Validity of field tests of upper body muscular strength

The purpose of this study was to determine the validity of five field tests (FTs) of upper body muscular strength and endurance (UBMSE) in 9-10-year-old children. Ninety-four children (38 boys, 56 girls) performed five FTs of UBMSE: pull-ups, flexed arm hang, push-ups, Vermont modified pull-ups (VMPU), and New York modified pull-ups. They also performed three criterion tests (CTs) of strength and three CTs of muscular endurance using a supported weight, set-resistance device. Zero-order correlations between the sum of the standard scores on the three CTs of strength (SUM1RM) and the FTs were nonsignificant. However, when SUM1RM was expressed relative to body weight (SUM1RM.kg-1), significant (p < .01) correlation coefficients were obtained for each FT. Highest correlations with SUM1RM.kg-1 were observed for the VMPU, and this same test yielded the smallest percentage of zero scores. Principal components analysis of the CTs, normalized for body weight, and FTs yielded a factor on which both the FTs and CTs of strength loaded significantly. These data indicate that the five FTs, though invalid as measures of absolute strength and muscular endurance, manifest concurrent and construct validity as measures of weight-relative muscular strength.