Bloomberg JJ, Reschke MF, Harm DL, Michaud LJ, Kulecz WB, Peters BT.

Aviat Space Environ Med. 1991 May; 62: 477.

Space Biomedical Research Institute, NASA Johnson Space Center, Houston, TX.

INTRODUCTION During locomotion the head is stabilized in space in a very precise fashion ensuring gaze stability and the maintenance of visual acuity. (Berthoz and Pozzo, 1988; Grossman et al. 1988, 1989). Berthoz and Pozzo suggest that gait motor control strategies are organized in a top down' fashion to achieve the goal of head and gate stabilization during locomotion. Gait instabilities experienced by returning astronauts during re-exposure to a 1-G environment may be caused, in part, by the utilization of inappropriate head stabilizing strategies during locomotion. The present study investigates z-axis linear head movement during walking in normal subjects to define the range of normative head movements prior to pre- and postflight studies on astronaut subjects. METHODS Four subjects walked (4.8 km/hr) on a motorized treadmill while visually fixating a target located 324 cm from the head. Head movements during locomotion were recorded and analyzed using a video-based motion analysis system (Motion Analysis Corp.). RESULTS During locomotion the mean peak to peak linear z-axis head displacement for each of the four subjects was 2.41 cm (+/- 0.30; mean +/- S.D.), 2.39 cm (+/- 0.20), 4.56 cm (+/- 0.60), and 2.13 cm (+/- 0.30). The predominant frequency of linear z-axis head movement ranged form 1.8-2.1 Hz. CONCLUSION The results demonstrate that linear z-axis head movements during walking are constrained presumably as a result of head and gaze stabilizing strategies evoked during locomotion. This ability may be diminished in returning astronauts, affecting their ability to perform an emergency egress from the Shuttle.

Publication Types:

• Meeting Abstracts

Keywords:

• Astronauts
• Gait
• Head
• Head Movements
• Locomotion
• Walking
• NASA Center JSC
• NASA Discipline Neuroscience
• NASA Discipline Number 16-10
• NASA Program Space Physiology and Countermeasures

Other ID:

• 95607627

UI: 102212601

From Meeting Abstracts