Article ID Journal Published Year Pages File Type
4064804 Journal of Electromyography and Kinesiology 2013 9 Pages PDF
Abstract

To assess the validity and reliability of the mechanomyogram (MMG) as a tool to investigate the fatigue-induced changes in the muscle during relaxation, the torque and MMG signals from the gastrocnemius medialis muscle of 23 participants were recorded during tetanic electrically-elicited contractions before and immediately after fatigue, as well as at min 2 and 7 of recovery. The peak torque (pT), contraction time (CT) and relaxation time (RT), and the acceleration of force development (d2RFD) and relaxation (d2RFR) were calculated. The slope and τ of force relaxation were also determined. MMG peak-to-peak was assessed during contraction (MMG p–p) and relaxation (R-MMG p–p). After fatigue, pT, d2RFD, d2RFR, slope, MMG p–p and R-MMG p–p decreased significantly, while CT, RT and τ increased (P < 0.05 for all comparisons), remaining altered throughout the entire recovery period. R-MMG p–p correlated with pT, MMG p–p, slope, τ and d2RFR both before and after fatigue. Reliability measurements always ranged from high to very high. In conclusion, MMG may represent a valid and reliable index to monitor the fatigue-induced changes in muscle mechanical behavior, and could be therefore considered an effective alternative to the force signal, also during relaxation.

Related Topics
Health Sciences Medicine and Dentistry Orthopedics, Sports Medicine and Rehabilitation
Authors
, , , ,