Exercise-induced strain and strain rate in the distal radius

Strains applied to bone can stimulate its development and adaptation. High strains and rates of strain are thought to be osteogenic, but the specific dose response relationship is not known. In vivo human strain measurements have been performed in the tibia to try to identify optimal bone strengthening exercises for this bone, but no measurements have been performed in the distal radial metaphysis, the most frequent site of osteoporotic fractures. Using a strain gauged bone staple, in vivo dorsal metaphyseal radial strains and rates of strain were measured in ten female patients during activities of daily living, standard exercises and falls on extended hands. Push-ups and falling resulted in the largest compression strains (median 1345 to 3146 microepsilon, equivalent to a 0.1345% to 0.3146% length change) and falling exercises in the largest strain rates (18582 to 45954 microepsilon/s). On the basis of their high strain and/or strain rates these or variations of these exercises may be appropriate for distal radial metaphyseal bone strengthening.