Circuit training involves doing several exercises in a row, with short rest periods between each exercise. Once the circuit is completed, you then take another rest break and repeat the entire circuit again as many times as you want. Exercises for circuits tend to be quick and involve multiple joint movements. If you do not have access to equipment, you can do circuit training with just the weight of your body.
A T-push-up is a variation of the traditional push-up. Not only does it work your chest, but it also recruits your core muscles as well. Lie on your stomach with your hands slightly wider than shoulder-width apart and your toes hip-width apart. In a steady motion, push yourself off the floor, tighten your abs and straighten your back. Slowly lower yourself down until your chest is within a fist-width of the floor, then push up and rotate your body to your left side. As you do this, raise your right arm straight in the air so your body forms a "T" shape. Carefully lower yourself back down and repeat going to your opposite side. Perform 15 to 20 reps. If you really want a challenge, extend your leg in the air as you come into the "T" position.
Reverse push-ups work your shoulders, chest, back and legs. Lie on your back with your knees bent, feet flat and hands placed on the floor above your shoulders with your fingers facing your body. In a controlled motion, lift your hips off the floor and push them up while straightening your arms and legs. Your body should be in an curved position at this point. Once you have pushed as far as possible, slowly lower and repeat 15 to 20 times.
Bicycle crunches work your obliques, upper abs and lower abs simultaneously. Lie on your back with your legs lifted, knees bent and shins parallel to the floor. After placing your hands on the sides of your head, lift your shoulders off the floor so you are looking at your thighs. In a twisting motion, bring your left elbow and right knee toward each other as you extend your left leg out straight. After holding for a second, reverse the motion and bring your right elbow and left knee toward each other while extending your right leg. Continue to alternate back and forth for 15 to 20 repetitions.
Jack Knife Sit-ups
Jack knife sit-ups work your upper and lower abs. Lie on your back with your arms at your sides and your legs straight. In a smooth motion, raise your shoulders and legs off the floor and tuck your knees into your chest. Slowly lower and repeat for 15 to 20 repetitions.
Supermans work your back, shoulders and glutes. Lie face-down with your arms extended in front of you and your legs straight. In a steady motion, lift your arms and legs off the floor as high as possible and pause for a second. Slowly lower and repeat for 15 to 20 repetitions.
Leaping lunges work your quads, hamstrings and glutes, and they are done in an explosive fashion. Stand with your right leg forward and left leg behind you in a staggered stance. Slowly descend toward the floor by bending both knees. Once your right thigh parallels the floor and your left knee is an inch above the floor behind you, jump in the air and switch your foot position. As soon as you land, do another lunge and leap again. Continue to alternate back and forth for 15 to 20 reps with each leg leading.
Burpees work every major muscle in your body. Stand with your feet shoulder-width apart, bend down and place your hands on the floor outside your feet. In a fast motion, hop your feet behind your body, land on your toes and do a push-up. As soon as you come up, snap your feet forward and leap into the air as high as possible. While doing this, reach your arms straight above you. After you land, go right into another burpee and repeat for 12 to 15 repetitions.