The Under Armour Race is a phenomenon in Costa Rica: in just its second edition it is already among the two or three largest races in the country, bringing together 5,100 officially registered runners and easily could have been many more. Both the first edition (2014) and the one that will be held this Sunday sold out their spots more than a month in advance.

Much of the excitement for the race is due to the quality of the package that athletes receive. "Any of the items that come in the package is worth what the registration costs," explains Rodolfo Villalobos, from Grupo Publicitario, the company in charge of the event's logistics. That includes an original Under Armour shirt, cap, and bag. But the race is also charged with emotion because it is, officially, the race that determines the National 10k Champion. So the best athletes face off to claim the title in a single event, all or nothing. This Sunday the two 2014 champions will defend their title, Alejandro Calderón and Cristina Marín. Alejandro will race against brothers Hibert and Gustavo Mora and against triathlete Leo Chacón. Mexican runner Trajano Nnera will also race, and if he wins he would take the prize money but the title would go to the first Costa Rican to cross the finish line.

The same happens with the women. Colombian Jenny Méndez won last year and will race this year too, but since she is not Costa Rican (yet) the title goes to the first Costa Rican woman to cross the finish line. Last year that was Cristina Marín.

Course analysis.

The 10k of the Under Armour Race has the advantage of being certified, meaning they are exactly 10.0 kilometers, no more, no less. So the time you achieve can be framed and you'll know that officially you ran 10k in that time. It's not easy, though. The race starts and ends with climbs, so a good strategy is vital to get a good result.

As seen in the graph above, the first 600 meters, which are in Sabana Norte, are uphill. And although you might think it's slight, the excitement of the first kilometer and that "slight" little climb can crush more than one runner's hopes. Then you enter the false flat of Avenida 10; at first glance it seems flat but in reality you continue climbing throughout the entire section. Finally, starting at kilometer 2.3, the descents begin. From there to kilometer 6 is a very slight descent, with just a brief interruption by a climb around kilometer 5, but very short. And from kilometer 6 to 8 is when the route really favors the athlete with a significant descent through Sabana Sur and the road toward Pavas.

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That said, don't give it all away because in the last 2k you have to climb the dreaded Rohrmoser boulevard until you reach the finish line again at the east side of the National Stadium (it does not enter the Stadium). At the end there will be music with a very well-known band (a surprise from the organizers) and more activities for athletes to stay and enjoy. "What we want is for this to be a party, so we have lots of activities, music, and sponsor events," says Daniel Espino, from Under Armour.

Other considerations

• There will be no parking inside the National Stadium, so the organizers' recommendation is to find parking in the areas around Sabana Norte. It's a good idea to arrive early, not only because of the number of cars looking for access (5,100 runners plus companions plus unregistered runners).

• Speaking of unregistered runners, the organizers warn that they will only allow athletes with a race number to enter the east side of the Stadium, from where the start and finish will be. So if you want to run without a number you will have to start and finish outside the Stadium.

• This year there will be no starting corrals; first come, first served for the best spot.

• There will be three aid stations on the route with water at kilometers 2.5, 5, and 8. Also at the finish line there will be water, sports drink, fruit, and other products.

• To pick up your package just present your ID or registration confirmation. If picking up for another person you must present a copy of the athlete's ID.