Evaluation of Resultant Ground Reaction Force and Its Velocity Using the Elapsed Time and Peak Reaction Force at 3-Dimensional Direction During Landing Task

Abstract

The purpose of this study was to analyze the effects of bilateral landing leg and sex on resultant ground reaction force (GRF) and its velocity, using peak vertical GRF and elapsed time during drop landing tasks. A repeated-measures two-way analysis of variance explored the impact of landing legs and sex on the resultant vector, three-dimensional GRF, elapsed time, and velocity in 40 participants (20 males and 20 females). Participants performed drop landings from a 35-cm box. Effects of sex and landing leg were analyzed using a repeated-measures model (two sexes × two legs) on GRF magnitude and velocity. Females displayed shorter elapsed times to peak GRF compared to males in the anterior-posterior and vertical directions. Significant differences emerged between sexes in both magnitude and velocity of resultant and peak vertical GRF, with females exhibiting higher values. This suggests the adoption of distinct landing strategies between sexes. Notably, no significant differences were found in GRF magnitude or velocity between bilateral leg landings. These results indicate that healthy individuals of both sexes utilize different landing strategies during drop landings. This knowledge has potential applications in clinical settings for evaluating impulse force and stress transfer to the musculoskeletal system during landing tasks.