2006 and 2006-2007 school years, athletes in this study sustained 805 shoulder injuries during 3 550 141 athlete-exposures (AEs), for an injury rate of 2.27 shoulder injuries per 10 000 AEs. This corresponds to an estimated 232 258 shoulder injuries occurring nationwide during this time. Shoulder injuries were more likely to occur during competition than practice (rate ratio = 3.01, 95% confidence interval = 2.62, 3.46). Shoulder injury rates per 10 000 AEs were highest in football (5.09), wrestling (4.34), and baseball (1.90). Common shoulder injury diagnoses included sprains/strains (39.6%), dislocations/separations (23.7%), contusions (11.5%), and fractures (6.6%). Although 44.8% of athletes sustaining a shoulder injury returned to play in less than 1 week, 22.9% were out of play for more than 3 weeks, and 6.2% of shoulder injuries required surgery. Common mechanisms of shoulder injury included player-to-player contact (57.6%) and contact with the playing surface (22.8%). High school shoulder injury rates and patterns varied by sport. Continued surveillance is warranted to understand trends and patterns over time and to develop and evaluate evidence-based preventive interventions.
Article
Injuries to the shoulder and elbow are common in baseball pitchers, with the incidence of disability directly related to the duration of exposure and to the intensity of participation. Adams, in a study of 80 Little League and Pony League pitchers, 9 to 14 years of age, reported significant problems in 95%, the most common being accelerated growth and separation of the medial epicondylar epiphysis. Torg et al., in a study of 49 pitchers 9 to 18 years of age, found that 70% had soreness when pitching, but there were fewer severe problems than in Adams' study. He felt the difference was due to a better attitude since, presumably, his pitchers were less competitive. Only studies performed or sponsored by the Little League have concluded that the incidence of injury is insignificant in pitchers. Professional pitchers uniformly show hypertrophy of the flexor forearm muscles, over 50% have a flexion contracture and 30% have an increased valgus angle compared with the opposite extremity. The elbow problems that occur appear to be related to valgus stress as the shoulder internally rotates from a position of maximum external rotation. The medial joint structures are subjected to traction, while compression occurs at the radial humeral joint. The results of this study suggest that the incidence of injury could be decreased if the causative mechanisms were better identified so that different training, and possible rule changes, could be instituted. However, the problem is complex and there are many variables. If coaches knew the correct fundamentals of pitching and had the ability to teach; if proper discretion on frequency or length of pitching time were followed; if older as well as young pitchers were brought along slowly; and if proper exercises were utilized to develop the muscles and ligaments, then the frequency of symptoms and injuries would be greatly reduced.
Article
The purpose of this study was to examine the motion-dependent interaction between adjacent lower extremity segments during the actions of kicking and the swing phases of running and walking. This was done to help explain the proximal-to-distal sequential pattern of segment motions typically observed in these activities and to evaluate general biomechanical principles used to explain this motion pattern. High speed film data were collected for four subjects performing each skill. Equations were derived which expressed the interaction between segments in terms of resultant joint moments at the hip and knee and several interactive moments which were functions of gravitational forces or kinematic variables. The angular motion-dependent interaction between the thigh and leg was found to play a significant role in determining the sequential segment motion patterns observed in all three activities. The general nature of this interaction was consistent across all three movements except during phases in which there were large differences in the knee angle. Support was found for the principle of summation of segment speeds, whereas no support was found for the principle of summation of force or for general statements concerning the effect of negative thigh acceleration on positive leg acceleration. The roles played by resultant joint moments in producing the observed segment motion sequences are discussed.
Article
Fifteen professional major league pitchers were filmed with high speed cinematography. One hundred forty-seven pitches were analyzed using an electromagnetic digitizer and a microcomputer. Three phases of throwing were studied: cocking, acceleration, and follow-through. The cocking phase is the period of time between the initiation of the windup and the moment at which the shoulder is in maximum external rotation. This phase occurs in approximately 1500 ms, and the shoulder is brought into an extreme position of external rotation. The acceleration phase and the initial stages of the follow-through phase produce extraordinary demands on the shoulder and elbow. The acceleration phase begins with the throwing shoulder in the position of maximum external rotation and terminates with ball release. This phase occurs in approximately 50 ms, and peak angular velocities averaging 6,180 deg/sec for shoulder internal rotation and 4,595 deg/sec for elbow extension were measured. The follow-through phase begins at ball release and continues until the motion of throwing has ceased. This phase occurs in approximately 350 ms.
Article
By understanding pitching biomechanics, therapists can develop better preventive and rehabilitative programs for pitchers. The purpose of this study was to quantify and explain the joint motions, loads, and muscle activity that occur at the elbow during baseball pitching. Seven healthy, adult pitchers were examined with synchronized high-speed video digitization and surface electromyography. Elbow extension before ball release corresponded with a decrease in biceps activity and an increase in triceps activity. A varus torque of 120 Nm, acting to resist valgus stress, occurred near the time of maximum shoulder external rotation. Previous cadaveric research showed that the ulnar collateral ligament by itself cannot withstand a valgus load of this magnitude. Triceps, wrist flexorpronator, and anconeus activity during peak valgus stress suggests that these muscles may act as dynamic stabilizers to assist the ulnar collateral ligament in preventing valgus extension overload.
Article
The American Sports Medicine Institute conducts research to increase understanding of mechanisms involved in upper extremity injuries to throwing athletes. This paper presents a qualitative overview of pitching and a detailed quantitative description of arm motion about the shoulder during this highly dynamic activity. Data on kinematics of arm motions about the shoulder are presented for 29 elite throwers. The major motion about the shoulder is external/internal rotation. Scapulothoracic and glenohumeral flexibility permit the arm to reach an externally rotated position of 175 degrees. Approximately 30 msec before release, the arm internally rotates 80 degrees, reaching peak angular velocities near 7,000 degrees/sec. In rehabilitation of injured throwers, there is a need to appreciate the highly dynamic nature of this skill and to attempt to simulate these dynamic motions and loads as part of the final phase of treatment before the athlete returns to competition.
Article
To establish the reliability of the BROM II device for measuring lumbar mobility in the sagittal, coronal and transverse planes and its validity against the double inclinometer method. Blind intra- and interexaminer reliability and concurrent validity. Interexaminer reliability was determined between two examiners. Chiropractice teaching college. Forty-seven asymptomatic chiropractic students (27 men and 20 women, age range 18 to 38 yr). Lumbar mobility measurement in degrees using the BROM II and double inclinometer techniques. Intraclass correlation coefficients (ICC) showed good intra- and interexaminer reliability of the BROM II for flexion (0.91 and 0.77, respectively) and lateral flexion (0.91 and 0.85 respectively). Less support was given to the reliability of the instrument in extension (0.63 and 0.35, respectively) and rotation (0.57 and 0.36 respectively). Concurrent validity of the BROM II and double inclinometer methods was partially supported (ICC in all planes range from 0.27 to 0.75). The BROM II was found to be a reliable instrument in the measurement of lumbar mobility in the sagittal (flexion) and coronal planes. However, before this device can be recommended as an assessment tool in clinical practice or clinical trials, further investigation into its reliability in a symptomatic group of patients is required. (J Manipulative Physiol Ther 1995; 18:497-502).
Article
Underhand pitching has received minimal attention in the sports medicine literature. This may be due to the perception that, compared with overhead pitching, the underhand motion creates less stress on the arm, which results in fewer injuries. The purpose of this study was to calculate kinematic and kinetic parameters for the pitching motion used in fast pitch softball. Eight female fast pitch softball pitchers were recorded with a four-camera system (200 Hz). The results indicated that high forces and torques were experienced at the shoulder and elbow during the delivery phase. Peak compressive forces at the elbow and shoulder equal to 70-98% of body weight were produced. Shoulder extension and abduction torques equal to 9-10% of body weight x height were calculated. Elbow flexion torque was exerted to control elbow extension and initiate elbow flexion. The demand on the biceps labrum complex to simultaneously resist glenohumeral distraction and produce elbow flexion makes this structure susceptible to overuse injury.
Article
Proper biomechanics help baseball pitchers minimize their risk of injury and maximize performance. However previous studies involved adult pitchers only. In this study, 23 youth, 33 high school, 115 college, and 60 professional baseball pitchers were analyzed. Sixteen kinematic (11 position and five velocity), eight kinetic, and six temporal parameters were calculated and compared among the four levels of competition. Only one of the 11 kinematic position parameters showed significant differences among the four levels, while all five velocity parameters showed significant differences. All eight kinetic parameters increased significantly with competition level. None of the six temporal parameters showed significant differences. Since 16 of the 17 position and temporal parameters showed no significant differences, this study supports the philosophy that a child should be taught 'proper' pitching mechanics for use throughout a career. Kinetic differences observed suggest greater injury risk at higher competition levels. Since adult pitchers did not demonstrate different position or temporal patterns than younger pitchers, increases in joint forces and torques were most likely due to increased strength and muscle mass in the higher level athlete. The greater shoulder and elbow angular velocities produced by high-level pitchers were most likely due to the greater torques they generated during the arm cocking and acceleration phases. The combination of more arm angular velocity and a longer arm resulted in greater linear ball velocity for the higher level pitcher. Thus, it appears that the natural progression for successful pitching is to learn proper mechanics as early as possible, and build strength as the body matures.
Article
The extreme forces and torques and the high speeds and excessive ranges of motion of baseball pitching place tremendous stress on the soft tissues of the throwing shoulder. Little is known about the relationship between pitching mechanics and shoulder joint stress, especially in professional athletes. The purpose of this study was to quantify joint loads and kinematic parameters of pitching mechanics at the major league level and to study their relationships. Three-dimensional, high-speed video data were collected on 40 professional pitchers during the 1998 Cactus League spring training. A clinically significant distraction force was calculated at the shoulder joint, which reached an average peak value of 947 +/- 162 N (108% +/- 16% body weight). Descriptive statistics and a multiple linear regression analysis were used to relate shoulder distraction to kinematic and kinetic parameters of pitching mechanics. This study was undertaken not only to investigate the peak forces and torques on the shoulder, but also to identify potential areas of intervention that might prevent throwing injuries. Knowledge of joint ranges of motion, angular velocities, and joint-reaction forces can provide a scientific basis for improved preventive and rehabilitative protocols for baseball pitchers.
Article
The aim of this study is to show the relationship between test-retest reproducibility and responsiveness and to introduce the smallest real difference (SRD) approach, using the sickness impact profile (SIP) in chronic stroke patients as an example. Forty chronic stroke patients were interviewed twice by the same examiner, with a 1-week interval. All patients were interviewed during the qualification period preceding a randomized clinical trial. Test-retest reproducibility has been quantified by the intraclass correlation coefficient (ICC). the standard error of measurement (SEM) and the related smallest real difference (SRD). Responsiveness was defined as the ratio of the clinically relevant change to the SD of the within-stable-subject test-retest differences. The ICC for the total SIP was 0.92, whereas the ICCs for the specified SIP categories varied from 0.63 for the category 'recreation and pastime' to 0.88 for the category 'work'. However, both the SEM and the SRD far more capture the essence of the reproducibility of a measurement instrument. For instance, a total SIP score of an individual patient of 28.3% (which is taken as an example, being the mean score in the study population) should decrease by at least 9.26% or approximately 13 items, before any improvement beyond reproducibility noise can be detected. The responsiveness to change of a health status measurement instrument is closely related to its test-retest reproducibility. This relationship becomes more evident when the SEM and the SRD are used to quantify reproducibility, than when ICC or other correlation coefficients are used.
Article
Valgus elbow stress leads to medial tension and lateral compression injuries in baseball pitchers of all ages. This study was undertaken to investigate the relationship between elbow stress in professional baseball pitchers and the kinematic parameters of pitching mechanics. This was done in an attempt to understand valgus extension overload better and in an effort to improve preventive and rehabilitative protocols. High-speed video data were collected on 40 professional pitchers in game situations during the 1998 and 1999 Cactus League season in Arizona, as part of Major League Baseball Spring Training. A multiple linear regression analysis was used to relate elbow valgus to kinematic parameters of pitching mechanics. The resulting analysis produced an adjusted multiple R2 value of 0.974, indicating that nearly 100% of the variance in valgus stress on the elbow was explained by the parameters in the regression equation. This ability to explain over 97% of the variance in valgus stress is significant. The parameters of pitching mechanics related to elbow valgus may be assessed and optimized, if necessary, in order to decrease the magnitude of elbow stress in pitching.
When shortening occurs during a maintained isotonic contraction, as Aubert (1956) found during shortening at constant speed, the 'efficiency' remains very constant throughout, even over a considerable range of length. The efficiency varies largely with the load P, being zero at P = 0 and P = P0 (isometric). Near its maximum around P/P0 = 0\cdot 5 the efficiency (in frog sartorii at 0 degrees C) is consistently about 0\cdot 45. The form of the relation between efficiency and load is discussed, particularly in view of recent findings on the heat of shortening of muscle. The mechanical power developed during shortening is greatest when P/P0 = v/v0 = about 0\cdot 3; but the efficiency here is only 3 to 5% less than its maximum.
Article
Efficient, sequential timing is essential for upper level pitching. Interestingly, pitchers vary considerably in timing related elements of pitching style including pelvis rotation, arm cocking, stride leg behaviour, and pitch delivery time. The purpose of this study was to determine whether relationships exist among these elements by examining the overall style of pitchers exhibiting different pelvis rotation patterns. Pitching styles were defined by pelvis orientation at the instant of stride foot contact. Pitchers demonstrating a pelvis orientation greater than 30 degrees were designated as 'early rotators', while pitchers demonstrating a pelvis orientation less than 30 degrees were designated as 'late rotators'. Kinematic and temporal differences were associated with the two styles. During the arm cocking phase, early rotators showed significantly greater shoulder external rotation at the instant of stride foot contact, earlier occurrence of maximum pelvis rotation angular velocity, and shorter time taken to complete the phase. However, by the instant of maximum shoulder external rotation, early and late rotators appeared remarkably similar as no significant difference occurred in pelvis and arm orientations. Therefore, it appears that early and late rotators used different methods to achieve similar results, including throwing velocity. Significant differences in throwing arm kinetics were also found for 10 of the 11 measures in the study. As the pelvis assumed a more open position at stride foot contact, maximum kinetic values were found to both decrease in magnitude and occur at an earlier time within the pitch.
Article
Published studies on asymptomatic athletes show an increase in external rotation and decrease in internal rotation while maintaining the total arc of motion of the glenohumeral joint. The purpose of this study was to determine whether overhand athletes with shoulder pain maintained their total arc of motion. Sixty-seven college-level baseball players were examined. Internal rotation and external rotation of the glenohumeral joint, measured at 90 degrees of abduction, and total arc of shoulder motion were compared between dominant and nondominant extremities in athletes with and without shoulder pain. Dominant shoulders in the pain group had a mean arc of 136.2 degrees compared with 145.8 degrees in the nondominant group, for a side-to-side difference of 9.6 degrees. We demonstrate that college-level baseball players with shoulder pain have a significant decrease in total arc of shoulder motion and internal rotation compared with their nondominant shoulder and with pain-free athletes.
Article
Joint range of motion and physical capacities have been shown to change with age in both throwing athletes and non-athletes. The age of professional baseball pitchers could span from late teens to mid-40s. However, the effects of age on the pitching kinematics among professional baseball pitchers are still unknown. In this study, 67 healthy professional baseball pitchers were tested using a 3D motion analysis system. Their mean age was 23.7+/-3.3 years (range 18.8-34.4). The 12 pitchers more than one standard deviation older than the mean (i.e., older than 27.0 years) were categorized into the older group, and the 10 pitchers more than one standard deviation younger than the mean (i.e., younger than 20.4 years) were defined as the younger group. In all, 18 kinematic variables (14 position and 4 velocity) were calculated, and Student's t-tests were used to compare the variables between the two groups. Six position variables were found to be significantly different between the two groups. At the instant of lead foot contact, the older group had a shorter stride, a more closed pelvis orientation, and a more closed upper trunk orientation. The older group also produced less shoulder external rotation during the arm cocking phase, more lead knee flexion at ball release, and less forward trunk tilt at ball release. Ball velocity and body segment velocity variables showed no significant differences between the two groups. Thus, differences in specific pitching kinematic variables among professional baseball pitchers of different age groups were not associated with significant differences in ball velocities between groups. The current results suggest that both biological changes and technique adaptations occur during the career of a professional baseball pitcher.
Article
A distraction force occurs at the shoulder joint in all throwing motions. At the professional level, the relationship between this force and pitching mechanics has been explained. Three-dimensional, high-speed (240 Hz) video data were collected on fastballs from 48 collegiate baseball pitchers. Kinematic parameters related to pitching mechanics and resultant kinetics on the throwing arm elbow and shoulder joints were calculated. Multiple linear regression analysis was used to investigate the relationships between shoulder distraction and pitching mechanics. Shoulder distraction stress averaged 81% body weight for the collegiate pitchers. The mean ball velocity was 81 mph. Ten parameters of pitching mechanics accounted for 89% of the variance in shoulder distraction. Two of the variables (maximum shoulder abduction torque and elbow angle at release) previously shown to affect shoulder distraction in professional baseball pitchers appear to be important for collegiate pitchers as well. These data provide a scientific basis for clinicians, athletes, and coaches to establish methods to reduce distraction force at the shoulder joint through modification of pitching mechanics.
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Measurement of Joint Motion: A Guide to Goniometry
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