Introduction: A table tennis drive may be described as a speed-accuracy trade-off. To win a point, player should induce the highest level of uncertainty in opponent, keeping the highest level of precision during the rally. In this study we have analyzed drive accuracy evolution depending on the intensity of the exercise. Players were faced with an easy to perform exercise with increasing intensity. Results concerning accuracy, movement execution and effort managing have been analyzed. Method: Players should perform a forehand drive towards a target, of 21 cm diameter, placed in the opponent half-table. The exercise intensity was controlled by increasing balls projection rate (steps of 6 balls/min every 30 seconds). Subjects were expert players (n=4, National ranking) or confirmed players (n=5, Regional ranking). Accuracy (% of balls hitting the target), movement kinematics (goniometer placed on elbow joint, 100 Hz acquiring frequency, Biopac) and heart rate (cardiofrequencemeter, Polar Accurex Plus) have been recorded. Main results: Results show a decadence in performance during the exercise (r2= .91) and an increasing heart rate. These two variables are correlated with a negative slope (r2= -.95). The evolutions observed in all variables depend on practice level for accuracy (p<.01), for movement speed (p<.05) and for heart rate (p<.05). Evolution analysis of backward swing and driving phase during exercise shows that main adaptations in kinematics are produced during backward swing (stability of speed profile and of lower rest point). Discussion and Conclusion: Gradually increasing exercise intensity, we can observe in table tennis players a decreasing in performance correlated with increasing in heart rate and mean execution speed. Moreover, adaptation mechanisms depend on practice level: movement speed is coupled to projection rate for regional level players while it proceeds by steps in national level players. Finally, backward swing movement appears to be a fundamental phase for drive movement efficiency. These results, without requiring sophisticated equipments, could help trainers in defining for a given subject the critical intensity and the exercise duration thresholds for which he/she cannot maintain an acceptable level of accuracy. Over these thresholds we can notice compensation movements which prevent players from developing an efficient game. * This study was supported by the French Table Tennis Federation
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