Fabre, Jean-Bernard Martin, Vincent Gondin, Julien Cottin, Francois Grelot, Laurent Comparative Study United States Medicine and science in sports and exercise Med Sci Sports Exerc. 2012 Nov;44(11):2182-9. doi: 10.1249/MSS.0b013e3182618cf9. ; PURPOSE: The aim of this study was to evaluate the effect of the playing surface properties on the development of neuromuscular fatigue in tennis. METHODS: 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). RESULTS: 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