Edna Kiplagat is to run the Boston Marathon at 42 years old ©Getty Images

The 2021 Boston Marathon has an array of great names in the men's and women's fields, but the return of Kenyan double world marathon champion Edna Kiplagat is the most notable of these.

Winning back-to-back world gold medals in 2011 and 2013, the 42-year-old has the fastest personal best in the women's race with 2 hours 19min 50sec, but much like many of the fastest athletes, these times are not based on current form.

She set her best at the 2012 London Marathon, having finished second to compatriot and recently-retired Mary Keitany.

Kiplagat also won the 2017 Boston Marathon.

Ethiopian Mare Dibaba's best is only two seconds slower but was also set in 2012.

Kenyan Angela Tanui has the best season's best in the race of 2:20:08, which is also her personal best.

She won the Siena Marathon in April with a new course record.

Only four runners in the top 10 personal bests set their quickest time in the past two years - the next fastest of these is Ethiopia's Workenesh Edesa, who ran 2:20:24 in Valencia in 2019.

Her compatriot Sutume Kebede ran 2:20:30 at the Tokyo Marathon last year, while Kenyan Diana Chemtai Kipyogei clocked 2:22:06 in Istanbul in 2020.

The United States' top hope is Jordan Hasay, but she has struggled to rediscover her pre-pandemic form.

Lelisa Desisa will look to bounce back from dropping out of the Tokyo 2020 Olympics marathon ©Getty Images
Lelisa Desisa will look to bounce back from dropping out of the Tokyo 2020 Olympics marathon ©Getty Images

None of the fastest runners in the men's race have finished a marathon this year or in 2020.

Ethiopian Lelisa Desisa will be regarded as one of the favourites, but the 2019 world champion has not run quicker since he won the 2013 Dubai Marathon in 2:04:45.

Desisa crossed the line first in 2013 and 2015, as well as second in 2016 and 2019.

His compatriot Asefa Mengstu has the fastest personal best - 2:04:06 - in the field, which was set at the 2018 Dubai Marathon, while team-mate Lemi Berhanu ran 2:04:33 at the 2016 Dubai Marathon.

There is also interest in another Ethiopian - this time a debutant.

Jemal Yimer holds the half marathon national record of 58:33 and could sweep away a field of runners who have largely run their best races a number of seasons ago.

Yimer technically ran a marathon before - the 2020 Valencia Marathon - but pulled out at 35 kilometres after taking a tumble early in the race.

Kenyan Benson Kipruto has at least won a marathon this season, crossing the line in Prague in 2:10:16, but this time should not threaten the lead - nor his team-mate Wilson Chebet's 2:08:38, which was only good enough for 13th in Milan.