Effect of wrist restraint on maximal exercise capacity in healthy volunteers

Each year, reports occur of deaths in individuals, while struggling against physical restraint. The mechanism of these deaths remains unclear. This study aimed to determine the effect of wrist restraint on cardiorespiratory function during maximal exercise. Twelve healthy volunteers underwent 3 incremental maximal exercise tests on a cycle ergometer. In a randomized order, they exercised while unrestrained, with the wrists tied in front of the body or wrists tied behind the back. The primary outcome measures were the number of minutes exercised in each position and heart rate and whole blood lactate level for each stage and on reaching maximum exercise capacity. The mean exercise duration was 19 minutes 6 seconds unrestrained (95% confidence interval [CI] 16 minutes 52 seconds to 20 minutes 57 seconds), 18 minutes 51 seconds (95% CI 17 minutes 51 seconds to 20 minutes 50 seconds) with arms restrained in front and 16 minutes 51 seconds (95% CI 14 minutes 6 seconds to 19 minutes 20 seconds) with the arms restrained behind the body (P = 0.16). There was no significant difference in heart rate or lactate measurements. It is probable that other factors make a more important contribution than wrist restraint behind the body to cardiorespiratory compromise in a struggling and fatigued individual.