PHYSICAL AND MOTOR FITNESS IN TWINS

Thirty pairs of monozygotic (MZ) and 20 pairs of dizygotic (DZ) twins, of both sexes, were studied to estimate the role of genetic and envir onmental factors determining fitness measurements comprising vital cap acity (VC), vertical jump, flexibility, agility, and PFI score. Intra- pair variances for VC, vertical jump, and heart rate were significantl y smaller (p < 0.05-0.01) in MZ than in DZ twins, where values for fle xibility, agility, and PFI were insignificant. Intra-pair correlations for VC, vertical jump, and heart rate were higher (p < 0.01) in MZ th an in DZ twins where the opposite was found in the case of flexibility and agility. The correlation value for PFI was higher in both MZ and DZ twins. Following adjustment for physical characteristics including age, weight, and height, none of the results of all the residual fitne ss measurements were similar to the unadjusted values. Both unadjusted and residual variables with smaller intra-pair variances showed highe r heritability estimates. These results suggest that VC, vertical jump , and heart rate are influenced more by genetic factors than environme ntal factors where the inverse is true of flexibility, agility, and PF I. Thus, the genetic and environmental influence of all the fitness me asurements, except VC, more or less depend upon physical characteristi cs in this study.