RECOVERY FROM A 1-MINUTE BOUT OF FATIGUING EXERCISE - CHARACTERISTICS, RELIABILITY, AND RESPONSIVENESS

Background and Purpose. The purposes of this study were (1) to describ e the characteristics of recovery of peak torque after a 1-minute bout of isokinetic exercise of the quadriceps femoris muscle, (2) to deter mine the short-term reliability of the recovery of peak torque, and (3 ) to determine whether the recovery of peak torque more closely associ ates with maximal endurance exercise capacity than does the decline in peak torque at the end of the fatigue test. Subjects. Thirty-three no ndisabled subjects, ranging in age from 23 to 34 years (XBAR = 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 (XBAR = 27.5, SD = 52), 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 mus cle fatigue tests (test-retest) on an isokinetic dynamometer. In phase 2, each subject performed a single fatigue test and a test of mammal oxygen uptake (VO2max) to examine the relationships between VO2max and percentage of decline in peak torque at the end of the fatigue test a nd recovery of peak torque. Results. Intraclass correlation coefficien t values at every 30-second interval during recovery were acceptable ( ICC = .67-.87), indicating recovery of peak torque is a consistent mea sure of quadriceps femoris muscle performance. A high negative correla tion (r = -.84) was found between the percentage of decline at 30 seco nds 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 s uggest recovery of peak torque is a reliable measure of muscle perform ance and closely associates with maximal aerobic exercise capacity.