While several Olympic sports could lay claim to being the quirkiest or most underappreciated in Rio, only one stands out for having a name that doth protest its relevancy a bit too much: the modern pentathlon.

The sport is the jumbo shrimp of the Games, an oxymoronic enterprise that measures an all-around athleticism better suited for life before the Model T started rolling off the assembly line. After all, there isn't much that feels contemporary about a competition that counts horseback riding, fencing, and shooting among its five elements.

That's not to take anything away from the athletes, who are among the most well-rounded at the Games. But at a time when decidedly modern sports like surfing, skateboarding, and sports climbing are being welcomed onto the Olympic roster (they'll debut in Tokyo in 2020), the modern pentathlon is finding it harder to hold onto its place. As recently as 2013, it was nearly booted from the Games.

There are of course reasons for the design of the contest, which also includes running and swimming. The "modern" moniker makes more sense when you consider that it was meant to distinguish the event from its counterpart in the ancient Greek Olympics. The original pentathlon, introduced in 708 BC, brought together a constellation of sports that included running, long jump, spear throwing, discus, and wrestling. The climactic event, its winner was victor ludorum ("winner of the Games").

Modern Olympics founding father Pierre de Coubertin shared the Greeks' admiration for the pentathlon, and conceived a new format — drawn from the skills a good cavalry soldier would possess — that would channel the spirit of its predecessor. He believed the pentathlon, more than any other sport, "tested a man's moral qualities as much as his physical resources and skills, producing thereby the ideal, complete athlete." It debuted in Stockholm in 1912. (The future general George S. Patton came in fifth after receiving a terrible score in shooting.) In a sense, Coubertin's vision for the sport's significance was challenged right out of the gate, when Sweden's King Gustav V told Jim Thorpe, who took gold in the decathlon, "You, sir, are the world's greatest athlete" — a nickname for decathlete winners that's still used today.

Still, more than a century later, the pentathlon persists. Tweaks have been made to the rules over the years, many with an eye toward making it feel more current and fan-friendly. The women's competition was added at Sydney in 2000. Running and swimming distances have been shortened. Laser shooting has replaced real guns, and running and shooting have been combined into one event. The entire thing has been compressed from five days to four days to, essentially, one day each for the men and women. Starting in Tokyo, plans call for the entire pentathlon to take place in a single stadium, over no more than five hours.

The caveat to the one-day competition in Rio is a preliminary fencing round on Aug.18. The pentathletes each face one another in a series of high-pressure, one-minute bouts that determine the rankings for the main competition. (Seventy-two athletes participate, split between the men's and women's sides.) Points are awarded based on an athlete's performance during the individual bouts as well as their overall win rate.

Points are everything in the modern pentathlon. They are added to and subtracted from an athlete's score over the course of the multi-part competition, and are the basis by which his or her handicap is calculated before the final event, running and shooting. The more points you have, the bigger the head start you're given.

The main day of competition begins with a 200-meter freestyle swim, followed by a fencing knockout round; the two lowest-ranked athletes face each other to start, with the victor moving up the ladder to face the next ranked athlete, and so forth. Next comes horse jumping, which involves clearing 12 obstacles in a fixed time, with a twist: The horses are assigned to the athletes at random, so no one has familiarity with their steed beforehand.

Final scores are then calculated, and the athletes are assigned their start times for the last event, running and shooting. The 3,200-meter course features four stops along the way for target shooting. An athlete can start running again once he or she has hit the target five times, or when 50 seconds have passed. The gold goes to the first person across the finish line.

The U.S. women haven't earned a medal in the modern penthathlon since 2000, but Margaux Isaksen will be looking to change that. In 2008 she finished in 21st place, and in 2012 she jumped to fourth, missing the bronze by just two seconds on the final run. (Her younger sister, Isabelle, is also competing.) Among the other big contenders are defending gold medalist Laura Asadauskaite of Lithuania; England's Samantha Murray, who took silver in London; Germany's Lena Schoneborn, the gold medalist in Beijing; and Brazil's own Yane Marques, who took bronze in London.

With a ranking of 40th in the world, Team USA's Army Sgt. Nathan Schrimsher isn't likely to break into the top three. The better bets are defending gold medalist David Svoboda of the Czech Republic; reigning world champion Pavlo Tymoshchenko of Ukraine; Russia's Aleksander Lesun; China's Cao Zhongrong, who took silver in London; Hungary's Adam Marosi, who took bronze in London; and Egyptian brothers Amro and Omar El Geziry.

The women's modern pentathlon takes place on Aug. 19 and the men's on Aug. 20. No sport is guaranteed an Olympic spot past 2020, so just in case, catch it before it's too late.