Both will join the John Hancock Elite Athlete Team, which will be subject to rigorous anti-doping monitoring under the initiative recently announced by the World Marathon Majors.

The news follows the withdrawal of Ethiopia's Ejegayehu Dibaba due to a leg injury.

Tegenkamp is the American record-holder in the outdoor two-mile with 8min 07.07sec.  

He made his debut over 26.2 miles at the 2013 Chicago Marathon, finishing10th in 2 hours 12min 28sec.

At the 2014 New York City Half Marathon, he finished seventh and top American in a personal best 1:02:04.

"It's an honour and privilege to have an opportunity to compete in America's greatest race," said Tegenkamp.  

"This being my first time on the Boston course I don't know what to expect, but I will bring my competitive fire and fitness."

Highlights of Tegenkamp's career include two national titles in the 3,000 metres indoors and a national title in the 5,000m outdoors.

He is one of only five American men to have broken the 13-minute barrier in the 5,000m with 12:58.56.

A three-time World Championships participant, Tegenkamp has finished as high as fourth in the 5,000m.

As a junior runner, Tegenkamp finished fifth at the 2011 International Association of Athletics Federations World Cross Country Championships, behind Dathan Ritzenhein and Kenenisa Bekele.

The 2015 Boston Marathon will be Tegenkamp's second marathon.

The women's elite field will this year be joined by naturalised American Adriana Nelson ©Getty Images

Nelson is one of America's best marathon runners.

In 2013, she won the US Half Marathon Championships and was the first American woman in that year's New York City Marathon.

Before becoming an American citizen in 2011, Nelson - formerly Pirtea -was a Romanian national champion in the 5,000m four times and 10,000m two-times.  

A career highlight for Nelson was her second place finish at the 2007 Chicago Marathon.

"Having raced marathons all over the world, I can say with 100 percent confidence there isn't another race like the Boston Marathon," said Nelson.

"I asked myself what makes it different and I think it comes down to the people.  

"It's not only the runners competing in the race, but all the passionate spectators and volunteers that make Boston such an iconic event.  

"I am so honoured and excited to be back this year and toe the line with the world's best."

Fastest male entrant for the Boston field is Patrick Makau, whose winning time of 2:03:38 at Berlin in 2011 was a world record at the time.

The fastest woman entrant is Mare Dibaba, who recorded 2:19:52 winning the 2012 Dubai Marathon.

Contact the writer of this story at [email protected]


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