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|Type:||Artigo de evento|
|Title:||Triaxial Mechanomyography Of The Biceps Brachii Muscle During Sustained Submaximal Isometric Contractions|
|Abstract:||The biceps brachii (BB) is a bi-articular muscle that acts in the elbow and shoulder joints. Mechanomyography (MMG) is a technique that uses accelerometers to monitor the muscle waves. The aim of this study is to model the behavior of BB MMG signals and elbow torque during sustained sub-maximal isometric contractions. Three MMG axes (Z, Y and X) and torque were recorded from BB during sustained elbow flexion at 70% of maximum voluntary contraction (MVC) and kept the longest time the volunteers could get. MMG and torque signals were analyzed in 3 different (Initial, Middle and Final) time windows (TW) with 1s duration specific to the protocol. Temporal parameters [Absolute mean, root mean square (RMS), number of zero-crossings, peak count, and absolute integral] were calculated for all signals and every TW. The ANOVA analysis showed that absolute mean, RMS and absolute integral parameters presented statistical difference only for X axis (accelerations in the proximal-distal direction) increasing amplitude with time. The Z axis (accelerations in the anterior-posterior direction) showed decrease of the zero-crossings in the first half of the test and had a second decrease between the Middle TW and the Final TW, but no difference was observed at any moment on X axis during this analysis. The unique parameter that presented statistical difference for all axis (Z, X, Y) and modulus among the three TW was number of peak counts and only X axis is not different between the Initial and Middle TWs. One possible hypothesis would be a tension increase in muscles that actuate on the scapula since the direction of the action force is parallel to the X axis. A purely spectral parameters analysis could help comprehending what does occur with MMG signal in sustained submaximal isometric contractions.|
|Appears in Collections:||Unicamp - Artigos e Outros Documentos|
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