The inter-segmental covariation of landing from a countermovement jump in hyper-gravity.

Details

Supervisors

Schepens, Bénédicte ; Toussaint, Thibaut

Faculty

Faculté des sciences de la motricité

Degree label

Master [60] en kinésithérapie et réadaptation

Abstract

Purpose: The central nervous system is responsible for the motor control of body segments, whose coordination might change due to additional constraints. In this study, we investigate the intersegmental covariation of landing in hyper-gravity (G) conditions, by assessing the effects of three levels of gravity and two environments, Real-G and Simulated-G. Methods: Eight subjects performed countermovement jumps in 1.2g, 1.4g, 1.6g. Simulated-G was obtained in a laboratory using a subject loading system, which applied a pull-down force to the body. Real-G was obtained through the centrifugal forces produced by the turn manoeuvres of an aircraft. The elevation angles (EA) of four segments (foot, shank, thigh, trunk) were calculated and a Principal Component Analysis was performed on their temporal waveforms. Results: The behaviour of shank, thigh, and trunk segments during landing in hyper-gravity is modulated by a law of linear covariation. The motor control of the task seems focused on regulating mainly the flexion-extension cycle of the entire body. However, the foot segment variates independently, due to its different kinematics after TD. Hyper-gravity levels and the environment do not alter substantially the law of linear covariation. The adopted intersegmental coordination of landing against increasing constraints seems to consist in a flatter foot and a globally more flexed lower limb at TD.