that, perhaps as a result of the recent emphasis on physical activity, many of the studies reviewed were not designed to assess the independent association between performance on a fitness test and a health marker or risk factor. This is a fundamental but crucial point that determined the value of studies for the committee’s work. Studies also would have been more valuable had they accounted for the effects of various modifying factors. Although not included in the Centers for Disease Control and Prevention’s (CDC’s) search strategy, studies predicting health outcomes in adulthood would be valuable as well. For example, selected measures of strength and power track both during adolescence and from adolescence into adulthood. For many test items, however, it remains to be determined whether fitness performance in youth is predictive of health outcomes in later life. In sum, the literature review revealed many gaps in our understanding of the relationship between fitness measures and health. The committee offers the following recommendations for designing and conducting research to address these gaps.

RECOMMENDATION 10-1. Well-designed research studies aimed at advancing understanding of the associations between fitness components and health in youth should be undertaken. Researchers should ensure that the interventions studied are both specific and sufficient (i.e., appropriate dosage and duration) to induce a change in fitness. In addition, studies should be designed so that the effect of potential confounders (e.g., nutrition, physical activity, demographic variables, maturity status) and the potential for adverse events can be analyzed.

RECOMMENDATION 10-2. Longitudinal studies should be conducted to provide empirical evidence concerning how health markers related to fitness track from youth into adulthood.

RECOMMENDATION 10-3. Randomized controlled trials and longitudinal studies should be undertaken to understand the following issues regarding the relationships between (1) specific fitness tests and health, and (2) fitness components and health:

  • Studies should explore the relationship between body composition measures and physical fitness tests and the potential interactions among body composition, fitness, and health in youth.
  • Studies should examine the relationship between changes in cardiorespiratory endurance as measured by field tests, including the shuttle run and timed and distance runs, and subsequent changes in health risk factors in youth beyond weight status and cardiometabolic risk factors. Examples include bone health and neurocognitive function and behavior.

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