The effects of mental fatigue on fine motor performance in humans and its neural network connectivity mechanism: a dart throwing study.

While it is well known that mental fatigue impairs fine motor performance, the investigation into its neural basis remains scant. Here, we investigate the impact of mental fatigue on fine motor performance and explore its underlying neural network connectivity mechanisms. A total of 24 healthy male university students were recruited and randomly divided into two groups: a mental fatigue group (MF) and a control group (Control). Both groups completed 50 dart throws, while electroencephalography (EEG) data were collected. Following the Stroop intervention, participants in the MF group exhibited a decrease in Stroop task accuracy and throwing performance, and an increase in reaction time along with VAS and NASA scores. The EEG data during dart-throwing revealed that the network connectivity strength of theta oscillations in the frontal and left central regions was significantly higher in the MF group compared with the Control group, while the network connectivity strength of alpha oscillations in the left parietal region was significantly enhanced. The interregional connectivity within the theta and alpha rhythm bands, particularly in the frontal-central-parietal network connections, also showed a significant increase in the MF group. Mental fatigue impairs dart throwing performance and is accompanied by increased connectivity in alpha and theta.

Sensorimotor prediction is used to direct gaze toward task-relevant locations in a goal-directed throwing task.

Previous research has shown that action effects of self-generated movements are internally predicted before outcome feedback becomes available. To test whether these sensorimotor predictions are used to facilitate visual information uptake for feedback processing, we measured eye movements during the execution of a goal-directed throwing task. Participants could fully observe the effects of their throwing actions (ball trajectory and either hitting or missing a target) in most of the trials. In a portion of the trials, the ball trajectory was not visible, and participants only received static information about the outcome. We observed a large proportion of predictive saccades, shifting gaze toward the goal region before the ball arrived and outcome feedback became available. Fixation locations after predictive saccades systematically covaried with future ball positions in trials with continuous ball flight information, but notably also in trials with static outcome feedback and only efferent and proprioceptive information about the movement that could be used for predictions. Fixation durations at the chosen positions after feedback onset were modulated by action outcome (longer durations for misses than for hits) and outcome uncertainty (longer durations for narrow vs. clear outcomes). Combining both effects, durations were longest for narrow errors and shortest for clear hits, indicating that the chosen locations offer informational value for feedback processing. Thus, humans are able to use sensorimotor predictions to direct their gaze toward task-relevant feedback locations. Outcome-dependent saccade latency differences (miss vs. hit) indicate that also predictive valuation processes are involved in planning predictive saccades.NEW & NOTEWORTHY We elucidate the potential benefits of sensorimotor predictions, focusing on how the system actually uses this information to optimize feedback processing in goal-directed actions. Sensorimotor information is used to predict spatial parameters of movement outcomes, guiding predictive saccades toward future action effects. Saccade latencies and fixation durations are modulated by outcome quality, indicating that predictive valuation processes are considered and that the locations chosen are of high informational value for feedback processing.

Influence of COVID-19 on the emergence of stone-tool use behavior in a population of common long-tailed macaques (Macaca fascicularis fascicularis) in Thailand.

Stone tool use is a rare behavior across nonhuman primates. Here we report the first population of common long-tailed macaques (Macaca fascicularis fascicularis) who customarily used stone tools to open rock oysters (Saccostrea forskali) on a small island along the Thai Gulf in Koh Ped (KPE), eastern Thailand. We observed this population several times during the past 10 years, but no stone-tool use behavior was observed until our survey during the coronavirus disease 2019 (COVID-19) pandemic in July 2022. KPE is located in Pattaya City, a hotspot for tourism in Thailand. Tourists in this area frequently provided large amounts of food for the monkeys on KPE. During the COVID-19 curfew, however, tourists were not allowed to access the island, and monkeys began to face food scarcity. During this time, we observed stone-tool use behavior for the first time on KPE. Based on our observations, the first tool manipulation was similar to stone throwing (a known precursor of stone tool use). From our observations in March 2023, we found 17 subadult/adult animals performing the behavior, 15 of 17 were males and mostly solitary while performing the behavior. The M. f. fascicularis subspecies was confirmed by distribution, morphological characteristics, and mtDNA and SRY gene sequences. Taken together, we proposed that the stone tool use behavior in the KPE common long-tailed macaques emerged due to the COVID-19 food scarcity. Since traveling is no longer restricted many tourists have started coming back to the island, and there is a high risk for this stone tool-use behavior to disappear within this population of long-tailed macaques.

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.

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.

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.

Medial elbow injuries in the throwing athlete.

There has been an epidemic increase in injuries to the elbow in our youth sports over the past 15 years. Initially, career-ending elbow injuries occurred almost exclusively in the professional population. The landmark procedure developed by Dr. Frank Jobe, colloquially termed "Tommy John surgery" after the initial player in whom he performed the surgical procedure, allowed roughly two-thirds of professional athletes to return to play at or near the same level. As the surgical procedure became more widespread, modifications of the technique by Jobe and many other contributors raised the return-to-play level to 85%-94% of players regaining the ability to return to sport at the preinjury level. Almost simultaneously, the emphasis on velocity in the professional ranks led to an unintentional increase in stress on the throwing elbow. This was magnified in our athletes by the advent of year-round sports, as well as the formation of "showcase" events to demonstrate skills and measure velocity. This, unfortunately, has resulted in an increase in both repetitive stress injuries and acute traumatic injuries in our young athletes. The purpose of this article is to discuss age-related injuries from both a preventative standpoint and a treatment standpoint.

Elbow valgus stress during towel drills in college baseball players.

BACKGROUND: In baseball players with elbow injuries, towel drills are clinically used before initiating active throwing exercises to gradually increase stress across the elbow. However, elbow valgus torque during towel drills remains unknown. Moreover, towel drills and active ball throws might have different relationships between biomechanical metrics, such as elbow stress, arm slot, and arm speed. Therefore, the aims of this study were 1) to demonstrate the difference in elbow valgus stress between towel drills and active ball throws and 2) to evaluate the correlation between elbow valgus torque and other biomechanical metrics including arm slot and arm speed in towel drills and active ball throws. METHODS: Seventeen healthy college baseball players performed three towel drills using a face towel, short foam tube, and long foam tube, followed by full-effort throwing on flat ground. Each participant completed five consecutive trials of each task, and the elbow valgus torque, arm slot, and arm speed were measured using wearable sensors. One-way repeated analysis of variance and post-hoc tests were used to determine the differences in biomechanical metrics among the tasks. Furthermore, the correlation between the elbow valgus torque and other metrics was evaluated using Pearson correlation coefficients. RESULTS: Elbow valgus torque was lower in towel drills compared to that of active ball throws; however, the stress during towel drills using a face towel reached almost 80% of the maximum effort of active ball throws. There was no relationship between elbow valgus stress and arm slot in either the towel or active ball throw tasks. However, a higher arm speed was associated with greater elbow valgus torque in towel drills, whereas no relationship between elbow stress and arm speed was found in active ball throws. CONCLUSION: Precaution must be taken in athletes following a progressive throwing program because elbow valgus stress reaches almost 80% of the full-effort throw, even when using a face towel in a towel drill. Hence, the subjective intensity must be controlled even in towel drills to gradually increase the medial elbow stress. Moreover, the mechanisms underlying changes in elbow stress may differ between towel drills and active ball throws. Future investigations on the difference between towel drills and active ball throws may help understand the underlying mechanism of alterations in elbow valgus torque during the throwing movement.

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.

Handball players have superior shoulder proprioception: a prospective controlled study.

BACKGROUND: Proper proprioceptive and neuromuscular control is crucial for the overhead athlete's performance. The aim of the present study was to evaluate the shoulder joint position sense (JPS) levels in overhead throwing athletes. The secondary aim was to confront the proprioceptive abilities with glenohumeral adaptive changes and pathologies among athletes. METHODS: Ninety professional handball players and 32 healthy volunteers were recruited. JPS levels were measured by an electronic goniometer and expressed as values of an active reproduction of the joint position (ARJP) and as error of ARJP (EARJP) in 3 different reference positions for each movement (abduction and flexion at 60°, 90°, and 120°; internal [IR] and external rotation [ER] at 30°, 45°, and 60°). RESULTS: Side-to-side differences revealed significantly better values of EARJP for the throwing shoulders in abduction at 90° and 120°, flexion at 90° and 120°, IR at 60°, and ER at 30° and 60° compared with the nonthrowing shoulders. Handball players showed significantly better proprioceptive levels in their throwing shoulder compared to the dominant shoulder of the control group in abduction at 90° (P = .037) and 120° (P = .001), flexion at 120° (P = .035), IR at 60° (P = .045), and in ER at 60° (P = .012). DISCUSSION: Handball players present superior shoulder JPS in their dominant throwing shoulder at high range of motion angles when compared to a nonathlete population and to their own nondominant shoulder.

Long Head of the Biceps Tendon Plays a Role in Stress Absorption and Humeral Head Restriction during the Late Cocking and Deceleration Phases of Overhead Throwing: A Finite Element Study.

BACKGROUND: Emerging evidence suggests that the long head of the biceps (LHBT) may play a role in stabilizing the glenohumeral joint, and this has led to controversy around the efficacy of biceps tenotomy for superior labral anterior and posterior (SLAP) lesions. Therefore, the aim of this finite element analysis (FEA) study was to determine the stress absorption and humeral head translation restriction effects of the LHBT within the glenohumeral joint during the late cocking and deceleration phases of overhead throwing with a view to resolving the controversy around tenotomy. METHODS: Eight FEA models were created using computed tomography and magnetic resonance imaging data from normal glenohumeral joints. The models represented four LHBT conditions: uninjured, subpectoral tenodesis, tenotomy, and type II SLAP lesions. The late cocking and deceleration phases of the overhead throwing were simulated for each model. The impacts of the four LHBT conditions on glenohumeral joint stress absorption and humeral head displacement restriction were studied based on 1) stress and related distributions on the cartilage, labrum, capsule, and LHBT and 2) humeral head translation variation. RESULTS: The FEA analysis showed that the magnitude of the contact stress on the articular cartilage, labrum, and capsule was the lowest in the uninjured models, followed by the subpectoral tenodesis, tenotomy, and type II SLAP lesion models. Humeral head translation was the most restricted in the subpectoral tenodesis models, followed by the tenotomy and type II SLAP lesion models. CONCLUSION: Finite element analysis demonstrated that the LHBT plays a significant role in stress absorption and displacement restriction in the late cocking and deceleration phases of overhead throwing. Subpectoral tenodesis of the LHBT exhibited lesser amount of stress and humeral head translation than those of tenotomy, thereby making it a better option for patients who engage in overhead throwing.

Shoulder Movement-Centered Measurement and Estimation Scheme for Underarm-Throwing Motions.

Underarm throwing motions are crucial in various sports, including boccia. Unlike healthy players, people with profound weakness, spasticity, athetosis, or deformity in the upper limbs may struggle or find it difficult to control their hands to hold or release a ball using their fingers at the proper timing. To help them, our study aims to understand underarm throwing motions. We start by defining the throwing intention in terms of the launch angle of a ball, which goes hand-in-hand with the timing for releasing the ball. Then, an appropriate part of the body is determined in order to estimate ball-throwing intention based on the swinging motion. Furthermore, the geometric relationship between the movements of the body part and the release angle is investigated by involving multiple subjects. Based on the confirmed correlation, a calibration-and-estimation model that considers individual differences is proposed. The proposed model consists of calibration and estimation modules. To begin, as the calibration module is performed, individual prediction states for each subject are updated online. Then, in the estimation module, the throwing intention is estimated employing the updated prediction. To verify the effectiveness of the model, extensive experiments were conducted with seven subjects. In detail, two evaluation directions were set: (1) how many balls need to be thrown in advance to achieve sufficient accuracy; and (2) whether the model can reach sufficient accuracy despite individual differences. From the evaluation tests, by throwing 20 balls in advance, the model could account for individual differences in the throwing estimation. Consequently, the effectiveness of the model was confirmed when focusing on the movements of the shoulder in the human body during underarm throwing. In the near future, we expect the model to expand the means of supporting disabled people with ball-throwing disabilities.

Seated-Shot-Put Equipment in Para Athletics-A Review and Presentation of Data From the Tokyo 2020 Paralympic Games.

This research provides a review of seated shot put alongside new data from the Tokyo 2020 Paralympic Games with the aim to understand the latest trends in equipment within a recently established rule set and how key equipment variables may impact performance for athletes in different classifications. First, a review of the literature found that the throwing pole is a key equipment aid that is not well understood, in part due to limitations in testing design. New data from the 2020 Paralympic Games showed inconsistent trends for the use of the throwing pole among athletes, particularly in transitionary classes (F33-34 and F54-55). A two-way analysis of variance found a main effect of classification on performance (p < .001), as well as an interaction effect between pole use and classification on performance (p < .05). Notably, pole users are seen to perform better than non-pole users in Class F32 (p < .05).

Effects of repetitive baseball throwing on hip muscle strength and trunk and pelvic motions at the shoulder's maximum external rotation position during the late cocking phase and ball release.

[Purpose] This study aimed to investigate the changes in the trunk and pelvic lateral tilt angles at the shoulder's maximum external rotation during the late cocking phase (MER) and ball release (BR) and hip muscle strength during repetitive throwing. [Participants and Methods] In this study, 12 male baseball players participated. During the throwing, which was filmed using a high-speed video camera, the trunk and pelvic lateral tilt angles toward the nonthrowing side were measured at the MER and BR. Hip muscle strength during abduction, adduction, and external internal rotations were measured on the throwing and nonthrowing sides. Repetitive throwing was performed for nine innings, with 15 pitches per inning. Throwing motion was compared during innings 1, 7, 8, and 9. Hip muscle strength was measured before and after repetitive throwing. [Results] Compared with the trunk lateral tilt angle toward the nonthrowing side at BR in inning 1, the angle in innings 8 and 9 increased. The strength of hip abduction, adduction, and external and internal rotations on the throwing and nonthrowing sides decreased after repetitive throwing. [Conclusion] Hip muscle strength decreases after 135 pitches, and throwing >120 pitches changes the trunk lateral tilt angle at BR.

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.

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.

Arm injury in youth baseball players: a 10-year cohort study.

BACKGROUND: Arm injuries are commonly encountered in baseball as young athletes play into adulthood. The purpose of this study was to examine the incidence of arm injury and risk for surgery in adolescent baseball players followed over a 10-year period from scholastic, age-group, and travel baseball leagues through their highest level of competition. METHODS: A prospective study was conducted enrolling middle and high school baseball players in 2010-2012, then followed for 10 years or until retirement from competitive baseball. Players were included if fully participating in team activities at the time of preseason study enrollment. Players with prior arm (shoulder or elbow) surgery or those diagnosed with time loss arm injury within the past year were excluded. Only shoulder and elbow overuse problems resulting in time-loss from sport and medical attention from a sports medicine physician or orthopedic surgeon were documented as injuries in this study. Musculoskeletal overuse injuries were classified based on the orchard injury classification system. Incidence proportion and risk ratio (RR) and 95% confidence intervals (CIs) for initial injury and injuries requiring surgery were calculated. RESULTS: A total of 261 pitchers (age: 14.2 ± 2.6 years; follow-up: 4.2 ± 2.7 years) were enrolled. Twenty percent of the cohort was followed for ≥7 years. The overall injury incidence was 25.6/100 athletes (95% CI 21-31) with a cumulative surgical incidence of 5.4/100 athletes (95% CI 3.2-8.8). The risk of experiencing shoulder injury (n = 25) and elbow injury (n = 38) were similar (n = 38) (RR 0.7, 95% CI 0.4-1.1). The athletes also presented with a similar frequency of requiring surgery regardless of the injured body part. However, the risk of surgery in those playing beyond the high school level was 4.3 times greater (95% CI 1.2-15.0) than those only playing high school. CONCLUSION: This is the first study to follow a large cohort of youth baseball players as they progress, showing a relatively high arm injury incidence. Shoulder and elbow injury incidence was similar but surgical risk increased playing beyond high school, specifically for the elbow. The high injury frequency and burden of care required by young baseball players as reported in this study is concerning, and strategies to reduce injury should be investigated.

Risk factors of throwing injuries related to pitching mechanics in young baseball players: a longitudinal cohort study.

BACKGROUND: Risk factors for throwing injuries related to pitching mechanics are unknown. Insufficient pelvic rotation during pitching may be a risk factor for shoulder and elbow injury. This cohort study aimed to identify biomechanics risk factors for throwing injuries in young baseball players. We hypothesized that excessive mechanical load and motion errors would be risk factors for throwing injuries. METHODS: Young baseball pitchers (aged 8-9 years) were recruited from regional baseball leagues between December 2016 and December 2019. Pitching measurements were performed before the start of each season and after the end of the last season in December 2019. The trunk tilt angular displacement, pelvic rotation angular displacement, and forearm rotation angle were calculated using a markerless motion capture system. We also measured elbow varus torque using an accelerometer. After the initial test session, each participant was followed up for 3 years to determine the occurrence of throwing injuries. Players with throwing shoulder and elbow injuries were categorized into the throwing injury group, and those without shoulder and elbow pain for 3 years were categorized into the noninjured group. RESULTS: In this study, 97 baseball pitchers completed a 3-year follow-up. Among those participants, 66 (68.0%) had throwing injuries. A significant difference was observed between the throwing injury and noninjured groups, whereby the injured players had less pelvic rotation angular displacement. CONCLUSION: Insufficient pelvic rotation during pitching is a newly discovered risk factor related to throwing injuries.

Arthroscopic findings of the glenohumeral joint in symptomatic anterior instabilities: comparison between overhead throwing disorders and traumatic shoulder dislocation.

BACKGROUND: The term shoulder instability refers to a variety of mechanisms and clinical presentations. One of the common pathologies of throwing disorders is internal impingement with anterior instability. Most throwing athletes with symptomatic internal impingement with anterior instability exhibit positive apprehension and relocation test results, whereas those with recurrent anterior shoulder instability display positive apprehension test results. While the glenoid labrum-inferior glenohumeral ligament complex is a significant critical stabilizer for the prevention of anterior shoulder dislocation, the characteristics of the essential lesion in internal impingement with anterior instability have not been determined yet. This study aimed to compare the intra-articular lesion of athletes with internal impingement related to the overhead throwing motion in athletes with a traumatic shoulder dislocation. METHODS: Sixty-one athletes (all men; mean age, 25.2 ± 12.6 yr) who underwent an arthroscopic procedure were divided into 2 groups: 25 in the throwing group and 36 in the dislocation group. All shoulders had subtle glenohumeral instability defined by a positive anterior apprehension test and a relocation test. Those with voluntary and multidirectional instability and large glenoid bone loss (more than 25%) were excluded from the current study. All shoulders were evaluated for the following evidence: rotator cuff injury, superior labrum tear anterior and posterior lesions, labral pathologies including Bankart lesions, osteochondral lesions to the humeral head, biceps tendon fraying or rupture, and inferior glenohumeral ligament and middle glenohumeral ligament (MGHL) conditions. RESULTS: Arthroscopic findings of the throwing group showed more supraspinatus injuries (92% and 25%, P < .001), type II superior labrum tear anterior and posterior lesions (60% and 3%, P < .001), posterosuperior labral lesions (92% and 39%, P < .001), and hypoplastic MGHLs (56% and 6%, P < .001) and lesser Bankart lesions (8% and 92%, P < .05) than those of the dislocation group. CONCLUSIONS: These results indicate that the characteristic lesions of internal impingement with anterior instability in throwing athletes include partial thickness rotator cuff tears, superior labrum tear anterior and posterior lesions, posterosuperior labral tears, and hypoplastic MGHLs. As expected, the physiopathology of internal impingement with anterior instability in throwing athletes may be related to the dysfunction of the anterosuperior glenohumeral capsular ligament, including the MGHL, rather than the inferior glenohumeral ligament as in traumatic anterior shoulder dislocations. These findings would be useful for defining treatment strategies for internal impingement with anterior instability in overhead throwing athletes.

The Effect of Neurofeedback Training on Executive Control Network of Attention and Dart-Throwing Performance in Individuals with Trait Anxiety.

This study aimed to investigate the effect of neurofeedback training on the executive control network of attention and dart-throwing skill performance in individuals with trait anxiety. Twenty girls (24.65 [Formula: see text] 2.83 years) participated in this study. They were divided into neurofeedback and control training groups. All participants practiced 14 sessions. The neurofeedback group performed neurofeedback training (increasing SMR wave, decreasing theta, and increasing alpha) and dart-throwing exercise, and the control group only completed the dart-throwing exercise. The post-test, including Attentional Networks Test (ANT) and dart-throwing, was conducted 48 h after the last training session. The results revealed a significant difference in the performance of the executive control network and dart-throwing skill between the neurofeedback and the control training group. In general, these findings support the effect of neurofeedback training on the neural mechanisms of the executive control network of attention, and performance in dart-throwing skill improves by improving attentional performance processes.