The effect of inter-trial rest interval on the assessment of isokinetic thigh muscle torque.

The purpose of this study was to examine the effect of two measurement protocols on the reliability of peak isokinetic knee extensor and flexor torques performed at 60 degrees /sec. Isokinetic knee extensor and flexor torques were measured using two test protocols on 16 subjects. The two reciprocal testing protocols consisted of five trials performed with either no rest or a 30-sec rest between trials. Each subject performed both protocols with the order of protocol administration balanced across subjects. The results indicated that the Rest protocol produced average torques which were 5% greater than the No Rest protocol and that higher reliability coefficients were obtained for the Rest protocol. These findings are likely due to a significant linear trend across trials evident with the No Rest protocol. It was also demonstrated that the measurement error calculated for the average of five trials was less than that of a single trial. These findings strongly suggest that a greater measurement precision can be achieved by averaging trials obtained using a rest protocol. J Orthop Sports Phys Ther 1990;11(8):362-366.