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.

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El objetivo del siguiente trabajo es el de evaluar los efectos de un programa específico de la mejora de la flexibilidad isquiotibial, utilizando la videografía como metodología para el cálculo del ángulo de extensión de rodilla. La muestra ha estado formada por 75 deportistas escolares con un rango de edad de entre 7 y 16 años. Los resultados nos muestran como antes de la intervención sólo un 5% de los casos era considerado flexible (ángulo<20º). Después de la intervención, el porcentaje de flexibles fue del 21% (p=0,002). No obstante, el 47% de los casos había mejorado su flexibilidad. Esta mejora estaba asociada al género (OR niños vs. niñas 3,7 (IC95% 1,04–13,16)), y a la edad (OR 0,78 por año (IC95% 0,62–0,97)), no observándose asociación con las características antropométricas. La intervención practicada fue efectiva, tanto en relación al aumento de casos considerados flexibles, como al número de casos que habían mejorado su flexibilidad. La posibilidad de mejora de la flexibilidad es mayor en los niños y disminuye con la edad. La videografía es un método objetivo para el cálculo del rango de movimiento, hace posible la comparación visual entre dos tests realizados y permite dar un feedback al deportista. The purpose of this study was to investigate the influence of a hamstring stretching program, using videography as the methodology to calculate knee extension range of motion. 75 scholar football players, between 7 and 16 years old, were evaluated. 5% (angle <20º) of the subjects had hamstrings flexibility limitation before the stretching program and 21% (p=0,002) of the total population had flexibility limitations after the program conclude. Nevertheless, 47% of subjects showed increases in their flexibility between first and second assessment. The improvement of flexibility is gender (OR boys vs. girls 3,7 (IC95% 1,04–13,16)) and age (OR 0,78 per year (IC95% 0,62–0,97)) correlated. No association was found with anthropometric characteristics. The stretching program was successful for the improvement of hamstrings flexibility. Boys have greater possibility to improve flexibility and it decreases in relation with age. Videography is an objective methodology to analyze range of movement, allows the visual comparison between tests and gives a feedback to the subject.