Jumping jacks are a calisthenic-type exercise that elevates the heart rate and works the major muscles of your body. Jacks are a high-impact exercise that can both build muscular and cardiovascular endurance. As a compound movement, both the upper body and the muscles of the lower body are activated as you jump to propel yourself up and down.
Performing a Jumping Jack
Jumping jacks are performed by standing with your feet together and your knees slightly bent. Correct form is crucial to preventing injuries and receiving the maximum benefits of your exercise. Draw your navel in and jump while raising your arms above your head and separating your feet to the sides. Avoid locking out your knees and slowly jump back to center, lowering your arms and returning your feet back to the midline. During the in and out movement of your lower body, your thighs are activated.
Using the Quadriceps
During jumping jacks, the lower body muscles are trained to generate force in the shortest amount of time. The quadriceps femoris, called the "quads," are the muscles on the front of your thighs. Your quads are actively engaged as you straighten your leg, creating knee extension. As you jump out, you extend your knee and activate your quadriceps by pulling them up and away from the kneecap. This repetitive motion during jumping jacks increases your lean mass in your quadriceps by using your own body weight for resistance.
Hip Adductors and Abductors
The hip adductors and abductors are known as your inner and outer thighs. Both of these muscles work during your jumping jacks. The hip abductors are active during the outward phase of your jumping jack, allowing your legs to spread apart. The hip adductors work as you bring your legs together on the return phase of your jumping jack. The in and out phase of your jack can slim the hip adductor and abductors.
Benefits of Jumping Jacks
Jumping jacks add power to your workout because they are a plyometric exercise that uses explosive movements to elevate your heart rate. As a high-impact exercise, jumping jacks produce a high calorie burn. A 150 pound person burns about 50 calories doing jumping jacks at a moderate intensity for 10 minutes and 90 calories when performed at a high intensity for the same duration. Although jacks have an explosive and a concentric phase, they also develop an eccentric or lengthening phase, allowing your muscles to stretch. They can increase flexibility and circulation.