Heart rate kinetics in tennis players during a 2 min groundstroke rally

The tennis players have a different physiological profile according to their defensive or offensive type play. Defensive players prefer to hit the balls from the baseline and the mean time of each rally was reported to be 8.2±5.1 s (±SD), i.e. significantly longer than that of offensive players (1). Even in defensive players the effective playing time was less than one third of the total time of a match and the heart rate (HR) changes during actual playing were moderate. We designed a simple and low cost specific test to evaluate the cardiovascular stress in “false” rallies in which couples of players of similar technical level were asked to hit shots as hard as possible parallel to the sidelines for 2 min. Players were asked to play the balls to the center of the court. HR was continously recorded over 5-s intervals with the aid of a Polar Sport Tester (Polar, Finland). In case of wrong shots a new ball was immediately put on the court. The peak ball velocity of 5 or more shots was measured by means of a radar Stalker ATS SystemTM (Minneapolis, MN, US). A 5 min pause of seated rest was interposed between rallies. The entire experimental session lasted about 50 min. Only forehand (FH) or backhand (BH) strokes were carried out in each of the six rallies. After a week from field measurements the relationship between HR and mechanical power were measured during an incremental walk on treadmill with increasing speed and constant slope (12%). Four players of each gender were studied and all of them took part to official amateur tournements of low or medium level. The mean maximal HRs of males and females were 189.3±8.1 and 193.0±4.3 b/min. No difference in HR kinetics were noted in FH and BH and data were pooled. HR increased in exponential way, the half times being 28.8±10.3 and 31.1±6.3 s, for males and females respectively. The corresponding half times during recovery were 88.5±26.8 and 99.8±32.2 s. The HR kinetics at onset and offset were significantly different (p<0.001) in both genders. The mean HRs in the last 20 s of each rally were 163.5±14.4 and 173.8±3.1 b/min in males and females (p=0.07). At the same HRs the mechanical powers during uphill walking were 195.3±10.0 and 112.7±16.1 W (p<0.001). The strokes per 2 minutes were 82.8±2.6 and 66.2±3.6 (p<0.001) and the corresponding peak ball speeds 106.7±5.3 and 84.3±5.5 km/h. In one subject the ball speed was significantly higher during FH and in two subjects during BH (two hands BH). In summary the cardiovascular stress was similar in both sexes in a 2 min tennis drill while the performance was significantly different.