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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 Res35(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.

Background: Softball pitchers accrue high rates of injury. Research suggests certain mechanics at discrete pitch events are related with pain. Here, we examine relationships between peak throwing shoulder kinetics and trunk/pelvis kinematics and compare trunk/pelvis kinematics between pitchers who were healthy and those currently experiencing pain.Hypothesis: (1) Peak shoulder kinetics would be positively related to greater trunk and pelvis flexion, lateral flexion, and rotation; and (2) pitchers in pain would exhibit greater trunk and pelvis flexion, lateral flexion, and rotation during the pitch than those who were pain-free.Study Design: Cross-sectional study.Methods: A total of 42 high school pitchers (height, 1.71 ± 0.06 m; weight, 75.0 ± 15.9 kg; age, 16 ± 2 years) were separated into 2 groups based on presence or absence of pain. Peak kinetic data from 3 pitches per pitcher were averaged and used as dependent variables. Kinematic data were averaged across 3 trials, and time normalized to 101 datapoints between foot contact and follow-through of the pitch. Statistical parametric mapping regressions were used to assess the relationships between peak shoulder kinetics and waveform of trunk and pelvis kinematics.Results: Pelvic lateral tilt significantly predicted peak throwing shoulder superior (P= 0.05) and lateral (P= 0.04) force. Pelvis rotation predicted peak superior force (P= 0.02). Waveform analyses revealed no waveform differences between healthy pitchers and those currently experiencing pain.Conclusion: Peak shoulder kinetic variables are related with pelvic positioning during the pitch; however, trunk and pelvis kinematics do not differ according to presence of pain.Clinical Relevance: Pitchers in pain do not adopt specific trunk and pelvic alterations during the pitch, potentially concealing the effects of pain from visual identification. Coaches and clinicians need to discuss health status with pitchers versus relying on visual observations to understand pain and injury risk.

Background: Softball research has investigated changes in physical characteristics, mechanics, and ball speed as elements of fatigue. However, the influence of pitch volume on ball metrics is unclear. The purpose of this study was to investigate the influence of pitch volume on ball performance and release metrics in softball pitchers across different pitch types.Hypothesis: As pitch volume increased, there would be a decrease in ball metrics of the fastball and changes in breaking pitches would be observed earlier than the fastball or changeup.Study Design: Descriptive laboratory study.Level of Evidence: Level 5.Methods: A total of 21 (15.4 ± 1.6 years; 1.6 ± 0.2 m; 76.0 ± 17.2 kg) softball pitchers participated. Procedures consisted of participants pitching a simulated game consisting of 100 pitches, taking a 30-minute break, and then throwing 12 pitches to simulate the first inning of a doubleheader. Participants randomly threw each pitch type (fastball, changeup, curveball, or dropball). Ball performance and release metrics were measured using a Rapsodo portable pitch tracker.Results: A 3 (time) by 4 (pitch type) multivariate analysis of variance revealed that pitch speed was significantly higher in the first inning compared with the last inning and the doubleheader inning. The fastball, curveball, and dropball revealed a significant difference in pitch speed between timepoints. Specifically, the curveball and dropball first-inning pitch speed was significantly greater than the last and doubleheader inning. Alternatively, the fastball had a significant increase in pitch speed from the last inning to the doubleheader inning.Conclusion: The typical 30-minute break given between games for doubleheaders may be sufficient recovery time for the fastball but not for the curveball and dropball.Clinical Relevance: The Rapsodo device is an accessible method of tracking ball performance and pitch release metrics and could be helpful in identifying when a pitcher may be experiencing performance detriments in response to increasing pitch count.