Is arm swing active or passive during human walking and running?
PONTZER, Herman*; RAICHLEN, David A.; LIEBERMAN, Daniel E.; Washington University; University of Arizona; Harvard University hpontzer@artsci.wustl.edu Humans habitually swing their arms in phase with the contralateral leg during walking and running. This arm motion is generally thought to counteract the torque about the bodys vertical axis (i.e., yaw moment) that is generated by the legs as they swing with each step. Thus it has been argued that the motion of the arms is a tuned, habitual, active response that is critical for maintaining stability during human locomotion, especially running. In this study, we investigated whether arm swing is in fact an active behavior, or is instead a passive response that follows solely as a consequence of our anatomical design. Human subjects walked and ran on a treadmill under different arm- and leg-weighting conditions, and without armswing, while kinematic and surface EMG data were recorded. A modeling study was also performed to determine the in
