Jumping Jack

A jumping jack (Canada & US) or star jump (UK and other Commonwealth nations), also called side-straddle hop in the US military, is a physical jumping exercise performed by jumping to a position with the legs spread wide and the hands touching overhead and then returning to a position with the feet together and the arms at the sides. The jumping jack name comes from the traditional toy of the same name, while "star jump" refers to the person's appearance with legs and arms spread.

More intensive versions of this jump include bending down (over) and touching the floor in between each jump.

A similar jump exercise is called half-jacks, which were created to prevent rotator cuff injuries, which have been linked to the repetitive movements of the exercise. They are just like regular jumping jacks, but the arms go halfway above the head instead of all the way above the head. The arms also hit the sides to help tighten the jump.

Although he played no part in inventing the exercise, the late fitness expert Jack LaLanne was given credit for popularizing the exercise in the United States. LaLanne utilized the jumping exercise during routines he promoted in decades of television fitness programming.

Troy Shawn Harris set the Guinness World Record for consecutive jumping jacks by doing 50,482 jumping jacks in 12 hours 27 minutes on August 20, 1988 at Fort Bragg, North Carolina, USA. Ashrita Furman set the Guinness World Record for number of star jumps (jumping jacks) in one minute at 61, on May 17, 2008.