That's to increase endurance and keep the heart healthy. I encourage people to move slowly, not throw the weights around. Moving the weights slowly and fully through the range of motion is what helps to make strength gains. To prevent osteoporosis Studies have shown that participating in weight-bearing exercise such as walking or jogging can help reduce the risk of developing osteoporosis, a disease in which the bones become brittle and fragile. When you're walking, for example, the bones are taking the stress of every step you take.
Weight training is still very important, however.
Walking, for example, does not strain the bones of the arms or the neck. Strength training is helpful because you can target more of the skeleton. When you move a weight through the range of motion, the tendons are stretching against the resistance of the bones. That strengthens them. Aim for a program that incorporates at least 20 minutes of walking three to five days a week, along with a strength training program that includes one set of 8-12 repetitions of exercises for the arms, back, shoulders, abdominals and legs.