Although the in vivo tibial loading model has been used to study the bone formation response of mice to exercise, little emphasis has been placed on the translation of architectural and compositional modifications to changes in mechanical behaviour.The goals of the studies discussed below were to investigate the mechanical responsein both healthy and osteolathrytic mice to this loading model and to determine the dose-depended effects of strain level on these properties. In two separately designed studies, strain levels ranging from 1700 to 2400μϵ were applied to the right tibiae of 8 week old female C57BL/6 mice, while the left tibiae were used as non-loaded control. The first study consisted of loading both PBS- and BAPN-injected mice to 1750μϵ which resulted in little bone formation but some tissue-level changes in mechanical analyses and an improvement in fatigue-resistance in terms of microdamage accumulation. The second study loaded healthy mice to three strain levels (1700, 2050, and 2400μϵ ). Results indicated that the low end of the strain range did not engender a robust formation response, while the high end of the strain range resulted in a woven bone response in half of the animals in that group. Future studies will focus on the mid-strain level of 2050μϵ which induced both significant architectural and mechanical improvements.