Sensors are increasingly making their way into sports; after all, there are so many people—coaches, athletes, support staff—who need to quantify what an athlete is doing. What's interesting in these newer developments, however, is the range of applications to which the sensors are being applied.
Why is this happening now? Mostly it's a confluence of maturing and mutually supportive technologies. Sensors are available that are small, accurate, and draw very little power when they operate and that's why they're being incorporated into so many of our devices. Microcontrollers and signal conditioning have also matured, now enabling more sophisticated system behavior and again, using far less power to operate than their older and more power-hungry predecessors. Couple that with an array of communication techniques, and you can create a sensor-enabled system to tell you what you want to know, whether it's to give training feedback, give an athlete early warning of heat exhaustion, or to tell support staff just how badly an athlete is hurt.
Within sports science, sensors are a boon. In Adam Hadhazy's TechNewsDaily article, "Going Deep: Future technology in the NFL," he lists a variety of technologies being evaluated by the NFL for both refereeing (sensing whether the ball has crossed the goal line) or player health (instrumented helmets to measure impacts). Carnegie Mellon University's Football Engineering group has several related projects underway. Students under Dr. Sinan Muftu of Northeastern University developed a helmet to measure the severity of head injuries. And researchers at the University of Auckland's Dept. of Mechanical Engineering are developing a wearable impact sensor to allow them to measure impacts experienced by rugby players, runners, and high jumpers. Thin pressure sensors in shoes can measure the way a runner's feet meet the ground and the forces experienced. Sensors for sport science is, in short, a very exciting field.
Sensor systems for sporting endeavors have to balance functionality with the need to be as unobtrusive as possible; if you're studying a runner's gait, a system that doesn't let the runner run normally isn't going to do you much good. But that very quality—of being unobtrusive but useful—also means that I expect a lot more applications to crop up, once the researchers have more experience with these types of systems.