The modeling industry consists of two distinct branches: print modeling and runway modeling. The modeling industry has become very popular, and it also is increasingly accessible due in part to shows such as "America’s Next Top Model." The fashion world has very high standards, and the requirements for a runway model are more strict than its print counterpart.

Runway models generally are required to be above a certain height to be booked for a job. The specific requirement varies the agency, but women generally must be between 5-foot-9 to 6-foot and men should be between 5-foot-11 to 6-foot-2.

Skinny models are common in the modeling industry because many agencies used to require that their models achieve a certain weight. The industry is becoming healthier and safer, however, and many requirements now ask for a body weight that is directly proportional to the model’s height.

Designers consider models to be a blank canvas for their clothing, so it is preferred that a model have pleasant features such as good posture, straight, white teeth and glossy hair.

Models can begin working on runway shows as early as 15, or younger if they are involved in a children’s wear fashion show. The maximum age of a model can vary, and there are no specific restrictions, but the industry is trending toward younger models. According to an ongoing health and safety initiative by the Council of Fashion Designers of America, it is important that minimum age restrictions be placed on the runway modeling industry to protect the younger models from what can be a potentially unhealthy lifestyle.