WASHINGTON — THURSDAY, Sept. 27, 2012 (MedPage Today) — Schools' fitness testing and national fitness surveys should include measurements of skinfolds, waist circumference, and body mass index (BMI) to determine body composition, a report stated.
"Each is a proximal estimation of body fat and has increased standard of error over laboratory measures," the Institute of Medicine (IOM) stated in its report, "Fitness Measures and Health Outcomes in Youth." "Moreover, the measurement of body composition is multidimensional; no single measure is considered representative of all body composition tenets for youth of all morphologies."
Also, further study is needed to link certain health markers from youth into adulthood, the IOM concluded in its 224-page report, released Thursday, on assessing the link between childhood fitness tests and health outcomes.
At the request of the Robert Wood Johnson Foundation, the IOM recommended the best fitness test items, provided guidance for interpreting fitness scores, and provided an agenda for needed research in the area. The appointed IOM committee reviewed literature from the CDC on fitness of children ages 5 to 18 during 2000 to 2010.
Public health and youth fitness experts have called for standardizing schools' testing of students' health, the report said.
Hopefully, schools can use the IOM's report to have an evidence-based approach for fitness testing, Russell Pate, PhD, chair of the study committee and professor of exercise science at the University of South Carolina in Columbia, said in a call with reporters Thursday.
Fitness tests have traditionally only included BMI measurements and not skinfolds and waist circumference. However, schools may struggle with training test administrators to correctly measure those body components and ensure student privacy concerns during testing, the IOM said.
Unlike those three body composition measures, schools need not test for flexibility in youth, traditionally done with a sit-and-reach test. "There was a lack of quality longitudinal and experimental studies measuring the association between flexibility and health markers in youth," the report stated.
The progressive 20-meter shuttle run is the best test for cardiorespiratory endurance. "The heart rate extrapolation and progressive shuttle run tests have high validity and reliability," the committee found. The traditionally conducted fitness test of a mile run was not recommended by the IOM.
As a test of musculoskeletal fitness, tests should include the standing long jump and handgrip strength test.
"Studies reviewed show a relationship between performance on these tests and bone health and body composition," the committee stated. "While these tests should not be interpreted in a health context until their relationships with health outcomes have been established more firmly in youth, they can be included for their educational value."
However, other measures of muscular strength such as the modified pull-up or push-up and curl-up could also be used to measure muscular and strength by schools, the IOM found.
The IOM lists a number of recommendations for future research, including:
- Conducting longitudinal studies providing evidence on how health markers relate to fitness from youth into adulthood.
- Conducting randomized controlled trials to determine the relationship between specific fitness tests and health components such as changes in cardiorespiratory endurance and bone health, behavior, and neurocognitive function.
- Developing age- and sex-specific cut points to determine which children are at risk of poor fitness-related health outcomes. Those cut points need to be adjusted for demographics, Pate said. "Intermediate cut points can be used until the ideal data are available."
Measuring fitness in schools and national surveys will generate data to increase our understanding of the importance of physical fitness in youth, the IOM report stated. "Collecting fitness data nationally and in schools helps with setting and achieving fitness goals and priorities for public health at an individual and national level."
Last Updated: 9/27/2012