RESEARCH ARTICLE


Effects of Different Practice Task Constraints on Fluctuations of Player Heart Rate in Small-Sided Football Games



R. Duarte1, 2, *, D. Araujo2, O. Fernandes1, B. Travassos2, 3, H. Folgado1, A. Diniz2, K. Davids4
1 Department of Sport and Health, University of Évora, Portugal
2 Faculty of Human Kinetics, Technical University of Lisbon, Portugal
3 University of Beira Interior, Portugal
4 School of Human Movement Studies, Queensland University of Technology, Australia


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Creative Commons License
© 2010 Duarte et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: https://creativecommons.org/licenses/by/4.0/legalcode. This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Department of Sport and Health, University of Évora, Portugal; Tel: 00351214196777; Fax: 00351214144712; E-mail: rduarte@fmh.utl.pt


Abstract

This paper analyzes effects of different practice task constraints on heart rate (HR) variability during 4v4 smallsided football games. Participants were sixteen football players divided into two age groups (U13, Mean age: 12.4±0.5 yrs; U15: 14.6±0.5). The task consisted of a 4v4 sub-phase without goalkeepers, on a 25x15 m field, of 15 minutes duration with an active recovery period of 6 minutes between each condition. We recorded players' heart rates using heart rate monitors (Polar Team System, Polar Electro, Kempele, Finland) as scoring mode was manipulated (line goal: scoring by dribbling past an extended line; double goal: scoring in either of two lateral goals; and central goal: scoring only in one goal). Subsequently, %HR reserve was calculated with the Karvonen formula. We performed a time-series analysis of HR for each individual in each condition. Mean data for intra-participant variability showed that autocorrelation function was associated with more short-range dependence processes in the “line goal” condition, compared to other conditions, demonstrating that the “line goal” constraint induced more randomness in HR response. Relative to inter-individual variability, line goal constraints demonstrated lower %CV and %RMSD (U13: 9% and 19%; U15: 10% and 19%) compared with double goal (U13: 12% and 21%; U15: 12% and 21%) and central goal (U13: 14% and 24%; U15: 13% and 24%) task constraints, respectively. Results suggested that line goal constraints imposed more randomness on cardiovascular stimulation of each individual and lower inter-individual variability than double goal and central goal constraints.

Keywords: Task constraints, time-series analysis, fluctuations.