Univariate biometric genetic model for binary measures of physical activity in UWTR same-sex twin pairs.

*ACE refers to a model that includes additive genetics (A), common environment (C), and unique environment (E), AE only includes additive genetics and unique environment, and CE only includes common and unique environment;
†Proportion of variance (and 95% confidence interval) due to additive genetics, shared environment, and unique environment factors according to each model;
‡Akaike's information criterion (AIC) is a global measure of goodness of fit, with the best-fitting and most parsimonious models shown in bold.