Inter-individual Variability in Responses to 7 Weeks of Plyometric Jump Training in Male Youth Soccer Players.

Rodrigo Ramirez-Campillo,Jason Moran,Cristian Alvarez,Paulo Gentil,Felipe García-Pinillos,Mikel Izquierdo,Alicia M Alonso-Martínez

doi:10.3389/fphys.2018.01156

Abstract

The purpose of this study was to compare the inter-individual variability in the effects of plyometric jump training (PJT) on measures of physical fitness (sprint time, change of direction speed, countermovement jump, 20- and 40-cm drop jump reactive strength index, multiple five bounds distance, maximal kicking distance, and 2.4-km time trial) in youth soccer players who completed a PJT program versus players who completed soccer training only. In a single-blinded study, participants aged between 10 and 16 years were randomly divided into a PJT group (n = 38) and a control group (n = 38). The experimental group participated in a PJT program twice weekly for 7 weeks, whereas the control group continued with their regular soccer training sessions. Between-group differences were examined using a Mann–Whitney U test. Nonresponders where defined as individuals who failed to demonstrate any beneficial change that was greater than two times the typical error of measurement from zero. The results indicated that the mean group improvement for all physical fitness measures was greater (p < 0.05) in the PJT group (Δ = 0.4 to 23.3%; ES = 0.04 to 0.58) than in the control group (Δ = 0.1 to 3.8%; ES = 0.02 to 0.35). In addition, a significantly greater (p < 0.05) number of responders across all dependent variables was observed in the PJT group (from 4 up to 33 responders) than in the control group (from 0 up to 9 responders). In conclusion, compared to soccer training only, PJT induced greater physical fitness improvements in youth soccer players, with a greater number of responders for all the physical fitness tests related to jumping, speed, change of direction speed, endurance, and kicking technical ability.

Highlights

The habitual development of “athleticism” to improve health, enhance physical fitness, reduce the relative risk of injury, and develop the confidence and competence of youths is relevant in programs for children and adolescents (Lloyd et al, 2014) into the holistic long-term athletic development process in youths
The purpose of this study was to compare the IVRET on measures of physical fitness in youth soccer players who completed Plyometric jump training (PJT) versus players who completed soccer training only
Improvements in jumping height ability may be a relevant aim for soccer players, since a greater jumping ability may be related to a better position in a competitive league (Arnason et al, 2004), and the integration of PJT in the regular training schedules of youth players may be an effective method of enhancing competitiveness

Summary

Introduction

The habitual development of “athleticism” to improve health, enhance physical fitness, reduce the relative risk of injury, and develop the confidence and competence of youths is relevant in programs for children and adolescents (Lloyd et al, 2014) into the holistic long-term athletic development process in youths. The PJT programs have the added advantages of not requiring expensive equipment or large spaces and have been shown to be an enjoyable (Ward et al, 2007) and effective form of training for youth soccer players (Bedoya et al, 2015), inducing physical fitness improvements such as jumping, sprinting, kicking, and change of direction, key traits for soccer (Barnes et al, 2014) These actions might precede most of the goals scored in competitive leagues (Faude et al, 2012) and may correlate with competition success (Arnason et al, 2004). PJT programs have received extensive attention from researchers in recent years (Ramirez-Campillo et al, 2018a)

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