The purpose of the present study was to elucidate the effects of chest wall restriction by external chest compression on endurance performance, and cardio-respiratory responses, muscle energy metabolism and oxygenation during exercise. Nine collegiate male subjects performed maximal exercise to exhaustion (MAX) under chest wall restriction (CR) and non restriction control (NR) conditions, and sub-maximal constant load exercise (SUB) for 15 min under both conditions at 40, 60, and 80% of peak oxygen uptake (peak VO₂) measured during CR conditions. We found that under CR conditions, as compared with NR, 1) peak VO₂ and endurance time were less by about 9% in MAX, and 3 of the subjects could not complete the 80% load task during SUB, 2) minute ventilation was greater at the sub-maximal level during MAX and at 40% and 60% load tasks during SUB, but the maximal value was lower in MAX, 3) tidal volume was less while respiratory rate was higher throughout the experiment, 4) oxygen saturation (SpO₂) became less at a higher exercise intensity during both MAX and SUB, 5) heart rate was higher during SUB and at exhaustion, 6) the muscle deoxygenation rate estimated by near-infrared spectroscopy showed no difference at only 80% load task but tended to decrease in the other cases, 7) blood lactate concentration was less at the maximal value in MAX, but showed no difference during incremental and sub-maximal exercise, 8) respiratory discomfort measured by the subjects rating of perceived exertion tended to be higher during SUB. These results indicate that endurance performance should be decreased by CR, and this would be attributed directly to impaired respiration due to CR.

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