About 100 riders are injured in eventing falls every year, and when a multimillion-dollar horse goes down, even a minor injury like a twisted ankle can end its career. Computerized bases on the ground could project holographic obstacles, such as four-foot fences and 15-foot-wide pools, in place of dangerous physical objects. Line-of-sight infrared beams could monitor the edges of the obstacles; if the horse breaks the beam, the system would instantly alert the judges—and the crowd—to the fault.

Scoring the exact length of a long or triple jump can be imprecise and time-consuming. Athletes land in a sand pit, where they make several marks; officials must locate the mark closest to the takeoff line before they can measure. Researchers at Arizona State University have developed a 2,016-pressure-sensor array to map where an athlete hits the ground. Placed underneath the sand in the landing pit, a dozen or so of the mats could record the exact point of touchdown, and a computer could automatically calculate the length of the jump.

Swimmers are often unaware of their standing in a race until it’s over. Goggles with an integrated head-up display could broadcast a live view of the competition and help racers to better pace themselves. Waterproofed with an invisible layer of hydrophobic nanoparticles, a technique currently used on cellphones and other gadgets, a small computer tucked in the lower right-hand corner of the goggles would gather position information from other wired racers over Bluetooth and display it on a quarter-inch LCD.