The second most frequently assessed relationship in the committee’s review was between muscle strength and power measures and bone health outcomes. Four studies provide indirect evidence of positive associations between measures of upper-body (i.e., the handgrip, shoulder flexion and extension, biceps curl, chest fly), trunk (i.e., chest press), and lower-body (i.e., knee-quadriceps extension, hamstring curl, squat, long jump) strength and power using a variety of skeletal measures (i.e., total-body, lumbar spine, femoral neck, and proximal femur bone mineral content [BMC] or bone mineral density [BMD]), mainly in normal pre- and pubertal/menarcheal girls of normal weight (Heinonen et al., 2000; Kontulainen et al., 2002; Morris et al., 1997). A single study by van der Heijden and colleagues (2010) was the only one to investigate this relationship in both sexes in obese peripubertal youth. Only two high-quality studies provide direct evidence of a relationship between musculoskeletal strength and bone health. Witzke and Snow (2000) demonstrated a positive link between changes in knee extensor isokinetic strength and changes in trochanter BMC in menarcheal adolescent girls. Nichols and colleagues (2001) report a positive link between measures of bench press and leg press strength and femoral neck BMC/BMD in a small sample of five menarcheal girls. Few studies have investigated this relationship in boys and youth in early to middle childhood.
Only four high-quality studies investigated the relationship between musculoskeletal fitness and markers of metabolic health in youth (Benson et al., 2008; Janz et al., 2002; Shaibi et al., 2006; van der Heijden et al., 2010). These studies involved exclusively overweigh/obese youth of both sexes ranging in age from late childhood to late adolescence. One of these studies provides associational evidence of a link between multiple measures of upper-body (i.e., biceps curl, fly), trunk (i.e., chest press), and lower-body (i.e., hamstring curl, quadriceps extension, squat) muscle strength and hepatic insulin sensitivity and glucose production (van der Heijden et al., 2010). Another provides more direct evidence of a link between bench press (i.e., trunk) and leg press (i.e., lower-body) strength and improved insulin sensitivity in overweight adolescent boys (Shaibi et al., 2006).
Two high-quality studies provide indirect evidence for a link between musculoskeletal fitness and cardiorespiratory health markers in youth (Janz