Sophie Orr

Date of Award

January 2019

Document Type


Degree Name

Master of Science (MS)


Space Studies

First Advisor

Pablo de León


Past research efforts have focused on the energy difference between altered locomotion methods in fractional gravity at different speeds, suggesting that skipping is energetically more efficient than walking and running in these environments. While skipping may be more beneficial from an energy standpoint, the full range of reasons behind the gait transition and locomotion selection have not been researched. This includes damage to the muscles of the leg, which is partially prevented by a transition from walking to running. In a space environment, these factors will play a role in astronaut health and injury prevention. For this study, participants walked, ran and skipped on a treadmill while being supported by an analog for activity on other planets called the Active Response Gravity Offload System (ARGOS). These intervals were performed under 1g, and then under simulated .38g, and .17g conditions to simulate gravity conditions on Mars and the Moon, respectively. Electromyography was used to monitor muscle activation, along with the Vicon motion capture system for 3D motion analysis. Results show that there are significant changes (p <.05) in activation energy in the tibialis anterior and medial gastrocnemius under simulated Martian and Lunar gravity conditions, as well as significant changes (p <.05) in dorsiflexion and plantar flexion. These findings suggest that there are fundamental changes in the way humans move in these fractional gravity environments, and that the effect these changes have on the body should be included in the development of astronaut training regimen development.