This is not a level playing field, and that’s the point. On flat ground, there would be no contest. Four legs will always outrun two. It wouldn’t be a case of man versus horse but rather “man watches horse disappear over the horizon.”

Consider this: A fit long-distance runner will average a speed of around 9 mph, while a horse can maintain a steady canter of up to 17 mph. The idea of pitting one against the other seems absurd. But that’s what bars are for. They provide a forum for the contemplation of the absurd. A seemingly redundant question such as, “Can a human win a race against a horse?” will not be dismissed automatically. Liberated by camaraderie and alcohol, the discussion will inevitably modify the question: not “can” but “how can.”

The bar in which this question was raised most productively is located in the Neuadd Arms Hotel in the tiny town of Llanwrtyd Wells in the heart of Wales. The year was 1980. No minutes were taken, though we can presume that at the center of the debate was a comparison of the physical pros and cons of the two creatures in question. A horse is larger, stronger and faster but unwieldy. A human compensates for the physical deficit with sprightliness.

To achieve a metaphorical level playing field, all you would need is an uneven, twisting course that would slow the horse down but not the human.

As luck would have it, the Welsh countryside around Llanwrtyd Wells is perfect for a human-versus-horse showdown, with hills and bogs, farm tracks and tricky river crossings. Equally fortuitously, Gordon Green, the hotel owner, immediately recognized the commercial appeal of such a race and set about organizing. It has been held annually since 1981.

Although billed as a marathon, the race is run over a 22-mile distance. Hundreds of runners take part, competing against up to 50 horses. Some of the runners tackle the entire course while others choose to participate in three-person relay teams.

For the first 24 years, the original question was answered emphatically. Can a human beat a horse? No. Year after year, horses were ridden across the finish line first, often beating the first human competitor by more than half an hour.

Modifications were made to the course. The runners were given a 15-minute head start. The horses were required to stop at the midway point for a mandatory vet check. Gradually the time deficit narrowed until, in 2004, Huw Lobb finally proved that it is possible for two legs to triumph over four. He completed the course in just over two hours, crossing the line two minutes ahead of the first horse.

Florian Holzinger repeated the feat in 2007. Since then, horses have had the upper hand. On June 8, 2013, another crowd of runners will line up in the hope of adding their names to the exclusive roll call of two-legged winners.

Even if a human does win this year, cynics will contend it is only made possible by rigging the race. Of course, it’s not as simple as that. The physical challenge is only part of the story. We should also take into account desire, cunning and a sense of direction.

The biggest advantage for the horses is the riders sitting on top of them. Without human guidance, there would be no competition. The runners would endure the course, huffing for breath, pounding their joints, spattering their weary bodies with mud, while the horses would amble off to graze.

Which begs another question: Who’s smarter?