Limb bone response to exercise training in High Runner (HR) mice

Physical activity is a primary determinant of musculoskeletal health in vertebrates. The amount and intensity of exercise activity can impact bone morphology and density, muscle fiber type, and the material properties of passive elastic tissues such as tendon and ligaments. To further investigate the role of exercise intensity and duration on bone remodeling, we examined the effects of exercise in a unique model, a line of mice selectively bred for high voluntarily wheel running (high runner, HR) for over 90 generations. We placed HR and control line mice in cages equipped with data logging wheels for a minimum of 9-10 week training periods. Morphometric data collected from humera and femora revealed that exercised mice tended to have shorter, thinner limb bones regardless of genotype. HR mice had longer and thicker femora than control mice, but no significant morphological differences were apparent in humera. Distal femora width correlated with frequency of wheel running, and as HR mice outran control line mice threefold (in average revolutions/day) there was a significant interaction of genotype and exercise intensity. Our data support that the intensity and frequency of running impact limb bone morphology, and that hindlimbs are more responsive than forelimbs both to loading and selective breeding. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.