How tighten stomach muscles - salad dressing , Most people want to tighten their stomach muscles and get rid of their stomach flab or love handles purely for vanity reasons. we think that with a flatter stomach. Staff.washington., Flexing the hip (resulting from the tension through the iliacus and psoas > muscles, which if tight would decrease head posture in those performing. Contour abs . slendertone™ & flex belt | ab belt review, The flex belt does work. of course with most exercise equipment it will work different for different people. i ordered the flex ab belt didn’t really have any.