MECHANOMYOGRAPHIC RESPONSES DURING RECRUITMENT CURVES IN THE SOLEUS MUSCLE

Introduction: In this study we examined relationships among mechanomyographic (MMG), electromyographic (EMG), and peak twitch torque (PTT) responses as well as test-retest reliability when recorded during recruitment curves in the soleus muscle. Methods: PTT, EMG (M-wave, H-reflex), and MMG responses were recorded during recruitment curves in 16 subjects (age 24 +/- 2 years) on 2 separate days. The sum of the M-wave and H-reflex (M1H) was calculated. Correlations among variables and test-retest reliability were determined. Results: MMG was correlated with PTT (mean r=0.93, range r=0.59-0.99), the M-wave (0.95, 0.04-0.98), and M1H (0.91, 0.42-0.97), but was unrelated to the H-reflex (-0.06, -0.56 to 0.47). Reliability was consistently high among most variables, but normalizing to the maximum value improved MMG reliability and the minimum detectable change. Conclusion: MMG responses predicted 86%-90% of the variability in PTT, M-wave, and M1H; thus, MMG may be a useful alternative for estimating twitch torque and maximal activation.