The Association of Upper-Body Kinematics and Earned Run Average of National Collegiate Athletic Association Division I Softball Pitchers.

ABSTRACT: Friesen, KB, Barfield, JW, Murrah, WM, Dugas, JR, Andrews, JR, and Oliver, GD. The association of upper-body kinematics and earned run average of national collegiate athletic association Division I softball pitchers. J Strength Cond Res 35(11): 3145-3150, 2021-Although recent literature has increased examination of the association of injury and biomechanics, there remains a lack of evidence supporting optimal windmill pitch mechanics. Therefore, the purpose of this study was to investigate trunk and pitching arm kinematics and their association with performance outcome: earned run average (ERA), in collegiate softball pitchers. Twenty-three NCAA Division I collegiate softball pitchers (20.14 ± 1.07 years; 173.93 ± 6.68 cm; and 85.79 ± 11.06 kg) performed 3 maximal effort rise ball pitches to a catcher located at a distance of 43 ft. (13.11 m). Kinematic data of the trunk and pitching arm were collected using an electromagnetic tracking system. A multiple regression analysis was performed at each pitch event: top of backswing, foot contact, ball release, and follow-through. The multiple regression at foot contact showed an overall statistically significant regression equation (F6, 16 = 3.7, p = 0.017) and explained approximately 42% of the variance in ERA (R = 0.579, Adj. R2 = 0.421). Results revealed that those pitchers who had greater trunk (SE = 0.018, t = -2.5, p = 0.023) and elbow flexion (SE = 0.006, t = -4.2, p = 0.001) at the event of foot contact had lower ERAs. This study supported previous research on the importance of trunk and elbow angle at front foot contact on rise ball pitch performance. These key technique points and the importance of elbow flexors should be explored in future research and potentially visually attended to by coaches and strength professionals.

Differences in the ultimate strength of the biceps anchor and the generation of type II superior labral anterior posterior lesions in a cadaveric model.

BACKGROUND: The pathogenesis of superior labral anterior posterior lesions remains controversial. HYPOTHESIS: The biceps anchor is more vulnerable to loading with a posterior vector as opposed to an in-line pull. STUDY DESIGN: Controlled laboratory study. METHODS: Eight pairs of cadaveric shoulders were dissected, and the biceps tendon was loaded to failure in 1 of 2 loading patterns. Loading pattern A was meant to simulate the eccentric load of the biceps in the deceleration phase of throwing; loading pattern B was meant to simulate the posterior biceps load of the late cocking phase. RESULTS: The biceps anchor demonstrated significantly increased ultimate strength with in-line loading (group A, 508 N) as opposed to posterior loading (group B, 262 N, P < .001). All group B specimens failed at the biceps anchor, resulting in a type II superior labral anterior posterior lesion. Specimens in group A did not create a superior labral anterior posterior lesion. CONCLUSIONS: Direction of biceps loading resulted in significant differences in the ultimate strength of the biceps anchor and the generation of superior labral anterior posterior lesions. The biceps anchor was significantly weaker when loaded with a posterior vector. RELEVANCE: The superior labrum may be most vulnerable to injury in late cocking. The reproducible generation of type II superior labral anterior posterior lesions may have applications as a biomechanical model.