Evaluation of counter movement jump parameters in young male soccer players

Purpose: The Counter Movement Jump (CMJ) is widely used as a field test to evaluate the muscular explosive power of lower limbs in various sports, including soccer. The aim of the present study was to verify the possibility to discriminate the effect of training level and age on young adult male soccer players, adopting the flight time, the peak force, or the peak power obtained from a countermovement jump. Methods: One hundred and twenty three young male soccer players were enrolled in the study; the participants were split into groups according to Tanner's stages (pre- and post-pubertal) and training level (high and low activity). A piezoelectric force plate was used to acquire the ground reaction force used to calculate the flight time, the peak value of the vertical component of the ground reaction force, and the peak value of the developed power. Results: As expected, the best performances were obtained by the post pubertal highly-trained soccer players. All performance parameters presented statistically significant differences between ages, while only the flight time exhibited statistically significant differences between training levels. After normalization of the experimental data to body height and weight, there were no statistical differences between ages; statistically significant differences were found only for the flight time and for peak power between training levels. Conclusions: The flight time was the parameter more sensitive to detect differences in the jump performance related to training and age. Adopting a normalization procedure it was possible to highlight that only the flight time and the peak power are sensitive to training effects on young adult male soccer players.