The purpose of this study was to investigate the effects of the interaction between respiration and muscle pump on venous blood flow (BF) return from right leg during right knee exercise in eight healthy males. BF was measured in femoral vein (FV) during respiration without knee exercise and during knee exercise synchronized with respiration. At semi-supine position, subjects performed a one-legged voluntary knee extension-flexion exercise for 2 s, at three different knee angle (low, middle and high) in arrested respiration (Protocol A), synchronized with normal-inspiration or normalexpiration (Protocol B). As the results, in Protocol A, BFFV at the middle and high knee angle exercise was a significantly (p<0.05) higher than that at the low knee angle exercise. In Protocol B, BFFV at low knee angle exercise during inspiration, and at low and middle knee angle exercise during exspiration significant (p<0.05) incresed compare to that during arrested respiration. This study demonstrated that higher range of knee angle at knee exercise showed the increasing in venous return from leg. As the combination of muscle pump and respiration, the middle knee angle exercise during expiration showed the increasing in venous return from leg effectively.

DESCENTE SPORTS SCIENCE Vol.22/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE