Reliability of mechanomyographic amplitude measurements for trunk muscles during maximal voluntary isometric contraction

BACKGROUND: Mechanomyography (MMG) has been used to investigate mechanical characteristics of muscle contraction in clinical and experimental settings. OBJECTIVE: The aim of this study was to determine the test-retest reliability of mechanomyographic amplitude (MMGRMS) measurements as a tool for measuring the maximal voluntary isometric contractions (MVICs) of trunk muscles in healthy participants. METHODS: There were ten young adults participating in this study. Accelerometers were used to detect surface MMG signals from three trials of 5-s MVICs of the rectus abdominis, external obliques, erector spinae, and multifidus in the vertical, transverse, and longitudinal directions. Intraclass correlation coefficient (ICC), standard error of measurement (SEM), and minimum detectable change were calculated. RESULTS: Good to excellent test-retest reliability of mechanomyographic amplitude (MMGRMS) measurements was achieved for all MVICs of trunk muscles in healthy participants, as indicated by ICCs ranging from 0.99 to 0.64 for MMGRMS of the trunk muscles during MVIC. CONCLUSIONS: This study demonstrates that MMG is a reliable measurement to detect the activation amplitudes of trunk muscles during MVIC.