Evolution of the throwing shoulder: why apes don't throw well and how that applies to throwing athletes

BACKGROUND

Humans have unique characteristics making us the only primate that can throw well while most other primates throw predominately underhand with poor speed and accuracy. The purpose of this study is to illuminate the uniquely human characteristics that allow us to throw so well. When treating an injury such as a labral tear or capsule tear, this study hopes the reader can gain a better understanding of the issues that lead to the tear and those that may determine the success of treatment besides the actual repair.

METHODS

In addition to a review of scientific and medical literature, information was obtained from interviews and experience with primate veterinarians, anthropologists, archeologists, and professional baseball players. These sources were used to study the connection between evolutionary throwing activities and current sports medicine issues.

RESULTS

Arm acceleration requires a functional kinetic chain, rapid motor sequences, and the ability to absorb elastic energy in the shoulder. Successful treatment of the throwing shoulder requires awareness of the shoulder's position in the kinetic chain and correction of defects in the ability to execute the kinetic chain. Some problems in the shoulder could reflect regression to a more primitive anatomy or dyskinesis. Return of performance requires regaining the elasticity in the tissues of the shoulder to temporarily store kinetic energy. For example, tissue remodeling after rotator cuff repair continues for months to years; however, the newly formed tissue lacks the same elasticity of the native tendon. This suggests why throwing performance typically does not return for 7 or more months after repair even though there may be structural integrity at 3-4 months.

CONCLUSION

The shoulder has developed uniquely in modern man for the act of throwing. The anatomic deficiencies in primates for throwing provide an illustration of the more subtle changes that a throwing athlete might have that are detrimental to throwing. Nonhuman primates have been unable to demonstrate the kinetic chain sequence for throwing secondary to the lack of neurologic pathways required. Humans are more sophisticated and precise in their movements but lack robusticity in their bone and muscle architecture, seen especially in the human rotator cuff. Successful treatment of a throwing injury requires familiarity with the conditions that cause the injury or affect the rehabilitation process. The return of performance following injury or surgery requires regaining the elasticity in the tissues of the shoulder to temporarily store kinetic energy from the kinetic chain.

The open Latarjet-Patte procedure for the treatment of anterior shoulder instability in professional handball players at a mean follow-up of 6.6 years

BACKGROUND

The popularity of team handball is increasing, with >10 million children playing this overhead throwing and collision sport with highest demands on the shoulder joint. Because of the risk of recurrent instability, the Latarjet-Patte (LP) procedure has been recommended to treat young competitive players. This is the first LP outcome study in professional handball players.

METHODS

We retrospectively included 20 shoulders (18 players [17 male patients]; mean age, 22.9 years [range, 17-35 years]; minimum follow-up period, 2 years; mean follow-up period, 6.6 years) operated on by 3 expert surgeons (2011-2020) with the Walch LP technique. We documented preoperative hyperlaxity (25%, n = 5), affected throwing arm (55%, n = 11), position (backcourt, winger, and goalkeeper, 22% each; full back and pivot, 17% each), >2 dislocations prior (20%, n = 4), >10 dislocations prior (5%, n = 1), previous failed Bankart or humeral avulsion of glenohumeral ligament (HAGL) repair (10%, n = 2), and large Hill-Sachs lesions (HSLs) (20%, n = 4). Clinical and radiographic outcomes, visual analog scale score, Subjective Shoulder Value, Walch-Duplay score, Rowe score, and return-to-sport (RTS) rate were recorded.

RESULTS

The RTS rate was 85% (17 of 20 shoulders); rate of RTS at the same level, 80% (16 of 20); and rate of RTS with no throwing pain, 73% (8 of 11). The time to training with a ball was 3.2 months, and the time to competition was 4.9 months. The mean Rowe score, Walch-Duplay score, and Subjective Shoulder Value were 90 points, 88 points, and 89%, respectively. Shoulder symptoms led players to give up handball in 2 cases (10%), whereas 1 player (5%) stopped playing handball for other reasons. We recorded 1 recurrent dislocation (5%) (non-throwing arm, winger, no recurrence after rehabilitation). Persistent apprehension occurred in 1 goalkeeper (5%). Residual pain was seen in 4 shoulders (20%); this was relieved by screw removal in 1. Resistant pain (throwing shoulder) was seen in 2 backcourt players (10%, 1 of whom had a large HSL) and 1 goalkeeper (5%; large HSL with >10 dislocations prior), all 3 of whom were aged > 30 years. Bone block positioning was correct (no lateral overhang) in all shoulders. At final follow-up, 1 shoulder (5%) showed mild arthritic changes (>10 dislocations, large HSL).

CONCLUSION

The open LP procedure is consistent in providing shoulder stability combined with return-to-throwing performance in professional handball players with a short time to RTS and high same-level RTS rate without increasing the risk of arthritic changes. Throwing shoulders of backcourt players, large HSLs, or age > 30 years may have an increased risk of persistent symptoms.

Adaptive pathology: new insights into the physical examination and imaging of the thrower's shoulder and elbow

Throwing with high velocity requires extremes of glenohumeral external rotation of the abducted arm where particularly high forces in the shoulder and elbow are endured. Repeated throwing leads to dominant-arm bony remodeling of the humerus, glenoid, and elbow, and multiple soft tissue changes that would be considered abnormal. Many of these features are thought to be adaptive and protective. The purpose of this work is to (1) define the concept of adaptive pathology; (2) review the mechanics of the throwing motion; (3) review pertinent physical examination and imaging findings seen in asymptomatic throwers' shoulders and elbows and describe how these changes develop and may be adaptive-allowing the thrower to perform at high levels; and then (4) review the principles of surgical treatment in the throwing athletes, which should focus on reducing symptoms, but not necessarily restoring the thrower's anatomy to normal.

Current concepts: the hip, core and kinetic chain in the overhead athlete

BACKGROUND

As overhead sports continue to grow in popularity, there has been increased interest in optimizing sports performance and injury prevention in these athletes. The hip, core, and kinetic chain have become a focus of research in recent decades, and their importance in upper extremity mechanics is now being recognized.

METHODS

An extensive review was carried out to identify papers correlating the hip, core and/or kinetic chain in overhead athletic performance and injury.

RESULTS

Recent literature has shown that efficiency and synchrony of the hips and core during an overhead movement (such as in baseball, golf, tennis, or volleyball) is essential for a powerful and precise execution of the task. Impairments of the hip and core, particularly abnormal joint mobility or weakness, can limit efficient energy transfer through the kinetic chain and may negatively impact performance. Recent epidemiologic studies have found hip pain to be common in adolescent, collegiate, and adult athletes. Moreover, hip pain in overhead athletes specifically has also been found to occur at a high rate. Abnormalities in hip range of motion, hip morphology, and core strength can lead to abnormal mechanics upstream in the kinetic chain, which may place athletes at risk of injuries.

CONCLUSION

In this review, the complex and multifaceted relationship between the hip, core, and kinetic chain is highlighted with an emphasis on recent literature and relevant findings.

Examining Single Session Peer-Teaching Instructional Approaches on Pre-Service Physical Education Teachers' Throwing Techniques

An important role of a Physical Education (PE) teacher is to assist students to develop the fundamental motor skills (FMS) that will allow them to participate in physical activities with competence and confidence. Thus, PE teachers require the knowledge and skills to carry out this crucial task. In the crowded curricula of Physical Education Teacher Education (PETE) programs, there are limited opportunities for pre-service PE teachers to learn how to analyze and perform a large list of motor skills. Our purposes in this study were to determine whether a single session peer-teaching intervention could improve pre-service PE teachers' short-term non-dominant hand overarm throwing performances and to examine these students' perceptions of the interventions. We allocated 47 pre-service PE teaching students (24 males; 23 females) to one of three experimental groups: a Video Analysis Group (VAG; n = 17), a Verbal Group (VG; n = 19), and a Control Group (CG; n = 11), based on the class in which they were enrolled. VAG and VG participants worked with a partner of their choice in reciprocal peer-teaching to improve each other's non-dominant hand throwing technique. VAG and VG interventions were identical except that VAG participants accessed video analysis technology. CG participants completed unrelated course work that involved no overarm throwing activities. A single 20-minute session of peer teaching with video analysis feedback during practice led to rapid enhancements in non-dominant hand overarm throwing skills. While all three groups improved their performance by retention testing, participants in the VAG group improved most quickly. Participants in both the VAG and VG groups reported that their respective interventions improved their throwing and Qualitative Movement Diagnosis (QMD) skills. Based on these results, we suggest that PETE programs integrate peer-teaching and video analysis sessions into fundamental movement courses to accelerate students' motor skill acquisitions.

Inter-Trial Rest Interval Affects Learning Throwing Skills among Adolescents

Newly acquired motor skills can be critically driven by different rest periods during practice. Specifically, in the initial stages of motor skill acquisition, the interval between individual trials plays a pivotal role in facilitating effective motor performance, such as in the case of throwing. The objective of this research was to determine the optimal inter-trial rest period promoting efficient motor performance, focusing on two specific motor task actions. In a randomized counterbalanced cross-over research design 169 high-school students aged 14 were studied (M = 150; F = 19). In one block, participants performed 10 basketball free throws with a short rest interval (< 5 s) and 10 other throws with a long rest interval (∼50-60 s). In a second block, they threw a regular size tennis ball into a 1-m diameter circle on the floor at 6.75 m, again throwing 10 times with a short inter-trial rest interval and 10 times with a long inter-trial rest interval. The order of the rest intervals within each block was randomized and counterbalanced. With a repeated measures two-way analysis of variance, greater accuracy seemed to be associated with short intra-set rest intervals as there were significant main effects of both conditions (F1,167 = 368.0, p < 0.001, η2p = 0.271) and resting time (F1,167 = 18.6, p < 0.001, η2p = 0.192) and no significant interaction "condition by time". Fast practice was efficient independently of the complexity of the throwing task, suggesting robust support for schema theory.

Adolescent track and field injuries presenting to US emergency departments

OBJECTIVES

Track and field (T&F) is a highly popular sport for adolescents. The diversity of running, jumping, and throwing events within the sport can result in unique injury patterns for adolescent track and field participants. The purpose of this study was to estimate injury risk in adolescent T&F and describe the types of injuries resulting in ED visits, classified by T&F events.

METHODS

Emergency department (ED) data from the National Electronic Injury Surveillance System were obtained for a 20-year period from 2000 through 2019. Cases involving 14- to 18-year-olds participating in T&F were classified by sex, case severity, involved body region, and the T&F event patients were engaged in at the time of their injury. National estimates and Injury rates were calculated using national high school T&F participation data. Longitudinal trends in ED visits were measured using linear regression. Rate ratios (RRs) were used to compare the risk and severity of ED visits by sex.

RESULTS

8,060 track and field related ED encounters were observed, representing an estimated 272,227 encounters nationally over the 20-year study period. The rate of ED encounters increased significantly over the study period (p < 0.001). Adolescent females exhibited a higher rate of ED encounters (RR: 1.23, 95% CI: 1.22-1.24), but a lower rate of hospital admissions (RR: 0.68, 95% CI: 0.64-0.73) compared to males. The lower extremity was the most commonly injured body region for most T&F events, but this differed for sprinting, high jumping, shot put, and javelin events. Most T&F events resulted in unique injury patterns characteristic of their athletic demands.

CONCLUSIONS

There was an increasing trend of ED visits from adolescent T&F participants throughout the 20-year study period with different injury patterns observed by sex and T&F event discipline.

Sports Physiology in Adolescent Track-and-Field Athletes: A Narrative Review

The present study aimed to review the physiological aspects of adolescent track-and-field (TAF) athletes. A search of Scopus on 27/12/2022 using the syntax ABS (track-and-field) AND ABS (children) OR ABS (adolescent) showed 121 documents, and 45 were considered for further analysis. In addition, handsearching was conducted to identify Russian literature missing in Scopus. Differences were shown in performance characteristics among disciplines, especially between throwers and the other athletes. The sex difference in performance (ie, a better performance in boys than in girls) started in early adolescence. A relative age effect was more pronounced in athletes under 13 years old. Despite the wide use of nutritional supplements, an insufficient intake of vitamins has been found. The age of training onset and body weight were identified as risk factors for problems with menarche. The inclusion of track-and-field training programs in physical education was beneficial for health and physical fitness. The need to collaborate closely with parents and coaches was identified, especially, regarding education in topics such as the age of training onset, relative age effect, and doping. In conclusion, the existence of many disciplines with different anthropometric and physiological characteristics highlighted the need for a discipline-specific approach.

Cricket fast bowling: The relationship between range of motion and key performance and injury technique characteristics

Fast bowling technique characteristics associated with performance and injury have been established; however, the effect of joint range of motion (ROM) on technique remains unknown. This study aimed to investigate ROM and its effect on fast bowling technique. Eighteen ROM measures and thirteen technique parameters were determined for 45 elite male fast bowlers. Twenty-three significant correlations were found between the shoulder, hip, and ankle ROM measures and technique parameters (r = 0.300-0.452; p < 0.05). Shoulder ROM was observed to have the highest number of correlations with fast bowling technique. Increased internal rotation, less external rotation, and greater total arc of rotation were associated with technique characteristics previously linked with increased ball release speed and decreased lumbar stress injury risk. Although hip and ankle ROM were also correlated with technique, their association is yet to be understood. Future research should aim to determine the impact of ROM on fast bowling movement patterns. This knowledge is likely to be useful in enhancing the coaching and rehabilitation of fast bowlers from lumbar stress injuries.

An Exploratory Investigation Evaluating the Impact of Fatigue-Induced Stride Length Compensations on Ankle Biomechanics among Skilled Baseball Pitchers

Altered propulsive and bracing ground reaction forces from lower-body fatigue significantly impact stride length to increase weakness in dynamic elbow stabilizers and risk of medial elbow injury in baseball pitchers. This work investigated altered stride length on three-dimensional ankle joint dynamics to illustrate fatigue-induced changes in ankle motion that can also be impacted by coaching errors. Nineteen pitchers (15 collegiate and 4 high school) were randomized in a crossover design study that encouraged fatigue by throwing two simulated 80-pitch games at ±25% of their desired stride length. An integrated motion-capture system with two force plates and radar gun tracked each throw. Retrospective analysis using pairwise comparisons, including effect size calculations, were undertaken to identify differences in ankle dynamics between stride length conditions for both the drive and stride leg. Longer strides were found to be more effective in drive ankle propulsion and stride-bracing mechanics. Conversely, shorter strides delayed bracing dynamics by demonstrating continued drive ankle plantar flexion moments after stride-foot contact to extend pitchers' time in propulsion (p < 0.001, d > 0.8). Additionally, heightened braking effects were seen during the acceleration phase of throwing with greater stride knee extension power when pitching with shorter strides (p < 0.001, d > 0.8). The knowledge gained from this work offers new insight into compensatory stride length adaptation that impacts systemic and throwing arm-specific fatigue to maintain ball velocity, as bilateral ankle joint dynamics can be significantly affected in response to cumulative workload.

Kinematic and kinetic comparison between preprofessional pitchers from the Dominican Republic and the United States

Introduction

Pitching biomechanical efficiency is defined as the association between pitch velocity and arm kinetics. Pitching mechanics inefficiency, an increase in arm kinetics without the resultant increase in pitch velocity, can lead to increased arm strain, increasing arm injury risk. The purpose of this study was to compare arm kinetics, elbow varus torque and shoulder force, in preprofessional United States (US) and Dominican Republic (DR) pitchers. Kinematics that are known to influence elbow varus torque and shoulder force as well as a representative of pitch velocity (hand velocity) were also compared.

Methods

A retrospective review was performed on baseball pitchers from the DR and US who participated in biomechanical evaluations conducted by the University biomechanics laboratory personnel. Three-dimensional biomechanical analyses were performed on US (n = 37) and DR (n = 37) baseball pitchers. Potential differences between US and DR pitchers were assessed through analysis of covariance with 95% confidence intervals [95% confidence Interval (CI)].

Results

Preprofessional DR pitchers experienced increased elbow varus torque compared with their US counterparts [DR: 7.5 (1.1); US: 5.9 (1.1) %BWxH; Beta: -2.0 (95% CI: -2.7, -1.2) %BWxH], despite throwing fastballs with slower hand velocity [DR: 3,967.1 (939.4); US: 5,109.1 (613.8) °/s; Beta: 1,129.5 (95% CI: 677.5, 1,581.4) °/s]. DR and US pitchers demonstrated similar shoulder force [DR: 136.8 (23.8); US: 155.0 (25.7); Beta: 0.4 (95% CI: -1.2, 19.7) %BW].

Discussion

Increased elbow varus torque although decreased hand velocity suggests inefficient pitching mechanics among DR pitchers. Inefficient pitching mechanics and increased elbow torque should be considered when developing training programs and pitching plans for professional pitchers from the Dominican Republic.

Neither Too Easy Nor Too Difficult: Effects of Different Success Criteria on Motor Skill Acquisition in Children

The purpose of this study was to examine the effects of different success criteria on motor learning in children. Forty-eight children threw soft-golf balls toward a circular target using their nondominant arm. On Day 1, they performed six blocks of 12 trials from 5.5 m. On Day 3, they performed a 12-trial retention test followed by a 12-trial transfer test. Participants were randomly assigned to one of four groups: difficult criteria for success, relatively easy criteria for success (RES), easy criteria for success, and control. Results demonstrated that there was a significant difference between the RES and control groups in their throwing accuracy on the retention and transfer tests, and the RES group had the highest score compared with the other two groups. This research suggests that providing relatively easy criteria facilitates motor skill acquisition in children.

Clinical outcomes and return to play in softball players following SLAP repair or biceps tenodesis

BACKGROUND

Shoulder pain due to labral tears and biceps tendonitis is commonly found in softball players. Surgical options include labral repair and biceps tenodesis. Although past studies are limited by heterogeneous study groups from multiple sports, this is the first study that assesses clinical outcomes and return to play rates for fast-pitch softball players.

PURPOSE/HYPOTHESIS

The purpose of this study was to evaluate the clinical outcomes and return to play for fast-pitch softball players treated for a superior labrum anterior posterior (SLAP) tear and recalcitrant biceps tendonitis with a biceps tenodesis compared with a traditional SLAP repair. We hypothesized that the biceps tenodesis would have comparable outcomes with a faster return to play compared with SLAP repair.

METHODS

We performed a retrospective analysis on fast-pitch softball players treated surgically for SLAP tear, recalcitrant biceps tendonitis, or a combination between 2001 and 2019 at our institution. Inclusion criteria were fast-pitch softball players who underwent biceps tenodesis or a SLAP repair with greater than 2-year follow-up. Exclusion criteria involved slow-pitch softball players, patients with less than 2-year follow-up, and patients who had undergone concomitant procedures on the ipsilateral shoulder at the time of SLAP repair or biceps tenodesis. Follow-up was either self-reported through OBERD, a patient-reported outcomes (PRO)-managing software, or achieved over the phone. Follow-up data included American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form score, Andrews Carson Score, Kerlan-Jobe Orthopaedic Clinic Shoulder and Elbow Score, Numeric Rating Scale for Pain, and our institution-specific return-to-play questionnaire. We statistically compared players who underwent biceps tenodesis or a SLAP repair, and compared pitchers with position players using Student t tests and Fisher exact test with statistical significance determined to be P < .05.

RESULTS

From 60 eligible patients identified, follow-up outcome data were successfully captured for 47 (78%). Of the 18 SLAP repair patients, 17 (94%) returned to full competition at an average of 7.9 months. Of the 29 patients who underwent biceps tenodesis, 27 (93%) returned to full competition at an average of 7.1 months. Statistical analysis of PRO scores for each group found no significant differences between any of the measures used to evaluate patient outcomes, including no statistical difference in pitchers compared with position players.

CONCLUSION

In conclusion, this study demonstrated comparable outcomes between SLAP repairs and biceps tenodesis procedures among our study group of fast-pitch softball players. There was no significant difference between RTP times between the 2 groups.

Using Sensors for Player Development: Assessing Biomechanical Factors Related to Pitch Command and Velocity

Pitching biomechanical research is highly focused on injury prevention with little attention to how biomechanical data can facilitate skill development. The overall purpose of this study was to explore how sensor-derived segment kinematics and timing relate to command and ball velocity during baseball pitching. We used a cross-sectional design to analyze a series of pitches thrown from 10 collegiate baseball pitchers. We collected biomechanical data from six inertial sensors, subjective command from the pitchers, and ball velocity from a radar device. Stepwise regression analyses were used to explore biomechanical variables associated with command for all pitches and ball velocity for fastballs only. We found that only peak forearm linear acceleration was significantly associated with command, whereas several segment kinematic measures were significantly associated with ball velocity. Our results suggest that different biomechanical variables are linked to specific pithing skills. Our findings suggest that end-effector (forearm) movement is more important for pitch command, whereas proximal-to-distal (pelvis, trunk, upper arm, forearm) segmental movement is important for ball velocity.

History of Ulnar Collateral Ligament Injury and College Pitcher Fastball Profiles: A Retrospective, Observational, Live Pitching Analysis

PURPOSE

The aim of this study was to retrospectively compare the fastball profiles of pitchers who had previously sustained grade I or II ulnar collateral ligament (UCL) injuries, were rehabilitated, and released back for competition with those of pitchers with no history of elbow injury.

METHODS

Eighteen pitchers from the pitching staff of 1 National Collegiate Athletic Association Division III team participated in this study. Group 1 had a history of grade I or II UCL injury (n = 8), and group 2 (n = 10) did not. A computerized pitch tracking device was used to analyze ball movement and pitching mechanics. The hypothesis was that the pitchers with a history of injury (group 1) would display differing fastball velocity-ball movement relationships compared to those without (group 2).

RESULTS

The groups had similar heights, weights, pitching experiences, and arm slot positions at ball release. The pitching coach-determined preinjury arm slot position and the postinjury computerized pitch tracking device measurements after return to competition displayed strong agreement (r = 0.83), suggesting comparable pre and postinjury pitching techniques. The groups had comparable glenohumeral joint range of motion and fastball profiles, except that group 1 released the ball at a 2.5 times lesser horizontal distance away from the pitching rubber center. Group 2 also displayed consistently more robust and more frequent fastball movement relationships with velocity, horizontal break, and vertical break than group 1.

CONCLUSIONS

Reduced horizontal ball release distances at comparable vertical ball release heights without changes in the arm slot position suggest that pitchers with a history of grade I or II UCL injury have greater contralateral trunk tilt and elbow flexion at ball release. Increased contralateral trunk tilt may occur to increase pitch velocity at the expense of ball movement while placing the pitching elbow in a potentially injurious position. Computerized fastball profile analysis using a computerized pitch tracking device, in conjunction with coach pitching technique observation, and team medical staff clinical examination may help better identify pitchers with an increased risk of UCL injury.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic II.

Evaluation of approaches to estimate scapular kinematics during baseball pitching

Biomechanical analyses of pitching possess limitations in accurately measuring dynamic scapular orientation and are thus unable to distinguish between glenohumeral and scapulothoracic contributions to global shoulder motion. In lieu of direct measurement, several methods to estimate scapular kinematics have been developed. This study evaluated the ability of the linear model and the double calibration acromion marker cluster (D-AMC) approaches to estimate scapular kinematics throughout a full-speed pitching motion. Each approach's estimates were compared against scapulothoracic range of motion limits established in a non-pitching biplane fluoroscopy study involving various functional arm movements that approximate physiological limits of scapular motion. Fourteen healthy collegiate pitchers participated. Motion capture measured upper extremity joint kinematics during full-speed fastball pitches. Linear model and D-AMC approaches estimated scapulothoracic kinematics during each pitch. Linear model estimates of scapulothoracic kinematics were largely within established physiological limits on each scapular axis of motion while D-AMC estimates exceeded fluoroscopy-established bounds for more subjects and by larger, less physiologically plausible amounts. These findings demonstrate that the linear model outperforms the D-AMC and suggest that it is a viable approach to estimate scapular kinematics during pitching. Finally, these results offer additional evidence to support the accepted pattern of scapular kinematics during pitching.

Does proximal versus distal injury location of the medial ulnar collateral ligament of the elbow differentially impact elbow stability? An ultrasound-guided and robot-assisted biomechanical study

BACKGROUND

The location (proximal vs. distal) of elbow medial ulnar collateral ligament (MUCL) tears impacts clinical outcomes of nonoperative treatment. The purposes of our study were to (1) determine whether selective releases of the MUCL could be performed under ultrasound (US) guidance without disrupting overlying soft tissues, (2) assess the difference in medial elbow stability for proximal and distal releases of the MUCL using stress US and a robotic testing device, and (3) elucidate the flexion angle that resulted in the greatest amount of medial elbow laxity after MUCL injury.

METHODS

Sixteen paired, fresh-frozen elbow specimens were used. Valgus laxity was evaluated with both US and robotic-assisted measurements before and after selective MUCL releases. A percutaneous US-guided technique was used to perform proximal MUCL releases in 8 elbows and to perform distal MUCL releases in their matched pairs. The robot was used to determine the elbow flexion angle at which the maximum valgus displacement occurred for both proximally and distally released specimens. Open dissection was then performed to assess the accuracy of the percutaneous releases.

RESULTS

Percutaneous US-guided releases were successfully performed in 15 of 16 specimens. The proximal release resulted in greater valgus angle displacement (11° ± 2°) than the distal release (8° ± 2°) between flexion angles of 30° and 70° (P < .0001 at 30°, P < .0001 at 40°, P = .001 at 50°, P = .005 at 60°, and P = .020 at 70°). Valgus displacement between release locations did not reach the level of statistical significance between 80° and 120° (P = .051 at 80°, P = .131 at 90°, P = .245 at 100°, P = .400 at 110°, and P = .532 at 120°). When we compared the values for the mean increase in US delta gap (stressed - supported state) from before to after MUCL release, the proximally released elbows had larger increases than the distally released elbows (5.0 mm proximal vs. 3.7 mm distal, P = .032). After MUCL release, maximum mean valgus displacement occurred at 49° of flexion.

CONCLUSIONS

US-guided selective releases of the MUCL can be performed reliably without violating the overlying musculature. Valgus instability is not of greater magnitude for distal releases when compared with proximal releases. This findings suggests there must be alternative factors to explain the difference in clinical prognosis between distal and proximal tears. The observed flexion angle for maximum valgus laxity could have important implications for elbow positioning during US or fluoroscopic stress examination, as well as surgical repair or reconstruction of the MUCL.

Determinants of Biomechanical Efficiency in Collegiate and Professional Baseball Pitchers

BACKGROUND

Biomechanical efficiency, defined as fastball velocity per unit of normalized elbow varus torque, is a relatively new metric applied to improving the performance and health of baseball pitching.

PURPOSE/HYPOTHESIS

The purpose of this work was to evaluate kinematic parameters influencing biomechanical efficiency among professional and collegiate pitchers. Kinematic differences were compared between pitchers of high and low biomechanical efficiency. We hypothesized that professional pitchers would have greater biomechanical efficiency than collegiate pitchers.

STUDY DESIGN

Descriptive laboratory study.

METHODS

A deidentified biomechanical database of 545 pitchers (447 professional, 98 collegiate) was analyzed. A multivariate linear regression model was used to evaluate significant findings a priori with α = .05. Additionally, biomechanical differences were identified between competition levels and between high and low biomechanical efficiency groups using Mann-Whitney U test (α = .05).

RESULTS

Competition level and 11 (of 21) kinematic variables explained 27% of the variance in biomechanical efficiency, with most of the predictors being throwing arm kinematics (elbow flexion at stride foot contact [SFC]: β, -1.47; SE, 0.26; shoulder abduction at SFC: β, -1.78; SE, 0.39; shoulder external rotation at SFC: β, 0.60; SE, 0.22; maximum external rotation [MER] angle: β, 1.82; SE, 0.42; shoulder horizontal adduction at MER: β, -3.42; SE, 0.71) (all P≤ .05). Professional pitchers had greater biomechanical efficiency than collegiate pitchers (711.0 ± 101.0 vs 657.0 ± 99.3, respectively; P < .001; d = 0.53). Compared with the low-efficiency group, the high-efficiency group had significantly lower normalized elbow varus torque with greater weight and height (high: 0.047 ± 0.004 %wt*ht vs. low: 0.063 ± 0.006 %wt*ht, P <.001; d = 3.20). At the instant of SFC, the high-efficiency group demonstrated greater shoulder external rotation and less elbow flexion, shoulder abduction, and pelvic rotation. The high-efficiency group also had greater MER and less shoulder horizontal adduction at MER, trunk side tilt at ball release, and knee excursion from foot contact to ball release.

CONCLUSION

Professional pitchers had greater biomechanical efficiency than collegiate pitchers. Biomechanical efficiency was also affected by 11 kinematic variables identified in this study. Pitchers with higher efficiency had distinct differences in arm position, trunk side tilt, and lead-knee extension range of motion in the delivery. Thus, pitchers and baseball organizations should focus on these factors to lower normalized elbow varus torque relative to ball velocity.

Increased external rotation related to the soft tissues is associated with pathologic internal impingement in high-school baseball players

BACKGROUND

Changes in soft-tissue structures such as anterior laxity and posterior tightness are thought to contribute to the development of pathologic internal impingement in baseball players. Although side-to-side differences in shoulder rotational range of motion (ROM) is commonly used in clinical practice to quantify the soft-tissue changes, the ROM does not accurately reflect the soft-tissue changes because the ROM is affected not only by the soft tissues, but also by the bone. Increased retroversion of the humeral head is often observed in the dominant shoulder of throwing athletes. The purpose of this study was to determine the relationship between the soft-tissue-related (STR) ROM and pathologic internal impingement in baseball players.

METHODS

Bilateral humeral retroversion and ranges of glenohumeral external rotation (ER) and internal rotation (IR) were investigated in 81 high-school baseball players. The players were divided into two groups: the internal impingement group (19 players) and the control group (62 players). Humeral retroversion was measured using the ultrasound-assisted technique to assess the bone-related ER and IR. The STR ER and IR were defined as subtracting the amount of humeral retroversion from the measured ER and IR.

RESULTS

The side-to-side difference (throwing shoulder - nonthrowing shoulder) in humeral retroversion showed no significant difference between the internal impingement group (6° ± 10°) and control group (11° ± 11°) (P = .064). The side-to-side difference in STR ER was significantly greater in the internal impingement group (12° ± 12°) than that in the control group (1° ± 14°) (P = .002). No significant difference was observed in the side-to-side difference in STR IR between the internal impingement group (-7° ± 16°) and control group (-5° ± 15°) (P = .696). Pathologic internal impingement was significantly associated with the side-to-side difference of STR ER (odds ratio, 1.06 for increase of 1°; 95% confidence interval, 1.02-1.11; P = .008).

CONCLUSION

In high-school baseball players, the increased STR ER in the throwing shoulder may be associated with pathologic internal impingement. An increase of 10° in side-to-side difference in STR ER would increase the risk of pathologic internal impingement by 1.8 times.

Acute caffeine supplementation enhances several aspects of shot put performance in trained athletes

The aim of this investigation was to determine the effect of a moderate dose of caffeine (3 mg/kg/b.m.) on muscular power and strength and shot put performance in trained athletes. Methods. Thirteen shot putters (eight men and five women) participated in a double-blind, placebo-controlled, randomized experiment. In two different trials, participants ingested either 3 mg/kg/b.m. of caffeine or a placebo. Forty-five min after substance ingestion, athletes performed a handgrip dynamometry test, a countermovement jump (CMJ), a squat jump (SJ), and a maximum-velocity push-up. The athletes also performed three types of throws: a backwards throw, a standing shot put and a complete shot put. Results. In comparison with the placebo, caffeine ingestion increased CMJ height (32.25 ± 7.26 vs. 33.83 ± 7.72 cm, respectively; effect size (ES) = 0.82, p = 0.012; +5.0%;) and SJ height (29.93 ± 7.88 vs. 31.40 ± 7.16 cm; ES = 0.63, p = 0.042; +6.4%) and distance in the standing shot put (10.27 ± 1.77 m vs. 10.55 ± 1.94 m; ES = 0.87, p = 0.009; +2.6%). However, caffeine ingestion did not increase strength in the handgrip test, power in the ballistic push-up, or distance in the backwards throw (all p > 0.05). Shot put performance changed from 11.24 ± 2.54 to 11.35 ± . 2.57 m (ES = 0.33, p = 0.26; +1.0%), although the difference did not reach statistically significant differences. Caffeine ingestion did not increase the prevalence of side effects (nervousness, gastrointestinal problems, activeness, irritability, muscular pain, headache, and diuresis) in comparison with the placebo (p > 0.05). Conclusion. In summary, caffeine ingestion with a dose equivalent to 3 mg/kg/b.m. elicited moderate improvements in several aspects of physical performance in trained shot putters but with a small effect on distance in a complete shot put.

Elbow Ulnar Collateral Ligament Injuries in Overhead Athletes: An Infographic Summary

Ulnar collateral ligament (UCL) injuries of the elbow are common in throwing athletes. Given that the UCL's primary function is to provide valgus stability during the deceleration phase of throwing, injury to the UCL will render throwing difficult to nearly impossible.¹⁵ Injuries will occur more so in the sports of baseball, softball, and javlineers participating in track and field.^5,10,14 Data has indicated that valgus torque reaches 64 N-m and proximal forces as high as 1000 N to prevent elbow distraction. Further, angular velocity across elbow may reach 1900-2480 degrees/second.^6,8 Imaging modalities that have the greatest accuracy for diagnosis include magnetic resonance imaging (MRI), MRI-arthrogram, and stress ultrasonography.^2,3,11,12 Treatment of UCL injury depends on multiple factors. These include if the injury is a partial tear or complete tear and the location (distal versus proximal) of the partial tear.⁷ Further, complete tears, as well as partial distal tears, are more likely to undergo surgical intervention.^1,13 Treatment decision-making is primarily dependent on following factors: location, severity, if the patient is a throwing athlete, and if the patient is in his or her last year of his/her throwing career due to the length of the rehabilitation process if surgery is pursued.¹⁵ Return-to-play success rates when treated conservatively vary from anywhere from 42% to 100%. Conservative treatment includes rest, rehabilitation, platelet-rich plasma injections, and a throwing program.⁴ Surgical treatment has evolved significantly with various reconstructive techniques and (when indicated) surgical repair with internal bracing. Return-to-play rates are high, ranging from 80% to 95% with low complication rates, but rehabilitation for reconstruction can range from 12-18 months or longer. Therefore, patients must be made aware of the commitment to the rehabilitation process if electing to undergo surgical reconstruction.⁹.

Relationship of Vertical Jump Performance and Ankle Joint Range of Motion: Effect of Knee Joint Angle and Handedness in Young Adult Handball Players

The purpose of the study is to examine the effect of the ankle joint range of motion (ROM) on the vertical jump (VJ) performance of adult handball players. The active (ACT) and passive (PAS) ankle joint ROM of 12 male members of the U21 National Handball Team with the knee joint at 0°, 40°, and 90° flexion (0° = fully extended knee) was evaluated using a video analysis measuring method. Participants also performed maximum VJ with (CMJ) and without (SQJ) countermovement, as well as with (AS) and without (NAS) an arm swing. Statistical analyses included 2 × 2 × 3 MANOVA, 2 × 2 repeated measures ANOVA, and Pearson’s correlation. Results reveal that PAS-ROM was larger (p < 0.05) in all knee joint flexion angles. ROM was smaller (p < 0.05) by approximately 10° at 0° compared to 90° knee flexion. No lateral effects on ROM due to the handedness of the players were observed. AS and CM resulted in increased jump height (p < 0.05). Finally, ACT-ROM when the knee joint was flexed at 40° was highly correlated (r ≥ 0.66, p < 0.05) with VJ performance except for CMJ-AS. In conclusion, the differences in the bi-articular gastrocnemius muscle flexibility due to the alteration of the angular position of the examined joints affected the ability to generate impulse during the VJ tests.

The Clinician's Guide to Baseball Pitching Biomechanics

CONTEXT

Improper baseball pitching biomechanics are associated with increased stresses on the throwing elbow and shoulder as well as an increased risk of injury.

EVIDENCE ACQUISITION

Previous studies quantifying pitching kinematics and kinetics were reviewed.

STUDY DESIGN

Clinical review.

LEVEL OF EVIDENCE

Level 5.

RESULTS

At the instant of lead foot contact, the elbow should be flexed approximately 90° with the shoulder at about 90° abduction, 20° horizontal abduction, and 45° external rotation. The stride length should be about 85% of the pitcher's height with the lead foot in a slightly closed position. The pelvis should be rotated slightly open toward home plate with the upper torso in line with the pitching direction. Improper shoulder external rotation at foot contact is associated with increased elbow and shoulder torques and forces and may be corrected by changing the stride length and/or arm path. From foot contact to maximum shoulder external rotation to ball release, the pitcher should demonstrate a kinematic chain of lead knee extension, pelvis rotation, upper trunk rotation, elbow extension, and shoulder internal rotation. The lead knee should be flexed about 45° at foot contact and 30° at ball release. Corrective strategies for insufficient knee extension may involve technical issues (stride length, lead foot position, lead foot orientation) and/or strength and conditioning of the lower body. Improper pelvis and upper trunk rotation often indicate the need for core strength and flexibility. Maximum shoulder external rotation should be about 170°. Insufficient external rotation leads to low shoulder internal rotation velocity and low ball velocity. Deviation from 90° abduction decreases the ability to achieve maximum external rotation, increases elbow torque, and decreases the dynamic stability in the glenohumeral joint.

CONCLUSION

Improved pitching biomechanics can increase performance and reduce risk of injury.

SORT

Level C.

Comparison of Flywheel and Pneumatic Training on Hypertrophy, Strength, and Power in Professional Handball Players

Purpose: The mechanical properties of resistance-training machines are a variable that may help to optimize sports performance and injury prevention protocols. The purpose of this study was to examine two non-gravity-dependent training modalities on muscle structure and function. Methods: Eighteen professional handball players were randomly divided into two experimental groups: 1) iso-inertial flywheel training (FW) and 2) pneumatic resistance training (PN). Participants in both groups completed twelve training sessions in six weeks consisting of three movements (lateral raise, internal and external rotation). Four sets of seven repetitions for each movement were performed during each session. Before and after training subscapularis and deltoid (anterior, middle, posterior) muscle thickness was measured. Isokinetic torque and power during internal and external rotation at 60, 180, and 240 deg·s^-1 was measured as well. Throwing speed was assessed before and after training while both sitting and standing situations. Results: Both groups showed similar significant increases in throwing speed and internal and external rotation peak torque, average and peak power at all angular velocities. Anterior and middle deltoid muscle thickness changes were greater after training in FW (20 and 22%) in comparison to PN (14 and 7%, respectively). Conclusions: In summary, both flywheel and pneumatic training resulted in similar increases in shoulder strength and power and throwing speed. However, flywheel training appeared to possibly result in a slightly greater level of muscle hypertrophy of the anterior and middle deltoid. Non-gravity dependent training appears to induce changes that would be beneficial to sports performance and perhaps injury prevention.

Variability of Performance and Kinematics of Different Shot Put Techniques in Elite and Sub-Elite Athletes-A Preliminary Study

The purpose of the study was to analyze the variability of performance and kinematics of different shot put techniques in elite athletes (group A: 5 athletes using the rotational technique and 3 athletes using the glide technique) and sub-elite athletes (group B: 3 athletes using the rotational technique and 3 athletes using the glide technique). Each athlete performed 6 trials. Only 34 trials in group A and 27 trials in group B were analyzed. Two high-speed digital cameras were positioned 8 m from the center of the shot put throwing circle. All throws performed during international and national competitions were analyzed using the Ariel Performance Analysis System. To estimate variability of kinematic parameters, the value of relative error was calculated. The average relative error generally showed low variability for the analyzed indicators. In only 4 analyzed cases, variability was high (>20%). Statistical analysis was used to find indicators which have a significant influence on the distance of the throw (according to the sports level and technique). Significant inverse correlations (at p < 0.05) between the distance and the average relative error of the selected indicators were mainly obtained, which meant that the distance was longer when the value of variability (average relative error) was low. The research results show that greater repeatability of the technique (lower RE) has a significant impact on the length of the shot put.

The Effects of a Five-Month Lockdown Due to COVID-19 on Physical Fitness Parameters in Adolescent Students: A Comparison between Cohorts

Background: This study examined the effects of a five-month lockdown due to COVID-19 pandemic on physical fitness parameters in urban adolescent male and female students. Methods: Two hundred and ninety-three male and female students (age: 15.8 ± 0.3 years) who attended the fourth grade of the same high school during the years 2016–2017 (first control group), 2018–2019 (second control group) and 2020–2021 (lockdown group) took part in the present study. Results: The percentage of overweight and obese students, according to body mass index, increased in males from 16.0% (2016–2017) and 14.6% (2018–2019), to 36.7% in 2020–2021 (p < 0.01), and in females from 8.6% (2016–2017) and 7.0% (2016–2017), to 25.6% in 2020–2021 (p < 0.01). Lower body fitness, as assessed by jumping, sprinting and agility tests, was impaired for both males and females after the lockdown compared with the 2016–2017 and 2018–2019 cohorts (vertical jumps: 10.4–15.1%; p < 0.01; d = 0.58–1.01, 30 m sprint: 3.7–4.9%; p < 0.01; d = 0.62–0.74; 505 agility test: from 6.1% to 9.4%; p < 0.01; d = 0.80–1.04). However, flexibility and performance in upper-body fitness tests (handgrip maximum isometric strength and medicine ball throws with different loads) was significantly reduced only in males after the lockdown (p < 0.05 to 0.01). Conclusions: These results suggest that a five-month lockdown negative influenced the physical fitness of adolescent students. Notably, greater reductions were observed in upper body strength, power and flexibility in males than in females. These results highlight the need to maintain strength, power and body mass during long periods of inactivity in adolescent populations.

Shoulder Strength and Upper Body Field Performance Tests in Young Female Handball and Volleyball Athletes: Are There Differences Between Sports?

CONTEXT

Volleyball and handball players have usually been studied collectively as "overhead athletes," since throwing present similarities in the proximal to distal movement sequencing and upper limb joints ranges of motion. However, each sport presents specificities in the objectives when accelerating the ball and a variety of possible throwing techniques. Therefore, it is expected there may be differences in the shoulder and upper body physical performance between sports.

OBJECTIVE

The aim of this study was to determine if there are differences in shoulder muscle strength and upper body field performance tests between volleyball and handball athletes.

DESIGN

Cross-sectional.

METHODS

Ninety-nine volleyball and handball female athletes aged between 13 and 20 years were evaluated for isometric shoulder abductor and rotator strength (handheld dynamometer) and upper body field performance tests: Y Balance Test-Upper Quarter, modified Closed Kinetic Chain Upper-Extremity Stability Test, and unilateral and bilateral Seated Medicine Ball Throw.

RESULTS

Handball athletes presented greater shoulder internal rotation strength (between-group difference: 2.84; effect size 0.70), higher medial (between-group difference: 9.54; effect size 0.90), superolateral (between-group differences: 8.9; effect size 0.68), and composite scores (between-group difference 5.7; effect size 0.75) of the Y Balance Test-Upper Quarter and higher unilateral (between-group difference: 41.92; effect size 0.91) and bilateral (between-group difference: 46.11; effect size 0.83) Seated Medicine Ball Throw performance. Groups were not different for Closed Kinetic Chain Upper-Extremity Stability Test, external rotation, and abduction isometric strength.

CONCLUSION

Our findings suggest that young female handball athletes present greater internal rotator strength and better performance in Y Balance Test-Upper Quarter and Seated Medicine Ball Throw compared to volleyball players. These differences may be related to the different demands required in the throwing movements performed in each sport and should be considered when assessing these populations.

Comparison of Glenohumeral Range of Motion Deficits in Youth, Collegiate, and Professional Baseball Players

BACKGROUND

Examining range of motion deficits across levels of baseball competition can result in a better understanding of the extent of altered range of motion patterns and identify competition levels that may require preventative interventions that target the deficits.

PURPOSE

The purpose of this study was to compare shoulder range of motion in baseball players across levels of competition and compare the prevalence of glenohumeral internal rotaton deficit (GIRD) and total arc of motion differences (TAMD) between competition levels in pitchers and position players.

STUDY DESIGN

Prospective descriptive cohort.

METHODS

Passive internal and external rotation range of motion was measured bilaterally. Individuals with current pain in the arm, shoulder, elbow or shoulder surgery within the prior two years were excluded. Measurements were taken during pre-season physical examinations. Players were divided into seven groups: 12u (11-12 years; n=30), 14u (13-14 years; n=30), High School 1 (HS 1; 15-16 year; n=42), High School 2 (HS 2; 17-18 years; n=25), College (n=22), Professional 1 (Pro1; 17-22 years; n=37) and Professional 2 (Pro2; 23 and older; n=37). Multiple one-way analyses of variance were performed to determine differences between groups. Tukey test for post-hoc analysis was employed to determine which competition levels were significantly different.

RESULTS

Two-hundred and twenty-three male baseball players ages 11-26 participated. The 12u (53.7°) and 14u (54.2°) groups had significantly less internal rotation than HS1 (65.2°), HS2 (63.9°), College (62.3°), Pro1 (64.9°), and Pro2 (64.5°) players (p<0.0001). The 12u, 14u, HS1, college, and Pro2 groups had greater than 50% of players with total arc of motion differences >5°. Conclusions: Range of motion alterations exist across ages and levels of competition with 12u and 14u players having less internal rotation than the older groups and youth pitchers having less total range of motion than HS1.

LEVEL OF EVIDENCE

2.

Control of Accuracy during Movements of High Speed: Implications from Baseball Pitching

Despite the well-known tradeoff between speed and accuracy, skilled people often demonstrate the ability to maintain high accuracy during fast movements. We focused on two strategies to improve accuracy, thereby increasing the reproducibility of individual parameters (certain parameters are maintained in low variability) and coordinating covariation among parameters (different parameters compensate each other's variability). The objective of this study was to determine whether coordinated covariation among release parameters is used for high accuracy by skilled baseball pitchers. A model was employed to simulate pitch location after eliminating the coordinated covariation by randomly reshuffling the release parameters, and the variability of simulated and measured pitch locations were compared. The results showed that there was no significant coordinated covariation for any of the release parameters for either the vertical or horizontal pitch location supports strategy of increasing the reproducibility of individual parameter. In addition, for the vertical pitch location, because there was coordinated covariation between the release angle and speed in slow pitching, it was suggested that, the higher speed the task requires, the more important the reproducibility of individual parameter becomes.

Comparison of Pelvis and Trunk Kinematics Between Youth and Collegiate Windmill Softball Pitchers

Background

The windmill softball pitch is a dynamic sporting movement that places softball pitchers at high risk of injury. Unlike baseball, there is limited research into the mechanical differences between softball pitchers of varying skill levels.

Purpose/Hypothesis

The purpose of this study was to compare pelvis and trunk kinematics between youth and collegiate softball pitchers. It was hypothesized that there would be significant differences in pelvis and trunk kinematics between these 2 groups.

Study Design

Descriptive laboratory study.

Methods

The pelvic and trunk kinematics of 90 softball pitchers were collected during full-effort pitching using a 3-dimensional motion capture system. Participants were grouped based on their age at the time of data collection (35 youth [mean age, 11 ± 1 years]; 55 collegiate [mean age, 20 ± 2 years]). We compared between-group differences in pelvic posterior tilt, lateral tilt, axial rotation, and axial rotation velocity as well as trunk extension, lateral flexion, axial rotation, and axial rotation velocity during the pitching phase between start of pitch and ball release (BR) using 1-dimensional statistical parametric mapping. Statistical significance was determined using Holmes-Šidák stepdown correction-adjusted P values (P ').

Results

Compared with youth pitchers, collegiate pitchers exhibited a more posteriorly tilted pelvis from the moment of start of pitch until 94% of the way between start of pitch and BR (P ' = .002) and a more laterally flexed trunk toward the glove side from the moment of start of pitch until 71% of the way between start of pitch and BR (P ' = .010).

Conclusion

Collegiate pitchers displayed a more posteriorly tilted pelvis and more laterally flexed trunk toward the glove side during the windmill pitching motion when compared with youth pitchers.

Clinical Relevance

These findings add to the growing body of softball research and help elucidate mechanical differences between youth and collegiate softball pitchers.

Diagnosis and Management of Little League Shoulder: A Systematic Review

Background:

Little League shoulder (LLS) is an overuse injury characterized by throwing-related pain that commonly presents in adolescent male athletes. Investigations into the optimal duration of rest from throwing and protocols for graduated return to sports (RTS) are lacking.

Purpose:

To summarize the current literature with respect to the diagnosis, management, RTS, and return to throwing for LLS.

Design:

Systematic review; Level of evidence, 4.

Methods:

The databases EMBASE, MEDLINE, and PubMed were searched between inception and April 22, 2020. References of retrieved records were reviewed for potentially eligible studies. English-language studies that reported the diagnosis and/or management of LLS in children or adolescents were included. Studies of animals or cadavers, review articles, and non—peer reviewed records were excluded. Data were summarized narratively using descriptive statistics.

Results:

Overall, 23 studies (21 level 4 studies, 2 level 3 studies) met the criteria for a total of 266 participants with a weighted mean age of 12.8 years (range, 7.4-17 years). Treatment recommendations evolved from prolonged rest and complete cessation of throwing to shorter periods of rest and graduated RTS. Less than half (11/23) of studies reported specific criteria to RTS; 1 case report discussed a coaching strategy to resume throwing, and 1 case report discussed a regimented throwing program. The proportion of participants returning to any sport participation was 94.0% (n = 157/167). The proportion returning to their preinjury level of sport was 92.5% (n = 123/133). Upon RTS, 18.7% (n = 35/187) of participants experienced a recurrence of symptoms. Premature closure of the epiphysis was reported in 1 participant.

Conclusion:

Young athletes with LLS may return to play after a period of rest, and a high proportion return to their preinjury level of sport. Further prospective studies are warranted to develop evidence-based, graduated RTS protocols and to better capture any long-term sequelae of the condition.

Biomechanical assessment of docking ulnar collateral ligament reconstruction after failed ulnar collateral ligament repair with suture augmentation

BACKGROUND

Ulnar collateral ligament (UCL) repair with single-strand suture augmentation has been introduced as a viable surgical option for throwers with acute UCL tears. For the original single-strand suture augmentation construct, revision UCL reconstructions can be challenging owing to the bone loss at the site of anchor insertion in the center of the sublime tubercle. This biomechanical study assessed a small-diameter (1.5-mm) ulnar bone tunnel technique for double-strand suture-augmented UCL repair that may be more easily converted to salvage UCL reconstruction if necessary, as well as a salvage UCL reconstruction with a docking technique after a failed primary suture-augmented UCL repair.

METHODS

In 7 fresh-frozen cadaveric upper extremities (mean age, 66.3 years), a custom shoulder testing system was used to simulate the late cocking phase of throwing. The elbow valgus opening angle was evaluated using a MicroScribe 3DLX device for sequentially increasing valgus torque (from 0.75 to 7.5 Nm in 0.75-Nm increments) at 90° of flexion. Valgus angular stiffness (in newton-meters per degree) was defined as the correlation of sequentially increasing valgus torque with the valgus opening angle through simple linear regression (slope of valgus torque - valgus opening angle curve). Four conditions were tested: intact elbow, distal UCL avulsion, primary UCL repair with double-strand suture augmentation using small-diameter bone tunnels, and subsequent docking UCL reconstruction in the same specimen. Load-to-failure tests were performed for primary UCL repair with double-strand suture augmentation and subsequent docking UCL reconstruction.

RESULTS

With increasing elbow valgus torque, the valgus opening angle increased linearly in each condition (R² ≥ 0.98, P < .001). Distal UCL avulsion resulted in significantly decreased angular stiffness compared with the intact UCL (P < .001). Both UCL repair with double-strand suture augmentation and subsequent UCL reconstruction showed significantly increased angular stiffness values compared with distal UCL avulsion (P < .001 and P < .001, respectively). On load-to-failure testing, there was no significant difference in stiffness, yield torque, and ultimate torque between the primary suture-augmented UCL repair and the subsequent UCL reconstruction (P = .11, P = .77, and P = .38, respectively). In all specimens undergoing the small-diameter ulnar bone tunnel technique for double-strand suture-augmented UCL repair, failure occurred by retear of the repaired ligament without causing an ulnar bone bridge fracture.

CONCLUSION

Primary UCL repair with double-strand suture augmentation using small-diameter bone tunnels was able to restore valgus stability. When failure occurs, this technique retains enough cortical bone to permit subsequent docking UCL reconstruction.

Individuals With Intellectual Disabilities Rely on Somatosensory Information Rather Than Visual Information to Catch a Ball

According to the literature, persons with intellectual disabilities have poor motor control in tasks in which motor anticipation is needed. Our study aimed to assess their motor behavior during interceptive tasks (a tennis ball interception with external-and-oneself throw conditions). A stick-bar was used as a reference or to support cloth to occlude a ball's trajectory. Catch performance and interceptive behavior were analyzed (26 persons). The results show that high/low values of the initial approaching movement led to successful/successful catches, respectively. Our results are in line with the literature about the impact of poor motor control on performance in those with intellectual disabilities. We suggest that low anticipation may relate to problems in real-life situations.

The effects of restricted glenohumeral horizontal adduction motion on shoulder and elbow forces in collegiate baseball pitchers

BACKGROUND

Decreased glenohumeral (GH) horizontal adduction range of motion (ROM) among baseball pitchers has been associated with the development of various shoulder and elbow pathologies. No research has examined how this tightness may affect the forces placed on the shoulder and elbow during the pitching motion.

METHODS

Fifty-five asymptomatic National Collegiate Athletic Association Division I baseball pitchers participated. Twenty-five participants had -10° or less horizontal adduction ROM in their throwing shoulder. The remaining 30 participants had greater than -10° of horizontal adduction. A digital inclinometer was used to measure GH horizontal adduction, internal rotation, and external rotation ROM while in 90° of shoulder abduction. Forces produced in the throwing shoulder and elbow were assessed with a 3-dimension, high-speed video capture system and based on the sum of angular momenta of the kinetic chain segments around the center of gravity. Separate 2-tailed t tests were run to determine significant differences between groups (P < .05).

RESULTS

Both groups presented with significant bilateral differences in their total arcs of motion (P < .04). This suggests that the loss of horizontal adduction in these groups was at least partially due to soft tissue tightness. There were no significant between-group differences for shoulder external rotation torque or shoulder and elbow distraction (P > .10). The restricted ROM group had significantly more shoulder abduction torque (P = .04), shoulder horizontal abduction torque (P = .004), elbow flexion torque (P = .002), and elbow valgus torque (P = .02) compared with the control group.

CONCLUSIONS

These results demonstrate that collegiate pitchers with -10° or less of horizontal adduction ROM in their throwing shoulder create significantly more shoulder abduction and horizontal abduction torque, as well as more elbow flexion and valgus torque, during the pitching motion than those with more ROM.

Back to reality: differences in learning strategy in a simplified virtual and a real throwing task

Virtual environments have been widely used in motor neuroscience and rehabilitation, as they afford tight control of sensorimotor conditions and readily afford visual and haptic manipulations. However, typically, studies have only examined performance in the virtual testbeds, without asking how the simplified and controlled movement in the virtual environment compares to behavior in the real world. To test whether performance in the virtual environment was a valid representation of corresponding behavior in the real world, this study compared throwing in a virtual set-up with realistic throwing, where the task parameters were precisely matched. Even though the virtual task only required a horizontal single-joint arm movement, similar to many simplified movement assays in motor neuroscience, throwing accuracy and precision were significantly worse than in the real task that involved all degrees of freedom of the arm; only after 3 practice days did success rate and error reach similar levels. To gain more insight into the structure of the learning process, movement variability was decomposed into deterministic and stochastic contributions. Using the tolerance-noise-covariation decomposition method, distinct stages of learning were revealed: While tolerance was optimized first in both environments, it was higher in the virtual environment, suggesting that more familiarization and exploration was needed in the virtual task. Covariation and noise showed more contributions in the real task, indicating that subjects reached the stage of fine-tuning of variability only in the real task. These results showed that while the tasks were precisely matched, the simplified movements in the virtual environment required more time to become successful. These findings resonate with the reported problems in transfer of therapeutic benefits from virtual to real environments and alert that the use of virtual environments in research and rehabilitation needs more caution.NEW & NOTEWORTHY This study compared human performance of the same throwing task in a real and a matched virtual environment. With 3 days' practice, subjects improved significantly faster in the real task, even though the arm and hand movements were more complex. Decomposing variability revealed that performance in the virtual environment, despite its simplified hand movements, required more exploration. Additionally, due to fewer constraints in the real task, subjects could modify the geometry of the solution manifold, by shifting the release position, and thereby simplify the task.

Concurrent validity, inter-unit reliability and biological variability of a low-cost pocket radar for ball velocity measurement in soccer and tennis

This study aimed to analyse the (i) concurrent validity, (ii) inter-unit reliability, and (iii) biological variability of a low-cost device called Pocket radar. Eleven men recreational soccer players performed 6 kicks to a soccer ball, whereas 13 men recreational tennis players conducted 10 shots to a tennis ball. All executions were simultaneously measured by two Pocket units and the Stalker radar (reference criterion). The within-subject variation among the executions was used for the biological variability analysis. The level of agreement and magnitude of errors included the intraclass correlation coefficient (ICC), Pearson's correlation coefficient (r), bias, and the smallest detectable change (SDC). A good agreement (ICC ≥ 0.98, r ≥ 0.98) and very low magnitude of error (SDC ≤ 7.70 km·h^-1, bias ≤ 3.19 km·h^-1) were found between both Pocket units and the Stalker, in soccer and tennis. Inter-unit analysis found limited technical errors (SDC ≤ 5.49 km·h^-1, bias ≤ -0.93 km·h^-1) and nearly perfect agreement (ICC = 0.99, r ≥ 0.98) in both sessions. These technical errors were lower than the variations due to the biological variability, in soccer (SDC = 2.47 km·h^-1 vs. SDC ≥ 8.6 km·h^-1) and tennis (SDC = 5.49 km·h^-1 vs. SDC ≥ 21.95 km·h^-1). These findings suggest the Pocket radar as a valid and highly sensitive tool for BV measurement.

Relatively Easy Criteria for Success Enhances Motor Learning by Altering Perceived Competence

The purpose of this study was to examine whether enhancing success expectation by providing relatively easy criteria for success would, in turn, enhance motor learning outcomes. Thirty university student participants threw soft-golf balls towards a circular target, using their non-dominant arm; they performed seven blocks of 12 trials from a distance of 5.5 meters on Day 1, and one block of 12 trials on separate retention and transfer tests on Day 2. After the first block on Day 1, participants were randomly assigned to one of two groups in which they practiced the remaining six blocks of 12 trials: (a) one with relatively easy success (RES) criteria or (b) one with difficult success (DS) criteria. After the practice, we administered a perceived competence scale, a sub-scale of the Intrinsic Motivation Inventory (IMI). On Day 2, participants in the RES group outperformed those in the DS group on both the retention and transfer tests, showing enhanced motor learning. The RES group also self-reported higher perceived competence than the DS group, indicating that the mechanism for benefiting from easier success criteria may have been an alteration in participants' perceived competence.

SHOULDER AND ELBOW INJURY RATES AND CHARACTERISTICS AMONG COLLEGIATE BASEBALL STUDENT-ATHLETES

Background

Recent research has focused on the epidemiology of shoulder and elbow injuries among high school and professional baseball players. Shoulder and elbow injury data has not been comprehensively reported among college baseball student-athletes.

Purpose

The purpose of this study is to describe shoulder and elbow injury rates and their characteristics among collegiate baseball student-athletes in order to improve injury prevention.

Study Design

Descriptive Epidemiology Study.

Methods

Shoulder and elbow injury data were obtained from the NCAA Injury Surveillance System for baseball from 2004-2014. Incidence rate ratios and descriptive analyses described injury characteristics for the shoulder and elbow, separately.

Results

The injury rate for the shoulder was 4.02/10,000 athlete-exposures and for the elbow was 2.44/10,000 athlete-exposures. During the ten-year period, the injury rate of the shoulder has approximately decreased by 75% and of the elbow by approximately 50%. Injury rates were higher during competitions compared to practice for the shoulder (rate ratio, 1.81;95% CI, 1.51, 2.18) and elbow (rate ratio, 2.19;95% CI, 1.73, 2.78). Freshmen and juniors were most likely to sustain shoulder (F=40.6%, J = 29%) and elbow (F=33%, J=33.7%) injuries. Regarding shoulder injuries, surgery was required for 7.1%, and the outcome was season ending for 14.5%. More elbow injuries (17.5%) ended in surgery, and a greater proportion (28.9%) had season-ending injuries.

Conclusion

In collegiate baseball, shoulder and elbow injury rates have decreased but still result in high morbidity. More granular analyses, especially during Division 1 competitions, are necessary for more specific interventions. While shoulder injuries are more common, elbow injuries result in a longer time to return to play and a higher proportion of surgical interventions.

Level of Evidence

Level 3.

Providing Choice Enhances Motor Performance under Psychological Pressure

The purpose of this present study was to examine whether providing choice would enhance motor performance under psychological pressure. Participants were asked to throw soft-golf balls toward a circular target. The practice phase consisted of 30 trials using three colored balls (i.e., blue, red, yellow) from 5.5 meters. Participants then performed 10 throws from 2 different distances: 5.5 meters (pressure phase) and 6.5 meters (transfer pressure phase) under psychological pressure. Prior to the pressure and transfer pressure phases, the choice group participants were asked to choose the color of the soft-golf ball whereas the control group participants were yoked to their counterpart participant based on the selections of their colored balls. Results demonstrated that despite similar throwing accuracy being produced at the pressure phase between the two groups, the choice group had significantly higher accuracy scores at the transfer pressure phase than the control group. Thus, the autonomy-supportive condition led to enhanced motor performance under psychological pressure.

Softball pitching mechanics and shoulder injuries: a narrative review

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.

Pitching shoulder passive flexibility: torque-angle analysis for external rotation and internal rotation

In this study, a custom device was developed to analyse the pitching shoulder's external rotation (ER) and internal rotation (IR) passive flexibility. We analysed three novel measures: the resistance onset angle (ROA = angle where the shoulder begins stretching), rotational stiffness, and torque at the end range of motion (ROM). The purpose was to conduct a bilateral analysis to determine if there are significant differences between the throwing and non-throwing shoulder. Participants were 30 upper level pitchers (13 division I, 17 minor league). During testing, pitchers laid supine on a treatment table and the arm was secured to a rotational wheel with the shoulder abducted 90° and elbow flexed 90°. Dependent t-tests revealed significant (p < 0.01) and relatively extreme bilateral differences for all three variables. The throwing shoulder had: increased ER ROA (9°), decreased IR ROA (5.3°), increased ER stiffness (17%), increased IR stiffness (34%), increased ER torque (21%), and increased IR torque (30%). Secondary correlation analysis was completed to determine if the torque-angle variables were good predictors of the end ROM. Stiffness correlations were weak for ER (r = 0.35, p = 0.048) and IR (r = 0.42, p = 0.017) but ROA correlations were strong for ER (r = 0.85, p < 0.001) and IR (r = 0.86, p < 0.001).

Posterior shoulder tightness can be a risk factor of scapular malposition: a cadaveric biomechanical study

BACKGROUND

Scapular malposition and posterior shoulder tightness are key pathologic processes in the shoulder of throwing athletes. The objective of this study was to investigate the effects of posterior capsule tightness, posterior rotator cuff muscle tightness, or both on scapular position.

METHODS

Ten shoulders from 5 fresh frozen cadaveric male torsos were tested in maximum internal, neutral, and maximum external shoulder rotations at 0°, 45°, and 90° of shoulder abduction. Scapular rotation-namely, upward and downward rotation, internal and external rotation, and anterior and posterior tilt-and the scapula-spine distance were measured by using a MicroScribe digitizer (Revware, Raleigh, NC, USA). Each shoulder underwent 4 experimental stages: intact; isolated posterior rotator cuff muscle (infraspinatus and teres minor) tightness; both posterior rotator cuff muscle and capsule tightness; and isolated posterior capsule tightness.

RESULTS

Posterior muscle tightness significantly decreased upward rotation (P< .05) only in maximum shoulder internal rotation at 45° or 90° of shoulder abduction, whereas posterior capsule tightness did not affect upward rotation (P= .09 to .96). Posterior capsule tightness significantly increased scapular internal rotation (P< .01), but posterior muscle tightness did not change scapular internal rotation (P= .62 to .89). Posterior capsule tightness significantly increased both the superior and inferior scapula-spine distance (ie, caused scapular protraction) in maximum shoulder external rotation at 90° of abduction (P< .01).

CONCLUSION

Posterior shoulder tightness resulted in scapular malposition. However, the muscular and capsular components of that tightness affected the scapular position differently. For the treatment of scapula malposition, stretching of the posterior shoulder capsule and muscles is recommended.

Curveballs in Youth Pitchers: A Review of the Current Literature

As the number of young people playing baseball has increased, so have the number of injuries. Throwing arm shoulder and elbow injuries are most common, and lead to both short and long-term consequences. Recent efforts have been made to identify risk factors for injury with corresponding regulations created to protect youth pitchers. Unlike rules enforcing pitch counts, prohibitions against curveballs are based on minimal objective evidence.

Can I Choose a Throwable Object for You? Perceiving Affordances for Other Individuals

Throwing is an important motor skill for human survival and societal development. It has been shown that throwers could select throwable balls for themselves and ball throwability was determined by its size and weight. In this study, we investigated whether throwers could perceive ball throwability for other throwers (experimental confederates) and whether the perceived throwability for others also followed a size-weight relation. Like other types of affordances, throwability entails a scaling between the thrower and the throwing object. This requires knowledge about the thrower and the object. In this study, knowledge about the objects was gained by hefting balls of various sizes and weights; knowledge about the throwers was gained by interacting with throwers in person (Experiment 1) and by viewing videos of confederates throwing (containing kinematic and anthropometric information) or photographs of the confederates standing (containing anthropometric information; Experiment 2). By comparing observers' perceived throwability for others using various materials, we attempted to uncover whether scaling of throwability was based on kinematic or anthropometric information. In this study, participants ranked throwability of balls of various sizes and weights for confederates of different sexes and fitness levels. In all experimental conditions, observers' ranking and confederates' actual throwing performances yielded linear relationships with slopes close to 1 and moderate to high r 2 values. These suggested that participants were able to accurately perceive throwability and choose throwable balls for the confederates. The throwable balls followed a size-weight relation, where bigger balls had to weigh more to be perceived as throwable as smaller balls. Furthermore, there was no difference between throwability perception based on in-person interaction, watching videos of confederates throwing and seeing pictures of the confederates standing. This suggested that the scaling of throwability was likely to be based on anthropometric information. These results enriched our understanding of whether one could perceive the action opportunities for others, and extended the canonical Gibsonian concept of affordance to a social setting and thus could be important for understanding team coordination in sports and interpersonal action collaboration in general.

Pre-programming in overhand throwing of children with Down syndrome: role of the generalized motor program

OBJECTIVE

It is unclear whether slowness and higher reaction time of individuals with Down syndrome (DS) are because of inability to pre-program and using the generalized motor program (GMP) or not. So, the purpose of this study was to examine the consistency of relative timing as a fixed feature of a GMP in overhand throwing with changing the distance to target as a varied feature.

METHODS

Fifteen individuals with DS (age = 13 ± 2 y) and a control group of 12 individuals without intellectual disability (ID; age = 13 ± 2 y) were asked to throw a tennis ball to a fixed target from three distances of 2, 2.75, and 3.25 m, respectively. Instant of occurrence of the following discrete variables was recorded by motion analysis: initiation of elbow extension, maximum shoulder angular velocity, maximum elbow angular velocity, and maximum resultant hand velocity.

RESULTS

Results of two-way analysis of variance test did not show any significant difference in any of the relative kinematic variables in distances and groups (p > 0.05).

CONCLUSION

It seems that individuals with DS are able to motor preprogram and they use a GMP to overhand throwing from different distances as well as those without ID. Also, slowness and reaction time are unrelated to pre-programming and GMP as it relates to overhand throwing.

Gender Differences in Throwing Revisited: Sensorimotor Coordination in a Virtual Ball Aiming Task

Numerous studies have demonstrated that boys throw balls faster, farther and more accurately than girls. This may be largely due to well-known anatomical and muscle-physiological differences that play a central role in overarm throwing. With the objective to understand the potential contribution of the equally essential coordinative aspects in throwing for this gender difference, this large cross-sectional study examined a simplified forearm throw that eliminated the requirements that give males an advantage.While the overall performance error indeed became similar in the age groups younger than 20 years and older than 50 years, it was attenuated for middle-aged individuals. The gender differences remained in individuals who reported no throwing experience, but females with throwing experience reached similar performance as males. Two fine-grained spatiotemporal metrics displayed similar age-dependent gender disparities: while overall, males showed better spatiotemporal coordination of the ball release, age group comparisons specified that it was particularly middle-aged females that made more timing errors and did not develop a noise-tolerant strategy as males did. As throwing experience did not explain this age-dependency, the results are discussed in the context of spatial abilities and video game experience, both more pronounced in males. In contrast, a measure of rhythmicity developed over successive throws only revealed weak gender differences, speaking to the fundamental tendency in humans to fall into rhythmic patterns. Only the youngest individuals between 5 and 9 years of age showed significantly less rhythmicity in their performance. This computational study was performed in a large cohort in the context of an outreach activity, demonstrating that robust quantitative measures can also be obtained in less controlled environments. The findings also alert that motor neuroscience may need to pay more attention to gender differences.

Differences in PlayerLoad and pitch type in collegiate baseball players

PlayerLoad is derived from a tri-axial accelerometer device and is a measure of an athlete's external training load. Tri-axial accelerometers (Optimeye S5, Catapult Sports, Melbourne, Australia) were worn by 25 collegiate pitchers during a pitching session. Pitches included fastballs, curve balls, sliders, and changeups. Peak and sum PlayerLoad were calculated for fastballs, curve balls, sliders, and changeups. Statistical analysis included paired t-tests (p < 0.01) and effect size indexes (ESI). Peak and sum PlayerLoad were higher for fastballs compared to changeups (N = 20; ESI_peak = 0.47, p= 0.001 and ESI_Sum = 0.13, p = 0.001, respectively). Peak and sum PlayerLoad were not different comparing fastball to curveball (N = 12; ESI_peak = 0.24, p = 0.050 and ESI_Sum<0.01, p = 0.106) and fastball to slider (N = 12; ESI_peak = 0.32, p = 0.088 and ESI_Sum = 0.02, p = 0.221). Fastball velocity (37.1 ± 2.1 m/s) differed from the changeup (33.8 ± 1.9 m/s; p < 0.001), curveball (32.2 ± 1.2; p < 0.001), and slider (33.8 ± 1.3 m/s; p < 0.001). Pitching workload may differ based on pitch type. Pitch counts may not capture true player fatigue due to variability in stresses resulting from different pitch types.

Target Size Manipulations Affect Error-Processing Duration and Success Perceptions but not Behavioural Indices of Learning

We evaluated if and how success perceptions, through target size manipulations, impact processes related to motor learning. This work was based on recent literature suggesting that expectations and self-efficacy exert a direct impact on learning. We measured arousal, kinematics, learner expectancies, motivation, and outcomes in a dart-throwing task. Novices (n = 29) were assigned to either a "Large-target" (horizontal target, 10-cm high) or "Small-target" (2-cm high) group for practice (t = 90), and both groups completed 24-h retention tests. The Small-target group took longer to plan and process feedback in the pre-throw and post-throw periods, respectively, and showed larger joint amplitudes early in practice compared to the Large-target group. As predicted, the Large-target group made more hits and had heightened outcome expectancies compared to the Small-target group. Surprisingly, only the Large-target group performed better than they expected. Despite the Large-target group having more target hits, enhanced expectancies, and more unexpected success, this group did not outperform the Small-target group on behavioural indices of performance and learning. This research questions assumptions and results related to success-related manipulations for task performance and mechanisms related to target size manipulations.

Epidemiology of Elbow Ulnar Collateral Ligament Injuries in Throwing Versus Contact Athletes of the National Collegiate Athletic Association: Analysis of the 2009-2010 to 2013-2014 Seasons

Background:

The management and outcomes of elbow ulnar collateral ligament (UCL) injuries in throwing athletes have been well investigated. However, less is known regarding the management, severity, and outcomes of such injuries in contact athletes.

Purpose:

To compare the incidence, severity, and outcomes of elbow UCL injuries between throwing and contact athletes in collegiate sports.

Study Design:

Descriptive epidemiology study.

Methods:

Elbow UCL injuries were queried from the National Collegiate Athletic Association (NCAA) Injury Surveillance Program between the seasons of 2009-2010 and 2013-2014 in 25 varsity sports. The rates and distribution of injuries by mechanism, participation restriction time, and outcomes (eg, season-ending injury, surgery) were examined. A severe injury was defined as loss of ≥21 days from participation, a season-ending injury, or requiring a surgical intervention. The injury frequency, incidence per 10,000 athlete-exposures (AEs), and injury proportion ratio comparing throwing and contact athletes were calculated with 95% CIs.

Results:

Over the course of 5 seasons, 109 UCL injuries were recorded, for an overall injury rate of 0.29 per 10,000 AEs. Of these injuries, 83 (76.1%) were a result of contact and 26 (23.9%) from throwing. Men’s wrestling (1.78 per 10,000 AEs) and men’s baseball (1.12 per 10,000 AEs) sustained the highest injury rates. A larger proportion of throwing (n = 8; 36.4%) compared with contact (n = –7; 9.1%) (P < 0.01) injuries results in >21 days of time loss. Additionally, more throwing-related UCL injuries required surgery (n = 2; 11.1%) compared with contact-related injuries (n = 1; 1.3%) (P < 0.01). As a result, throwing athletes demonstrated a significantly higher proportion of severe injuries than contact athletes (injury proportion ratio, 4.62 [95% CI, 1.72-12.40]).

Conclusion:

The evaluation of athletes in 25 collegiate varsity sports across 5 seasons found over 3 times more elbow UCL injuries in contact versus throwing athletes. However, the number of severe injuries in throwing athletes was significantly higher than in contact athletes. These findings demonstrate that although elbow UCL injuries are prone to occur in both contact and throwing athletes, their prevention, management, and outcomes must be framed on a sport-by-sport basis.

Repair of the Ulnar Collateral Ligament of the Elbow: Rehabilitation Following Internal Brace Surgery

Injuries to the elbow in athletes who play overhead sports, especially in baseball pitchers, continue to increase in frequency. The anterior band of the ulnar collateral ligament (UCL), the primary restraint to valgus stress, is commonly injured from throwing. Historically, such injuries have been treated with surgical reconstruction techniques, using a tendon autograft. A recently developed UCL repair procedure with an internal brace, utilizing collagen tape, is gaining popularity. The primary goal of this surgery is to enhance elbow joint stability while the ligament is healing and to allow earlier return to sport after UCL reconstruction. The rehabilitation program following UCL repair with internal brace progresses through a different time frame than after UCL reconstruction. The purpose of this commentary, based on our experience with more than 350 cases, including 79 patients with at least a 1-year postsurgical follow-up, was to describe and provide the rationale for the rehabilitation process following UCL repair with internal brace. J Orthop Sports Phys Ther 2019;49(4):253-261. doi:10.2519/jospt.2019.8215.