Abstract
The purpose of this study was to determine how stride length, segmental sequencing
of the pelvis, trunk, humerus, and forearm velocities and accelerations, and the timing
of these values change as youth mature. Thirteen youth baseball pitchers participated
at three consecutive time points: visit 1 (10.7±1.3 years; 151.8±10.7 cm; 45.0±9.65 kg),
visit 2 (11.5±1.6 years; 155.5±11.1 cm; 50.4±10.0 kg), and visit 3 (12.4±1.7 years;
161.5±11.7 cm; 56.4±10.8 kg). Participants executed three pitches for a strike to
a catcher. The maximum value of stride length and segmental speeds and accelerations
was recorded. The point at which these maximum values occurred during the throw was
calculated as a percentage from hand separation to maximum internal rotation of the
shoulder. Repeated measures ANOVAs and Friedman Tests revealed no statistically significant
differences between stride length, segmental speeds and accelerations, and their percentage
of the pitch between the three visits. However, there was a significant increase in
ball velocity across visits. No significant changes occurred in pitching mechanics
between the ages of 10–12. The authors speculate the lack of differences can be accounted
for because these ages are prior to any significant pubescent changes. Future research
should consider pre- and post- pubescent age groups.
Key words
pre-pubescent - performance - throwing mechanics
