quadriceps.pdf (681.32 kB)
Download file

Reliability of quadriceps surface electromyography measurements is improved by two vs. single site recordings

Download (681.32 kB)
journal contribution
posted on 23.05.2017, 13:13 by Tom BalshawTom Balshaw, A. Fry, Thomas M. Maden-Wilkinson, Pui W. Kong, Jonathan FollandJonathan Folland
Purpose: The reliability of surface electromyography (sEMG) is typically modest even with rigorous methods, and therefore further improvements in sEMG reliability are desirable. This study compared the between-session reliability (both within participant absolute reliability and between-participant relative reliability) of sEMG amplitude from single vs. average of two distinct recording sites, for individual muscle (IM) and whole quadriceps (WQ) measures during voluntary and evoked contractions. Methods: Healthy males (n = 20) performed unilateral isometric knee extension contractions: voluntary maximum and submaximum (60%), as well as evoked twitch contractions on two separate days. sEMG was recorded from two distinct sites on each superficial quadriceps muscle. Results: Averaging two recording sites vs. using single site measures improved reliability for IM and WQ measurements during voluntary (16–26% reduction in within-participant coefficient of variation, CVW) and evoked contractions (40–56% reduction in CVW). Conclusions: For sEMG measurements from large muscles, averaging the recording of two distinct sites is recommended as it improves within-participant reliability. This improved sensitivity has application to clinical and research measurement of sEMG amplitude.


The study was financially supported by the Arthritis Research UK Centre for Sport, Exercise, and Osteoarthritis (Grant reference 20194).



  • Sport, Exercise and Health Sciences

Published in

European Journal of Applied Physiology


1 - 10


BALSHAW, T.G. ... et al, 2017. Reliability of quadriceps surface electromyography measurements is improved by two vs. single site recordings. European Journal of Applied Physiology, 117 (6), pp. 1085-1094.


Springer / © The Authors


VoR (Version of Record)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution 4.0 International (CC BY 4.0) licence. Full details of this licence are available at: http://creativecommons.org/licenses/ by/4.0/

Acceptance date


Publication date



This is an open access article published by Springer and distributed under the terms of the Creative Commons Attribution Licence, http:// creativecommons.org/licenses/by/4.0/