Athletics - New York City Marathon - New York City, New York, U.S. - November 4, 2018 Second placed Vivian Cheruiyot of Kenya, first placed Mary Keitany of Kenya and third placed Shalane Flanagan of the U.S. celebrate after the Professional Women's race REUTERS/Brendan McDermid

Athletics - New York City Marathon - New York City, New York, U.S. - November 4, 2018 Second placed Vivian Cheruiyot of Kenya, first placed Mary Keitany of Kenya and third placed Shalane Flanagan of the U.S. celebrate after the Professional Women's race REUTERS/Brendan McDermid

Athletics - New York City Marathon - New York City, New York, U.S. - November 4, 2018 Race winner Mary Keitany of Kenya is congratulated by third placed Shalane Flanagan of the U.S. after the Professional Women's race REUTERS/Brendan McDermid

Athletics - New York City Marathon - New York City, New York, U.S. - November 4, 2018 Shalane Flanagan of the U.S. reacts after finishing third in the Professional Women's race REUTERS/Brendan McDermid

Winner of the 2017 New York City Marathon Women's race Shalane Flanagan of the U.S. speaks to reporters in New York City, in New York, U.S. November 6, 2017. REUTERS/Shannon Stapleton

Winner of the 2017 New York City Marathon Women's race Shalane Flanagan of the U.S. speaks to reporters in New York City, in New York, U.S. November 6, 2017. REUTERS/Shannon Stapleton

Winner of the 2017 New York City Marathon Women's race Shalane Flanagan of the U.S. blows a kiss to people in New York City, in New York, U.S. November 6, 2017. REUTERS/Shannon Stapleton

Winner of the 2017 New York City Marathon Women's race Shalane Flanagan of the U.S. speaks to reporters in New York City, in New York, U.S. November 6, 2017. REUTERS/Shannon Stapleton

Athletics - New York City Marathon - New York, USA - November 5, 2017 - Shalane Flanagan of the U.S. wins the Women's race. REUTERS/Brendan McDermid

Shalane Flanagan of the U.S. celebrates winning the Professional Women's Division with Mary Keitany of Kenya and Mamitu Dasku of Ethiopia during the New York City Marathon in Central Park in New York, U.S., November 5, 2017. REUTERS/Brendan McDermid

Athletics - New York City Marathon - New York, U.S. - November 5, 2017 - Shalane Flanagan of the U.S. wins the women's race. REUTERS/Brendan McDermid

Athletics - New York City Marathon - New York, U.S. - November 5, 2017 - Shalane Flanagan of the U.S. wins the women's race. REUTERS/Brendan McDermid

Athletics - New York City Marathon - New York, U.S. - November 5, 2017 - Shalane Flanagan wins the women's race. REUTERS/Brendan McDermid

Athletics - New York City Marathon - New York, U.S. - November 5, 2017 - Shalane Flanagan wins the women's race. REUTERS/Brendan McDermid

Athletics - New York City Marathon - New York, U.S. - November 5, 2017 - Shalane Flanagan wins the women's race. REUTERS/Brendan McDermid

Shalane Flanagan of the U.S. crosses the finish line to win the Women's race of the New York City Marathon in Central Park in New York, U.S., November 5, 2017. REUTERS/Brendan McDermid

Shalane Flanagan of the U.S. crosses the finish line to win the Women's race of the New York City Marathon in Central Park in New York, U.S., November 5, 2017. REUTERS/Brendan McDermid

Shalane Flanagan of the U.S. crosses the finish line to win the Women's race of the New York City Marathon in Central Park in New York, U.S., November 5, 2017. REUTERS/Brendan McDermid

Shalane Flanagan of the U.S. crosses the finish line to win the Women's race of the New York City Marathon in Central Park in New York, U.S., November 5, 2017. REUTERS/Brendan McDermid

Shalane Flanagan of the U.S. crosses the finish line to win the Women's race of the New York City Marathon in Central Park in New York, U.S., November 5, 2017. REUTERS/Brendan McDermid

Emily Infeld of U.S. (R) celebrates winning third place in the women's 10,000 metres final with Shalane Flanagan of U.S. during the 15th IAAF World Championships at the National Stadium in Beijing, China August 24, 2015. REUTERS/David Gray

Emily Infeld of the U.S. (R) and Shalane Flanagan of the U.S. react after finishing the women's 10,000 metres final during the15th IAAF World Championships at the National Stadium in Beijing, China August 24, 2015. REUTERS/David Gray

Emily Infeld of the U.S. (C) in congratuled by Shalane Flanagan of the U.S. (L) and Molly Huddle of the U.S. after finishing third in the women's 10,000 metres final during the15th IAAF World Championships at the National Stadium in Beijing, China August 24, 2015. REUTERS/David Gray

Boston Marathon runner Shalane Flanagan of the United States speaks to the media during a press event in Boston, Massachusetts, April 17, 2015. A field of 30,000 runners is set to line up for the Boston Marathon, in the 119th running of the world's oldest annual marathon. REUTERS/Dominick Reuter

Second placed Feyse Tadese of Ethopia, her campatriot and first placed Tirfi Tsegaye and third placed Shalane Flanagan of the U.S. (L-R) celebrate during the awards ceremony for the women's race of the 41st Berlin marathon September 28, 2014. Tsegaye won the race in a time of two hours, twently minutes and eighteen seconds. REUTERS/Hannibal Hanschke (GERMANY - Tags: SPORT ATHLETICS)

Second placed Feyse Tadese of Ethopia, her campatriot and first placed Tirfi Tsegaye and third placed Shalane Flanagan of the U.S. (L-R) celebrate during the awards ceremony for the women's race of the 41st Berlin marathon September 28, 2014. Tsegaye won the race in a time of two hours, twently minutes and eighteen seconds. REUTERS/Hannibal Hanschke (GERMANY - Tags: SPORT ATHLETICS)

Shalane Flanagan of the U.S. holds her third place trophy during the awards ceremony for the women's race of the 41st Berlin marathon September 28, 2014. Tirfi Tsegaye of Ethopia won the race in a time of two hours, twently minutes and eighteen seconds. REUTERS/Hannibal Hanschke (GERMANY - Tags: SPORT ATHLETICS)

Kara Goucher of the U.S. (L) helps her compatriot Shalane Flanagan after finishing the women's marathon final at the London 2012 Olympic Games at The Mall August 5, 2012. REUTERS/Mark Blinch (BRITAIN - Tags: OLYMPICS SPORT ATHLETICS)

Kara Goucher of the U.S. (L) helps her compatriot Shalane Flanagan after finishing the women's marathon final at the London 2012 Olympic Games at The Mall August 5, 2012. REUTERS/Chris Helgren (BRITAIN - Tags: OLYMPICS SPORT ATHLETICS)

The top three men's and women's finishers gather on a stage at the end of the U.S. Olympic Trials Marathon in Houston January 14, 2012. From (L-R) are Desiree Davila, Ryan Hall, Abdi Abdirahman, Shalane Flanagan, Meb Keflezighi and Kara Goucher.
REUTERS/Richard Carson (UNITED STATES - Tags: SPORT OLYMPICS)

Top woman finisher Shalane Flanagan poses with her cowboy hat, roses and flag on the stage at the end of the U.S. Olympic Trials Marathon in Houston January 14, 2012. REUTERS/Richard Carson (UNITED STATES - Tags: SPORT OLYMPICS)

Top three women finishers (L-R), Desiree Davila, second, Shalane Flanagan, first, and Kara Goucher, third, with cowboy hats and roses, stand on the stage at the end of the U.S. Olympic Trials Marathon in Houston January 14, 2012. REUTERS/Richard Carson (UNITED STATES - Tags: SPORT OLYMPICS)

Top three women finishers (L-R), Desiree Davila, second, Shalane Flanagan, first, and Kara Goucher, third, wrap themselves with the U.S. flag at the end of the U.S. Olympic Trials Marathon in Houston January 14, 2012. REUTERS/Richard Carson (UNITED STATES - Tags: SPORT OLYMPICS)

Joan Benoit Samuelson (2nd L), the first gold medal winner in the women's marathon, congratulates the top three women finishers (L) Shalane Flanagan, first, Kara Goucher, third and Desiree Davila (R), second, at the finish line of the U.S. Olympic Trials Marathon in Houston January 14, 2012. REUTERS/Richard Carson (UNITED STATES - Tags: SPORT OLYMPICS)

Shalane Flanagan hits the banner for the first place finish in the women's U.S. Olympic Trials Marathon in Houston January 14, 2012. REUTERS/Richard Carson (UNITED STATES - Tags: SPORT OLYMPICS)

Shalane Flanagan hits the banner for the first place finish in the women's U.S. Olympic Trials Marathon in Houston January 14, 2012. REUTERS/Richard Carson (UNITED STATES - Tags: SPORT OLYMPICS)

Top three women finishers (L-R) Shalane Flanagan, first, Desiree Davila, second and Kara Goucher, third, celebrate at the finish line of the U.S. Olympic Trials Marathon in Houston January 14, 2012. REUTERS/Richard Carson (UNITED STATES - Tags: SPORT OLYMPICS)

Shalane Flanagan competes in the women's 10,000 meters at the U.S. Outdoor Track and Field Championships in Eugene, Oregon June 23, 2011. REUTERS/Steve Dykes (UNITED STATES - Tags: SPORT ATHLETICS)

Shalane Flanagan leads the pack down the backstretch during the women's 10,000 meters at the U.S. Outdoor Track and Field Championships in Eugene, Oregon June 23, 2011. REUTERS/Steve Dykes (UNITED STATES - Tags: SPORT ATHLETICS)

Vivian Jepkemoi Cheruiyot (C) of Kenya, Linet Chepkwemoi Masai (L) of Kenya and Shalane Flanagan of the U.S. display their medals during the World Cross Country Championships in Punta Umbria, southwest Spain March 20, 2011. Cheruiyot won the race, Masai was second and Flanagan third. REUTERS/Marcelo del Pozo (SPAIN - Tags: SPORT ATHLETICS)

Vivian Jepkemoi Cheruiyot of Kenya celebrates after winning the World Cross Country Championships in Punta Umbria, southwest Spain March 20, 2011. Cheruiyot won the race, Linet Chepkwemoi Masai of Kenya was second and third for Shalane Flanagan of the U.S. REUTERS/Marcelo del Pozo (SPAIN - Tags: SPORT ATHLETICS)

Vivian Jepkemoi Cheruiyot of Kenya crosses the finish line during the World Cross Country Championships in Punta Umbria, southwest Spain March 20, 2011. Cheruiyot won the race, Linet Chepkwemoi Masai of Kenya was second and third for Shalane Flanagan of the U.S. REUTERS/Marcelo del Pozo (SPAIN - Tags: SPORT ATHLETICS)

Vivian Jepkemoi Cheruiyot of Kenya crosses the finish line during the World Cross Country Championships in Punta Umbria, southwest Spain March 20, 2011. Cheruiyot won the race, Linet Chepkwemoi Masai of Kenya was second and third for Shalane Flanagan of the U.S. REUTERS/Marcelo del Pozo (SPAIN - Tags: SPORT ATHLETICS)

Edna Kiplagat of Kenya, who won the women's marathon celebrates with American Shalane Flanagan (R) and Mary Keitany of Kenya (L) after receiving her trophy in the New York City Marathon November 7, 2010. REUTERS/Ray Stubblebine (UNITED STATES - Tags: SPORT ATHLETICS)

Shalane Flanagan of the U.S. is embraced by her husband Steve Edwards after she finished second in the women's division of the New York City Marathon, November 7, 2010. REUTERS/Mike Segar (UNITED STATES - Tags: SPORT ATHLETICS)

Shalane Flanagan of the U.S. is escorted by New York Road Runners President Mary Whittenberg after Flanagan finished second in the women's division of the New York City Marathon, November 7, 2010. REUTERS/Mike Segar (UNITED STATES - Tags: SPORT ATHLETICS)

Edna Kiplagat of Kenya (L) embraces Shalane Flanagan of the U.S. after they finished first and second respectively in the women's division of the New York City Marathon, November 7, 2010. REUTERS/Mike Segar (UNITED STATES - Tags: SPORT ATHLETICS)

Shalane Flanagan of the U.S. drops to her knees after she finished second in the women's division of the New York City Marathon, November 7, 2010. REUTERS/Mike Segar (UNITED STATES - Tags: SPORT ATHLETICS)

Shalane Flanagan of the U.S. drops to her knees as she is draped with an American flag by New York Road Runners President Mary Whittenberg after Flanagan finished second in the women's division of the New York City Marathon, November 7, 2010. REUTERS/Mike Segar (UNITED STATES - Tags: SPORT ATHLETICS)

Second placed Shalane Flanagan (R) hugs winner Amy Begley after the women's 10,000 meter finals race at the U.S. track and field championships in Eugene, Oregon June 25, 2009. REUTERS/Richard Clement (UNITED STATES SPORT ATHLETICS)

Women's 10,000m medallists (from L to R): Elvan Abeylegesse of Turkey (silver), Tirunesh Dibaba of Ethiopia (gold) and Shalane Flanagan of the U.S. (bronze) hold their medals on podium during the medal ceremony in the National Stadium at the Beijing 2008 Olympic Games, August 16, 2008. REUTERS/Ruben Sprich (CHINA)

Women's 10,000m medallists (from L to R): Elvan Abeylegesse of Turkey (silver), Tirunesh Dibaba of Ethiopia (gold) and Shalane Flanagan of the U.S. (bronze) hold their medals on podium during the medal ceremony in the National Stadium at the Beijing 2008 Olympic Games, August 16, 2008. REUTERS/Hans Deryk (CHINA)

Bronze medallist Shalane Flanagan of the U.S. stands on the podium during the women's 10,000m medal ceremony in the National Stadium at the Beijing 2008 Olympic Games, August 16, 2008. REUTERS/Hans Deryk (CHINA)

Shalane Flanagan of the U.S. holds the American flag after coming in third in the women's 10,000m final of the athletics competition at the National Stadium during the Beijing 2008 Olympic Games, August 15, 2008. REUTERS/Dylan Martinez (CHINA)

Shalane Flanagan of the U.S. reacts after coming in third in the women's 10,000m final of the athletics competition at the National Stadium during the Beijing 2008 Olympic Games, August 15, 2008. REUTERS/David Gray (CHINA)

Shalane Flanagan of the U.S. reacts after finishing third in the women's 10,000m final of the athletics competition in the National Stadium at the Beijing 2008 Olympic Games August 15, 2008. REUTERS/Dylan Martinez (CHINA)

Shalane Flanagan of the U.S. reacts after finishing third in the women's 10,000m final of the athletics competition in the National Stadium at the Beijing 2008 Olympic Games August 15, 2008. REUTERS/Kai Pfaffenbach (CHINA)

Shalane Flanagan of the U.S. reacts after finishing third in the women's 10,000m final of the athletics competition in the National Stadium at the Beijing 2008 Olympic Games August 15, 2008. REUTERS/Kai Pfaffenbach (CHINA)

Shalane Flanagan of the U.S. reacts after finishing third in the women's 10,000m final of the athletics competition in the National Stadium at the Beijing 2008 Olympic Games August 15, 2008. REUTERS/Kai Pfaffenbach (CHINA)

Shalane Flanagan of the U.S. waves her national flag after the women's 10,000m final of the athletics competition in the National Stadium at the Beijing 2008 Olympic Games August 15, 2008. REUTERS/Kai Pfaffenbach (CHINA)