M-mode ultrasound used to detect the onset of deep muscle activity

Differentiation of gluteus medius and minimus activity in weight bearing and non-weight bearing exercises by M-mode ultrasound imaging

“…EMG and ultrasound measurements of muscle activity are not equivalent (Vasseljen et al, 2006;Dieterich et al, 2014). Differences in sample volume and the influence of mechanical motion transmission contribute to discrepancies between electrical and mechanical aspects of muscle activity.…”

“…Using a custom programmed LabVIEW application (2013 SP1., National Instruments, Texas, USA), ultrasound grayscale signals of each pixel-line in the depth of analysis were transformed for detecting the signal's energy level by use of the Teager Kaiser Energy Operator (TKEO); TKEO ¼ x 2 (n) À x(n À 1)*x(n þ 1) (Li et al, 2007;Dieterich et al, 2014). The TKEO indicates changes in the amplitude and frequency of continuous signals (Kaiser, 1990) and has been used on acoustic and EMG signals (Lauer and Prosser, 2009;Solnik et al, 2010;Henriquez Rodriguez et al, 2013).…”

“…The TKEO indicates changes in the amplitude and frequency of continuous signals (Kaiser, 1990) and has been used on acoustic and EMG signals (Lauer and Prosser, 2009;Solnik et al, 2010;Henriquez Rodriguez et al, 2013). As motion changes the grayscale frequency in M-mode traces, the TKEO allows for computed detection of motion onsets (Dieterich et al, 2014). Fully computed onset detection on trials with sufficient baseline quality (see data inclusion) was chosen to ascertain onset reliability.…”

“…Ultrasound imaging reflects mechanical aspects of muscle activity, typically changes of muscle thickness. M(otion)-mode ultrasound imaging has been used to estimate the onset of deep trunk muscle activity (Vasseljen et al, 2006(Vasseljen et al, , 2009 and hip abductor activity (Dieterich et al, 2014) and has been used to demonstrate altered timing of gluteus minimus activity-related muscle motion in subjects with hip pain (Dieterich et al, 2012). M-mode ultrasound enables the measurement of temporal parameters, e.g.…”

Differences in muscle contraction onset as determined by ultrasound and electromyography

“…Reasonable correlations between sEMG and fwEMG were found in the lower limb during walking, while inconsistent correlations were found in shoulder muscles during abduction . The fwEMG and ultrasound onset were inconsistent with each other, while others have reported moderate relationships between sEMG and ultrasound onset . Differences in muscles, contraction tasks, and experimental designs (e.g., number of repetitions, averaging methods) may explain specific levels of agreement between studies; however, during a re‐analysis of published EMG‐ and ultrasound‐derived contraction onset studies, Dieterich et al noted a surprisingly high number of trials within each study (17–72%) where ultrasound onset was detected before electrical activation.…”