Upright posture control in changing gravity conditions

Abstract

In order to be able to withstand and to take advantage of external forces and to be able to direct motor actions, living organisms developed ability to sense environmental impacts. For instance, proprioceptors and cutaneous receptors allow vertebrates to take into account, above all, gravitational influences. These receptors participate in planning and correcting posture, locomotion and other movements. In this thesis mechanisms of equilibrium control in changing gravity conditions were studied by means of literature analysis and analysis of data obtained in parabolic flight. This analysis revealed that standing balance in overloading is likely controlled in a manner resembling a single-link inverted pendulum. Such behavior could be beneficial to take advantage of passive body structures and to more actively involve foot receptors in balance regulation in challenging conditions. This adaptation also resembles typical postural responses in balance perturbation tasks. The latter were then studied in more detail. Further literature overview supported the suggestion that plantar foot receptors play an essential role in dynamic stability of upright posture. The obtained conclusions allowed to formulate possible mechanisms of sway and balance control and make suggestions on possible implementation of these mechanisms into the neuromusculoskeletal human model proposed by Walter, Gunther, Haeufle, and Schmitt (2021) in order to make equilibrium control of this model robuster.