This article details the horrible complications one young man dealt with as a result of over-working himself at the gym -- he was quite literally "muscle bound," and suffered a blood clot that started in the shoulder area and traveled to his lungs. The condition, called thoracic outlet syndrome, happens mostly in athletes who use their arms and shoulders extensively, or workers like painters that commonly have their arms over head level. The abnormally large muscles constrict the vessels traveling through the already tight arm to shoulder area, and then blood flow gets interrupted and clotting can occur.

Luckily, the guy in the article underwent treatment and is perfectly fine today. Just goes to show, though, that anything can be taken too far -- even fitness!