The wild world of so-called extreme sports ranges from motorcyclists executing double back flips to kayakers navigating deadly Class 5 rapids to mixed martial arts (MMA) -- also known as "ultimate fighting" -- where combatants use kicks, punches and stress holds. But many "extreme" athletes reject the label, arguing that the term marginalizes their sports as the sole province of adrenaline and violence junkies, when they actually require high degrees of skill. Now legislatures in New York and other states are considering bans on MMA. Proponents say the matches, legal at the pro level in 37 states, are safer than boxing and emphasize fighters' broad-based martial-arts training. But opponents argue that allowing such a wide variety of aggressive moves in a single fight is barbaric. However, skateboarders and other extreme athletes cite statistics showing that traditional sports such as boxing and football cause injuries and deaths at a higher rate than any of the extreme sports.

Marcia Clemmitt is a veteran social-policy reporter who joined CQ Researcher after serving as editor in chief of Medicine and Health, a Washington-based industry newsletter, and staff writer for The Scientist. She has also been a high school math and physics teacher. She holds a bachelor's degree in arts and sciences from St. Johns College, Annapolis, and a masters degree in English from Georgetown University.