A variety of abdominal exercises can be used to strengthen your central, upper, and lower abdominal muscles, as well as your back muscles. However, in order to strengthen, tone, and reshape your side abdominal muscles, also known as obliques, you must engage in specific abdominal muscle exercises. When performed correctly, the oblique twist and its variants will help you achieve a leaner, more muscular mid-section. Perform two to three sets of 10 to 12 repetitions of each exercise for a basketball legends total of two to three sets. oblique twists and other new exercises should not be performed if you are new to exercise or if you have recently suffered a back injury. Consult your doctor before beginning any new exercise program.