Arm Swinging - Experiment

Video of the Experimental Conditions: We asked subjects to walk with their arms swinging in several ways: Normal arm swinging (left) in which we asked subjects to walk normally; Anti-Normal arm swinging (second from left) in which we instructed subjects to walk with normal arm amplitude but opposite phasing; Held (second from right) in which we instructed subjects to hold their arms loosely at their sides; and Bound (right) in which subjects arms were held at their sides by elastic sports bands. Inverse dynamics analysis revealed that very little work was performed by the shoulders to induce arm swinging in either the Normal or Anti-Normal modes. However, twisting forces in the legs were much higher with Anti-Normal, corresponding to a 26% increase in effort for walking, as measured by metabolic expenditure. Similarly, increased vertical ground reaction moments were associated with a 12% increase in the energy use in the Held condition. Binding the arms actually made walking easier than holding them at the sides (7% higher energy use than Normal) indicating that some effort was actually required at the shoulders to keep the arms from swinging. See attached article for details. Videos by Steve Collins and Peter Adamczyk (shown). Download: AVI (1 MB).