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Comparing the reliability of voluntary and evoked muscle actions
Author(s) -
Jenkins Nathaniel D. M.,
Palmer Ty B.,
Cramer Joel T.
Publication year - 2014
Publication title -
clinical physiology and functional imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.608
H-Index - 67
eISSN - 1475-097X
pISSN - 1475-0961
DOI - 10.1111/cpf.12113
Subject(s) - medicine , physical medicine and rehabilitation , reliability (semiconductor) , physical therapy , neuroscience , anesthesia , power (physics) , physics , quantum mechanics , biology
Summary Purpose The purpose of this exploratory study was to quantify the test–retest reliability, intertrial variability and correlations between variables calculated during voluntary and evoked muscle actions. Methods During three separate trials of isometric leg extension muscle actions with 14 men [mean age (± SD ) = 21·9 (±3·2) years; height = 179·2 (±8·0) cm; mass = 77·7 (±10·9) kg], peak torque ( PT V ), time to peak torque ( TPT V ), rate of torque development ( RTD V ), time to peak rate of torque development ( TRTD V ), electromechanical delay ( EMD V ) and EMG amplitude ( EMG RMS ) were quantified for voluntary muscle actions. Peak twitch torque ( PT E ), time to peak twitch torque ( TPT E ), rate of torque development ( RTD E ), time to peak rate of torque development ( TRTD E ), electromechanical delay ( EMD E ), peak‐to‐peak M‐wave (M p‐p ) and M‐wave area (M area ) were calculated for evoked twitches. All electromyographic measurements were recorded over the vastus lateralis. Results Voluntary intraclass correlation coefficients ( ICC ) were 0·84–0·96, except for TRTD V (0·30) and EMD V (0·74). Evoked ICC were 0·80–0·95, except for EMD E (0·52). Relative standard errors of measurement for TPT and TRTD were greater for voluntary than evoked, whereas the value for PT E was greater than PT V . There were low to moderate correlations ( r = −0·41–0·51) between common voluntary and evoked variables. Conclusions Evoked variables showed lower intertrial variability than voluntary. Overall, voluntary and evoked muscle actions provide unique, complimentary information regarding neuromuscular function that cannot be used interchangeably.