While many types of exercise may be beneficial to your health, only a few can increase bone strength. Researchers at Washington University recently studied the effects of both resistance (weight training) and impact training (aerobic exercise, running) on 27 non-active women. Both styles of training put pressure on the skeletal framework, thus provoking a rise in calcium absorption. One group performed only resistance training while the other did only impact training. After nine months, both groups increased bone density by 2 percent. However, those who did only impact training showed a greater increase in the hip, a region more susceptible to fractures with age.