What you must do to keep your muscles and bones healthy:  

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To have strong bones and promote the growth of them, you have to take foods with calcium, such as milk and its derivatives, to strengthen the muscles you need meat and fish, vitamin D, avoid smoking and do not drink alcoholic beverages.  

With physical exercise you get muscles that have electricity and strength, but you have to be very careful, you have to prepare before practicing any sport or type of gymnastics and stay well informed about the type of training required, as well as the necessary equipment to practice it.  

We must take care of the postures when sitting down so as not to deform the spine, when we are going to lift a heavy object from the floor, we must first think about the knees so as not to load the back.