The Effects of Body Mass Index on Softball Pitchers' Hip and Shoulder Range of Motion

Currently it is hypothesized that increased body mass index may contribute to overuse injuries. Thus, if hip or shoulder range of motion is affected by body mass index, pitchers may be placing additional stress on joints as they seek to pitch at maximal velocity. The purpose of this study was to examine if range of motion at the hips and shoulders were related to body mass index classification. A sample of 147 female softball pitchers (17.0±4.2 years; 167.6±11.8 cm; 70.6±17.5 kg; body mass index=24.8±4.7 kg/m ² ) participated. Bilateral hip and shoulder range of motion were assessed. Multivariate analysis of variance results indicated body mass index [Wilks' Λ =0.742, F=1.722, p=0.014, η ² =0.095] significantly affected range of motion of the shoulder and hip. Post hoc results indicated the underweight group had significantly more range of motion than the obese group in hip internal range of motion on both the throwing side (mean difference=12.39, p=0.005) and glove side (mean difference=11.98, p=0.004). Although body composition is not overly emphasized among softball pitchers, the current study reveals excess weight may inhibit proper mechanics. Coaches, athletic trainers, strength and conditioning personnel, and athletes should acknowledge the role that body composition can play in affecting pitch outcomes.