Abstract

Objective: To compare the effects of an isokinetic fatigue protocol and a functional fatigue protocol on time to stabilization (TTS), ground reaction force (GRF), and joint kinematics during a jump landing. Design and Setting: Subjects were assessed on 2 occasions for TTS, GRF, and joint kinematics immediately before and after completing a fatigue protocol. One week separated the 2 sessions, and the order of fatigue protocols was randomly assigned and counterbalanced. Subjects: Twenty healthy male (n = 8, age = 21.8 ± 1.4 years, height = 180.6 ± 7.6 cm, and mass = 74.1 ± 13.0 kg) and female (n = 12, age = 22.2 ± 2.1 years, height = 169.3 ± 9.8 cm, and mass = 62.5 ± 10.1 kg) subjects volunteered to participate. Measurements:
Subjects performed 2-legged jumps equivalent to 50% of maximum jump height, followed by a single-leg landing onto the center of a forceplate 70 cm from the starting position. Peak vertical GRF and vertical, medial-lateral, and anterior-posterior TTS were obtained from forceplate recordings. Maximum ankle dorsiflexion, knee-flexion, and knee-valgum angles were determined using 3-dimensional motion analysis. Results: A 2-way analysis of variance with repeated measures revealed no significant differences when comparing TTS, GRF, and joint kinematics after isokinetic and functional fatigue protocols. Conclusions: No difference was noted between isokinetic and functional fatigue protocols relative to dynamic stability when landing from a jump. Verf.-Referat