Postural stability when walking and exposed to lateral oscillatory motion: benefits from hand supports

Abstract

While walking on a treadmill, 20 subjects experienced lateral oscillations: frequencies from 0.5 to 2 Hz and velocities from 0.05 to 0.16 m s^− 1 rms. Postural stability was indicated by ratings of ‘discomfort or difficulty in walking’, the movement of the centre of pressure beneath the feet and lateral forces applied to a hand support. Hand support improved postural stability with all frequencies and all velocities of oscillatory motion: the lateral velocity of the centre of pressure reduced by 30–50% when using support throughout motion, by 20–30% when instructed to use the support only when required and by 15% during normal walking without oscillation. Improvements in stability, and the forces applied to the hand support, were independent of support height when used continuously throughout motion. When support was used only when required, subjects preferred to hold it 118–134 cm above the surface supporting the feet.

Abstract

Practitioner Summary: Lateral oscillation is a main cause of postural instability when standing or walking in transport. A hand support provides mechanical stabilisation and, if held continuously, it provides cues to relative motion that assist the maintenance of postural stability.

Keywords::

• postural stability
• walking
• hand support
• lateral oscillation
• perturbed locomotion

Acknowledgements

This study was conducted with the support of Société Nationale des Chemins de fer Français (SNCF), Paris, France. The assistance of Cedric Gallais is gratefully acknowledged.