When animals carry loads, there is a proportionate increase in metabolic cost, and in humans this increase in cost is reduced when the load is elastically coupled to the load bearer. Major horse race times and records improved by 5 to 7% around 1900 when jockeys adopted a crouched posture. We show that jockeys move to isolate themselves from the movement of their mount. This would be difficult or impossible with a seated or upright, straight-legged posture. This isolation means that the horse supports the jockey’s body weight but does not have to move the jockey through each cyclical stride path. This posture requires substantial work by jockeys, who have near-maximum heart rates during racing.



from the teaser to the article

In 1897, an American jockey named Todd Sloan came to the United Kingdom and revolutionized the world of horse racing. Instead of dangling his legs down the sides of his horse, he squatted high in his stirrups. The British called the awkward-looking position the "monkey crouch," but the new seat quickly caught on: In the past century, jockeys using Sloan's technique have improved their race times by about 6%. Now researchers have figured out why the strategy is so effective.

NY Times overview by Joe Drape