Jumping jack

A jumping jack is a popular physical jumping exercise. It is often called a star jump. In the United States military, the move is known as a side-straddle hop. This exercise is a form of aerobic activity. It helps people stay active by using large movements of the limbs. People value it because it is a simple way to move the body. It can be done in many different settings, from schools to military training.

The movement follows a specific sequence of actions. To begin, a person stands with their feet together and arms at their sides. The person then jumps to a position where the legs are spread wide. At the same time, the arms swing overhead. Sometimes, the hands meet in a clap at the top. After this, the person jumps again to return to the starting position. This brings the feet back together and the arms back to the sides.

There are many variations that change the intensity of the exercise. Low impact versions involve stepping the legs to the side without jumping. In an intermediate version, the legs hop out to shoulder width while the arms rise. Power jacks are more intense because the person lands in a wide squat position. Squat jacks require the person to stay in a half squat while jumping. Star jumps are even more explosive. In a star jump, the legs swing out laterally in the air. The person then pulls the legs back to land in a tucked, narrow squat.

Other versions exist to protect the body or change the movement pattern. Half jacks are similar to regular jumping jacks. However, the arms only go halfway above the head. This variation was created to prevent rotator cuff injuries. These injuries can be linked to the repetitive motions of the standard move. Split jacks use a staggered stance. In this version, the right foot is in front of the left. The person swings an arm opposite to the jumping foot. They switch legs throughout the process to complete the exercise.

The history of the jumping jack is quite colorful. Some accounts suggest it dates back to 1885 at West Point Military Academy. A man named John J. "Black Jack" Pershing is said to have used it. He reportedly used the move as a method of hazing underclassmen, known as plebes. He would order them to count off into odd and even groups. He would then mimic pulling an imaginary string to make them move. The students moved their limbs like marionettes while upperclassmen watched.

While some think the name comes from the general, that is not true. The name actually comes from a jumping jack children's toy. This toy makes similar motions when the strings are tugged. Even though he did not invent the move, Jack LaLanne helped it become famous. He was a fitness expert who used the exercise in his television programs. His work helped popularize the jumping jack across the United States. This helped turn a military drill into a common fitness tool.

People have used jumping jacks to set impressive records and participate in large events. In 2010, National Geographic Kids organized a massive event. This was part of Michelle Obama's "Let's Move!" campaign. The event took place in 1,050 different locations. During a 24-hour period, 300,365 people were measured doing jumping jacks for one minute. This showed how the exercise can bring huge groups of people together. It also demonstrated the scale of global fitness campaigns.

Individual skill can also be measured through speed and repetition. A significant record was set recently in Kathmandu, Nepal. On July 28, 2023, a man named Binod Thapa performed 136 jumping jacks in one minute. This shows the high level of coordination and stamina required. Science also looks at how different squat depths affect the jump. Studies show that jumping from a shallower squat helps achieve greater height. However, deeper squats are better for improving vertical jump height. These details show how much science is involved in simple movement.