In vivo tibia deformation regimes and strain distribution during different locomotive activities

Bones’ structure and strength are highly regulated in response to local bone strains, caused by muscle and inertial loading during movement. In order to examine the osteogenic stimulus provided by different habitual activities and exercises we measured human tibia deformation in vivo using motion capturing and analyzed that data with individualized finite element models. This technique opens up a novel, mechanically robust approach to bone strains. Results demonstrate that bone strains are substantially greater than previously thought, in particular in the distal tibia, and especially during hopping, where they are up to two thirds larger compared to running or walking. These findings challenge the idea of a single mechanostat with fixed set-value. Regardless, the regular performance of high-impact movements combining regional muscle contractions and inertial loading – whether through everyday physical activity or targeted exercise interventions - is key to maintenance of optimum bone strength.