The women's Olympic marathon will be a family affair in Rio de Janeiro on Sunday with triplets and twins both running, albeit likely finishing well out of the medals.

The Luiks will make history at in the marathon on Sunday by becoming the first triplets to compete in an Olympic event while the presence of the Hahner twins ensures it really will be a family affair.

The Estonians Leila, Liina and Lily Luik, the so-called 'Trio for Rio', will line up together at the start and some time, around 2 hours 40 minutes, later they will be reunited in the Sambodromo arena at the finish.

"Three together, we get so much energy from each other," Leila told the New York Times before the Games. "No one wants to be the slowest. We push, push, push."

Even seasoned fans and reporters watching the event are likely to struggle to tell who is who as the triplets are identical.

"When they run I can see who is who," their coach Harry Lemberg told dpa at sponsor's event Thursday. However, he laughingly admitted that the Estonian delegation conduct 'who's who' quizzes with photographs of the trio and "some don't get any points".

In Rio, differing race numbers mean they should be identifiable as the pound out 26.2 miles through the city.

And their performances, while broadly, similar are not identical either.

Leila has the strongest personal best of 2 hours 37 minutes 11 seconds while Lina follows with 2:39:42 and Lily brings up the rear with 2:40:30.

Ironically this is the same order in which they were born on Oct 14, 1985.

Even in the unpredictable Olympic marathons, where usual form counts for less than in the traditional big city races, their times will not put them in medal contention.

That raises the question of whether one or more of the triplets would ease up a little to ensure they cross the line together, completing their long journey together.

"If you think like a team or like sisters or with your heart, maybe the best way is to finish together," Liina said. "It's good if we are together. But if I feel my personal best coming, I'll go."

Normally twins running in the same race would attract attention but the presence of the triplets means the 26-yeas-old Anna and Lisa Hahner are receiving less attention than usual.

The pair have cultivated a strong commercial brand in their native Germany but had an anxious wait to see if they were going to Rio together.

While Lisa qualified second behind surprise package Anja Scherl in the German team in 2:28:39, Anna's 2:30:19 only earned the final berth in the team.

"Of course we will compete with each other," Lisa said. "But we are firstly happy to have a twin sister. "That way we can experience everything together and push each other along."

They are also likely to be well short of the medal battle with Ethiopia's Tirfi Tsegaye holding the year's best time of 2:19:21 and her world champion compatriot Mare Dibaba joined by London marathon runner-up Tigist Tufa.

In London in April Tufa was second to Kenyan Jemima Sumgong, who won a tight race despite suffering a head injury when tripped. Helah Kiprop, a disappointing sixth in London, and Paris marathon winner Visiline Jepkesho.

Away from traditional African distance running powerhouses, former race walker Olga Mazuronak of Belarus could hold an outside medal chance.

- dpa