Affiliations: [a] School of Human Sciences, St Mary's University
College, Twickenham, UK | [b] School of Life Sciences, Kingston University,
Kingston-upon-Thames, UK
Note: [] Address for correspondence: Glyn Howatson, School of Human
Sciences, St Mary's University College, Strawberry Hill, Twickenham, Middlesex,
TW1 4SX, UK. Tel.: +44 208240 4076; Fax: +44 208240 4255; E-mail:
[email protected]
Abstract: The aim of this investigation was to examine the intra-subject and
group reproducibility of isometric muscle function testing and the associated
surface EMG signal repeated over five consecutive days using isokinetic
dynamometry. Fifteen physically active volunteers that were unfamiliar with
isokinetic dynamometry participated in this study and were asked to attend the
laboratory on five consecutive days to complete maximal isometric testing.
Surface electromyography was recorded from biceps brachii to examine the
electrical activity associated with the peak torque. The intra-subject
reproducibility was moderate for isometric torque (mean coefficient of
variation (CV) of 6.65%), however the EMG and EMG:torque ratio were somewhat
more variable (mean CV of 18.20% and 18.49%, respectively). The group
reproducibility showed an intra-class correlation coefficient of r = 0.99,
0.92 and 0.96 for isometric peak torque, EMG and torque: EMG ratio. In
addition, the group CV for isometric peak torque, EMG and torque:EMG ratio was
1.03%, 4.10% and 3.38%, respectively. Individuals can show large variations
in torque and EMG, however when reproducibility is examined as a group both
torque and the associated EMG activity have high reproducibility in physically
active subjects, unfamiliarised with isometric dynamometry.
