Resumen de Acute Effects of Static Stretching on Squat Jump Performance at Different Knee Starting Angles
Antonio La Torre, Carlo Castagna, Elisa Gervasoni, Emiliano Cè, Susanna Rampichini, Maurizio Ferrarin, Giampiero Merati
The purpose of this study was to examine the effects of static stretching on leg extensor muscles during squat jump (SJ) at different knee starting angles. Seventeen male subjects (23 ± 3 years, 179 ± 5 cm, and 74 ± 6 kg) performed on a force platform 2 series (preceded or not [control condition] by 10-minute static stretching of quadriceps and triceps surae muscles) of SJs at different knee starting angles: 50°, 70°, 90°, and 110°. Squat jump height, peak force, maximal acceleration, velocity, and power were calculated for each jump. The angle that maximized power development was obtained from the power-angle relationship. The SJ height, peak force, and maximal velocity increased according to angle amplitude in both control and stretching conditions (p < 0.01), performance being significantly lower in the stretching condition (p < 0.01). Peak power was obtained at 90° in both control and stretching conditions, but was significantly lower (p < 0.01) after stretching. These results suggest that an acute bout of static stretching reduces power and force development during SJ, decrements being significantly higher at lower knee starting angles. Therefore, the use of static stretching may be questionable in those power activities requiring maximal power output at knee angles near full extension.
