Dr. Sinacore et al., QUADRICEPS FEMORIS MUSCLE RESISTANCE TO FATIGUE USING AN ELECTRICALLYELICITED FATIGUE TEST FOLLOWING INTENSE ENDURANCE EXERCISE TRAINING, Physical therapy, 74(10), 1994, pp. 930-939
Background and Purpose. Electrical stimulation has been used to assess
skeletal muscle resistance to fatigue. The purpose of this study was
to test the hypothesis that 12 weeks of intense endurance exercise tra
ining on a bicycle ergometer would reduce the percentage of decline in
quadriceps femoris muscle torque during an electrically elicited fati
gue test. Subjects and Methods. Emery nondisabled subjects performed 1
2 weeks of high-intensity endurance exercise training, a 6 subjects se
rved as controls and did not exercise. Two electrically elicited fatig
ue tests, one with and one without prior voluntary fatiguing exercise,
were administered to each subject before and after the 12-week traini
ng period. Results. The percentage of decline in peak torque of the qu
adriceps femoris muscle over 50 electrically elicited muscle contracti
ons did not change as a result of endurance exercise training, despite
significant improvements in maximal oxygen consumption and quadriceps
femoris muscle endurance. The recovery of maximal isometric torque im
mediately after exhausting voluntary exercise followed by electrical s
timulation was significantly greater after 12 weeks of intense exercis
e training. Conclusion and Discussion. The percentage of decline in pe
ak torque during an electrically elicited fatigue test does not detect
improvements in quadriceps femoris muscle endurance induced by endura
nce exercise training. The percentage of initial torque recovered imme
diately after fatiguing exercise, however, is improved by endurance tr
aining.