During men's single tennis of the mean match characteristics were: rally time, 4~12 s; recovery time, 20~23 s; total time, 137~166 min; work-to-recovery rate, 1:2.4~3.9. The percentage of VO2(subscript max), heart rate and plasma concentrations of lactate were 46.4%~81.1%, 144~165 beats/min and 2.3~7.2 mmol/L. Although tennis is characterized by periods of high-intensity exercise, the over response resembles prolonged moderate-intensity exercise.