The former Soviet sports program scientists considered direct abdominal training a waste of time, since they noted that the abdominal and oblique muscles functioned to stabilize the torso, and therefore were heavily involved in most lifting movements. The late Casey Viator, the youngest man ever to win the Mr.America contest at age 19, once told me that his abs were purely the result of dietary changes, and he did nothing for them. On the other hand, Bill Pearl, a 4-time Mr.Universe, was a strong believer in lots of direct ab exercises, and he usually started his workout by doing 12 different ab exercises, 1 set of 100 reps each. Pearl told me that he judged his overall conditioning by the appearance of his abdominals, and he firmly believed that the level of exercise that he did maintained their condition. That, of course, is spot reduction, which doesn't exist. My feeling is that the appearance of abdominals is related more to diet, and reducing body fat to a lower level will along produce prominent abdominals. However, doing some direct ab exercise will produce thicker abdominal "cubes," since abdominals are capable of hypertrophy as are all muscles. Since the obliques work in concert with the rectus abdominus in stabilizing the torso, they are automatically activated in most abdominal exercises, so no direct work is necessary, and exercises such as side bends and torso twists do little to enhance abdominal appearance, but they do provide a shearing effect to the spinal vertebrae.