Warming Up Strengthening Exercises As you develop your aerobic fitness, you can start introducing elements of strength training into your exercise program. Good muscle strength can have a marked effect on appearance as it improves the tone and shape of muscles, improves posture and helps prevent lower back problems. Strength training involves activities that require short bursts of power and muscular strength. The following exercises use your own body weight, and are safe and easy to perform. Try and do these three times a week, starting with around five repetitions and building up to ten repetitions of each exercise. As with all exercise, make sure you breathe evenly: breathe out on the effort of the exercise and do not hold your breath. Remember to warm up first! Upper Body Push-ups will strengthen your shoulders, arms and chest. Balance the weight between your hands, which should be placed under your shoulders. Keeping your back straight, gradually lower your chest to that it nearly touches the floor by bending your elbows. Then, push-up so that you return to the starting position - without locking out at the elbow. If you wish to concentrate on strengthening your arm muscles, put your hands closer together.