relationships with health outcomes have been established more firmly in youth.

Limitations of the studies reviewed include that studies were not designed to answer questions about the relationship between the fitness tests studied and health, that interventions were inadequate, or that confounders were not considered. Although effects of age, gender, body composition, maturation status, and ethnicity on performance on the various tests have been suggested in the past, this review provided insufficient data for assessing the influence of such modifiers.

For school and other educational settings, administrators should consider the handgrip strength and standing long jump tests, as well as alternative tests that have not yet been shown to be related to health but are valid, reliable, and feasible. The modified pull-up and the push-up are possible alternatives for measuring upper-body musculoskeletal strength and power. The curl-up could also be considered for measuring an additional construct, core strength.

In the absence of criterion-referenced cut-points (cutoff scores) for youth or adults, interim cut-points corresponding to the lower percentile limit (20th percentile) should be used for tests of musculoskeletal fitness, analogous to the cut-points for cardiorespiratory endurance, until better evidence for criterion-referenced health-related cut-points is established by further research.

The functions and capacities of the neuromuscular and musculoskeletal systems play important roles in defining the physical fitness status of individuals and populations. Assessment of musculoskeletal fitness has traditionally included assessment of muscle strength, muscle endurance, flexibility, and bone health (Bouchard et al., 2007). With increasing interest in and study of the role of muscle power in the elderly, it is likely that muscle power will emerge as another important characteristic of musculoskeletal fitness worthy of inclusion in future youth fitness assessments (Ashe et al., 2008; Bonnefoy et al., 2007; Reid and Fielding, 2012).

This chapter addresses musculoskeletal fitness (muscle strength, endurance, and power) as it relates to health markers in youth; the flexibility component of musculoskeletal fitness is considered in Chapter 7. The committee’s recommendations for selection of musculoskeletal fitness tests are based primarily on an extensive review of the literature provided by the Centers for Disease Control and Prevention (CDC). The CDC search strategy and data extraction procedures are described in Chapter 3. To

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