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 [Ucol] 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 (RJMCT) (12%, ES=-0.35, P<0.05) and dehydration status increases (BM reductions -2.7%, ES=0.24, P<0.001; Ucol: 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 Ucol and the RJMJH 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 (Ucol) and the RJMJH post-TMR combined with the runners' chronological age seemed to be good predictors of the final running performance.

Efecto de los pantalones compresivos en la amplitud articulary el rendimiento en el salto vertical / Compression shorts effects in the hip range of motion and in vertical jump

Objetivo: Este estudio pretende determinar si la compresión provoca cambios mecánicos en el movimiento y se producen incrementos del rendimiento deportivo. Material y métodos: Participaron en el estudio 8 sujetos de sexo masculino ([mediana ± DE] edad: 25,6 ± 10,3 años, talla: 177,9 ± 2,9 cm, peso: 71,9 ± 7,4 kg). Se evaluó la amplitud articular pasiva mediante tres pruebas: Thomas, Ridge y flexión de cadera con la pierna estirada, y la amplitud articular activa durante el salto vertical. Los valores del ROM fueron determinados utilizando un sistema de videografía 2D. La altura del salto y la fuerza máxima realizada durante la impulsión se utilizaron para comparar el rendimiento. Cada una de las pruebas se realizó utilizando pantalones de compresión (tejido indesmallable por urdimbre, 57% poliamida y 43% elastómero), mallas de lycra convencionales y ropa interior como caso control, mediante un método aleatorio balanceado. Resultados: No se observaron diferencias significativas entre las tres condiciones en los dos parámetros de rendimiento. En cambio, se observó que la compresión limita significativamente la amplitud articular de la cadera, disminuyendo la extensión y la flexión máxima durante la valoración pasiva y la flexión máxima durante la valoración activa. Conclusiones: Los pantalones compresivos actúan en la misma línea que los vendajes funcionales, no varían el rendimiento de la actividad deportiva pero restringen la movilidad de las articulaciones afectadas por la compresión. Esta limitación puede tener efectos profilácticos al prevenir lesiones cuando se excede súbitamente el límite articular individual(AU)

Objective: The purpose of this study was to asses whether compression affects movement mechanics and increases sport performance. Material and methods: Eight subjects participated in the study ([mean±SD] age: 25.6±10.3 years, height: 177.9±2.9cm, weight: 71.9±7.4kg). Passive range of movement was evaluated by means of Thomas, Ridge and hip flexion with straight leg tests. The active range of movement was assessed during vertical jump. Values were determined using 2D analysis. Jump height and peak force applied during impulse phase were used for performance comparison. Tests were performed in three different conditions, using compression shorts (warp knitted fabric 57% Polyamide and 43% Elastan), standard lycra shorts and underwear as a control using a balanced, randomised design. Results: There were no significant differences between the three conditions in the performance parameters, whereas compression significantly limited the hip range of motion (ROM) during either passive or active evaluations. Conclusions: Compression garments act as functional bandages, allowing normal functional movement but restricting ROM. These limitations could have prophylactic effects, preventing injuries when suddenly exceeding the limit of individual joints(AU)

Vertical jump assessment on volleyball: a follow-up of three seasons of a high-level volleyball team.

This is a longitudinal descriptive study whose purpose is to assess the physical state of male volleyball players competing at the international level, comparing their jump heights during 3 different seasons. National team sample relies upon trainer decisions, and it was different every season. There were 23, 15, and 13 players in the first, second, and third years, respectively. Subjects underwent a vertical test protocol consisting of rocket jump, squat jump (SJ), countermovement jump (CMJ), CMJ with arms (CMJa), and spike jump (DJb) at the preparation period of the national team season. In 2007, an extra evaluation was performed during the competitive period. A contact mat was used for the assessment. An increase of jump height was observed over the years, with SJ and DJb increasing significantly (FSJ = 5.4; FDJb = 4.7; p < 0.05). The elasticity index decreased significantly between 2007 and 2008 (FEI = 8.5; p < 0.05), whereas arm utilization index and approach index increased, but this increase was not statistically significant. A significant increase in SJ and DJb was also observed between the 2 tests performed in 2007, whereas a nonsignificant increase was observed for CMJ and CMJa. The results indicate a better performance of explosive strength, elastic-explosive strength, and reflex-elastic-explosive strength and a better use of arms during jumps.