“Higher-impact exercise, including running and jumping, is the most important type of activity for building stronger bones -- especially around the time of puberty, according to a research review. The review, which included dozens of studies published since the 1960s, confirms the importance of weight-bearing exercise in bone health across a person's lifespan. Weight-bearing activities, such as running, jumping rope and lifting weights, put the bones under stress. This forces the bones to respond by becoming stronger. In contrast, low-impact exercise, like biking or swimming, works the heart and trims the waistline, but puts little strain on the bones. In the new review, researchers led by Dr. Ron F. Zernicke, of the University of Michigan in Ann Arbor, found that a range of activities appear beneficial for bone mass and strength. Some activities -- like gymnastics, ballet and competitive rope jumping -- have been found to boost young people's bone mass because of the ‘magnitude’ of the stress they place on the bones. In other cases, it's the rate of the stress - as in ‘power’ lifting, which involves quick muscle contractions -- that appears to benefit bone strength, the researchers report in the journal Sports Health.