Crosstalk in Mechanomyographic Signals From Elbow Flexor Muscles During Submaximal to Maximal Isometric Flexion, Pronation, and Supination Torque Tasks

Abstract

This study analysed crosstalk in mechanomyographic (MMG) signals from elbow flexors during isometric muscle actions from 20% to 100% maximum voluntary isometric contraction (MVIC). Twenty-five young, healthy, male participants performed isometric elbow flexion, forearm pronation and supination tasks at an elbow joint angle of 90°. The MMG signals from the biceps brachii (BB), brachialis (BRA) and brachioradialis (BRD) muscles were recorded using accelerometers. Cross-correlation coefficient was used to quantify the crosstalk in MMG signals, recorded in a direction transverse to muscle fibre axis, among the muscle pairs (P1: BB and BRA, P2: BRA and BRD and P3: BB and BRD). In addition, the MMG RMS and MPF were quantified. Mean normalized RMS and mean MPF exhibited increasing (r > 0.900) and decreasing (r < -0.900) trends, respectively, with increases in the effort levels in all three tasks. The magnitude of crosstalk ranged from 0.915 to 21.565% in all muscle pairs. Crosstalk was found to exhibit high positive correlations with submaximal to maximal flexion [P1 (r = 0.970), P2 (r = 0.951), and P3 (r = 0.824)], pronation [P1 (r = 0.811), P2 ( r = 0.763), and P3 (r = 0.901)] and supination [P1 (r = 0.898), P2 (r = 0.838), and P3 (r = 0.852)] torque levels (eight out of nine p-values were < 0.05). Regardless of the high positive correlation between crosstalk and level of effort, the crosstalk remained at a low range (0.915% to 21.565%) with increases in the torque levels.

Analysis of anthropometrics and mechanomyography signals as forearm flexion, pronation and supination torque predictors

“…MMG signals were collected using three triaxial accelerometers (ADXL335, Analogue Devices, USA; full-scale range = ± 3 g; typical frequency response = 0.5–500 Hz; sensitivity = 330 mVg -1 ; size = 15 mm × 15 mm × 1.5 mm; weight < 1.5 g). The design of experiment and procedures followed, were similar to our previous studies 1 , 17 , 18 . During the flexion task, accelerometers were placed on muscle bellies and attached using double-sided adhesive tape.…”

“…The acquired MMG signals were digitally sampled at 1 kHz. Data acquisition and storage were performed using custom-made programs in LabVIEW™ (version 2016, National Instruments, Austin, TX, USA) 1 , 17 , 18 , 20 .

Figure 1 Placement of accelerometers on three elbow flexor muscles.

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“…Mechanomyography (MMG) is a non-invasive technique for recording low-frequency oscillations in active skeletal muscle fibers 1 . MMG offers notable benefits, which include but not limited to, minimal skin preparation, negligible effect of skin impedance, and lower susceptibility to external noise 2 , 3 .…”

Effects of blood flow restriction training on muscle fitness and cardiovascular risk of obese college students

“…This test started with a knee isometric test for 5 s, with the knee flexion angle set to 100° ( Steidl-Müller et al, 2018 ) and a 1- minute rest for a 180°/s centripetal-centripetal contraction pattern of the same joint. Isometric elbow test for 5 s, with the elbow joint set to a flexion angle of 90° ( Talib et al, 2021 ) and a 1-min rest for a centripetal-centripetal contraction mode of 180°/s of the same joint. At least 3 trials were performed in each mode and the maximum value was taken.…”

MMG-Based Knee Dynamic Extension Force Estimation Using Cross-Talk and IGWO-LSTM

“…MMG, which is pressure waves created by the activation of muscle fibers and their dimensional changes during muscle contraction [5], and represents the muscles' mechanical output, is comparable to sEMG. Thus, MMG can also provide important information on muscle activity and motor unit recruitment patterns [16], which can be detected on the skin surface above the target muscle by accelerometers, piezoelectric microphones, etc. [1,4,13,17].…”