Considerations of the new field test to evaluate the speed endurance in tennis

Introduction

In recent years tennis rallies have increased in speed. Furthermore, several recent cases [1] have been described in which mean blood lactate levels approached the onset of blood lactate accumulation (OBLA). Defining contemporary tennis as an intermittent high intensity exercise, the authors aimed to determine a method of evaluating the physical ability of speed endurance that tennis athletes are required to acquire at present. The purpose of this study was firstly to elucidate the optimum form of intermittent exercise for use as field test for tennis players, and secondly to clarify the relationships among speed endurance, ventilatory threshold (VT: %VO2max) and post-exercise blood lactate level.

Methods

All subjects were tennis athletes (42 males and 34 females, ranging in age from 12 to 21 years) who competed at the university, regional (state), or national junior level. The physical tests evaluated were as follows: intermittent 5 m, 10 m and 40 m sprint runs, and intermittent 10 m shuttle runs, 10 m repeated double shuttle runs and intermittent 50m change-of-direction runs. These exercises were performed as intermittent exercises and were performed 10 times with 20-second intervals. Twelve-minute-runs, shuttle-stamina-test (10 m shuttle runs in 3 minutes), 10 sessions of intermittent pedaling (0.075% weight kp/5 second) with 20-second intervals, and treadmill measurement of VT were also performed. Post-exercise blood lactate was sampled after the intermittent shuttle runs and the intermittent pedaling. Each series, comprising 10 trials of the above-mentioned intermittent exercises, was divided into 4 phases: first phase (1st trial), primal phase (2nd to 4th trial), middle phase (5th to 7th trial), and final phase (8th to 10th trial). The extent to which performance time in the final phase was prolonged in comparison to the previous phases was regarded an indicator of speed endurance.

Results and Conclusion

Performance time showed a gradual increase for intermittent 40 m sprint runs and 10 m double repeat shuttle runs, while power decreased similarly in the intermittent pedaling. In intermittent 10 m double repeat shuttle runs, prolongation of performance time was inversely proportional to VT and a linear relationship was found to exist between post-exercise blood lactate and ventilatory threshold. It seems reasonable to conclude from these results that the optimum field test to evaluate speed endurance in tennis is an intermittent shuttle or splint run of about 40 m in total. Considering the inverse relationship between the prolongation of performance time and VT (which is a reliable indicator of maximum aerobic work capacity or anaerobic threshold (AT)), it is reasonable to presume that speed endurance for high-intensity intermittent exercise is based on aerobic work capacity [2].

Reference

[1] Yoji Sato, Kaoru Umebayashi, Toshio Chohmabayashi et al., The Research Reports of Sport and Medical Science , Japan Sports Association, No.Ⅱ, Vol.21, p.63-74, 1998 [2] Masayoshi Yamamoto, J.J.SPORT SCI., p.13-25, 1994