Exercise is truly the fountain of youth. However, all exercise is not created equal. It is important that the exercises you choose are done with good form and within your physical limits. It can be tempting when you are working out with others to try to equal their efforts and do exercises that are not a good match for your body type. If you are starting a new exercise program, you may benefit from working, at least for a while, with a certified trainer to learn correct form in order to prevent back injury.