Bordelon N, Friesen K, Fava A, Plummer H, Oliver G. Peak Elbow Flexion Does Not Influence Peak Shoulder Distraction Force or Ball Velocity in NCAA Division I Softball Pitchers.
Orthop J Sports Med 2022;
10:23259671211067828. [PMID:
35071659 PMCID:
PMC8777352 DOI:
10.1177/23259671211067828]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 10/03/2021] [Indexed: 11/15/2022] Open
Abstract
Background:
High shoulder distraction force has been observed in softball pitchers during
the acceleration phase (top of the pitch to ball release) of a pitch.
Increasing elbow flexion may reduce shoulder forces and the susceptibility
to pain by shortening the lever arm of the throwing arm.
Purpose:
To determine the association of peak elbow flexion during the acceleration
phase of the pitch with peak shoulder distraction force and ball
velocity.
Study Design:
Descriptive laboratory study.
Methods:
A total of 61 female collegiate softball pitchers (mean age, 19.9 ± 1.9
years; mean height, 175.7 ± 5.7 cm; mean weight, 83.6 ± 12.7 kg; 49
right-handed) volunteered for this study. Biomechanical data were collected
with a 3-dimensional electromagnetic tracking system while the pitchers
threw 3 maximal-effort fastballs at a regulation distance. Peak elbow
flexion and peak shoulder distraction force were calculated for the
acceleration phase and averaged across the 3 trials. Ball velocity was
assessed with a radar gun.
Results:
Simple linear regression analyses indicated that peak elbow flexion did not
influence peak shoulder distraction force during the acceleration phase of
the pitch (F(1,59) = 2.412; P = .126),
with R2 = 0.023. Additionally, peak elbow flexion during the
acceleration phase of the pitch did not influence ball velocity
(F(1,59) = 2.435; P = .124), with
R2 = 0.023. A bivariate correlation analysis showed a significant
association between ball velocity and shoulder distraction force
(R2 = 0.343; P = .007) in which ball velocity
constituted approximately 34% of the variance in shoulder distraction
force.
Conclusion:
Peak elbow flexion did not influence ball velocity or peak shoulder
distraction force during the acceleration phase of a windmill softball
pitch. However, there was a significant and positive relationship between
ball velocity and peak shoulder distraction force. These results may
indicate that ball velocity and other kinematic variables may be more
related to shoulder distraction force than elbow flexion.
Clinical Relevance:
Increasing elbow flexion can shorten the lever arm, but it did not reduce
shoulder distraction force or increase ball velocity. Therefore, elbow
flexion may be more useful as a description of the pitching style rather
than a single measure related to increased performance or the risk of
injuries. Future research should continue to examine the relationship
between other kinematic parameters with shoulder distraction force.
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