Jumping jacks are a form of calisthenics in which people jump energetically. This exercise is sometimes used as a warmup, and it can also be a form of aerobic exercise. Many people associate jumping jacks with the schoolyard, and they are indeed part of some school calisthenics programs, but they are also used by professional athletes. There are some variations on the basic exercise which people can use in different settings to mix things up in order to prevent boredom, or if they have concerns about injuries or physical limitations.
It is important to stretch before doing jumping jacks, to get the body ready for the exercise and to loosen up. After stretching, people move into a standing position and jump up, with the legs ending up shoulder width apart and the arms over the head. Then, they jump back into a standing position which brings the legs together and the arms back by the sides. These exercises can be repeated a set number of times, or within a set time period, such as five minutes.
Jumping jacks act as a form of advanced warmup, getting the blood flowing and the body loosened for more intensive exercise. They also work the calves, thighs, back, and shoulders when they are done properly. In addition, because jumping jacks are usually done in quick succession, the exercise will also elevate the heart rate, turning it into a form of cardiovascular exercise. Research has shown that daily cardiovascular exercise, even in small amounts, can be highly beneficial for physical health and wellness.
Also known as star jumps because of the five-pointed star formed by the body during jumping jacks, jumping jacks can be made easier or harder with some variations. Some people like to bend to touch the toes between jacks to increase flexibility. Others may bring the arms only partway up. Clapping, a common accompaniment to jumping jacks, is actually not recommended because it can strain the shoulders, and people shouldn't try to force their arms if they cannot bring them together over their heads.
A personal trainer can provide tips and advice for someone who is learning jumping jacks, including tips to help the exerciser hold form. It's important to stand up straight, to avoid twisting, and to keep the abdomen firm. If form is poor, the exercise will not be as beneficial, and sometimes it can put people at risk of injury.