FATIGUE AFFECTS THE FREQUENCY CONTENT OF THE GROUND REACTION FORCES, BUT NOT MAGNITUDE, IN DROP LANDING TASKS

Abstract

The aim of this study was to investigate the changes in the lower extremity kinematics, ground reaction forces, and frequency content of the vertical ground reaction forces between two fatigue protocols in a landing task. Eight trained male participants were instructed to perform drop-jump landings before and after two randomly fatigue protocols, namely, long-term running and functional short-term fatigue protocols. We found that the functional short-term fatigue protocol would induce an increase in hip and knee flexion, which resulted in a more flexed landing posture. Furthermore, the functional short-term fatigue protocol would decrease amplitudes in lower frequencies while increasing amplitudes in higher frequencies. These results will provide a preliminary reference for the selection of fatigue protocols in laboratory tests.