Movie S1

A representative subject displays the pronounced difference in center-of-mass running kinematics resulting from a change in gravity. In the first half of the video, the runner experiences normal gravity (9.8 m/s²), and exhibits large vertical excursion of the center of mass during the flight phase. In the second half of the video, the runner experiences simulated lunar gravity (approximately one-sixth of Earth-normal), and the center-of-mass excursions in flight are comparatively shallow. In both cases, the treadmill speed is 2 m/s. The video is slowed by a factor of four. Consent to publish this video was obtained from the subject depicted.