Correlates of upper and lower body muscular strength in children

Milliken, LA, Faigenbaum, AD, Loud, RL, and Westcott, W. Correlates of upper and lower body muscular strength in children. J Strength Cond Res 22:1339-1346, 2008-Despite the widespread use of and acceptance of muscular fitness field tests in national youth fitness test batteries, little is known about how these field tests compare to 1 repetition maximum (1 RM) strength in children. Therefore, the aim of this study was to characterize and identify correlates of muscular strength in children 7 to 12 years of age. Ninety children (39 girls and 51 boys) between the ages of 6.7 and 12.3 years volunteered to participate in this study. Children were tested on 1 RM chest press (CP) strength, 1 RM leg press (LP) strength, handgrip strength, vertical jump, long jump, sit and reach flexibility, and height and weight (used to determine body mass index [BMI]). For the combined sample, LP 1 RM ranged from 75% to 363% of body weight and CP 1 RM ranged from 25% to 103% of body weight. Multiple regression analyses predicting LP 1 RM showed that BMI and long jump were significant (R² = 44.4% with age and gender not significant) and BMI and vertical jump were significant (R² = 40.8% with age and gender not significant). Multiple regression analyses predicting CP 1 RM showed that BMI and handgrip strength were significant (R² = 58.6% with age and gender not significant). Age and gender alone accounted for 4.6% (not significant) of the variation in LP 1 RM and 15.4% (significant) in CP 1 RM. In summary, these data indicate that BMI, handgrip strength, long jump, and vertical jump relate to 1 RM strength in children and therefore may be useful for assessing muscular fitness in youths.