Abstract
To optimize pitching performance, pitchers must generate substantial ground
reaction forces to aid pitch velocity while minimizing the forces experienced in
their throwing shoulder. Extremely high shoulder forces are generally thought
to be injurious for softball pitchers. Therefore, this study aimed to identify
the relationship between ground reaction forces during the propulsion phase of
the pitch and peak shoulder forces during the pitch. Thirty-two high school
softball pitchers (1.70±0.06 m, 76.09±17.50 kg, and 15±1 y) pitched fastballs
for strikes. Kinematic and kinetic data from the three fastest pitches were
averaged for analysis. The relationships between ground reaction forces during
pitch propulsion and peak shoulder kinetics during the propulsion and
acceleration phases were examined via multiple regressions and correlations. A
vertical ground reaction force was significantly associated with a peak
resultant shoulder force (t=–3.176 and p=0.003). The rate of
ground reaction force development was correlated with the peak shoulder
distraction force (r=–0.367 and p=0.033) and the resultant force
during propulsion (r=–0.439 and p=0.009). These observations
underscore the potential significance of lower body contributions and kinetic
chain sequencing in reducing shoulder forces during the early stages of the
pitch, which may have implications for injury risk as ground reaction forces
during pitch propulsion may decline with fatigue.
Keywords
biomechanics - softball - windmill pitching - kinetics - kinematics
