Women Bodybuilding: Then & Now (Part 4) :

In late 2004, the IFBB introduced a new rule that required women bodybuilding participants decrease their amount of muscularity by 20%, which is now referred to simply as the '20% rule.' The rule applies to those whose physique requires the decrease. In 2005, another rule was introduced that would abolish the weight class system beginning with the 2005 Ms. Olympia. In addition to women bodybuilding, there are two additional categories that are closely related and often held as part of the same event.

The fitness competition includes a swimsuit round, along with a round that has the entrants judged on their performance in aerobics, dance or gymnastics. The second category is a figure competition, which is a newer format, and has the participants being judged exclusively on their symmetry and muscle tone. This category focuses less on muscle size than does women bodybuilding. Although women bodybuilding has continued to grow in popularity, the prize money remains significantly less than is awarded to male bodybuilders.