Effects of fatigue induced by repeated-sprint on kicking accuracy and velocity in female soccer players.

Víctor Torreblanca-Martínez,José A Gonzalez-Jurado,Fernando M Otero-Saborido,Fabio Nevado-Garrosa,Moacir Marocolo

doi:10.1371/journal.pone.0227214

Víctor Torreblanca-Martínez, José A Gonzalez-Jurado + Show 3 more

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https://doi.org/10.1371/journal.pone.0227214

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Abstract

The aim of this study was to investigate the effects of fatigue induced by repeated sprint in the kicking accuracy and velocity in female soccer players. Eighteen Under-23 female soccer players from a Spanish professional club were subjected to a fatigue protocol based on a repeated-sprint ability (RSA) test. Measurements of the kicking velocity (maximal ball velocity) and accuracy (Loughborough Soccer Shooting Test) were taken before and after fatigue induction. Correlations between the change in the maximal ball velocity/accuracy and the heart rate (HR), the fatigue index (FI), the sprint decrement (Sdec) and the rating of perceived exertion (RPE) were made. There was a significant difference between maximal ball velocity under fatigue conditions with respect to non-fatigue conditions (p = 0.001; ES = 0.89). However, despite a lower kicking accuracy punctuation with fatigue, this was not statistically significant (p = 0.433; ES = 0.22). Significant correlations were found between the maximal kicking velocity and the FI (r = 0.632, p < 0.01) and the Sdec (r = -0.554, p < 0.05) and between the kicking accuracy and the RPE (r = -0.506, p < 0.05). In conclusion, there was a significant reduction in the maximal kicking velocity, but not in the kicking accuracy, under fatigued conditions. The RSA-related FI and Sdec were the best predictors of the maximal kicking velocity and the RPE for the kicking accuracy.

Highlights

Kicking is the most widely studied soccer skill [1], as it is the defining action in the game [2], with 80.69% of goals being scored by means of this action [1]
We found different measurements to ensure the presence of fatigue when the player kicks under fatigue conditions in the previously described protocols, such as the heart rate [5,6,7,8,9,10,12,16], the rate of perceived exertion (RPE) [5,7,12,16], or the blood lactate [5,7,8,12]
High fatigue values are achieved after the fatigue protocol, with an average in the final heart rate of 178.61 beats per minute, a score of 15.22 in the rating of perceived exertion (RPE) Borg’s scale and a decrement in repeated-sprint ability (RSA) performance, showing an fatigue index (FI) in RSA of -12.52% and an sprint decrement (Sdec) in RSA of -6.53%

Summary

Introduction

Kicking is the most widely studied soccer skill [1], as it is the defining action in the game [2], with 80.69% of goals being scored by means of this action [1]. Maximal ball velocity and accuracy have been the most studied variables related to the kicking action, with studies on the effects of diverse exercise protocols in both factors [5], such as match simulations [5], circuits [6,7,8,9], running on a treadmill at different intensities [10,11], incremental tests [12], squats [13], countermovement jumps [14], knee flexion and extension. A large number of fatigue protocols are found, which makes it difficult to interpret the results of this concerning the kick and the capacity to generate fatigue; in some cases, the physiological demands of the game are not faithfully reproduced [5]. We found different measurements to ensure the presence of fatigue when the player kicks under fatigue conditions in the previously described protocols, such as the heart rate [5,6,7,8,9,10,12,16], the rate of perceived exertion (RPE) [5,7,12,16], or the blood lactate [5,7,8,12]

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