Effects of Long-duration Space Flight on Toe Clearance During Treadmill Walking

Upon returning from long-duration space flight, astronauts and cosmonauts must overcome physiologic and sensorimotor changes induced by prolonged exposure to microgravity as they readapt to a gravitational environment. Their compromised balance and coordination lead to an altered and more variable walking pattern (Bloomberg & Mulavara, 2003; McDonald, et al., 1996). Toe trajectory during the swing phase of locomotion has been identified as a precise motor control task (Karst, et al., 1999), thus providing an indication of the coordination of the lower limbs (Winter, 1992). Failure to achieve sufficient toe clearance may put the crew member at a greater risk of tripping and falling, especially if an emergency egress from the vehicle should be necessary upon landing. The purpose of this study was to determine the pre- to post-flight changes in toe clearance in crew members returning from long-duration missions and the recovery thereafter.