Influence of mass and velocity of the tendon tap on the stretch reflex response

Abstract

The purpose of this study was to investigate the magnitude of the stretch reflex response and the threshold at which it appears by changing the mass of the reflex hammer and the velocity of the tendon tap. Tendon taps were applied to the tendon of the quadriceps femoris of 20 healthy volunteers using four levels of reflex hammer mass and five levels of velocity for each mass. We found that the magnitude of the reflex response, as measured by integrated electromyography, increased with an increase in velocity and with an increase in the mass of the reflex hammer. However, there was a threshold of tendon tap velocity to elicit the reflex response, below which no reflex appeared. The findings of this study indicate that the velocity of the tendon tap required to elicit a response was 1-2 m/s.