Affiliations: Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, Lincoln, NE 68505, USA
Correspondence:
[*]
Corresponding author: Ethan C. Hill, Department of Nutrition and Health Sciences, 110 Ruth Leverton Hall, University of Nebraska-Lincoln, Lincoln, NE 68583-0806, USA. Tel.: +1 402 472 2690; E-mail:ethan.hill@unl.edu
Abstract: BACKGROUND: It has been
hypothesized [1] that the
amplitude of the mechanomyographic (MMG) signal should track mean power
output (MP) during dynamic muscle actions. Bodor's hypothesis has been
supported in studies of non-fatigued muscles where MMG amplitude was shown
to track velocity-related changes in MP, but not moment production, during
concentric and eccentric muscle actions. OBJECTIVE: The purpose of this study was to further test the
hypothesis of Bodor [1] by examining the patterns of MMG
amplitude responses during a fatiguing workbout that included repetitions
that were characterized by constant moment production, but decreasing MP. METHODS: Eleven subjects performed 50 submaximal (65% of peak
moment), concentric, isokinetic, forearm flexion repetitions at 60°/s.
Polynomial regression analyses were used to examine the composite patterns
of responses for moment, MP, and MMG amplitude from the biceps brachii
across the fatiguing workbout. RESULTS: There were linear decreases across the repetitions for MP
(r = 0.93) and MMG amplitude (r= 0.70), but no change in moment production. CONCLUSIONS: The current findings extend the hypothesis of
Bodor [1] to the process of fatigue and suggested that MMG
amplitude may be useful for monitoring decreases in MP during submaximal,
fatiguing workbout where moment production is maintained.
