This article is a US Government work and as such, is in the public domain in the United States of America.
Comparison of potentiated and unpotentiated twitches as an index of muscle fatigue†
Version of Record online: 31 JAN 2002
Copyright © 2002 Wiley Periodicals, Inc.
Muscle & Nerve
Volume 25, Issue 3, pages 438–444, March 2002
How to Cite
Kufel, T. J., Pineda, L. A. and Mador, M. J. (2002), Comparison of potentiated and unpotentiated twitches as an index of muscle fatigue. Muscle Nerve, 25: 438–444. doi: 10.1002/mus.10047
- Issue online: 19 FEB 2002
- Version of Record online: 31 JAN 2002
- Manuscript Accepted: 2 OCT 2001
- Grant-in-Aid from the American Heart Association, New York State Affiliate, Inc.
- magnetic stimulation;
- muscle fatigue;
- skeletal muscle;
- twitch potentiation
Recent data suggest that the potentiated twitch is a more sensitive index of contractile fatigue than is the unpotentiated twitch. We hypothesized that after a potentially fatiguing load, the fall in twitch amplitude of the potentiated twitch would be significantly greater than that of an unpotentiated twitch. We compared the response of the potentiated and unpotentiated twitches to a series of potentially fatiguing loads using magnetic stimulation of the femoral nerve in 10 healthy subjects. The baseline unpotentiated quadriceps twitch force (TwQu), potentiated quadriceps twitch force (TwQp), and maximal voluntary contraction (MVC) were 129 ± 6 N, 198 ± 6 N, and 622 ± 25 N, respectively. During a fatigue protocol that was designed to induce a spectrum of fatigue from mild to marked, the percent fall in quadriceps twitch force was significantly greater for the potentiated method than for the unpotentiated method at all levels of fatigue (P < .005). The within-subject within-day coefficient of variation was 7.5 ± 0.5% for TwQu and 5.6 ± 0.9% for TwQp. Thus, TwQp is reproducible and is superior to TwQu for detecting early muscle fatigue. © 2002 Wiley Periodicals, Inc. Muscle Nerve 25: 000–000, 2002