Lightly gripping a motionless handle: Study of postural sway decrease and correlation between transient force changes applied to the handle and balance

Abstract

Lightly touching (<1N) a stable surface with a finger reduces postural sway magnitude [1]. Lightly holding a stick, i.e. Lightly Gripping (LG) it while it is touching the ground, also reduces postural sway magnitude [2][3]. As the light touch does not provide mechanical support, it is assumed that the Central Nervous System (CNS) integrates the light touch as a new sensory input to reduce postural oscillations. The transient forces at the point of contact may also be relevant to the CNS as estimates of postural sway and thus contribute to sway oscillations decrease [4]. Our first aim is to study the effect of lightly gripping a stable handle on postural sway. The handle is motionless with respect to the environment. Our second aim, which is our main contribution, is to study the correlation of the forces applied to the handle and the sway in the Anterior-posterior (AP) direction. An experiment including No Grip (NG) and Light Grip (LG) conditions has been conducted to that end