Jackknife

Jackknife is a term that is used for a number of different items and activities. One such activity is an abdominal exercise that requires access to an exercise or yoga ball. The Jackknife is said to be useful for helping to strengthen and flatten stomach muscles such as the obliques and the rectus abdominis, as well as the thighs or quadriceps. Again, while some abdominal workouts require no equipment, the Jackknife must be performed with an inflatable fitness ball.

The participant begins the workout by putting his or her body into a normal pushup position, but with his or her ankles and shins resting on the top of the fitness ball. With palms flat on the floor and arms spread about shoulder width apart, the individual then pulls the knees up to the chest and the buttocks upward in the air, rolling the ball forward a bit so that only the toes are touching the top of the ball. When at the height of this arched position, the individual must contract his or abdominal muscles. Repeating this routine over and over again is one of many ways to use a fitness ball in order to tone and flatten stomach regions. Some individuals may find it quite useful for achieving their fitness goals.