Explore the vast range of titles available.

The relationship between ankle joint function and throwing-related injuries has not been demonstrated. We hypothesized that limited ankle joint range of motion (ROM) was related to risk factors for shoulder and elbow injuries in young baseball players. This 12-month prospective cohort study evaluated the age, height, weight, playing position, shoulder, elbow, and ankle function of 228 enrolled baseball players. Shoulder and elbow injuries were tracked during the season. Univariate and multivariate analyses were performed to identify risk factors for shoulder and elbow injuries among participants divided into non-injured and injured groups. Univariate analysis showed that age, height, weight, ROM of elbow flexion in the dominant arm, muscle strength ratio of shoulder abduction, and the likelihood of being a pitcher or a catcher were significantly greater in the injured group than in the non-injured group. ROM of shoulder abduction-external/internal rotation, shoulder total arc on the dominant arm, ankle joint dorsiflexion, and plantar flexion on the back (non-lead) and front (lead) legs were significantly less in the injured group than in the non-injured group. In conclusion, ROM dorsiflexion deficits in the back leg, shoulder abduction-external rotation in the dominant arm, ROM increase in elbow flexion on the dominant side, older age, and being a pitcher were significant independent risk factors for injury.

Glenohumeral internal rotation deficit (GIRD) and weakness in prone external rotation are risk factors for shoulder and elbow injuries in high school baseball pitchers. While a shoulder-stretching prevention program to improve GIRD decreases the injury rate, the effects of external rotation strength remain unclear. This non-inferiority (NI) study investigates the hypothesis that external rotation strength training is not inferior to sleeper stretching for shoulder and elbow injury prevention in high school baseball pitchers. Participants were randomly allocated to the stretching (n = 62; active control group) and muscle-training (n = 51) groups. Specific exercises were performed each night. Elbow and shoulder injuries were monitored for 150 days. Kaplan–Meier survival curves were generated, and the hazard ratios (HRs) for injury occurrence were calculated using multivariate Cox regression. The log-rank test was used to compare the injury-free time. A one-sided NI test using a fixed NI margin was performed (significance level, P  = 0.025). The injury rates were 22.6% (n = 14) in the stretching group and 9.8% (n = 5) in the muscle-training group. The muscle-training group had a lower injury rate ( P  < 0.001) and a lower risk of injury than the stretching group (HR = 0.489). Therefore, external rotation muscle strength training is not inferior to stretching for preventing baseball-related arm injuries.

Some studies have reported that upper limb tightness is a risk factor for shoulder/elbow pain in high school baseball pitchers; but there has been insufficient research on the relationship between lower limb tightness and shoulder and elbow pain in pitchers. This study aimed to clarify the correlation among pre-season hip range of motion (ROM) and shoulder and elbow disorders in high school baseball pitchers. We surveyed 125 high school pitchers. Hip ROM was measured in the supine and prone positions. After the season, based on their answers to the self-recorded questionnaire, a “shoulder or elbow injury” was defined as any condition resulting in the pitcher being considered disabled for ≥ 8 days. An independent t-test and logistic regression analysis were used for statistical analysis. Eleven disabled pitchers (9%) were identified during the season. In the injured group, the ROM of the plant side hip with 90° flexed external rotation was smaller than that in the non-injured group. Preseason limited ROM in the plant side hip with 90° flexed external rotation was a risk factor for the occurrence of shoulder/elbow pain in the season.

While previous studies have revealed factors affecting the progression of rotator cuff tear (RCT), none have yet described factors affecting its onset. The purpose of this longitudinal observational study was to analyze factors affecting the RCT onset and progression in the general population. The present study included 185 shoulders from 93 participants who completed all the examinations in both 2012 and 2017. Participants received a questionnaire with age, gender, arm dominance, and presence of pain at rest, in motion, and at night. The range of motion (ROM), simple shoulder test (SST) were also examined. Anteroposterior radiograph of the shoulder joint was performed to evaluate the degree of osteoarthritic changes by the Samilson-Prieto (S-P) classification. The degree of RCT was examined by ultrasonography. There were 132 shoulders without RCT and 53 with RCT in 2012. RCT occurred in 21 of 132 shoulders, and the factor affecting the RCT onset was S-P grade 2 osteoarthritic change in 2012 (odds ratio [OR] 10.10). RCT progressed in 22 of 53 shoulders, and the factor affecting RCT progression was the presence of motion pain in 2012 (OR 13.76). These results added new knowledge regarding the natural course of RCT onset and progression.

Asymptomatic elbow abnormalities are relatively common in young baseball players, but the factors responsible are unclear. To prospectively identify risk factors related to symptom manifestation in asymptomatic elbow abnormalities, we recruited 573 baseball players (age: 7–14 years) at a pre-participation medical/physical examination in the preseason who were right-handed and had asymptomatic medial elbow abnormalities on ultrasound (US). Baseline preseason and postseason participant characteristics were assessed. A “symptomatic” elbow was defined as an elbow with medial elbow joint problems that prevented ball throwing for ≥ 8 days. After exclusions, 82 players were enrolled, of whom 22 (26.8%) developed a symptomatic elbow. In univariate analyses, the external and internal rotation strengths of the dominant shoulder were significantly greater in the symptomatic group than in the asymptomatic group ( P  = 0.021). Multivariate logistic regression analysis showed that the internal rotation strength of the dominant shoulder was a significant independent risk factor (odds ratio = 1.091, P  = 0.027) for developing a symptomatic elbow. In young asymptomatic baseball players with abnormalities in the medial elbow region of the dominant arm on US, stronger preseason internal rotation strength of the dominant shoulder was a significant independent risk factor for the development of a “symptomatic” elbow.

Baseball players frequently injure their shoulders and elbows. Preseason risk factors for such injuries have been relatively well studied, but in-season risk factors are less known, and the relationship between the number of pitches and the incidence of such injuries in baseball pitchers of any level is unclear. Identifying the risk factors related to the number of daily pitches is particularly important to prevent baseball-related arm injuries among young pitchers. Thus, we prospectively investigated the relationship between the number of daily full-power pitches in high school baseball pitchers and the incidence of shoulder and elbow injuries. We observed that a small number of daily full-power pitches, < 30 pitches per day, in high school baseball pitchers, significantly increased the risk of shoulder and elbow injuries: these players had a 2.3-times greater risk of injuries and a 45-day earlier occurrence of injuries than those pitching ≥ 30 pitches per day. Although unexpected, this was plausible as continuous daily pitching is required to maintain physical condition in growing and maturing high school pitchers. These findings may form the basis for establishing guidelines regarding the appropriate number of daily pitches required to prevent shoulder and elbow injuries in high school baseball pitchers.

Studies on the relationship between baseball loads (practice, training, and competition hours) and shoulder and elbow injuries among high school pitchers are limited. Therefore, this study included 92 male high school baseball pitchers and evaluated their preseason shoulder and elbow conditions. All participants completed a self-recorded questionnaire regarding baseball load, presence of shoulder pain or elbow pain, or both, and pitching limitations due to shoulder and/or elbow pain experienced daily to determine the occurrence of injuries and record the baseball load. The optimal load cutoff value was determined using a receiver operating characteristic curve analysis. Participants were categorized into high-load and low-load groups according to the aforementioned cutoff value. The Kaplan–Meier method was used to obtain time-to-event curves, and cox proportional hazards models were used to calculate the hazard ratios for injury rates. The cutoff value of the average baseball load was 324.4 min per day. A high load (> 5.5 h/day) led to a 2.6-times greater risk of injuries and 3.3-times earlier occurrence of injuries than a low load (< 5.5 h/day). Therefore, a high load is a risk factor for shoulder and elbow injuries in high school baseball pitchers.

Pitching motion requires whole-body coordination; therefore, poor control of the lower extremities, pelvis and trunk may cause shoulder and elbow injuries. However, few studies have described the relationship between the shoulder joint function and low back injury in high-school baseball pitchers. A total of 128 healthy high school pitchers underwent pre-season medical checkups, where their shoulder range of motion and shoulder strength were measured. The participants completed a self-recorded daily questionnaire regarding the presence of low back pain. Pitchers were divided into injured and non-injured groups. Low back injury was observed in 13 participants (13.4%). In the injured group, horizontal adduction on the dominant shoulder was significantly less than in the non-injured group. A logistic regression analysis showed that horizontal adduction on the dominant side was a significant independent risk factor for low back injury during the season. It is important to recognize that restriction of the shoulder function not only causes shoulder and elbow injuries but can also risk low back injury.

Introduction Ulnar nerve instability (UNI) is a common cause of ulnar neuropathy. The relationship between UNI and medial elbow instability has not yet been investigated in baseball pitchers. We investigated the association between UNI and the degree of ulnar collateral ligamentous laxity in high school baseball pitchers. Methods We examined 172 local high school baseball pitchers. A clinical examination assessed pitchers' physical condition during the winter off-season from 2021 to 2023. Ultrasound examinations were conducted on the medial joint gap of both sides of the pitchers during valgus stress and non-stress conditions. The participants were divided into three groups based on the ultrasonographic findings of UNI: no instability (type N), subluxation (type S), and dislocation (type D). For the pitching side, we assessed the relationship between the type of UNI and medial elbow instability and other clinical and physical findings, including ulnar nerve symptoms, grip strength, and key pinch strength. Results The prevalence of UNI on the throwing side was 62% (subluxation, 32%; dislocation, 30%) and 60% (subluxation, 26%; dislocation, 34%) on the non-throwing side. Regarding the rates according to the three types of UNI, there was no significant difference between the pitching and non-pitching sides. There was a significant difference in the distance between the medial joint gap under stress and non-stress conditions, with 0.59 mm on the throwing side and 0.36 mm on the non-throwing side; however, no significant difference was found in the degree of ulnar collateral ligamentous laxity when comparing each type of UNI on the throwing side. Conclusion In this study of 172 high school baseball pitchers, UNI occurred on the throwing side in 62% of subjects (32% subluxation, 30% dislocation) and on the non-throwing side in 60% of subjects (26% subluxation, 34% dislocation). There was no significant difference in the rates of the three types of UNI between the pitching and non-pitching sides. Additionally, there was no association between UNI type and the presence or absence of ulnar nerve symptoms. The medial joint gap distance under both stress and non-stress conditions was significantly larger on the throwing side compared to the non-throwing side. However, no significant association was found between the different types of UNI and the degree of ulnar collateral ligamentous laxity on the throwing side in this population.

Background: Differences in shoulder range of motion (ROM), shoulder muscle strength, and humeral torsion between left- and right-handed high school baseball pitchers remain poorly characterized. Hypothesis: Similar differences in shoulder ROM, strength, and humeral torsion between right-handed pitchers (RHPs) and left-handed pitchers (LHPs) observed in professionals will also be present in high school pitchers, with potential variations due to developmental stages. Study Design: Cross-sectional study; Level of evidence, 3. Methods: The authors included 921 high school baseball pitchers (706 RHPs and 215 LHPs) and evaluated their age, height, weight, body mass index, baseball experience, shoulder ROM, and muscle strength. Humeral torsion was measured in 211 RHPs and 57 LHPs. The Mann-Whitney U test was performed to determine the differences between the RHPs and LHPs and between the dominant and nondominant sides in each group. Pearson correlation analysis was performed to test the relationship between humeral torsion and shoulder ROM. Logistic regression analysis was conducted to determine the independent factors associated with LHP. Results: LHPs exhibited increased nondominant external rotation (ER) (103.1° vs 100.0°; P = .004), dominant horizontal adduction (HA) (23.0° vs 19.6°; P = .015), and side-to-side ratio in prone internal rotation (PIR) strength (107.6% vs 98.3%; P < .001) compared with RHPs. Additionally, LHPs were shorter (171.4 vs 172.9 cm; P = .002) with lower side-to-side differences in ER (5.7° vs 8.9°; P < .001) and HA (–6.5° vs −11.3°; P < .001), dominant prone ER (PER) strength (15.4 vs 16.8 kgf; P = .040), side-to-side ratio in PER strength (93.1% vs 103.7%; P < .001), and side-to-side differences in humeral torsion (5.8° vs 9.9°; P = .011) compared with RHPs. After adjusting for confounding factors, a smaller side-to-side ratio in PER strength (P < .001; OR, 0.911) and larger side-to-side ratio in PIR strength (P < .001; OR, 1.031) were independent factors associated with being an LHP. Conclusion: LHPs have a decreased side-to-side ratio in PER strength and increased side-to-side ratio in PIR strength compared with RHPs. These findings suggest that shoulder-related biomechanical differences between right- and left-handed pitchers are evident in high school athletes.