Reliability of EMG normalisation methods for upper-limb muscles

Abstract

The study investigated different electromyographic (EMG) normalisation methods for upper-limb muscles. This assessment aimed at comparing the EMG amplitude and the reliability of EMG values obtained with each method. Eighteen male tennis players completed isometric maximal voluntary contractions and dynamic strength exercises (push-ups and chin-ups) on three separate test sessions over at least 7 days. Surface EMG activity of nine upper body muscles was recorded. For each muscle, an analysis of variance for repeated measures was used to compare maximal EMG amplitudes between test conditions. The intra-class correlation coefficient, the coefficient of variation and the standard error of measurement were calculated to determine the EMG reliability of each condition. On the basis of a compromise between maximal EMG amplitude and high reliability, the chin-ups appeared to be the optimal normalisation method for M. latissimus dorsi, M. posterior deltoid, M. biceps brachii, M. flexor carpi radialis and M. extensor carpi radialis. The push-ups seemed relevant to normalise M. anterior deltoid and M. triceps brachii activity, while isometric maximal voluntary contraction remained the most appropriate method for M. pectoralis major and M. middle deltoid. Thus, original methods are proposed to normalise EMG signal of upper-limb muscles.

Neck and shoulder muscle activity among ophthalmologists during routine clinical examinations

“…For the upper trapezius, reference contractions were obtained while the participant held a 2 kg weight in each hand with the upper arms elevated to 90 in the scapular plane, elbows fully extended and forearms pronated (Mathiassen et al 1995). For the anterior deltoid, participants held a 2 kg weight in each hand with the upper arms flexed forward to 90 of elevation and the elbows fully extended (Cook et al 2004;Yoo et al 2010;Rota et al 2013). Three repetitions of each reference contraction were performed, with a 1-min rest between repetitions.…”

The magnitude of neuromuscular fatigue is not intensity dependent when cycling above critical power but relates to aerobic and anaerobic capacities

“…* P < 0.05 versus PRE. (Ball & Scurr, 2010;Buckthorpe, Hannah, Pain, & Folland, 2012;Rota, Rogowski, Champely, & Hautier, 2013) may be considered when discussing meaningful change. ‡ n = 11.…”

“…stimulation technique, electrode placement). Furthermore, the modest reliability reported for surface EMG recordings of voluntary and evoked contractions (Ball & Scurr, 2010;Buckthorpe, Hannah, Pain, & Folland, 2012;Rota, Rogowski, Champely, & Hautier, 2013) may be considered when discussing meaningful change.…”

Do surface electrode recordings validly represent latissimus dorsi activation patterns during shoulder tasks?

“…A simple, electronic search of the literature between 2011 and 2013 found over 20 papers reporting LD activity recorded with the use of surface electrodes. The scope of these studies ranged from investigating LD activity during: normal shoulder function (Hawkes et al, 2012b;Rota et al, 2013); various sporting activities including rowing (Bazzucchi et al, 2013), tennis (Rota et al, 2012), pole vaulting (Frere et al, 2012), skiing (Nilsson et al, 2013), baseball (Reyes et al, 2011), golf (Lim et al, 2012) and swimming (Ikuta et al, 2012); exercises (Marchetti and Uchida, 2011); shoulder and trunk dysfunction (Hawkes et al, 2012a;Ntousis et al, 2013;Wood et al, 2011); classical singing (Watson et al, 2012); and muscle fatigue (Balasubramanian et al, 2014).…”