Popular with athletes and the military, burpees can be used in circuit training or as a standalone workout. Burpees employ a large number of muscles in the motion of flowing through a squat, a single pushup, a jump and then repeating the motions.
Bending your legs and lowering your hands to the ground involves an eccentric or lengthening contraction of your leg muscles. The quadriceps at the front of your thigh, the hamstrings at the rear of your thighs and your gluteus maximus or butt muscles work together to control your rate of descent. The erector spinae muscles of your lower back also engage for stability.
The Leg Thrust
You next place your hands on the floor and undertake a powerful hip extension to drive your legs back into the pushup position. This action uses your hamstrings and gluteus maximus. As your toes hit the floor, your quadriceps and hip flexors contract to stop your legs and hips collapsing, and your rectus abdominus muscle, abs for short, contracts to stabilize your spine. Your upper-back muscles contract as you bend forward and bring your hands to the ground. The muscles in your arms, chest and shoulders also contract to hold your upper body off the ground.
Pushups target your pectoralis major or chest muscles, your deltoids or shoulder muscles and the triceps brachii muscles located on the rear of your upper arm. These muscles contract eccentrically to lower your chest towards the floor and then concentrically to push you back up. Your rectus abdominus and quadriceps muscles must remain tense to hold your body straight so that your arms have a strong platform from which to push. Failure to keep your spine correctly aligned can result in back injury -- burpees are a tough core exercise.
The Forward Jump
Jumping your legs forwards so that your feet land between your hands uses your hip flexor and abdominal muscles. During this phase of the exercise, your upper-body muscles must remain tense so that your arms do not collapse. Once your feet are between your hands, your weight should shift off your hands and fully onto your feet so that you are ready for the final part of the exercise.
The Vertical Jump
Jumping up into the air uses the same muscles as the squatting movement at the beginning of the exercise. The quadriceps, hamstrings and gluteus maximus muscles contract powerfully to drive you up into the air. This type of action is called a concentric contraction and describes how muscles shorten to generate force. Swinging your arms forward and up as you leap into the air uses the deltoids or shoulder muscles.
Increased Blood Circulation
Although burpees are an anaerobic exercise, meaning that the muscles involved work without the need for oxygen, your body still pumps blood to your working muscles. Pumping blood around your body is the job of your cardiac muscle or myocardium, commonly known as your heart. Because so many skeletal muscles are involved in burpees, your heart rate can become very elevated when performing this exercise.