Reliability of isokinetic decay slope is superior to using fatigue indices for shoulder horizontal abduction.

INTRODUCTION: Reliable and valid measurements for shoulder muscular endurance should be available for clinical use. The posterior shoulder endurance test offers a potential clinical assessment, but its construct validity isn't available. Since a criterion measure of muscular endurance is not available, this study's purpose was to determine a reliable method for testing shoulder muscular endurance using an isokinetic dynamometer. METHODS: The test-retest reliability, standard error measurement, and minimal detectable change were calculated on four different paradigms to quantify muscular fatigue using two isokinetic speeds (60°sec-1,180°sec-1). Calculation paradigms included peak torque fatigue index (FI), average torque FI, area-under-the-curve FI, and peak torque decay slope. Testing occurred on two days. Repeated measures analysis of variance compared the two peak torque decay slopes across both testing days. RESULTS: Superior reliability was found within the decay slope measurements at both 60°sec-1 (ICC = 0.941) and 180°sec-1 (ICC = 0.764) speeds, with the 60°sec-1 decay slope being the highest reliability between the two angular velocities. There was a greater amount of fatigue in the 60°sec-1 decay slope compared to the 180°sec-1 decay slope. CONCLUSION: Using the decay slope of isokinetic shoulder horizontal abduction at 60°sec-1 is a reliable method to validate other muscular endurance clinical measures. Rehabilitation specialists should utilize the decay slope of the isokinetic dynamometry to monitor responsiveness.

The supine moving apprehension test-Reliability and validity among healthy individuals and patients with anterior shoulder instability.

Background: Performance-based tests for patients with anterior shoulder dislocation are lacking. This study determined the reliability and validity of the supine moving apprehension test designed to assess the ability to control anterior instability loads. Methods: Thirty-six participants were recruited (18 healthy individuals, and 18 patients following anterior shoulder dislocation). Healthy participants performed the supine moving apprehension test on 2 separate occasions to determine test-retest reliability. Patients completed the supine moving apprehension test and the Western Ontario Shoulder Instability index before and 6 months after surgical stabilization of their shoulder. The presence of anterior apprehension was also documented post-operatively. Results: The supine moving apprehension test demonstrated good test-retest reliability (intraclass correlation coefficient = 0.74-0.84). Patients performed 18-30 repetitions less than healthy individuals during the supine moving apprehension test (P < 0.01). A strong correlation was found between supine moving apprehension test scores and Western Ontario Shoulder Instability post-operatively (r = -0.74, P ≤ 0.01). Supine moving apprehension test scores significantly improved among patients following surgery (P < 0.01). Patients with a negative apprehension test post-operatively performed the supine moving apprehension test significantly better than patients with a positive apprehension test (P < 0.01). Conclusions: The supine moving apprehension test is reliable and valid among patients with anterior shoulder dislocation and may serve to assess patients' ability to control shoulder anterior instability loads.

Regaining motion among patients with shoulder pathology - are all exercises equal?

Background: Little information exists to guide the choice of exercise for regaining shoulder range of motion (ROM). The purpose of this study was to compare the maximal ROM reached, pain and difficulty associated with 4 commonly prescribed exercises. Methods: Forty (9 females) patients with various shoulder disorders and a limited flexion ROM performed 4 exercises for regaining shoulder flexion ROM in a randomized order. Exercises included the self-assisted flexion, forward bow, table slide and rope-and-pulley. Participants were videotaped while performing all exercises and the maximal flexion angle reached during each exercise was recorded using Kinovea motion analysis freeware (Kinovea 0.8.15). Pain intensity and the perceived level of difficulty associated with each exercise were also recorded. Results: The forward bow and table slide generated significantly greater ROM compared with the self-assisted flexion and rope-and-pulley (P ≤ 0.005). The self-assisted flexion was associated with a greater pain intensity compared with the table slide and rope-and-pulley (P = 0.002) and a greater perceived level of difficulty compared with the table slide (P = 0.006). Conclusions: Due to the greater ROM allowed, and similar or even lower level of pain or difficulty, clinicians may wish to initially recommend the forward bow and table slide for regaining shoulder flexion ROM.

Prevalence and Impact of Musculoskeletal Pain Due to Operating Among Surgical Trainees.

OBJECTIVE: Upwards of 79%-88% of practicing surgeons report musculoskeletal pain due to operating. However, little is known about when these issues begin to become clinically significant. This survey evaluates the prevalence and impact of musculoskeletal pain among surgical residents. DESIGN: After IRB approval, an anonymous 19-question survey based on Cornell Musculoskeletal Discomfort Questionnaire was sent to current surgical residents measuring frequency and degree of pain at 5 sites (neck, shoulder, upper back, lower back, and elbow/wrist) as well as impact on activities both at work and outside of work. Chi square analysis was used to identify differences between groups. SETTING: Single academic medical center. PARTICIPANTS: Trainees in all surgical-based specialties. RESULTS: Fifty-three residents responded from 8 different specialties (38% response rate). Respondents were a representative balance of male (53%)/female (47%) with a mean age of 30 ± 2 years. Residents in all specialties and all years of clinical training responded, with the greatest number from general surgery (the largest program with 48% of respondents), second year of clinical training (30%) and an overwhelming 96% of residents reported experiencing pain they felt was due to operating. The most common sites of pain were the neck (92%) and lower back (77%). This pain was a frequent issue for most with 74% reporting multiple times per month and 26% reporting pain nearly every day. Nearly half of residents reported that pain slightly to substantially interfered with their ability to work (44%) and with activities outside of work (47%). Most residents (75%) sought no treatment. No residents missed work despite reporting pain. CONCLUSIONS: Musculoskeletal pain begins during training, occurs regularly, and affects function. Neck pain is the most frequent, severe, and disabling site. This provides a target for interventions to reduce the impact of chronic pain on patient care, surgeon wellness, and career longevity.

A Plague of Their Own: Injury Incidence Remains Elevated in the 2021 Major League Baseball Season Compared to Pre-COVID-19 Seasons.

Background: Significant increases in injuries were observed in the 2020 Major League Baseball (MLB) season; these were attributed to an increased acute to chronic workload due to the interrupted preseason and compressed season during the coronavirus disease of 2019 (COVID-19) pandemic. In 2021, the MLB resumed its regular schedule. Hypothesis/Purpose: The purpose of this study was to determine the injury incidence and epidemiology of the 2021 MLB season compared to the injury incidence in the 2020 season and pre-COVID-19 seasons. The hypothesis was that, with the return to normal preseason training, injury incidence in 2021 would return to pre-COVID-19 rates. Additionally, it was hypothesized that injury list (IL) placements at midseason 2021 would be decreased relative to 2020 due to the uninterrupted preseason yet increased at full season 2021 due to increased overall workload from 2020. Study Design: Descriptive epidemiology study. Methods: The MLB transactions database was searched for players placed on the IL between 2018 and 2021. Injuries were categorized by body part and player position. Incidence per 1000 athlete-exposures was calculated for the pre-COVID-19 (2018-2019), 2020, and 2021 seasons. The z test for proportions was used to determine significant differences between injury incidences. Results: The injury incidence rate by midseason 2021 (9.32) compared to 2020 (8.66) was not significantly different (p=0.234). At full season 2021, injury incidence rate (8.69) was significantly higher than pre-COVID-19 seasons (5.13, p<0.001), but not 2020 (p=0.952). When comparing full season 2021 to 2020, increased foot/ankle (0.50 vs 0.14, respectively, p<0.001) and miscellaneous (1.92 vs 0.68, respectively, p<0.001) injuries were observed. Conclusion: The overall injury incidence in 2021 was significantly higher than pre-COVID-19 seasons, and no significant difference was observed between both mid- and full season 2021 and 2020, refuting the hypotheses. This signifies that injury incidence remained elevated in the 2021 season despite resumption of preseason training and a regular season. Level of Evidence: 3.

Effect of Pitching Restrictions and Mound Distance on Youth Baseball Pitch Counts.

Background: Studies have shown that higher pitch counts are directly related to a greater incidence of elbow and shoulder pain among youth baseball pitchers. Purpose/Hypothesis: The purpose of this study was to examine the effect of different pitching restriction rules on the number of pitches thrown in youth baseball leagues. We hypothesized that more pitches would be thrown in leagues with inning restrictions versus leagues with pitch count restrictions as well as in leagues with a longer mound distance (from pitching mound to home plate). Study Design: Cohort study; Level of evidence, 2. Methods: Pitch count data were collected for 2 consecutive years over a 10-week season from 3 different leagues of 9- to 12-year-old baseball players in a single city. The Eastern league had a pitch count restriction and 46-ft (14.02-m) mound distance. The Southeastern and South leagues' pitching restrictions were based on innings per week. The Southeastern league had a 50-ft (15.24-m) mound distance, while the South league had a 46-ft mound distance. Comparisons of total seasonal pitches thrown were made of the 3 highest-volume pitchers on each team. League averages for each value were then compared utilizing analysis of variance with Bonferroni post hoc analysis. The number of pitchers in each league who threw >600 pitches per season was compared using the chi-square test. Results: No significant difference in seasonal pitch counts or innings pitched was noted between the Eastern and South leagues, which differed only in their pitching restrictions. The Southeastern league, with a longer mound distance, was found to have higher seasonal pitch counts per thrower (598 ± 195 pitches) than the South league (463 ± 198 pitches) for the 3 highest-volume throwers for each team (P = .004). The Southeastern league also had a significantly larger number of pitchers who threw >600 pitches per season (33 vs 20 for Eastern and 13 for South; P = .009). Conclusion: There was no significant difference in seasonal pitch counts when the leagues in this study differed based on pitching restrictions. However, the league with a greater mound distance (Southeastern) had higher seasonal pitch counts for the highest-volume throwers. Pitching restrictions based on pitch counts, as opposed to innings, may be advisable.

Efficacy of power training to improve physical function in individuals diagnosed with frailty and chronic disease: A meta-analysis.

Muscle power training with emphasis on high-velocity of concentric movement improves physical functionality in healthy older adults, and, maybe superior to traditional exercise programs. Power training may also be advantageous for patients with acute and chronic illnesses, as well as frail individuals. To determine the efficacy of power training compared with traditional resistance training on physical function outcomes in individuals diagnosed with frailty, acute illness or chronic disease. PubMed (MEDLINE), CINAHL, PEDro, Web of Science, and Google Scholar. (1) at least one study group receives muscle power training of randomized controlled trial (RCT) (2) study participants diagnosed as prefrail, frail or have an ongoing acute or chronic disease, condition or illness; (3) study participants over the age of 18; (4) publication in English language; (5) included physical function as the primary or secondary outcome measures. Two independent reviewers assessed articles for inclusion and graded the methodological quality using Cochrane Risk-of-Bias tool for RCTs. Fourteen RCTs met the inclusion criteria. In seven studies, muscle power training was more effective at improving physical function compared to control activities with a mean fixed effect size (ES) of 0.41 (p = 0.006; 95% CI 0.12 to 0.71). Power training and conventional resistance training had similar effectiveness in eight studies with a mean fixed ES of 0.10 (p = 0.061; 95% CI -0.01 to 0.40). Muscle power training is just as efficacious for improving physical function in individuals diagnosed with frailty and chronic disease when compared to traditional resistance training. The advantages of power training with reduced work per session may support power training as a preferential exercise modality for clinical populations. The findings should be interpreted with caution since generalizability is questioned due to the heterogeneity of patient populations enrolled and participants were relatively mobile at baseline.

More Elevated Fastballs Associated With Placement on the Injured List due to Shoulder Injury.

Purpose: To evaluate whether impending shoulder injury was associated with changes in pitch location or velocity immediately preceding injury. Methods: Pitchers placed on the injured list (IL) due to a shoulder injury between 2015 and 2020 were identified in the Major League Baseball transactions database. Four-seam fastball velocity and frequency of pitch location for each pitch type was collected for each player in the season before placement on the IL and within 1 month of placement on the IL with a minimum of 55 pitches thrown of 1 type. Pitch locations were collected as identified by Baseball Savant's Game-Day Zones. Game-Day Zones were consolidated into high (above the strike zone midpoint) versus low, arm side (closer to the pitcher's arm side of the plate) versus opposite side, and within the strike zone versus out of zone. Repeated measures analysis of variance determined differences in four-seam velocity and the location distribution of 4-seam fastballs, change-ups, and breaking balls among each group. Results: In total, 267 pitchers were placed on the IL for a shoulder injury with the majority diagnosed with inflammation (89/267) followed by strain or sprain (69/267). Four-seam fastball locations significantly increased above the mid-point of the zone (45.9% vs 42.4%, P = .008) and out of the strike zone (48.5% vs 46.5%, P = .011) within a month before IL placement. There was no significant change in 4-seam fastball velocity immediately before IL placement. Conclusions: Pitchers threw more elevated 4-seam fastballs and out-of-zone 4-seam fastballs in the month before IL placement for shoulder injury. These findings suggest that a loss of 4-seam fastball command decreases with impending shoulder injury. Level of Evidence: IV, prognostic case series.

Bending the Elbow During Shoulder Flexion Facilitates Greater Scapular Upward Rotation and a More Favorable Scapular Muscle Activation Pattern.

CONTEXT: Decreased scapular upward rotation (UR) and diminished activation of the serratus anterior (SA) and lower trapezius (LT) are often observed among patients with subacromial impingement syndrome. Maintaining the elbow fully flexed during shoulder flexion may limit glenohumeral motion due to passive insufficiency of the triceps brachii and therefore facilitate greater scapular UR and increased scapular muscle activation. OBJECTIVES: To compare scapular UR, SA, upper trapezius (UT), middle trapezius, and LT activation levels between shoulder flexion with the elbow extended (Flexion-EE) to shoulder flexion with the elbow fully flexed (Flexion-EF). This study hypothesized that Flexion-EF would result in greater scapular UR, greater SA and LT activation, and a lower UT/SA and UT/LT activation ratio compared with Flexion-EE. DESIGN: Cross-sectional study. SETTING: A clinical biomechanics laboratory. PARTICIPANTS: Twenty-two healthy individuals. MAIN OUTCOME MEASURES: Scapular UR and electromyography signal of the SA, UT, middle trapezius, and LT, as well as UT/SA and UT/LT activation ratio were measured during Flexion-EE and Flexion-EF. RESULTS: Flexion-EF resulted in greater scapular UR compared with Flexion-EE (P < .001). Flexion-EF resulted in greater SA activation, lower UT activation, and a lower UT/SA activation ratio compared with Flexion-EE (P < .001). CONCLUSIONS: Fully flexing the elbow during shoulder flexion leads to increased scapular UR primarily through greater activation of the SA. This exercise may be of value in circumstances involving diminished scapular UR, decreased activation of the SA, and an overly active UT such as among patients with subacromial impingement syndrome.

Injury Rates in Major League Baseball During the 2020 COVID-19 Season.

BACKGROUND: The 2020 Major League Baseball (MLB) season was drastically altered because of the COVID-19 pandemic. The changes included an extended layoff between March and July as well as a shortened preseason. PURPOSE/HYPOTHESIS: To determine the incidence and epidemiology of MLB injuries in the abbreviated 2020 season compared with prior seasons. We hypothesized that there was an increase in the overall injury rate in the 2020 season compared with the 2018-2019 seasons and that it equally affected all body regions. STUDY DESIGN: Descriptive epidemiology study. METHODS: The MLB transactions database was queried to find players who had been placed on the injury list between 2018 and 2020. Injuries were categorized into upper extremity, lower extremity, spine/core, and other injuries. Incidence per 1000 athlete-exposures was calculated for the prior 2 seasons (2018-2019) and for the 2020 season separately. Incidence for each category was also calculated separately for pitchers and fielders. Incidence rate ratios (IRRs) and confidence intervals were used to compare injury rates in 2018-2019 versus 2020. The z test for proportions was used to determine significant differences between injury incidences. RESULTS: In 2020, the overall incidence rate per 1000 athlete-exposures was almost twice the rate compared with the 2 seasons before COVID-19 (8.66 vs 5.13; IRR, 1.69 [95% CI, 1.53-1.87]; P < .001). Injury incidence increased similarly in 2020 for both pitchers (IRR, 1.68 [95% CI, 1.47-1.91]; P < .001) and fielders (IRR, 1.68 [95% CI, 1.45-1.96]; P < .001). Increases in injury incidence were seen in the upper extremity, spine/core, and other injury categories; however, the incidence of the lower extremity did not change significantly. CONCLUSION: There was a significant increase in injury incidence for both pitchers and fielders in 2020. Injury rates increased in anatomic zones of the upper extremity and spine/core but were not significantly changed in the lower extremity. The overall increase in injury rate suggests that irregular or insufficient sport-specific preparation prior to the start of the season placed athletes at a greater risk of injury when play resumed.

A quantitative comparison of arm activity between survivors of breast cancer and healthy controls: use of accelerometry.

PURPOSE: Survivors of breast cancer (BC) on the non-dominant side have more persistent deficits than those with cancer on the dominant limb. What is not known is whether those with BC use their involved upper limbs more, less, or at the same level as women without BC. Accelerometer use offers a quantifiable method to measure activity levels of upper limbs. The purpose of this study was to quantify the activity levels of the non-dominant involved limb among survivors of BC and compare these values to their dominant limb, as well as the non-dominant limb of a control group. METHODS: Participants (n = 30) were women with unilateral BC on the non-dominant limb, diagnosed between 6 and 24 months prior to data collection, and a matched healthy group of women as controls. Participants completed the following questionnaires: medical and demographics, Brief Fatigue Inventory, Brief Pain Inventory - Short form, Disabilities of the Arm, Shoulder and Hand (DASH), and Beck Depression Index. Participants wore an accelerometer on each wrist during waking hours for 7 days. Arm activity was measured using vector magnitude activity counts extracted from the accelerometers. RESULTS: There were no significant differences in total vector magnitude activity counts between groups for either limb. Within group dominant to non-dominant comparison was significantly different (p ≤ 0.001). No significant difference in pain was present but significant differences for fatigue (p = 0.002), depression (p = 0.004), and DASH scores (p = 0.035) were present. CONCLUSIONS: Women with non-dominant BC use their involved limb similar to healthy controls but less than their dominant limb.

Comparison of Upper Extremity Function in Women With and Women Without a History of Breast Cancer.

BACKGROUND: Breast cancer treatments often result in upper extremity functional limitations in both the short and long term. Current evidence makes comparisons against a baseline or contralateral limb, but does not consider changes in function associated with aging. OBJECTIVE: The objective of this study was to compare upper extremity function between women treated for breast cancer more than 12 months in the past and women without cancer. DESIGN: This was an observational cross-sectional study. METHODS: Women who were diagnosed with breast cancer and had a mean post-surgical treatment time of 51 months (range = 12-336 months) were compared with women who did not have breast cancer (CTRL group). Self-reported upper extremity function using the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire and shoulder range of motion, strength, and muscular endurance were measured. Participants were divided into 3 groups: breast cancer involving the nondominant limb (BC-ND), breast cancer involving the dominant limb (BC-DOM), and CTRL. RESULTS: A total of 59 women in the CTRL group, 23 women in the BC-ND group, and 28 women in the BC-DOM group completed measures. Mean DASH scores in women with breast cancer were higher than those of women in the CTRL group, regardless of the limb on which cancer occurred (Cohen d = 1.13; 95% CI = 2.20 to 16.21) Range of motion for the BC-ND group was significantly less for flexion (Cohen d = 1.19, 95% CI = -13.08 to -0.11) and external rotation (Cohen d = 1.11, 95% CI = -18.62 to -1.98) compared with the CTRL group. Strength in the BC-ND group was 23% to 25% lower in the CTRL group for external (Cohen's d = 0.89, 95% CI = 0.09 to 0.12) and internal rotation (Cohen d = 0.92, 95% CI = 0.10 to 0.13). Endurance was not significantly different in the 3 groups. LIMITATIONS: Some participants had rehabilitation, which may have skewed results. The range of post-surgical treatment times was broad, making it difficult to determine when function returned. Muscular endurance measures demonstrated a ceiling effect and large variance, limiting the ability to distinguish differences among participants. These results may not be generalizable to the subset of women who were treated with lumpectomy, sentinel node biopsy, or chest wall radiation alone or who underwent a contralateral prophylactic mastectomy. CONCLUSION: In the long term, women with breast cancer have lower self-reported shoulder function than women without breast cancer. Motion and strength are lower among women who have experienced cancer on the nondominant limb.

A COMPREHENSIVE REHABILITATION PROGRAM FOR TREATING LATERAL ELBOW TENDINOPATHY.

Scapular muscle weakness in patients with lateral elbow tendinopathy is an identified impairment and is part of a multimodal rehabilitation approach. The published literature provides little information regarding specific rehabilitation guidelines that address both the proximal scapular muscle weakness and local elbow/wrist dysfunctions common in patients with lateral elbow tendinopathy. The purpose of this clinical commentary is to describe a comprehensive rehabilitation strategy for individuals with lateral elbow tendinopathy. This program emphasizes a phased therapeutic strategy that addresses proximal and local dysfunction along the kinetic chain. This clinical protocol is currently being tested for efficacy as part of a randomized controlled trial. The information in this commentary is intended to provide clinicians with sufficient detail to comprehensively guide the rehabilitation of a patient with lateral elbow tendinopathy. LEVEL OF EVIDENCE: 5.

National Athletic Trainers' Association Position Statement: Evaluation, Management, and Outcomes of and Return-to- Play Criteria for Overhead Athletes With Superior Labral Anterior-Posterior Injuries.

OBJECTIVE: To present recommendations for the diagnosis, management, outcomes, and return to play of athletes with superior labral anterior-posterior (SLAP) injuries. BACKGROUND: In overhead athletes, SLAP tears are common as either acute or chronic injuries. The clinical guidelines presented here were developed based on a systematic review of the current evidence and the consensus of the writing panel. Clinicians can use these guidelines to inform decision making regarding the diagnosis, acute and long-term conservative and surgical treatment, and expected outcomes of and return-to-play guidelines for athletes with SLAP injuries. RECOMMENDATIONS: Physical examination tests may aid diagnosis; 6 tests are recommended for confirming and 1 test is recommended for ruling out a SLAP lesion. Combinations of tests may be helpful to diagnose SLAP lesions. Clinical trials directly comparing outcomes between surgical and nonoperative management are absent; however, in cohort trials, the reports of function and return-to-sport outcomes are similar for each management approach. Nonoperative management that includes rehabilitation, nonsteroidal anti-inflammatory drugs, and corticosteroid injections is recommended as the first line of treatment. Rehabilitation should address deficits in shoulder internal rotation, total arc of motion, and horizontal-adduction motion, as well as periscapular and glenohumeral muscle strength, endurance, and neuromuscular control. Most researchers have examined the outcomes of surgical management and found high levels of satisfaction and return of shoulder function, but the ability to return to sport varied widely, with 20% to 94% of patients returning to their sport after surgical or nonoperative management. On average, 55% of athletes returned to full participation in prior sports, but overhead athletes had a lower average return of 45%. Additional work is needed to define the criteria for diagnosing and guiding clinical decision making to optimize outcomes and return to play.

Effectiveness of a Home-Based Eccentric-Exercise Program on the Torque-Angle Relationship of the Shoulder External Rotators: A Pilot Study.

CONTEXT: The role of the rotator cuff is to provide dynamic stability to the glenohumeral joint. Human and animal studies have identified sarcomerogenesis as an outcome of eccentric training indicated by more torque generation with the muscle in a lengthened position. OBJECTIVE: The authors hypothesized that a home-based eccentric-exercise program could increase the shoulder external rotators' eccentric strength at terminal internal rotation (IR). DESIGN: Prospective case series. SETTING: Clinical laboratory and home exercising. PARTICIPANTS: 10 healthy subjects (age 30 ± 10 y). INTERVENTION: All participants performed 2 eccentric exercises targeting the posterior shoulder for 6 wk using a home-based intervention program using side-lying external rotation (ER) and horizontal abduction. MAIN OUTCOME MEASURES: Dynamic eccentric shoulder strength measured at 60°/s through a 100° arc divided into 4 equal 25° arcs (ER 50-25°, ER 25-0°, IR 0-25°, IR 25-50°) to measure angular impulse to represent the work performed. In addition, isometric shoulder ER was measured at 5 points throughout the arc of motion (45° IR, 30° IR, 15° IR, 0°, and 15° ER). Comparison of isometric and dynamic strength from pre- to posttesting was evaluated with a repeated-measure ANOVA using time and arc or positions as within factors. RESULTS: The isometric force measures revealed no significant differences between the 5 positions (P = .56). Analysis of the dynamic eccentric data revealed a significant difference between arcs (P = .02). The percentage-change score of the arc of IR 25-50° was found to be significantly greater than that of the arc of IR 0-25° (P = .007). CONCLUSION: After eccentric training the only arc of motion that had a positive improvement in the capacity to absorb eccentric loads was the arc of motion that represented eccentric contractions at the longest muscle length.

Wearable IMU for Shoulder Injury Prevention in Overhead Sports.

Body-worn inertial sensors have enabled motion capture outside of the laboratory setting. In this work, an inertial measurement unit was attached to the upper arm to track and discriminate between shoulder motion gestures in order to help prevent shoulder over-use injuries in athletics through real-time preventative feedback. We present a detection and classification approach that can be used to count the number of times certain motion gestures occur. The application presented involves tracking baseball throws and volleyball serves, which are common overhead movements that can lead to shoulder and elbow overuse injuries. Eleven subjects are recruited to collect training, testing, and randomized validation data, which include throws, serves, and seven other exercises that serve as a large null class of similar movements, which is analogous to a realistic usage scenario and requires a robust estimator.

Neuromuscular Alterations After Ankle Sprains: An Animal Model to Establish Causal Links After Injury.

CONTEXT: The mechanisms that contribute to the development of chronic ankle instability are not understood. Investigators have developed a hypothetical model in which neuromuscular alterations that stem from damaged ankle ligaments are thought to affect periarticular and proximal muscle activity. However, the retrospective nature of these studies does not allow a causal link to be established. OBJECTIVE: To assess temporal alterations in the activity of 2 periarticular muscles of the rat ankle and 2 proximal muscles of the rat hind limb after an ankle sprain. DESIGN: Controlled laboratory study. SETTING: Laboratory. PATIENTS OR OTHER PARTICIPANTS: Five healthy adult male Long Evans rats (age = 16 weeks, mass = 400.0 ± 13.5 g). INTERVENTION(S): Indwelling fine-wire electromyography (EMG) electrodes were implanted surgically into the biceps femoris, medial gastrocnemius, vastus lateralis, and tibialis anterior muscles of the rats. We recorded baseline EMG measurements while the rats walked on a motor-driven treadmill and then induced a closed lateral ankle sprain by overextending the lateral ankle ligaments. After ankle sprain, the rats were placed on the treadmill every 24 hours for 7 days, and we recorded postsprain EMG data. MAIN OUTCOME MEASURE(S): Onset time of muscle activity, phase duration, sample entropy, and minimal detectable change (MDC) were assessed and compared with baseline using 2-tailed dependent t tests. RESULTS: Compared with baseline, delayed onset time of muscle activity was exhibited in the biceps femoris (baseline = -16.7 ± 54.0 milliseconds [ms]) on day 0 (5.2 ± 64.1 ms; t4 = -4.655, P = .043) and tibialis anterior (baseline = 307.0 ± 64.2 ms) muscles on day 3 (362.5 ± 55.9 ms; t4 = -5.427, P = .03) and day 6 (357.3 ± 39.6 ms; t4 = -3.802, P = .02). Longer phase durations were observed for the vastus lateralis (baseline = 321.9 ± 92.6 ms) on day 3 (401.3 ± 101.2 ms; t3 = -4.001, P = .03), day 4 (404.1 ± 93.0 ms; t3 = -3.320, P = .048), and day 5 (364.6 ± 105.2 ms; t3 = -3.963, P = .03) and for the tibialis anterior (baseline = 103.9 ± 16.4 ms) on day 4 (154.9 ± 7.8 ms; t3 = -4.331, P = .050) and day 6 (141.9 ± 16.2 ms; t3 = -3.441, P = .03). After sprain, greater sample entropy was found for the vastus lateralis (baseline = 0.7 ± 0.3) on day 6 (0.9 ± 0.4; t4 = -3.481, P = .03) and day 7 (0.9 ± 0.3; t4 = -2.637, P = .050) and for the tibialis anterior (baseline = 0.6 ± 0.4) on day 4 (0.9 ± 0.5; t4 = -3.224, P = .03). The MDC analysis revealed increased sample entropy values for the vastus lateralis and tibialis anterior. CONCLUSIONS: Manually inducing an ankle sprain in a rat by overextending the lateral ankle ligaments altered the complexity of muscle-activation patterns, and the alterations exceeded the MDC of the baseline data.

Preseason Perceived Physical Capability and Previous Injury.

CONTEXT: Patient opinion about the ability to perform athletic maneuvers is important after injury; however, prospective assessment of self-perceived physical capability for athletes before the beginning of a season is lacking. OBJECTIVE: To perform a descriptive analysis of knee, shoulder, and elbow self-perceived measures of physical capability specific to athletics and to compare the measures between athletes with and without a history of injury. DESIGN: Cross-sectional study. SETTING: Preparticipation physical examinations. PATIENTS OR OTHER PARTICIPANTS: A total of 738 collegiate athletes (486 men, 251 women; age = 19 ± 1 years) were administered questionnaires after receiving medical clearance to participate in their sports. Of those athletes, 350 reported a history of injury. MAIN OUTCOME MEASURE(S): Athletes self-reported a history of knee, shoulder, or elbow injury. Perceived physical capability of the 3 joints was evaluated using the Knee Injury and Osteoarthritis Outcome Score Sport and Recreation Function and Knee-Related Quality of Life subscales and the Kerlan-Jobe Orthopaedic Clinic Shoulder and Elbow Score. We conducted nonparametric analysis to determine if scores differed between athletes with and without a history of injury. RESULTS: Median values for the Knee Injury and Osteoarthritis Outcome Score Sports and Recreation Function and Knee-Related Quality of Life subscales and the Kerlan-Jobe Orthopaedic Clinic Shoulder and Elbow Score for all athletes were 100. Median values for perceived physical capability of athletes with a history of injury were 3 to 12 points lower for each questionnaire before the start of the season (P < .001). CONCLUSIONS: Our study provided descriptive values for individual perceived knee, shoulder, and elbow physical capability of collegiate athletes participating in 19 sports. Athletes who did not report previous injuries perceived their physical capabilities to be nearly perfect, which could set the goal for these athletes to return to participation after injury. Athletes reporting previous injuries perceived less physical capability before the competitive season. Self-assessment of joint-specific capability may supplement preseason physical examinations, identifying particular athletes needing further monitoring or care during a season.

Return to Preinjury Levels of Participation After Superior Labral Repair in Overhead Athletes: A Systematic Review.

CONTEXT: Athletes often preoperatively weigh the risks and benefits of electing to undergo an orthopaedic procedure to repair damaged tissue. A common concern for athletes is being able to return to their maximum levels of competition after shoulder surgery, whereas clinicians struggle with the ability to provide a consistent prognosis of successful return to participation after surgery. The variation in study details and rates of return in the existing literature have not supplied clinicians with enough evidence to give overhead athletes adequate information regarding successful return to participation when deciding to undergo shoulder surgery. OBJECTIVE: To investigate the odds of overhead athletes returning to preinjury levels of participation after arthroscopic superior labral repair. DATA SOURCES: The CINAHL, MEDLINE, and SPORTDiscus databases from 1972 to 2013. STUDY SELECTION: The criteria for article selection were (1) The study was written in English. (2) The study reported surgical repair of an isolated superior labral injury or a superior labral injury with soft tissue debridement. (3) The study involved overhead athletes equal to or less than 40 years of age. (4) The study assessed return to the preinjury level of participation. DATA EXTRACTION: We critically reviewed articles for quality and bias and calculated and compared odds ratios for return to full participation for dichotomous populations or surgical procedures. DATA SYNTHESIS: Of 215 identified articles, 11 were retained: 5 articles about isolated superior labral repair and 6 articles about labral repair with soft tissue debridement. The quality range was 11 to 17 (42% to 70%) of a possible 24 points. Odds ratios could be generated for 8 of 11 studies. Nonbaseball, nonoverhead, and nonthrowing athletes had a 2.3 to 5.8 times greater chance of full return to participation than overhead/throwing athletes after isolated superior labral repair. Similarly, nonoverhead athletes had 1.5 to 3.5 times greater odds for full return than overhead athletes after labral repair with soft tissue debridement. In 1 study, researchers compared surgical procedures and found that overhead athletes who underwent isolated superior labral repair were 28 times more likely to return to full participation than those who underwent concurrent labral repair and soft tissue debridement (P < .05). CONCLUSIONS: The rate of return to participation after shoulder surgery within the literature is inconsistent. Odds of returning to preinjury levels of participation after arthroscopic superior labral repair with or without soft tissue debridement are consistently lower in overhead/throwing athletes than in nonoverhead/nonthrowing athletes. The variable rates of return within each group could be due to multiple confounding variables not consistently accounted for in the articles.