[Application of energy cost in evaluating energy expenditure in multi-ball practice with table tennis players]

To investigate the feasibility of applying the measure of energy cost, utilized widely in cyclic sports, in table tennis multi-ball practice.

Eleven collegiate table tennis players volunteered (18±1 yrs, 177±2 cm, 71±3 kg, approximately 10 yrs' training experience) to participate in one graded exercise test on treadmill, and two step tests (forehand and backhand, 3 min × 6, 35～85 stroke/min). A portable spirometric system and heart rate monitor were utilized for the three trials. Earlobe blood samples were collected and analyzed prior to and post the test. Energy cost was calculated for one stroke at each stroke frequency.

The energy cost of loop drive multi-ball practice was decreased with increased stroke frequency (P＜0.05). The energy cost of forehand loop drive was higher than backhand, with the difference significant at 35, 45, 55, 65, and 85 stroke·min^-1 (P＜0.05). The function between energy cost and frequency were y=166.4x^-0.731 (R²=0.9731), and y=33.21x^-0.392 (R²=0.8423), respectively, where y was energy cost, and x was stroke frequency.

The measure of energy cost utilized in cyclic sports could be applied to evaluate the energy expenditure in table tennis multi-ball practice of single technique, and indicate the stroke efficiency of table tennis muti-ball practice with different stroke frequencies.