Effect of a standardized, submaximal fatigue protocol on the maximal power output of the quadriceps muscles in college-aged females.
Stauber-WT; Barill-ER; Stauber-RE; Miller-GR
Muscle Nerve 1996 Jan; 19(Suppl 4):S52
A dynamic fatigue test was developed: (1) to measure maximal power using submaximal, isotonic loading; (2) to identify individuals with low resistance to fatigue. Thirty-four college-aged females were tested using torque-velocity tests on a Dynatrac dynamometer before and after a fatigue protocol. The torque-velocity tests of the left knee extensors were performed at 4 isotonic loads (20, 30, 40, and 50 ft-lbs) and were used to calculate maximal power (408 +/- 67 W). The fatigue protocol consisted of "maximal effort" knee extensions against a 25 ft-lb load for three bouts of 15 repititions with a 15-s rest between bouts. After a 4-minute rest, the torque-velocity tests were repeated and power was calculated (343 +/- 56 W). The maximal power decreased by 15.3% (p<0.01). However, there was a wide variation with a few individuals actually improving slightly (1.6%), while others lost as much as 30% of their power capacity. The differences in power following fatigue induced by high-velocity contractions were probably due to a selective effect on the fast fatigue-sensitive fibers. The advantage of this unique protocol is its ability to measure maximal power of the knee extensors without producing high tibiofemoral forces. High compressive forces of the knee, which can produce reflex inhibition of the quadriceps muscles, have been reported for maximal isokinetic testing.
Muscles; Skeletal-system; Musculoskeletal-system; Fatigue; Fatigue-properties; Demographic-characteristics; Sex-factors; Age-factors; Age-groups
Department of Biochemistry, P.O. Box 9142, West Virginia University Health Sciences Center, Morgantown, WV 26506-9142
Muscle and Nerve
West Virginia University, Morgantown, West Virginia