A STUDY OF THE REFLEX TIME OF THE KNEE-JERK AND THE ACHILLES-JERK

Abstract

Study of 8 subjects showed: (1) the average reduced reflex time, i.e., the time elapsing between application of stimulus and arrival of the action current at the muscle, was 0.0194 sec. for the knee-jerk and 0.0347 sec. for the Achilles-jerk; (2) the gross reflex time for the same group was 0.0796 sec. for the knee-jerk (this time was not determined for the Achilles-jerk). The relatively great range of the reduced reflex times and the much longer reduced reflex time of the Achilles-jerk, together with the periodic nature of the action currents of the 2 responses, indicate that these responses are true reflexes.