Mecanomiografia Triaxial Analysis And Isokinetic Torque: Preliminary Results [mecanomiografia Triaxial E Análise De Torque Isocinético: Resultados Preliminares]

In mechanomyography (MMG), there seems to be more studies in isometric contractions than isokinetic ones. MMG amplitude can be used to track torque decline in fatiguing isokinetic contractions. This study aims to determine good MMG/torque correlation indicators. Three volunteers performed 50 isokinetic contractions at 300°s-1. The MMG acquisition system is based on a triaxial accelerometer sensor. It was positioned on the belly of the rectus femoris muscle. The acquired RMS and derived signals were first analyzed for determining whether they have normal distribution. Then, the linear correlation coefficients were calculated. Sensor's axis 1 presented weaker correlation with torque variables than axis 2 and 3. The modulus of the three signals (axes 1, 2, and 3) had the highest correlation values. The RMS MMG amplitude had better correlation with RMS torque than peak torque. However, with the averaged values, correlation coefficients were R=0.89 and R=0.89 (p<0.01) for peak torque and RMS value, respectively. Two main conclusions were drawn: the modulus is a good indicator of torque amplitude in isokinetic contractions at 300°s-1, and peak torque and maximum RMS torque values occur after the first extension. However, tests with more volunteers are needed in order to precisely assess these results. © Springer-Verlag Berlin Heidelberg 2007.18555558Orizio, C., Perini, R., Veicsteinas, A., Muscular sound and force relationship during isometric contraction in man (1989) Eur J Appl Phys Occup Physiol, 58, pp. 528-533Brozovich, F.V., Pollack, G.H., Muscle contraction generates discrete sound bursts (1983) Biophys J, 41, pp. 35-40Stokes, M.J., Cooper, R.G., Muscle sounds during voluntary and stimulated contractions of the human adductor pollicis muscle (1992) J Appl Physiol, 72, pp. 1908-1913Mealing, D., McCarthy, P.W., Muscle sound frequency analysis from fast and slow twitch muscle (1991) IEEE Proc. Annual Conference On Eng Med and Biol Soc, pp. 948-949Watakabe, M., Mita, K., Akataki, K., Reliability of the mechanomyogram detected with an accelerometer during voluntary contractions (2003) Med Biol Eng Comp, 41, pp. 198-202Søgaard, K., Orizio, C., Søgaard, G., Surface mechanomyogram amplitude is not attenuated by intramuscular pressure (2006) Eur J Appl Physiol, 96, pp. 178-184Orizio, C., Perini, R., Diemont, B., Muscle sound and electromyogram spectrum analysis during exhausting contractions in man (1992) Eur J Appl Physiol, 65, pp. 1-7Ebersole, K.T., Housh, T.J., Johnson, G.O., The effect of leg flexion angle on the mechanomyographic responses to isometric muscle actions (1998) Eur J Appl Phys Occup Physiol, 78, pp. 264-269Ebersole, K.T., O'Connor, K.M., Wier, A.P., Mechanomyographic and electromyographic responses to repeated concentric muscle actions of the quadriceps femoris (2006) J Electromyogr Kinesiol, 16, pp. 149-157Perry-Rana, S.R., Housh, T.J., Johnson, G.O., MMG and EMG responses during fatiguing isokinetic muscle contractions at different velocities (2002) Muscle & Nerve, 26, pp. 367-373Evetovich, T.K., Housh, T.J., Stout, J.R., Mechanomyographic responses to concentric isokinetic muscle contractions (1997) Eur J Appl Phys Occup Physiol, 75, pp. 166-169Chambers, J.M., (1983) Graphical Methods For Data Analysis, , Chapman & Hall, BostonBox, G.E., Cox, D.R., An analysis of transformations (1964) J Royal Stat Soc. Series B (Methodological), 26, pp. 211-252Hudash, G., Albright, J., McAuley, E., Cross-sectional thigh components: Computerized tomographic assessment (1985) Med Sci Sports Exerc, 17, pp. 417-421Cramer, J.T., Housh, T.J., Johnson, G.O., Mechanomyographic amplitude and mean power output during maximal, concentric, isokinetic muscle actions (2000) Muscle & Nerve, 23, pp. 1826-1831Perry-Rana, S.R., Housh, T.J., Johnson, G.O., MMG and EMG responses during 25 maximal, eccentric, isokinetic muscle actions (2003) Med Sci Sports Exerc, 35, pp. 2048-205