Effect of voluntary vs. artificial activation on the relationship of muscle torque to speed

摘要: The speed-torque relationship of the right knee extensor muscle group was investigated in eight untrained subjects (28 +/- 2 yr old). Torque measured at a specific angle during isokinetic concentric or eccentric actions nine angular velocities (0.17-3.66 rad/s) and isometric actions. Activation by "maximal" voluntary effort transcutaneous tetanic electrical stimulation that induced an torque equal to 60% (STIM 1) 45% 2) value. increased (P less than 0.05) 1.4 times as speed 1.57 rad/s for STIM 1 2. Thereafter, increases did not further increase torque. greater above As from 0.00 3.66 rad/s, decreased more both (two-thirds) activation (one-half). result these responses, changed three much across speeds with artificial (3.4-fold) (1.1-fold) activation. results indicate normalized extensors situ is remarkably similar isolated muscle. activation, contrast, suggests ability central nervous system activate maximal efforts depends on type action performed.