Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8799759 | Journal of Electromyography and Kinesiology | 2018 | 8 Pages |
Abstract
Introduction: This study employed a unique stimulation paradigm which allowed for the simultaneous assessment of voluntary activation levels (VA) via twitch-interpolation, and the evoked V-wave responses of the plantar flexors during submaximal and maximal contractions. Test-retest reliability was also examined. Methods: Fourteen participants repeated a stimulation protocol over four visits to assess VA and evoked V-wave amplitude across torque levels ranging from 20% to 100% MVC. MVC torque and EMG amplitude were also measured. Results: VA increased nonlinearly with torque production and plateaued by 80% MVC. V-wave amplitude increased linearly from 20% to 100% MVC. There were no differences in any dependent variable across visits (pâ¯>â¯0.05). VA demonstrated moderate to substantial reliability across all torque levels (ICCâ¯=â¯0.76-0.91) while V-wave amplitude exhibited fair to moderate reliability from 40% to 100% (ICCâ¯=â¯0.48-0.74). Discussion: We were able to reliably collect VA and the V-wave simultaneously in the plantar flexors. Collection of VA and V-wave during the same contraction provides distinct information regarding the contribution of motor-unit recruitment and descending cortico-spinal drive/excitability to force production.
Keywords
ICCRTTRMSFCRMVCH-reflexEMGelectromyographyITTNerve stimulationTranscutaneous electrical nerve stimulationanalysis of varianceANOVAInterpolated twitch techniquemaximal voluntary contractionTwitch interpolationTENSflexor carpi radialisHoffman reflexintraclass correlation coefficientNeuromuscular functionVoluntary activationM-wave
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Authors
Robert E. Hight, Alwyn T. Quarshie, Christopher D. Black,