Effects of a trail mountain race on neuromuscular performance and hydration status in trained runners

BACKGROUND: The aims of this study were to examine the effects of a trail mountain race (TMR) on hydration status and neuromuscular performance of recreational trail runners, and to determine the relationship among these parameters, subject's characteristics and competitive performance. METHODS: Thirty-five male recreational trail runners (age 38.1 +/- 9.5 years; height 177.3 +/- 5.8 cm; body mass 73.8 +/- 8.4 kg) were assessed before and after a 21.1-km TMR. Hydration status (urine color [U-col] and body mass [BM]) and neuromuscular performance (countermovement jump [CMJ] and rebound jumps [RJ]) were assessed. RESULTS: Significant changes following the TMR included RJ mean contact time (RJ(MCT)) (12%, ES=-0.35, P<0.05) and dehydration status increases (BM reductions -2.7%, ES=0.24, P<0.001; U-col: 147% increase, ES=-1.8, P<0.001). Low to moderate positive correlations were found between pre- and post-TMR BM (r=0.5-0.54; P<0.01), post-race Ucol (r=0.37; P<0.05), age (r=0.57; P<0.01) and TMR performance. Participants' age combined with U-col and the RJ(MJH) post-TMR, explained 65% of the variance in the final running time (r=0.81; P=0.000). CONCLUSIONS: Participation in a 21.1-km TMR in recreational runners results in small reductions of the neuromuscular function and increases in dehydration levels. The hydration status (U-col) and the RJ(MJH) post-TMR combined with the runners' chronological age seemed to be good predictors of the final running performance.