Bodybuilding is the use of progressive resistance exercise to control and develop one's musculature (muscle building) by muscle hypertrophy for aesthetic purposes. It is distinct from similar activities such as powerlifting because it focuses on physical appearance instead of strength. An individual who engages in this activity is referred to as a bodybuilder. In professional bodybuilding, competitors appear in lineups and perform specified poses (and later individual posing routines) for a panel of judges who rank them based on symmetry, muscularity, size, conditioning, posing, and stage presentation. Bodybuilders prepare for competitions through the elimination of nonessential body fat, enhanced at the last stage by a combination of extracellular dehydration and carbo-loading, to achieve maximum muscular definition and vascularity; they also tan and shave to accentuate the contrast of their skin under the spotlights.