Energy Contributions of Short-distance Running with Change of Direction in Tennis Baseline Practice

Abstract

Short-distance running with change of direction (SR-COD) is one of the baseline practice regulary performed in tennis training, but the energy contributions of this practice is relatively lacking. PURPOSE: To investigate the energy contributions of tennis SR-COD, with the emphasis on the duration, distance, and frequency. METHODS: 16 collegiate male tennis players (22.2 ± 1.7yrs, 175 ± 5cm, 69.2 ± 6.1kg) volunteered to this study. Two duration (1 and 2min), two distance (1 and 2min) and two frequency (20 and 30 stroke/min) were utilized, i.e. 1min-2m-20stroke/min, 2min-2m-20stroke/min, 1min-4m-20stroke/min and 1min-2m-30stroke/min. A portable spirometric system (K4b2, Cosmed, Italy) was utilized to measure the ventilatory activities. Capillary blood from earlobe was collected and analyzed with blood lactate analyzer (Biosen C-line, EKF, Germany) prior to and post the test. The aerobic (Aer), anaerobic lactic (Anl), anaerobic alactic (Anal) energy contributions were calculated with the method based on the accumulated oxygen uptake and blood lactate during the practice, as well as the fast part of the oxygen uptake kinetics during the recovery, respectively. The relative energy contributions from the coresponding three pathways were also calculted as Aer%, Anl%, and Anal%. RESULT: The energy contributions of SR-COD was Anal 37.4~40.1kJ (32.1~41.7%), Anl 15.1~33.5kJ (14.8~30.4%) and Aer 37.8~100.8kJ (33.9~61.9%), respectively. With the increase of duration, distance and frequency, there was no significant change in Anl, there was significant increase in Anal and Aer (P<0.05, except Aer when increasing frequency). Further, %Anal decreased with the increase of duration, distance, and frequency (P<0.05). %Anl enhanced significantly with the increased distance and frequency (P<0.05), but declined insignificantly with increased duration (P<0.05). %Aer increased significantly with longer duration (P<0.05), but reduced with longer distance and higher frequency (P<0.05). CONCLUSION: Longer duration of SR-COD mainly increases the stimulation on Aers system, while longer distance and higher frequency of SR-COD mainly increases the stimulation on Anl energy. These findings should be taken into account when designing the SR-COD training program in tennis.