Fast movements exhibit spring-like braking

Absfmct To test the hypothesis that elastic energy storage in the antagonist muscle is used to brake rapid movements, we stopped voluntnry wrist flexion movements at various angular positions and measured isometric torque production after the movement was stopped. For movements stopped between the intended final position and maximum overshoot, the peak torque wos negative and proportional to the difference between the stopped position and the intended final position. After the peak, torque followed a pat tem stereotyped for each subject, but offset by the peak torque. The results are consistent with braking by a spring-like antagonist muscle.