The Side Flexor machine is a superb exercise targeting the oblique muscles, creating a narrow waistline plus firming and flattening of the abdominal wall. The internal and external obliques are diagonal muscles which lie underneath the Rectus Abdominus. These muscles are responsible for twisting actions. The erector spinae muscles are also used, therefore strengthening the lower back. This unique exercise combination will provide fast results, creating a slim waist and firm flat abdominals.