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Combining Multiple Data Acquisition Systems to Study Corticospinal Output and Multi-segment Biomechanics
Published on: January 9, 2016
Potentiation of the triceps brachii during voluntary submaximal contractions
Cameron B Smith1, Arthur J Cheng, Charles L Rice
1School of Kinesiology, Arthur and Sonia Labatt Health Sciences Building, University of Western Ontario, London, Ontario N6A 5B9, Canada.
Introduction:
The effects of postactivation potentiation (PAP) on evoked contractions are well understood, but less is known about the effect of PAP on voluntary submaximal contractions. Using a measure of neuromuscular efficiency (NME) [NME = (mV EMG / Nm torque)] we explored the effects of PAP in the triceps brachii at two muscle lengths.
Methods:
Evoked twitch and NME were compared at short (40° elbow flexion) and long (120°) muscle lengths. At each length, 12 subjects performed a contraction of 25% maximum voluntary contraction (MVC) torque before and after a potentiating MVC.
Results:
Twitch torque potentiated more at short length (216.9 ± 169.3%) than at long length (77.3 ± 32.6%), but PAP moderately improved NME only at short length (12.2 ± 8.7%).
Conclusions:
The greater capacity for PAP at the short length is reflected by greater NME. Compared with evoked responses, the relatively small change in NME suggests a different and more modest role of PAP during voluntary submaximal contractions.
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