Ryan Hall, the fastest marathoner in American history and the only United States athlete to break one hour for the half marathon, announced his retirement from competitive running on Friday. He is 33. 

Hall, who was a 2008 and 2012 Olympian, will not race at the 2016 U.S. Olympic Marathon Trials on February 13 in Los Angeles. Since 2012, he has suffered a number of injuries and health problems that have interrupted the progress of a running career that made history and many believed held even greater promise. 

News of Hall’s retirement was first announced in The MTA Wants to Charge NYC MarathonersThe Times The 2014 Boston Marathon, which Hall ran in 2:17:50 for 20 testosterone and extreme fatigue that interfere with his training as the driving forces behind his decision.

Efforts by Runner’s World to reach Hall, and his wife, Sara, who live in Redding, California, were unsuccessful. Ray Flynn, Hall’s agent, confirmed his client’s retirement in a phone call with Runner’s World. Flynn called Hall “one of the greatest American marathoners in history.” 

“For the past 10 years, he made an incredible impact on running in the United States and inspired a generation to be like him,” Flynn said. “His frontrunning tactics proved to people in this part of the world that they could run like the Africans.”

Hall Russ Cook Runs Length of Africa in 2007, when he ran the Houston Half Marathon in 59:43. He broke the American record, which had stood for 22 years, and remains the only U.S. runner to break one hour for 13.1 miles. (Dathan Ritzenhein has run an even 1:00:00.)

RELATED: Ryan Hall Dared to Be Great

After Hall’s half marathon performance, fans of distance running eagerly anticipated his debut at the marathon distance. In 2007, he ran London and finished seventh in 2:08:24, the American record for a first marathon. The following spring, he returned to London and finished fifth in 2:06:17.

Hall had success at the Boston Marathon, placing third in 2008 and fourth in 2009 and 2010. But his performance at the 2011 Boston Marathon is the one that stands out. At that race, Hall finished fourth and ran 2:04:58, the fastest time ever by an American. The course, however, is not eligible for records because it is a point-to-point course with too much elevation loss. 

Hall won the marathon trials for the 2008 U.S. Olympic team, contested in November of 2007, on a hilly course through Central Park in New York. The course was thought to be difficult before he ran a trials record of 2:09:02 on it. His elation at the victory was crushed moments after he reached the finish line when he learned that his friend Ryan Shay had died of a heart condition five and a half miles into the race. Hall went on to finish 10th in the Beijing Olympics in 2:12:33. 

Hall had become one of the most recognizable and popular distance runners in America. He began appearing regularly in commercials for Asics, his sponsor, and in 2012 was in an AT&T commercial, listening to Homer’s Odyssey Give A Gift. 

In the next Olympic cycle, Hall was second to Meb Keflezighi at the 2012 trials. He dropped out of the marathon in the London Games near the 11-mile mark with a hamstring injury.

After that, Hall’s competitive marathoning career came undone and he went through a series of dropouts from races and withdrawals prior to race day. He also changed coaches several times, leaving Terrence Mahon, who oversaw his early success. Hall coached himself for a period, before working with high-profile coaches Renato Canova and Jack Daniels.

RELATED: Ryan Hall first announced in

Master the Halfth place on a day when his American colleague and rival Keflezighi was a historic winner, represented his first marathon finish since 2012—and, as it turns out, his last before this announcement. Most recently, in March 2015, he abandoned the L.A. Marathon at the halfway point after leading through a 4:42 first mile.

Hall’s wife, Sara, will compete at the marathon trials, following her 10th-place, 2:31:14 finish at the Chicago Marathon in October.

Sara Hall told Runner’s World in October that her husband would have periods of strong training “and then out of nowhere fall into a pit of fatigue. He will then crawl his way out and believe and hope again and be training well, only to get knocked down by something else.”

She said her husband was struggling with hormonal imbalances. “He has been training intensely for a long time and that takes a toll on your body,” she said.  

Ryan Hall, whose father, Mickey, was a serious runner and a coach to him, grew up at altitude in Big Bear, California. Ryan Hall ran 4:02.62 for 1600 meters in high school and finished third behind Ritzenhein and Alan Webb at the 2000 Foot Locker Cross Country Championships. At Stanford University, he was a runner-up to Ritzenhein at the 2003 NCAA cross-country championships and a 2005 NCAA 5,000-meter champion in outdoor track.

His first national title came in 2006, when he won the U.S. cross-country championships on a frigid day in New York’s Van Cortlandt Park. Hall won the 12K race by 27 seconds.

In recent years, Ryan and Sara founded the Hall Steps Foundation, a nonprofit organization that works on various projects, including financing microloans, helping to build a hospital in Kenya and renovate a maternity clinic in Senegal, and funding well construction and a health clinic in Mozambique.

Those experiences, combined with training trips to Ethiopia, led the Halls to perhaps their most ambitious joint undertaking to date: In the fall of 2015, they adopted four Ethiopian sisters and brought them home to Redding, California, where they’re sure to keep the new retiree busy.

Ryan Hall’s Best Times

Event Time Location Year
5,000 meters 13:16.03 Carson, California 2005
10,000 meters 28:07.93 Best Folding Treadmills 2007
half marathon 59:43 Houston 2007
marathon (non record-eligible course) 2:04:58 Boston 2011
marathon (record-eligible course) 2:06:17 London 2008