Belly rolls are an essential dance concept for belly dancing. To the viewer, it appears that the stomach is rolling like an ocean wave. To perform a roll, a belly dancer sucks in the upper abdominal muscles and the diaphragm and lets the pelvic muscles relax, then she slowly alternates between sucking in the pelvic muscles and relaxing the abdominal muscles and diaphragm.
Backbends use many different muscle groups and take time to master. There are two positions used regularly in belly dancing backbends: kneeling and standing. The same muscles are used in both: thigh, abdominal, lower- and upper-back muscles, ilio-psoas, the pelvic floor muscles and the pectoral muscles. Daily exercises help strengthen these muscles to allow the belly dancer to slowly lower herself to the floor while arching her back.
The arms accompany the movements of the abdomen in belly dancing. They contribute to the overall shape and feel of the dance. One common arms concept in belly dancing is "snake arms." One arm arches down as if holding a large ball and the other arches upwards as if balancing the same size ball. Then the upper arm slowly lowers and the upper slowly raises until the two sides are in the opposite position.
A shimmy can be loosely translated as a shake. A belly dancer shimmies throughout the dance. The hip shimmy can be performed side to side, front and back or while walking. A scarf with small plastic coins is often worn around the waist to accentuate the hips and make a soft jingle when the dancer shimmies her hips. Bracelets and ankle bracelets are often worn to bring attention to the shimmies and movements of those parts of the body.