Seasonal Changes of Jumping Performance and Knee Muscle Strength in Under-19 Women Volleyball Players (original) (raw)

2013, Journal of Strength and Conditioning Research

Rousanoglou, EN, Barzouka, KG, and Boudolos, KD. Seasonal changes of jumping performance and knee muscle strength in under-19 women volleyball players. J Strength Cond Res 27(4): 1108-1117, 2013-The purpose of the study was to compare the seasonal changes (preparation period [PP] and competition period [CP]) of vertical jumping performance and knee muscle strength in a team of under-19 women volleyball players (N = 12, 16.2 6 1.5 years). The countermovement jump was used to evaluate jumping performance. The isometric knee extension moment at 150 ms from the onset of contraction (T 150 ) and at a maximum of contraction (T MAX ) were determined at 9 knee angles (from 108 to 908, full knee extension = 08). The peak isokinetic knee extension (T ISOK-EXT ) and flexion (T ISOK-FLEX ) moment were determined at 60, 180, and 2408$s 21 . Repeated-measures analysis of variance was applied to the differences between PP and CP (p # 0.05). Significant increases in jumping performance were found for jump height, peak impulse, total impulse, peak power, and takeoff velocity (p # 0.05). At the knee flexion angles from 408 to 908, T 150 was significantly increased (p # 0.05), whereas the increase was not significant at the rather extended knee angles of 108, 208, and 308 (p . 0.05). Only at 908 of knee flexion (p # 0.05), T MAX was significantly increased. With the exception of T ISOK-FLEX at 608$s 21 (p # 0.05), the increases of T ISOK-EXT and T ISOK-FLEX were not significant (p . 0.05). The T ISOK-EXT /T ISOK-FLEX ratios were not significantly changed (p . 0.05). The main application of the study is that it provides performance standards and potential criteria for variable selection for jumping performance and knee muscle strength seasonal evaluation.