Performing calisthenics -- defined as repeating a series of high-intensity muscle movements for the purpose of physical conditioning -- can be an effective way of maintaining your physical fitness. Calisthenics are used by sports teams, military units and law enforcement professionals, not only for physical conditioning but to build discipline and morale as well. Among the advantages of calisthenics are the fact that they require no equipment and cost nothing to perform. Consult your doctor before beginning a program of calisthenics.
Calisthenics are actually a form of resistance training, with your body's own weight -- plus gravity -- providing the resistance. Calisthenics originated with the ancient Greeks; the word "calisthenics" comes from the Greek words for beauty and strength. Calisthenics provide the same benefits as other forms of aerobic exercise, including helping to maintain a healthy weight, prevent diabetes and heart disease, increase cardiovascular fitness, and promote positive mood due to the release of endorphins. Some calisthenics -- such as jumping jacks and squat thrusts -- are also weight-bearing, and can help build bone density and ward off osteoporosis. According to the Health Status Calories Burned Calculator, 45 minutes of vigorous calisthenic exercise causes a 160-lb. person to burn a substantial 439 calories; in contrast, the same time spent in jogging or moderate swimming only burns a respective 382 and 331 calories.
Pushups -- which strengthen and develop your core muscles -- can also help to strengthen the serratus anterior muscle in your shoulder, as well as promoting proper bench-pressing form. Start out suspended over the ground, supporting yourself on your palms and tiptoes with your elbows locked. Your hands should be apart, slightly wider than shoulder-width, and turned out 45 degrees; your chin should be tucked in. Bend your elbows to lower your body in a smooth, controlled motion, until your chest almost touches the floor, then raise your body back up, pushing your palms down into the floor. As you become stronger, you can try more challenging types of pushups, such as one-handed pushups, explosive pushups and pushups using resistance bands.
Abdominal crunches work the abdominal muscles, including the rectus abdominus, otherwise known as the six-pack muscle. Begin by lying on your back with your lower back flat on the ground and your feet on the floor or draped over a bench. Don't clasp your hands behind your head and don't tuck your chin in; rather, you should place your fingertips just in back of your ears, and gaze at the ceiling while performing the exercise. Contract your abdominal muscles -- exhaling at the same time -- and raise your shoulders off the ground, rising up as high as you can without your lower back coming up from the ground. Then lower your shoulders back down while inhaling.
Jumping jacks, also known as star jumps, are an extremely effective cardiovascular training technique. Begin with your feet apart at the width of your shoulders, arms by your sides. Jump up off the ground, spreading your legs as you simultaneously lift your arms over your head from the sides; allow your open palms to almost touch each other, then jump again, this time bringing your feet back to their original position and bringing your arms back down to your sides. You can make jumping jacks even more challenging by wearing wrist and ankle weights, increasing the length of your jumping jack session, and increasing the intensity or speed. Make sure you still keep proper form.