NON-HIP FRACTURE COMPARISON. Bone loss that occurs in older women is believed to result from uncoupling of bone remodeling. Despite the loss of BMD with aging, the cellular mechanisms for fracture healing appear to remain intact. Fracture healing can be divided into three phases: inflammatory, reparative, and remodeling. The first two phases are dependent primarily on the local trauma effects of the fracture and are completed within approximately five weeks; hence, exercise intervention would be expected to have little or no effect on these processes. The remainder of the approximately six-month duration of femoral neck fracture healing involves modeling and remodeling of the callus. Because skeletal loading may modulate remodeling, exercise should have an effect during this period. Even after completion of healing, mechanical factors are expected to continue to affect remodeling of the femur. Bone resorption, mediated by osteoclastic activity, is the first phase of a remodeling cycle. In the post-fracture context, in which both fracture debris removal and callus remodeling are ongoing, high levels of markers of resorption would be anticipated.