Biomechanical characteristics of scapula and glenohumeral movements during pitching motion in injury-prone college baseball pitchers

Coordination of glenohumeral and scapular movements plays an important role in the injury prevention of baseball pitchers. However, there is no objective data establishing the direct relationship between pitching injuries and associated glenohumeral and scapular movements. Therefore, the objectives of the present study were to demonstrate biomechanical differences in scapular and glenohumeral movements during pitching between injury-prone pitchers and healthy college baseball pitchers. Thirty collegiate baseball pitchers were classified into two groups according to their injury status: injury-prone group (N=15, 20.7±1.4 years, 180.1±6.5 cm, 78.9±5.4 kg) and control group (N=15, 20.9±1.1 years, 177.1±6.6 cm, 72.3±6.7 kg). We obtained the pitching motion data using the three-dimensional motion analysis technique with four high-speed cameras. The horizontal abduction angles of the glenohumeral joint during cocking and acceleration phases were significantly greater in injury-prone pitchers [19.0° (95% CI: 14.4–23.6) at foot contact, −4.0° (95% CI: −7.7 to −0.2) at maximum external rotation (MER), and −0.3° (95% CI: −4.8 to −4.2) at ball release] than in healthy controls [11.7 °(95%CI:7.1 to 16.3) at foot contact, −10.0°(95%CI: −13.7 to −6.3) at MER, and −6.9°(95%CI: −11.4 to −2.4)]( p <0.01). In addition, the external rotation angle (ER) of the scapula at MER was significantly greater in the injury-prone group [−0.1° (95% CI: −5.0 to 4.8)] than in the control group [−12.3° (95% CI: −17.2 to −7.4)] (p<0.01), but there was no difference in the scapular ER during foot contact between the two groups. These results suggests that injury-prone pitchers have less internal rotation of the scapula and more horizontal abduction of the glenohumeral joint during cocking and acceleration phases. Therefore, sports medicine practitioners may need to pay more attention to coordination of scapular and glenohumeral movements during the cocking and acceleration phases of pitching for prevention of shoulder injuries.

Relationship Differences in Pre-season Isometric Shoulder Strength, Humeral Torsion and Shoulder Range of Motion in Collegiate Baseball Players (218)

Objectives: Muscle strength, humeral torsion (HT) and shoulder range of motion (ROM) have been linked to throwing performance and injury risk in baseball players. Research suggests that players who demonstrate an isometric shoulder external rotation (ER)/internal rotation (IR) strength ratio of <0.75 are at a higher risk for developing a throwing-related upper extremity injury. While the relationships between HT and shoulder ROM have been examined in the literature, few studies have examined the potential relationships between these variables and isometric shoulder strength. The purpose of this study was to examine the relationships between isometric shoulder strength, HT and shoulder ROM at the start of each baseball season in a cohort of healthy junior college baseball players. Methods: Ninety-two healthy junior college baseball players (mean age=19.9±0.8 years) were prospectively assessed at the start of 2 consecutive spring seasons. Variables measured included HT, shoulder ROM and isometric shoulder strength. Both the dominant (D) and non-dominant (ND) shoulders of each player were assessed throughout the study. Chi square tests and bivariate Pearson correlation coefficients were calculated to examine between group differences and the relationships between variables. Statistical significance was set a priori at α=0.05. Results: 33.7% of junior college players demonstrated a D shoulder ER/IR strength ratio of <0.75 at the start of baseball season. Pitchers and position players demonstrated no significant differences in D shoulder ER/IR strength ratios at the start of the season (P=.40). Additionally, moderate positive relationships were observed between D HT and D IR ROM (r=0.35; P=.001) as well as D horizontal adduction (HA) ROM (r=0.43; P<.001). A moderate relationship was also observed between ND HT and ND IR ROM (r=0.56, P<.001), however ND ER and HA ROM demonstrated weaker relationships respectively (ER: r=-0.27; P=.01; HA: r=0.26; P=.01). Inverse relationships were observed between HT and ER strength in both the D and ND shoulders (D: r=-0.27, P=.01; ND: r=-0.28, P=.007). Internal rotation ROM was also inversely correlated with ER strength (r=-0.29, P=0.005) and ER/IR strength ratios (r=-0.31, P=.003), but only in the D shoulder. No significant correlations were observed between ROM and strength in the ND shoulder. Conclusions: One third of the junior college baseball players in this study began the season with marked deficits in D shoulder strength, irrespective of their position. We then examined the relationships between HT, shoulder ROM and isometric shoulder strength and confirmed the previously established correlation between HT and shoulder ROM. Moreover, there appeared to be inverse relationships between HT and ER strength in both the D and ND shoulders as well as IR ROM and ER strength in the D shoulder. This study emphasizes the importance of pre-season rotator cuff strength training, with an emphasis on improving ER strength, to potentially aid in the prevention of throwing-related upper extremity injuries in collegiate baseball players. Humeral torsion and shoulder ROM may influence isometric shoulder strength, however more research is needed to better understand these relationships in the throwing shoulder.

Hypermobility of ulnar nerve does not affect throwing performance (122)

Objectives: Ulnar nerve neuropathy around the elbow is a common pathology in throwing athletes, and occurs due to many factors including valgus elbow, and ulnar nerve hypermobility. For patients with ulnar nerve neuropathy, anterior transposition of the ulnar nerve is common procedures. Meanwhile, Ulnar nerve hypermobility has been reported to be present in 2% to 47% of asymptomatic individuals. However, no studies have investigated the rate of ulnar nerve hypermobility in throwing athletes, and the relationship between ulnar nerve mobility, and clinical symptom and throwing performance. This study was designed to classify the sonographic assessment for the mobility of the ulnar nerve compared to physical evaluation, and to determine whether ulnar nerve hypermobility is associated with clinical symptoms and throwing performance in baseball players. We investigated ulnar nerve hypermobility using ultrasound to evaluate the relationship between the ulnar nerve hypermobility and clinical sign including throwing performance in college baseball players. Methods: 138 elbows in 69 college baseball players were examined. Each participant was queried regarding symptoms attributable to the ulnar nerve. In addition, structural measurements consisting of the tinel test and elbow flexion compression testing were examined. Sonographic examiners were, unaware of reported symptoms, independently performed a standardized examination of both elbows to assess ulnar nerve hypermobility. For sonographic assessment, the ultrasound probe was located at the medial condyle of the humerus to visualize the ulnar nerve in short-axis view in the extended elbow position. During extension to flexion of the elbow, the mobility of ulnar nerves was assessed, and categorized as stable, or hypermobile, which was further subclassified as subluxation, or dislocation (Figure 1A, 1B, 1C). Pared t-test was used to compare the mobility of the ulnar nerve between throwing and non-throwing sides. Fisher’s exact test was used to assess the relationship between physical exams and the mobility of the ulnar nerve. Values of p<0.05 were considered statistically significant. Results: Ulnar nerve hypermobility was identified in 54 (78.3%) of the 69 elbows in throwing side. Meanwhile, hypermobility was 53 (76.8%) in non-throwing side without significant difference, compared to non-throwing side. Elbows with nerve hypermobility did not experience a higher prevalence of subjective symptoms (snapping, pain, and tingling) than did elbows with stable nerves. Provocative physical examination testing for ulnar nerve irritability, however, showed consistent trends toward heightened irritability in hypermobile nerves (p = 0.04 to 0.16). Demographic data and anatomic measurements were similar between the subjects with stable nerves and those with hypermobile nerves. Additionally, all participants did not show decrease of throwing performance. Conclusions: Ulnar nerve hypermobility occurs in over half of the baseball players in throwing and non-throwing sides. Utilizing a standardized sonographic examination, a diagnosis of ulnar nerve hypermobility can be established with substantial interobserver reliability. In baseball players, ulnar nerve hypermobility does not appear to be associated with an increased symptomatology attributable to the ulnar nerve and throwing performance. Anterior transplantation of ulnar nerve may not be needed for baseball players with ulnar nerve neuropathy.

Memoria de trabajo y control inhibitorio en beisbolistas universitarios (Working Memory and Inhibitory Control in College Baseball Players)

El rendimiento óptimo en el deporte requiere de procesos neuropsicológicos como las funciones ejecutivas. Entre estas, están la memoria de trabajo (MT) y el control inhibitorio (CI). Se ha descrito que quienes practican deportes de ritmo propio como el béisbol obtienen puntajes ubicados en el rango alto en tareas correspondientes a la MT y el IC, así como que los bateadores suelen obtener puntajes más altos en tareas de control inhibitorio en comparación con quienes no batean y atletas de otros deportes. Este estudio evalúa las diferencias en el rendimiento en tareas de IC y MT de beisbolistas universitarios y su relación con el tiempo practicando este deporte. Treinta y dos jugadores pertenecientes a un selectivo de béisbol universitario fueron evaluados por medio de subpruebas pertenecientes a la Batería BANFE-2. Los resultados muestran puntajes correspondientes al rango alto en las tareas correspondientes a la MT y el IC para todos los participantes. Se encontraron diferencias significativas en los puntajes de IC entre los bateadores y los lanzadores (p < .01). En las tareas de MT las diferencias no fueron significativas (p < .5). Los resultados obtenidos apoyan la hipótesis de que los bateadores obtienen puntajes más altos que en IC que quienes no batean y que los beisbolistas en general tienen un desempeño alto en capacidades como el IC y la MT por lo que se puede inferir que las exigencias del béisbol son un factor importante en el desarrollo de procesos como los abordados en este estudio. Abstract. Optimal performance in sport requires neuropsychological processes such as executive functions. Among these are working memory (WM) and inhibitory control (IC). It has been described that those who practice self-paced sports such as baseball obtain scores located in the high range in tasks corresponding to the WM and IC, as well as batters tend to obtain higher scores in tasks of inhibitory control compared to those who do not hit and athletes from other sports. This study evaluates the differences in the performance of university baseball players in IC and WM tasks and their relationship with the time practicing this sport. Thirty-two players belonging to a university baseball team were evaluated by means of subtests belonging to Battery BANFE-2. The results show scores corresponding to the high range in the tasks corresponding to the WM and the IC for all participants. Significant differences were found in CI scores between hitters and pitched (p <.01). In the TM tasks the differences were not significant (p <.5). The results obtained support the hypothesis that hitters obtain higher scores than in IC than non-hitters and that baseball players in general have a high performance in capacities such as IC and WM, so it can be inferred that the demands of baseball they are an important factor in the development of processes such as those addressed in this study.

Supraspinatus Tendon Changes and Glenohumeral Range of Motion in College Baseball Players

Baseball players commonly show altered glenohumeral range of motion during internal rotation, external rotation, total rotation, and horizontal adduction. These altered ranges of motion appear to be associated with throwing shoulder injuries, which frequently involve the supraspinatus tendons; thus, we aimed to examine the relationship between altered glenohumeral range of motion and supraspinatus tendon changes in collegiate baseball players. To investigate this association using the Pearson correlation coefficient, we measured glenohumeral internal rotation, external rotation, total rotation, and horizontal adduction ranges of motion and supraspinatus tendon thickness in 22 college baseball players. Consequently, there was a significant relationship between increase in supraspinatus tendon thickness and greater deficit of internal rotation (r=–0.520, P=0.013). Increased supraspinatus tendon thickness tended to be associated with greater external rotation gain (r=0.394, P=0.073). No other range of motion had any relationship with supraspinatus tendon changes. These results might indicate that restricted glenohumeral internal rotation and excessive gain in external rotation increase the risk of supraspinatus tendon abnormalities in baseball players.

Quantifying the Outfield Shift Using K-Means Clustering

Sports teams constantly search for a competitive advantage (e.g. bidding for free agents or scouting nontraditional markets). As popularized by Moneyball, we focus on advanced analytics in baseball. These sabermetrics are employed to provide objective information to management and coaches to support player management and in-game strategy decisions. Though widely used at the professional level, analytics use in college baseball is limited. Air Force Academy Baseball has been one win short of qualifying for the Mountain West tournament three straight years, resulting in the loss of potential income from media payouts and exposure for future recruiting efforts. Using a K-means clustering method for defensive shifting, we calculate an overall catch probability increase of 7.4% with a shifted outfield in a one-game case study. Based on our analysis, we provide evidence that Air Force Baseball can benefit from an outfield defensive shifting scheme that drives a competitive advantage and additional wins.