Energy expenditure performing gymnastic-like motion in spacelab during spaceflight

Abstract

To prevent biological deconditioning during missions in Spacelab, astronauts are required to exercise and typically use a bicycle ergometer, treadmill, or other equipment for resistance exercise. However, some exercise equipment, a treadmill in particular, may cause serious vibratory disturbance in the spacecraft. In the present study, we attempted to estimate the energy expenditure of a freely performed whole-body exercise in the atmosphere of a spacecraft, that was demonstrated by a Japanese astronaut in 1992. The exercise consisted of a repeated gymnastic-like motion with whole-body flexion and extension. The mechanical work performed internally against the inertial load by the body segments during exercise was calculated, and the energy cost was estimated after assuming the efficiency to be 25%. Our results showed that the energy cost was 0.11 kcal/kg of body mass/min, which equivalent to the energy expended during a fast walk. We concluded that this exercise could be recommended as one of the exercise programs because of its safety, since it does not involve shifting the COM of the body and requires no equipment, thus negating the problem of vibration.