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

Abstract

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 ± 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 (T150) and at a maximum of contraction (TMAX) were determined at 9 knee angles (from 10° to 90°, full knee extension = 0°). The peak isokinetic knee extension (TISOK-EXT) and flexion (TISOK-FLEX) moment were determined at 60, 180, and 240°·s. 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 40° to 90°, T150 was significantly increased (p ≤ 0.05), whereas the increase was not significant at the rather extended knee angles of 10°, 20°, and 30° (p > 0.05). Only at 90° of knee flexion (p ≤ 0.05), TMAX was significantly increased. With the exception of TISOK-FLEX at 60°·s (p ≤ 0.05), the increases of TISOK-EXT and TISOK-FLEX were not significant (p > 0.05). The TISOK-EXT/TISOK-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.

The effect of the prolonged competitive season on semi-elite female volleyball players’ physical performance

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Profiling the Isokinetic Muscle Strength of Athletes Involved in Sports Characterized by Constantly Varied Functional Movements Performed at High Intensity: A Cross‐Sectional Study

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Potencia del salto en jugadores de fútbol sala después de la utilización del rodillo de espuma y la facilitación neuromuscular propioceptiva en la musculatura isquiosural

“…Esto se debe, en gran parte, a que las técnicas de estiramiento utilizadas con el rodillo de espuma y de facilitación neuromuscular propioceptiva mejoran el ciclo de estiramiento -acortamiento, activando el reflejo miotático, lo cual ayuda a aprovechar la energía elástica, es decir, la capacidad que tiene el músculo para almacenar energía durante el estiramiento y utilizarla en una posterior contracción o acción de potencia (Belmonte-Férez, 2015). Por esta razón, los valores de la RMS disminuyeron después de la intervención, ya que los músculos isquiosurales necesitaron una menor activación para generar una actividad explosiva, aumentando la potencia media de los músculos involucrados en el salto vertical sin ocasionar un mayor gasto energético (Rousanoglou, et al, 2013).…”