A comparison of surface and fine wire EMG recordings of gluteus medius during selected maximum isometric voluntary contractions of the hip

Abstract

Electromyographic (EMG) studies into gluteus medius (GMed) typically involve surface EMG electrodes. Previous comparisons of surface and fine wire electrode recordings in other muscles during high load isometric tasks suggest that recordings between electrodes are comparable when the muscle is contracting at a high intensity, however, surface electrodes record additional activity when the muscle is contracting at a low intensity. The purpose of this study was to compare surface and fine wire recordings of GMed at high and low intensities of muscle contractions, under high load conditions (maximum voluntary isometric contractions, MVICs). Mann-Whitney U tests compared median electrode recordings during three MVIC hip actions; abduction, internal rotation and external rotation, in nine healthy adults. There were no significant differences between electrode recordings in positions that evoked a high intensity contraction (internal rotation and abduction, fine wire activity >77% MVIC; effect size, ES<0.42; p>0.277). During external rotation, the intensity of muscle activity was low (4.2% MVIC), and surface electrodes recorded additional myoelectric activity (ES=0.67, p=0.002). At low levels of muscle activity during high load isometric tasks, the use of surface electrodes may result in additional myoelectric recordings of GMed, potentially reflective of cross-talk from surrounding muscles.

Comparison of gluteus medius and minimus activity during gait in people with hip osteoarthritis and matched controls

“…However, the use of a surface electrode on GMed in these studies precludes the evaluation of individual segments of GMed and brings into question the accuracy of muscle activity recordings since EMG signal contamination from surrounding muscles is probable. 16 The function of GMin has not been examined in these studies. Considering the functional importance of individual segments in both GMed and GMin in a normal healthy population 17,18 and the deficits identified in pathological 11,14,15 and normal aging, 13 investigating the segmental differences in GMin and GMed activation is important in people with hip OA.…”

Ultrasound Imaging of the Gluteal Muscles During the Y-Balance Test in Individuals With or Without Chronic Ankle Instability

“…Muscle thickness has been found to be correlated with gluteal muscle torque during isometric testing (r ¼ 0.80) and has been upheld against fine-wire EMG analyses. 21 Ultrasound imaging may be favorable, as it is a more clinically applicable but noninvasive tool. 21 Furthermore, USI may be superior to surface EMG, as it is not subject to cross-talk.…”

“…21 Ultrasound imaging may be favorable, as it is a more clinically applicable but noninvasive tool. 21 Furthermore, USI may be superior to surface EMG, as it is not subject to cross-talk. 21 The use of USI under static conditions has expanded to quantifying muscles of the lumbopelvic-hip complex, and functional-activation ratios (FARs) have been used to describe the extent of musclethickness changes from resting to exercise conditions.…”

Differences in muscle contraction onset as determined by ultrasound and electromyography

“…In contrast to fwEMG, sEMG is highly influenced by superficial muscle fibers, subcutaneous tissue, and cross‐talk from other muscles . Inconsistent agreement in EMG amplitude between surface and fine wire electrodes have been found in the gluteus medius during various hip actions, in the lower leg muscles during cycling, in the quadriceps during walking, and even during manual muscle tests . Muscle activation onset is commonly determined by amplitude‐based thresholds, and consequently, may be different depending on electrode choice.…”