Abstract
The purpose of the present study is twofold: 1) to elucidate the effect of applying lower body positive pressure (LBPP) on circulatory and musculoskeletal parameters, and 2) to compare the changes in circulatory and musculoskeletal parameters during treadmill exercise in human subjects with and without LBPP. We hypothesized that application of LBPP decreases net ground reaction force (GRF), apparent body weight, and that a low level of LBPP causes minimal changes in cardiovascular parameters and produces beneficial effects on musculoskeletal parameters. Ten male and five female subjects, who gave their informed consents, participated in this study. After body weight of the subjects was measured, the pressure inside LBPP chamber was increased until it reached 15 mmHg above the atmospheric pressure, resulting in 30-35 kg decrease of the net GRF. Electrocardiogram, arterial blood pressure, skin blood flow in the lower extremity, skin temperature, electromyogram from the gastrocnemius, gait pace were monitored during treadmill exercise (4 km/h walking). Exposure to LBPP did not change significantly the heart rate, arterial blood pressure, skin blood flow in the leg, and gastrocnemius EMG during rest. On the other hand, exercise-induced increases in heart rate and EMG were reduced by exposure to LBPP. These results suggest that LBPP reduces the net GRF effectively without changing cardiovascular functions and that the reduction of net GRF may play a beneficial role in rehabilitation. [J Physiol Sci. 2007;57 Suppl:S192]
