Genetic architecture of motives for leisure-time physical activity: a twin study.
Level 4 - case-series / case-control
Cross-sectional twin study analyzed via structural equation modeling (Level 4 by observational design analogy)
PubMed 27704630 · doi:10.1111/sms.12779
What was done
Researchers assessed motives for leisure-time physical activity in 2,542 twin individuals (mean age 34.1 years) from the FinnTwin16 cohort using a modified version of the Recreational Exercise Motivation Measure. Linear structural equation modeling was used to estimate the relative contributions of genetic and environmental influences across motive dimensions.
What was found
Heritability was highest for enjoyment (men: 33% [95% CI 23–43%], women: 53% [95% CI 45–60%]) and affiliation (men: 39% [95% CI 28–49%], women: 35% [95% CI 25–43%]). The lowest heritability was for others' expectations (men: 13% [95% CI 4–25%], women: 15% [95% CI 7–24%]). Summary heritability estimates for intrinsic and extrinsic motives were 36% and 32% for men, and 40% and 24% for women, respectively. Unique environmental influences explained the remaining 47% to 87% of the variance.
Why it matters
This study shows that while biology moderately predisposes individuals toward certain physical activity motives (especially enjoyment in women), unique environmental factors account for the majority of variance, suggesting motives are largely modifiable.
Limits
The findings rely solely on self-reported questionnaires, and measurement error is aggregated into the unique environmental variance. The sample is restricted to young-adult Finnish twins, limiting generalizability to other ages, ethnicities, and cultural contexts. Actual physical activity volume was not reported.
Cited by
- supports Individual differences in exercise enjoyment, pain tolerance, and muscle damage recovery have measurable genetic bases.