The Effect of External Ankle Support on Vertical Ground-Reaction Force and Lower Body Kinematics

Abstract

Objective: To examine the effects of external ankle support on vertical ground-reaction forces (VGRF) and kinematic data. Methods: Subjects completed 2 braced and 2 nonbraced 0.61-m hanging drop landings onto a force platform. Kinematic data were collected with 8 digital-optical cameras sampling at 120 Hz. Subjects: 12 Division I female volleyball players. Statistical Analysis: A repeated-measures ANOVA with Bonferroni correction ( P < .05) was used to determine whether significant differences existed between test conditions for peak VGRF, loading rate, hip angle, knee angle, and ankle angle at right-foot contact for peak 1 and peak 2 of the VGRF curve over the first 100 milliseconds of the landing phase, as well as total hip range of motion (ROM), total knee ROM, and total ankle ROM for the entire landing phase. Results: There were significant increases in peak P 1 and LR 1 and a significant decrease in ankle-angle change at right-foot contact in braced trials compared with the nonbraced condition.