Muscle activation during maximal voluntary eccentric and concentric knee extension.

摘要: The aim of this investigation was to study the relationships among movement velocity, torque output and electromyographic (EMG) activity knee extensor muscles under eccentric concentric loading. Fourteen male subjects performed maximal voluntary constant-velocity extensions at 45, 90, 180 360 degrees.s-1. Myoelectric signals were recorded, using surface electrodes, from vastus medialis, lateralis rectus femoris muscles. For comparison, full-wave rectified EMG amplitude-averaged through central half (30 degrees-70 degrees) range motion. each test greater than (range mean differences: 20%-146%, P less 0.05). In contrast, for all lower loading velocity-matched (7%-31%, Neither nor three changed across velocities (P While increased with decreasing decreased velocity These data suggest that certain high-tension conditions (especially during muscle actions), neural drive agonist reduced, despite effort. This may protect musculoskeletal system an injury could result if become fully activated these conditions.