A comparative study was made of the effects of varied time intervals of rest between warm-up and performance in the 440-yard dash by students in selected physical education classes at North Texas State University during the spring semester of 1967. This study was made to determine if the length of a rest interval after cessation of warm-up activity has any significant effect upon the subsequent performance in a 440-yard dash, and to determine if any length of rest interval facilitates performance in a 440-yard dash.