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Box Jumping: A Bone-Building Exercise for Elementary School Children

O steoporosis, a disease characterized by low bone mass, afflicts over 10 million individuals in the United States (NIH Consensus Development Panel, 2001). The maximum amount of bone mineral accumulated in one's lifetime-peak bone mass-is usually attained by the third decade of life and naturally declines thereafter. While osteoporosis commonly arises in men and women as a result of normal age-related deterioration in bone strength and density, failure to attain maximum peak bone mass may increase the risk of developing osteoporosis sooner than normal (Bachrach, 2001; NIH Consensus Development Panel, 2001). Since low peak bone mass is a primary risk factor for both childhood fractures and osteoporosis (Bachrach, 2001), attaining a higher peak bone mass during growth may be the most effective strategy for promoting lifelong skeletal health (Kemper, 2000). Even though genetic factors account for a large portion of an individual's peak bone-mass potential (Pocok et al., 1987; Seeman et al., 1989), environmental factors such as proper nutrition and regular participation in weight-bearing physical activities may enhance the development of peak bone mass (Bass et al., 1998; Kannus et al., 1995; Slemenda, Miller, Hui, Reister, &Johnston, 1991). This article focuses on the use ofboxjumping exercises as a strategy for increasing peak bone mass. It presents the results of two longitudinal, exerciseintervention studies that demonstrate