Effect of circumferential pressure on response parameters during ballistic ankle plantar flexion in healthy adults.

This study investigated the effect of circumferential pressure on timing and muscle-response parameters during ballistic ankle plantar flexion in 15 young healthy subjects. Circumferential pressure was provided by an air-splint applied around the lower calf. Data were collected at 1, 3, and 5 min. prior to, during, and following application of pressure. A 3 x 3 repeated-measures analysis of variance indicated significant increases in premotor and reaction times during application of pressure. There was no main effect for magnitude of muscle activity or motor time. Results support previous studies showing decreases in the excitability of the motor-neuron pool with circumferential pressure and an inverse relationship between excitability and premotor time.