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General Medicine
Children’s fitness and health: an epic scandal of poor methodology, inappropriate statistics, questionable editorial practices and a generation of misinformation
  1. Jo Welsman,
  2. Neil Armstrong
  1. Children's Health and Exercise Research Centre, University of Exeter, Exeter, UK
  1. Correspondence to Dr Jo Welsman, Children's Health and Exercise Research Centre, University of Exeter, Exeter, UK; j.r.welsman2{at}

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A global explosion of research into children and adolescents’ health and cardiorespiratory or aerobic fitness has resulted in a flurry of papers and subsequently systematic reviews revealing apparently worrying but fallacious assumptions such as: (1) aerobic fitness is declining1; (2) aerobic fitness expressed in ratio with body mass reflects present2 and predicts future3 cardiovascular and metabolic health risk; (3) a single sex-specific ‘cut-point’ of aerobic fitness expressed in ratio with body mass identifies children and adolescents who ‘may benefit from primary and secondary cardiovascular prevention programming’, (Ruiz et al p1451)4- the so-called ‘clinical red flags’.

Our serious concerns with these conclusions, despite their basis in large data sets and publication in internationally respected journals, is that they are not founded on rigorous science but on flawed methodology, namely predicting aerobic fitness from the 20 metre shuttle run test (20mSRT)5 and interpreting paediatric fitness data expressed in ratio with body mass.

Problem 1: the 20mSRT is not a valid measure of children’s aerobic fitness

Over 30 years ago6 we demonstrated the poor criterion validity of the 20mSRT or ‘bleep’ test.5 We discounted the test as a research tool not only because of poor statistical validity but because of its dependence on participant motivation and body size, particularly fatness. The 20mSRT was never originally validated against laboratory-determined peak oxygen uptake (Embedded Image) (the internationally …

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