Bigelow EMR, et al. - In view of previous work showing associations between remodeling and external bone size, researchers tested the premise that wide bones would show a greater negative correlation between whole-bone strength and age vs narrow bones. Using height-adjusted robustness, cadaveric male radii were assessed biomechanically and samples were sorted into narrow and wide subgroups. The divergent strength–age regressions indicated that narrow radii maintained low resistance with aging by increasing external size and mineral content to mechanically offset porosity increases. The significant negative strength–age correlation for wide radii suggested that changes in outer bone size or mineral content did not offset the deleterious effect of higher porosity further from the centroid. The low strength of elderly male radii, therefore, arose through various biomechanical mechanisms. Taking into account different regressions of the strength-age (trajectories) can inform clinical decisions on how best to treat people to reduce the risk of fracture.