5. ATVs

All-terrain vehicles can be fun, unless you were one of the 230,666 riders sent to emergency rooms in 2010 with ATV-related injuries. That number may be high because this pastime has been steadily growing since its introduction in the 1970s, the experts say. In fact, ATV use grew about 183 percent from 1999 to 2008—from about 3.6 million units in use to 10.2 million—according to a 2010 report to Congress from the Government Accountability Office. The GAO discovered another cause for the high number of injuries: youths are using adult-sized ATVs, rather than smaller units meant for their age and size. In an undercover operation the GAO conducted in four states, it found that seven out of 10 ATV dealers were willing to sell adult-sized ATVs for use by children.

(AP Photo/Jim Cole)

4. Baseball & Softball

The national pastime and its closest competitor together make up the fourth-most dangerous sport for amateurs, tallying some 282,008 emergency room visits in 2010. Experts say the most common body part affected is the face, and 68 percent of those facial injuries result from direct contact with the ball. Ouch.

About two-thirds of injuries reported were from male players, and a small percentage of the overall visits to ERs—5,468 injured ballplayers—were admitted to the hospital for an overnight stay.

(AP Photo/Matt Slocum)

3. Football

It may be no surprise that football ranks as the third-most dangerous recreational sport in the country, considering the sport's massive focus on concussion injuries in recent years. According to the NEISS, some 489,676 amateur football players made trips to the emergency room in 2010.

Some experts feel that modern football helmets and shoulder pads may be creating a false sense of security, allowing players to believe they can hit each other harder. For the record, they say, not even a helmet can prevent a concussion, which occurs when the brain gets bounced around inside the skull—which can result from a hard enough hit to either the body or the head.

(AP Photo)

2. Basketball

Whether it's shooting a few hoops with neighborhood friends or traveling in a competitive league, basketball ranks as the second-most dangerous sport in the country, with 528,584 emergency room visits in 2010. Some 49 percent of those visits were made by players in the 15 to 24 age group, as basketball is the most popular organized team sport for young Americans. Over the past 20 years, participation has grown more than 10 percent for boys and almost 20 percent for girls. The most common injury: twisted ankles.

(AP Photo/Mark Humphrey)

1. Cycling

From road cycling to extreme mountain biking, bicycling sends more people to the emergency room than any other sport or activity. Some 541,746 injured cyclists made ER trips in 2010, per the NEISS. Off-road bikers are 40 percent less likely to be injured than on-road cyclists, for one reason: motor vehicles, which tend to stay away from mountain trails, but can be quite hazardous on the roads. “Share the Road” grassroots campaigns across the country and tips from the National Highway Traffic Safety Administration, such as following the rules of the road and avoiding night cycling, may help prevent future injuries.

(AP Photo/Peter Deconinck)