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J Sci Med Sport. 2013 Sep;16(5):460-5. doi: 10.1016/j.jsams.2012.10.009. Epub 2012 Dec 12.

Influence of an intensified competition on fatigue and match performance in junior rugby league players.

Author information

1
School of Exercise Science, Australian Catholic University, Brisbane, Queensland, Australia. richard.johnston@acu.edu.au

Abstract

OBJECTIVES:

The aim of this study was to assess the physiological responses to an intensified rugby league competition and explore the relationships between fatigue and match performance.

DESIGN:

Prospective cohort study.

METHODS:

Fifteen junior rugby league players (n=8 forwards, 7 backs; mean±SE, age 16.6±0.2 years; body mass 81.6±3.0kg; and height 178.9±1.8cm) competed in five 40min games over 5 days (two games each on days 1 and 2, one game on day 4, and no games on days 3 and 5). Over the competition, players performed a countermovement jump to assess neuromuscular fatigue, provided a fingertip blood sample to measure blood creatine kinase, and completed a questionnaire to monitor perceived wellbeing; ratings of perceived effort were recorded following each game. Global positioning system and video analysis of each game were used to assess match performance.

RESULTS:

Over the first 3 days, there were progressive and large increases in neuromuscular fatigue which peaked 12h after game 4 (forwards ES=4.45, p=0.014; backs ES=3.62, p=0.029), and muscle damage which peaked 1h post game 4 (forwards ES=4.45, p=0.004; backs ES=3.94 p=0.012), as well as reductions in perceived wellbeing. These measures gradually recovered over the final 2 days of the competition. Compared to the backs, the forwards experienced greater increases in creatine kinase following game 2 (ES=1.30) and game 4 (ES=1.24) and reductions in perceived wellbeing (ES=0.25-0.46). Match intensity, high-speed running, and repeated-high intensity effort bouts decreased in games 4 and 5 of the competition. Small to large associations were observed between the changes in fatigue, muscle damage and match performance, with significant correlations between creatine kinase and repeated high-intensity effort bout number (r=-0.70, p=0.031) and frequency (r=0.74, p=0.002) and low-speed activity (r=-0.56, p=0.029).

CONCLUSIONS:

Fatigue and muscle damage accumulate over an intensified competition, which is likely to contribute to reductions in high-intensity activities and work rates during competition.

KEYWORDS:

GPS; Game intensity; Muscle damage; Neuromuscular fatigue; Team sports

PMID:
23245879
DOI:
10.1016/j.jsams.2012.10.009
[Indexed for MEDLINE]

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