At Wimbledon every year, the world’s elite tennis players compete knowing they can appeal to God if a human line caller gets something wrong. That God’s name is Hawk-Eye, and it makes decisions like this:
Hawk-Eye uses six cameras placed around a stadium to track the flight of a ball accurately, to within five millimeters, and provides a near-infallible second opinion if there is doubt over whether a ball has crossed a line. With its origins in military research, it doesn’t just change matches and tournaments. Along with other similar advances, it’s transforming sports as we know them.
Sports have had a long relationship with the military–warriors competed in the Ancient Olympics, and likewise many of the earliest known ball sports were played by soldiers. More recently, sports were considered vital to the training of 19th- and early 20th-century British soldiers. But over the past decade or so at least one aspect of that connection has deepened: technological innovations developed for military purposes are making their way into sports of all kinds.
Hawk-Eye was invented in 2001 by Roke Manor Research Limited, a British company that specializes in developing sensors for military applications–for example, in 1995 it put out a system called Halo that detects and locates gun noise for peacekeepers to use when monitoring the ceasefire in then-Yugoslavia. Though Hawk-Eye’s now a sports system, its ball-tracking capabilities were originally adapted from a fighter pilot training project.
Many sports now use it–like cricket, where Hawk-Eye has been a favorite of television broadcasters since its first trials in 2001. Since 2009, it’s been part of the sport’s official “Umpire Decision Review System,” the technologies that the game’s rule makers have decided are allowed during top-level international matches, alongside video replays.
One of these is the Snickometer–a microphone that can pick up the minute noise of a bat “nicking” a ball as it passes, signaling a hit. The other is Hot Spot, which uses an infrared camera to spot impact points between a ball and pad or bat, signifying a hit that might cause a batsman to be called out. And, like Hawk-Eye, it’s a product of military research–originally developed for detecting and tracking tanks, fighter jets, and warships in the dark or through smoke.
Neither Hot Spot nor Hawk-Eye are strangers to controversy, thanks to some high-profile blunders and system-fooling tricks, but they’ve been a fixture in the last decade of top-level cricket. And their successes are instrumental in the acceptance and spread of video review rulings in other sports.
Those are only the well-covered examples of this phenomenon, though–the trickle-down of military technology into sports is increasingly happening behind the scenes.
Sports scientist and physiologist Dean McNamara is one of the developers behind a wearable device that repurposes missile guidance technology for injury prevention and performance monitoring in cricket fast bowlers. (In cricket, the bowlers are like pitchers in baseball, throwing the ball at the batters; the two main styles are either fast and direct, or slower and with spin.) They’ve combined a number of other, smaller technologies. A custom software algorithm reads and analyzes the interactions between three positioning sensors–magnetometers, gyroscopes, and accelerometers, the same as used to guide submarine torpedoes–to precisely track their movements, along with the stresses on bowlers’ bodies as they throw a ball.
Training using this kind of idea isn’t radically new, and training kits with GPS trackers in them are standard issue at many professional clubs across the world. The Australian Institute of Sport developed a simpler wearable system with sports analytics company Catapult for athlete tracking back in the early 2000s, for example. (It’s also worth noting that GPS itself was designed by the U.S. Department of Defense around 40 years ago.) “They [the sensors] sit in a little device that’s about the size of half a mobile phone,” McNamara said. “And they sit in a wearable harness at the back around their thoracic spine region.”
Typically, though, the measurements these trackers record is limited to the journey of the ball–not the effort or strain on the human body. Fast bowlers typically bowl the ball between 80 and 99 miles per hour [130 and 160 kilometers per hour] and poor technique can cause physical damage. “How the ball is bowled is a big predictor of injury in fast bowlers,” McNamara explained.
He and his team at the Australian Catholic University’s School of Exercise Science have taken advantage of advances in guided missile technology to track that physical load instead. It’s sophisticated enough to quantify the forces at work during fast bowling while ignoring everything else that isn’t relevant. It can determine automatically when the ball has been bowled–a distinct action that’s different from the random events that occur throughout play, such as diving, catching, and fielding. By looking at the variables and how they change with each delivery, it’s possible to determine which training and in-game workload is appropriate for a particular bowler, and monitor them to ensure they aren’t fatigued.
Australian fast bowlers started using the new wearable about a year ago. McNamara says it’s still early, but the technology has been well received by both players and support staff. “Our elite fast bowlers and elite sportsman are very data-driven–especially in cricket. They want to know what they’re doing, and they want to know how hard they’ve been working,” he continued. “That’s not just for fast bowling. That’s for all their workload. They always want to know what’s going on with their GPS or micro-technology data.”
An Israeli company, PlaySight, is banking on the love of data as something universal across all sports–not only at the elite level, but all the way down to the amateur hobbyist and junior levels, too.
“We wanted to bring the know-how of how fighter pilots are being trained into sports,” CEO Chen Shachar said. He and his two other co-founders come from a military background: One was a fighter pilot, another an officer developing military systems, and Shachar himself had a stint as a major in the Israeli army reserve before holding senior roles at military training simulation and homeland security companies.
What they developed together is a product called SmartCourt. Six fully-automated HD cameras are installed around a tennis court and feed into a computer unit, which immediately provides feedback and advice players can use to analyze practice drills or full-blown matches. The technology was initially developed for tennis, but recently it’s become available for other sports, and–perhaps unexpectedly–professional dancers.
Its inspiration is the U.S. Air Force, which has long relied on “after-action review” in an effort to maximize pilot performance. “The idea is that the first thing in analyzing your performance, or after-action review, or even real-time feedback is getting the information,” Shachar explained. “So we call it “‘what happened,’ and then there is “‘why did it happen,’ and then it’s “‘how can I improve for the next time?’
“The most difficult thing is to understand what happened. Usually when you are tired and under stress, and there is a lot going on, the gap between what you think happened and what actually happened is very big.”
To help establish “what happened,” the technology borrows another military concept: event-based analysis. In military training simulations and real-world combat sessions, specific events are automatically given a classification. SmartCourt does the same thing for tennis.
SmartCourt also tracks the players–position, movement around the court, shots, serves–as well as the ball, and understands complex combinations such as a backhand cross-court winner. It does this using similar image-processing techniques to military and homeland security automated visual tracking systems.
Shachar believes tennis players have a lot in common with fighter pilots. Coaches can’t talk to them during a battle. Matches are long. Pressure’s high. And success requires not only good technique and mental strength, but also exceptional hand-eye coordination. “The best tennis players could probably have been good fighter pilots,” he suggested. The system itself, while still expensive for most tennis clubs ($10,000 plus a monthly subscription of $750), is significantly cheaper than the military technology it draws from.
Shachar thinks the trend of military and homeland security technologies coming to sports will continue. “The cameras are becoming cheaper, and the computers are becoming stronger in the ability to do interesting and fascinating things in sports,” he said. “The opportunities are becoming bigger.”
We can expect military innovations to continue filtering down to our local sports clubs, from protective gear to coaching techniques. We’ll see more things like the app the U.S. Army released last year, GoArmy Edge, that lets users draw American football plays on the screen like it’s a whiteboard– making lines, X’s, and O’s–before converting them into a 3D visualization.
Many gridiron football players now wear modified military vests as protective gear, and the U.S. Army Research Lab is developing a head-to-body tether system for NFL helmets that it originally created for protecting soldiers’ joints. The system attaches a player’s helmet to their waist and torso via a lightweight harness made from elastic tubes filled with a fluid. This fluid thickens and solidifies under sudden, dramatic changes in speed and stress–such as when a player is thrown backward–to cushion the impact of their head onto the ground.
While all this is going on, the British government’s sports research body, U.K. Sport, has been working with defense and engineering giant BAE Systems to prepare British athletes for the Olympics and Paralympics. Top Paralympians David Weir and Shelly Woods have practiced in the same wind tunnels used to design the Eurofighter Typhoon fighter jet, for instance, while kayakers have been training in water tanks used to test prototype war ships.
The reality, of course, is that sports and war share much in common. Most technologies that help soldiers and pilots will likely also aid athletes–helping them to jump higher, but also to land more safely. And many of these innovations are transforming competition not only for the players but for the fans as well.
Those GPS-based wearable sensors don’t just help players and their coaches. When the data gets shared with broadcasters, it gives us all new insight into the incredible athleticism and skill of the world’s greatest competitors. And we may just be getting started.
How We Get To Next was a magazine that explored the future of science, technology, and culture from 2014 to 2019. This article is part of our Playing the Field section, which examines how innovations in sports affect the wider world. Click the logo to read more.