many of the studies reviewed were not designed to assess the independent association between performance on a fitness test and a health outcome or marker. Moreover, while not included in the search strategy, studies predicting health outcomes in adulthood would be valuable in characterizing the importance of a health marker. For example, it remains to be determined whether changes in muscle strength and power during youth are predictive of health outcomes in later life.
The committee offers the following recommendations for designing and conducting research on some of the most pressing questions that must be answered if progress is to continue in selecting the best measures of fitness in youth. It should be noted that the committee is recommending research only for those test items that have been studied well enough to justify their inclusion here. At the same time, it is not the intent of the committee to eliminate from future consideration those test items that currently do not meet the level of evidence necessary for inclusion in a battery of tests.
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: