Performing the crunch.

The crunch, also known as curl-up, is one of the most common exercises for the abdominal muscles, primarily the rectus abdominis. It is performed while lying face up on the floor with knees bent, by curling the shoulders up towards the pelvis. The hands may be placed behind the head, but care should be taken not to pull on the neck, as this can cause injury. Alternatively, the hands may be placed on the shoulders, with the forearms crossed over the chest, or by the sides resting on the floor. Image File history File links Thanks go to the model, Emily. ... Image File history File links Thanks go to the model, Emily. ... The term Exercise can refer to: Physical exercise such as running or strength training Exercise (options), the financial term for enacting and terminating a contract Category: ... The human abdomen (from the Latin word meaning belly) is the part of the body between the pelvis and the thorax. ... The rectus abdominis muscle is a paired muscle running vertically on each side of the anterior wall of the human abdomen (and in some animals). ... For other uses, see Knee (disambiguation). ... This article is about the body part. ... The pelvis (pl. ...

Crunch exercises may be performed on swiss balls. Weights may be used, typically held under the chin, to increase resistance. Holding a medicine ball behind the head exercises the triceps, as well as the abs. A Swiss ball allows a wide range of exercises to be performed. ... A medicine ball is a heavy ball, roughly the size of a volleyball. ... The triceps brachii muscle is a large three-headed skeletal muscle found in humans. ...

Unlike the sit-up, the lower back should not leave the floor. This is said to eliminate any involvement by the hip flexors, and make the crunch an effective isolation exercise for the abdominals. The difficulty of the crunch can be increased by lying on a decline bench and/or holding a weight on the chest. Alternatively, a crunch machine may be used. This article does not cite any references or sources. ... In anatomy, the back usually refers to the posterior side of the torso in humans and primates. ... It has been suggested that this article or section be merged with iliopsoas group. ...

Critics of the crunch have pointed out that the hip flexors are not in fact eliminated from the movement by the lower back being kept on the ground. Tension spreads from the abdominals to the hip flexors, and the tension of the hip flexors reduces the workload on the rectus abdominis.

Variants include:

• The reverse crunch is performed by curling the legs and pelvis towards the shoulders. More emphasis is placed on the lower abdominals.
• The twisting crunch is performed by lifting one shoulder at a time. More emphasis is placed on the obliques.
• The cable crunch is performed while kneeling upright by curling the body to pull down on a cable machine. The hips should be kept motionless, so that the individual's bodyweight does not assist the movement.
• The bicycle crunch is performed by bringing together alternating elbows and knees, resulting in a leg motion similar to pedaling a bicycle.

The Obliquus externus abdominis muscle (or external oblique) is a muscle of the human body. ... The upright row is one exercise that can be performed on the cable machine. ... A bicycle crunch is a form of abdominal exercise. ...

External Links

• Illustrations of How to Do an Abdominal Crunch