Function of Arm Swing

INTRODUCTION

Arm swing is a distinctive readily apparent characteristic of human walking and running. Our arms tend to swing out of phase with our legs, the right arm swinging forward with the left leg and vice versa. Although it has long been established that the arms do not swing as simple, unrestrained pendulums (Elftman, 1939; Fernandez Ballesteros et al., 1965; Jackson et al., 1978; Hinrichs, 1987; Ohsato, 1993; Webb et al., 1994; Gutnik et al., 2005), the extent to which the shoulder muscles actively drive the arms, and the effect of arm swing on stability and economy during walking and running are poorly understood. In this paper, we examined the control of arm swing during walking and running, and investigated the effect of restricting arm swing on stability and metabolic cost. In a seminal study examining the movements of the torso and arms during walking, Elftman suggested that the arms did not move as simple pendulums, but instead were driven by muscle activation