ABSTRACT
Physical activity (PA) is a broad concept containing a variety of different human behaviors that share the common denominator of expected beneficial effects on mental and somatic health. PA behaviors appear to “run in the family,” for example, the chance of one family member being a regular exerciser increases the chance of all other family members to be, or to become, an exerciser. Familial aggregation of PA can be investigated by computing correlations among relatives such as siblings, and parents and their offspring. In the final set of 27 adult twin studies, we encountered a large variation in measurement instruments and PA measures used. By far the largest common denominator was the use of survey-based methods using subjective PA reporting on self or family members. In large population-based twin registries, surveys are often considered the only feasible strategy.
