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Children are more susceptible to central fatigue than adults

Authors

  • Vytautas Streckis PhD,

    1. Laboratory of Human Motorics, Department of Physiology and Biochemistry, Lithuanian Academy of Physical Education, Kaunas, Lithuania
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  • Albertas Skurvydas PhD,

    1. Laboratory of Human Motorics, Department of Physiology and Biochemistry, Lithuanian Academy of Physical Education, Kaunas, Lithuania
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  • Aivaras Ratkevicius PhD

    Corresponding author
    1. Laboratory of Human Motorics, Department of Physiology and Biochemistry, Lithuanian Academy of Physical Education, Kaunas, Lithuania
    2. School of Medical Sciences, College of Life Sciences and Medicine, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
    • School of Medical Sciences, College of Life Sciences and Medicine, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
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Abstract

Performance in high-intensity exercise is dependent on the ability to activate motor units. The main aim of this study was to test the hypothesis that adult men and women (age 19–27 years) are able to maintain higher levels of voluntary activation (VA) in knee extensor muscles than boys and girls (age 12–14 years). The volunteers (n = 7 in each group) performed three 5-s maximal voluntary contractions (MVCs) and a continuous 2-min MVC. The VA and fatigue of the muscles was assessed by applying 250-ms 100-HZ test tetani (TT100HZ). During brief MVCs girls showed lower VA than women, but the difference between boys and men was not significant. During the 2-min MVC, VA in boys and girls was more depressed than in adults. The end-exercise values of the relative TT100HZ torque correlated with the average VA during the exercise. Thus, the results of the study support the hypothesis that children are more susceptible to central fatigue than adults. This should be taken into account when evaluating results of fitness tests that require high levels of motor unit activation. Muscle Nerve, 2007

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