Effect of Playing Surface Properties on Neuromuscular Fatigue in Tennis

The aim of this study was to evaluate the effect of the playing surface properties on the development of neuromuscular fatigue in tennis. Ten subjects played randomly two tennis matches on hard court (HARD) and clay court (CLAY) for an effective playing duration of 45 min (i.e., corresponding approximately to a 3-h game). Before and after each match, the maximal voluntary contraction (MVC) force of the plantar flexors, the maximal voluntary activation level, the maximal compound muscle action characteristic, and the EMG activity were determined on the soleus (SOL) and lateralis gastrocnemius (LG) muscles. Tetanic and single stimulations were also delivered to evaluate the presence of low-frequency fatigue and contractile impairment. Finally, reflex responses were evoked on the relaxed muscle (H-reflex) and during MVC (H-reflex and V-wave). Statistical analysis did not reveal any significant difference between playing surfaces. MVC was similarly reduced after the game (HARD, -9.1% ± 8.7%; CLAY, -4.3% ± 19.9%) and was associated with alterations of the contractile properties of the plantar flexor muscles. The implication of central factors was less clear, as evidenced by the significant reduction (P < 0.05) of the H-reflex on the relaxed LG (HARD, -16.2% ± 33.3%; CLAY, -23.9% ± 54.0%) and SOL (HARD, -16.1% ± 48.9%; CLAY, -34.9% ± 35.9%) and the nonsignificant reduction of the activation level. In addition, the reflex responses evoked during MVC were not significantly modified by the exercise. These results suggest that the ground surface properties influence neither the extent nor the origin of neuromuscular fatigue in tennis. The moderate force decrement observed in the current study was mainly associated with peripheral fatigue.