It's all fun and games until somebody ends up in the hospital.That's evident in the way many Americans unwind, as some of themost enjoyable recreational sports in the country are also the mostdangerous, according to the website of Discover Fit & Health.Americans tend to play hard, and hospital emergency rooms acrossthe nation are evidence of that: of some 14.7 million emergencyroom visits in 2010 cited by the U.S. Consumer Product SafetyCommission (the last year data is available), 4.1 million visitswere for sports-related injuries, according to the CPSC's NationalElectronic Injury Surveillance System. The NEISS collectsinformation from some 100 emergency rooms across the country.

And while more glamorous sports like heli-skiing and cave divingare edgy enough to warrant “dangerous” status, this list spotlightsthe recreational sports that are more common to all Americans—themore popular a sport is, the more players it will have, and thus ahigher potential for injury. Here's the Top 5.

5. ATVs

All-terrain vehicles can be fun, unless you were one of the230,666 riders sent to emergency rooms in 2010 with ATV-relatedinjuries. That number may be high because this pastime has beensteadily growing since its introduction in the 1970s, the expertssay. In fact, ATV use grew about 183 percent from 1999 to 2008—fromabout 3.6 million units in use to 10.2 million—according to a 2010report to Congress from the Government Accountability Office. TheGAO discovered another cause for the high number of injuries:youths are using adult-sized ATVs, rather than smaller units meantfor their age and size. In an undercover operation the GAOconducted in four states, it found that seven out of 10 ATV dealerswere 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 upthe fourth-most dangerous sport for amateurs, tallying some 282,008emergency room visits in 2010. Experts say the most common bodypart affected is the face, and 68 percent of those facial injuriesresult 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 injuredballplayers—were admitted to the hospital for an overnightstay.

(AP Photo/Matt Slocum)

3. Football

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

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

(AP Photo)

2. Basketball

Whether it's shooting a few hoops with neighborhood friends ortraveling in a competitive league, basketball ranks as thesecond-most dangerous sport in the country, with 528,584 emergencyroom visits in 2010. Some 49 percent of those visits weremade by players in the 15 to 24 age group, as basketball is themost popular organized team sport for young Americans. Over thepast 20 years, participation has grown more than 10 percent forboys 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 sendsmore 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 thanon-road cyclists, for one reason: motor vehicles, which tend tostay away from mountain trails, but can be quite hazardous on theroads. “Share the Road” grassroots campaigns across the country andtips from the National Highway Traffic Safety Administration, suchas following the rules of the road and avoiding night cycling, mayhelp prevent future injuries.

(AP Photo/Peter Deconinck)