Recently, accelerometers have been used to acquire mechanomyography signals. These signals are due to muscle lateral oscillations during contraction. In this study, a sensor acquired such vibrations in three directions. A triaxial accelerometer-based sensor was constructed and tested with a controlled mechanical vibrator and subwoofer speaker (both from 10Hz up to 40Hz) during isokinetic muscle contraction (3 volunteers, 50 extensions at 300 degrees/s). With triaxial accelerometry it was possible to compute the MMG modulus signal. For normalised and average values, MMG amplitude presented strong correlation coefficients (R=0,89) with RMS and peak torque. Below 80% of normalised data, MMG amplitude and torque values (RMS and peak) seem to converge.2 176179Brozovich, F.V., Pollack, G.H., Muscle contraction generates discrete sound bursts (1983) BiophysicalJournal, 41 (1), pp. 35-40Cescon, C., Farina, D., Gobbo, M., Merletti, R., Orizio, C., Effect of accelerometer location on mechanomyogram variables during voluntary, constant-force contractions in three human muscles (2004) Medical and Biological Engineering and Computing, 42 (1), pp. 121-127Evetovich, T.K., Housh, T.J., Stout, J.R., Johnson, G.O., Smith, D.B., Ebersole, K.T., Mechanomyographic responses to concentric isokinetic muscle contractions (1997) European Journal of Applied Physiology and Occupational Physiology, 75 (2), pp. 166-169Fitts, R.H., Cellular mechanisms of muscle fatigue (1994) Physiol Rev, 74 (1), pp. 49-94Hudash, G., Albright, J., McAuley, E., Martin, R., Fulton, M., Cross-sectional thigh components: Computerized tomographic assessment (1985) Med Sci Sports Exerc, 77 (4), pp. 417-421Orizio, C., Muscle sound: Bases for the introduction of a mechanomyographic signal in muscle studies (1993) Crit Rev Biamed Eng, 21 (3), pp. 201-243Orizio, C., Gobbo, M., Diemont, B., Esposito, F., Veicsteinas, A., The surface mechanomyogram as a tool to describe the influence of fatigue on biceps brachii motor unit activation strategy. Historical basis and novel evidence (2003) European Journal of Applied Physiology, 90 (3-4), pp. 326-336Orizio, C., Perini, R., Veicsteinas, A., Changes of muscular sound during sustained isometric contraction up to exhaustion (1989) Journal of Applied Physiology, 66 (4), pp. 1593-1598Orizio, C., Perini, R., Veicsteinas, A., Muscular sound and force relationship during isometric contraction in man (1989) European Journal of Applied Physiology and Occupational Physiology, 58 (5), pp. 528-533Salles, F.A., Müller, R.W., Nogueira-Neto, G.N., Button, V.L., Nohama, P., Sistema de análisis de senales mecanomiográficas (MMG) (2006) XXIV Congreso Anual de la Sociedad Espanola de Ingenieria Biomédica, , Paper presented at the, Pamplona, SpainShinohara, M., Kouzaki, M., Yoshihisa, T., Fukunaga, T., Mechanomyogram from the different heads of the quadriceps muscle during incremental knee extension (1998) European Journal of Applied Physiology, 78 (4), pp. 289-295Stokes, M.J., Cooper, R.G., Muscle sounds during voluntary and stimulated contractions of the human adductor pollicis muscle (1992) Journal of Applied Physiology, 72 (5), pp. 1908-1913Watakabe, M., Mita, K., Akataki, K., Ito, K., Reliability of the mechanomyogram detected with an accelerometer during voluntary contractions (2003) Medical and Biological Engineering and Computing, 41 (2), pp. 198-202Zagar, T., Krizaj, D., Validation of an accelerometer for determination of muscle belly radial displacement (2005) Medical and Biological Engineering and Computing, 43 (1), pp. 78-84