Genetic Influences on Individual Differences in Exercise Behavior during Adolescence

Figure 1

Univariate liability threshold model for twin data. Exercise behavior was measured with 3 categories (hence 2 thresholds are estimated). The total variance in liability is one and is modeled as caused by latent factors A (additive genetic influences), C (common or shared environment) and E (unique environment). The square of path coefficients a, c, and e gives the variance due to A, C and E.