Stability of internal response and external load during 4-a-side football game in an indoor environment

Abstract

Background: Small-sided games (SSG) are spontaneous forms of specific training where exercise intensity can be manipulated mainly by modifying external factors. When using the SSG, there is a risk that the variability of intensity between players and on repetition of SSG may lead to some players training at inappropriate exercise intensities. Objective: The purpose of this study is to determine intra-individual repeatability and inter-individual variability in exercise intensity in small-sided 4on4 football games. Methods: Twenty five highly trained junior football players (age 17.68 ± 1.52 years; BMI 23.8 ± 1.92 kg . m-2) participated in the study. Distance covered (software package Video Manual Motion Tracker 1.0) and heart rate (HR, expressed as a percentage of peak heart rate) were measured. All participants completed three measurements of 4-a-side games for three consecutive weeks. Results: The high intraclass correlation coefficient value (Heart rate [HR]: ICC = .88, 95% CI [.65, .94]; Distance covered [DC]: ICC = .76, 95% CI [.66, .96]) implies a very high level of intra-individual repeatability. The Pearson's correlation coefficient value (HR: r = .93; DC: r = .85) indicates a high correlation between the results of any measurement. Bland and Altman's 95% limits of agreement were ± 10.32 beats . min-1 and ± 65.46 m of distance covered. Conclusions: The results of this study demonstrated that measured SSG elicit consistent heart rate responses and external load of the players.

Keywords

• time-motion analysis
• heart rate
• reliability