Role of across-muscle motor unit synchrony for the coordination of forces.

摘要: Evidence from five-digit grasping studies indicates that grip forces exerted by pairs of digits tend to be synchronized. It has been suggested motor unit synchronization might a mechanism responsible for constraining the temporal relationships between forces. To evaluate this possibility and quantify effect synchrony on force relationships, we used model simulate produced two muscles using three physiological levels across muscles. In one condition, units in discharged independently another. other conditions, timing randomly selected discharges muscle was adjusted impose low or high with muscle. Fast Fourier transform analysis performed compute phase differences 0.5 17 Hz. We circular statistics assess whether at each frequency were non-randomly distributed (Rayleigh test). The mean difference then computed non-random distributions. found number significant phase-difference distributions increased markedly increasing strength 18% no 65% 82% modest strong respectively. Importantly, most angles clustered very small values (approximately 0 10 degrees), indicating tendency synchronous fashion. These results suggest could play functional role coordination