Recovery from a 1-minute bout of fatiguing exercise: characteristics, reliability, and responsiveness.

BACKGROUND AND PURPOSE

The purposes of this study were (1) to describe the characteristics of recovery of peak torque after a 1-minute bout of isokinetic exercise of the quadriceps femoris muscle, (2) to determine the short-term reliability of the recovery of peak torque, and (3) to determine whether the recovery of peak torque more closely associates with maximal endurance exercise capacity than does the decline in peak torque at the end of the fatigue test.

SUBJECTS

Thirty-three nondisabled subjects, ranging in age from 23 to 34 years (X = 27, SD = 3.4), participated in the reliability portion (phase 1) of the study. A different group of 21 nondisabled subjects, ranging in age from 21 to 47 years (X = 27.5, SD = 5.2), participated in the correlational portion (phase 2) of the study.

METHODS

The short-term reliability of percentage of decline in peak torque and recovery of peak torque was assessed in phase 1. Each subject performed two quadriceps femoris muscle fatigue tests (test-retest) on an isokinetic dynamometer. In phase 2, each subject performed a single fatigue test and a test of maximal oxygen uptake (VO2max) to examine the relationships between VO2max and percentage of decline in peak torque at the end of the fatigue test and recovery of peak torque.

RESULTS

Intraclass correlation coefficient values at every 30-second interval during recovery were acceptable (ICC = .67-.87), indicating recovery of peak torque is a consistent measure of quadriceps femoris muscle performance. A high negative correlation (r = -.84) was found between the percentage of decline at 30 seconds of recovery and VO2max, but a lower negative correlation (r = -.48) was found between the percentage of decline in torque at the end of the fatigue test and VO2max.

CONCLUSION AND DISCUSSION

These results suggest recovery of peak torque is a reliable measure of muscle performance and closely associates with maximal aerobic exercise capacity.