How Are Player Actions Tracked So Accurately In Sports?

data tracking sportsThe development of technology has been a blessing and a curse for sports. From a bettor’s point of view, the ability to place wagers on live events means that we can have a bet on virtually every aspect of what we’re watching, all kept up-to-date in real time by the companies that give us the chance to spend our money.

When it comes to the actual sport, every technological advancement that seems to take away from the game, such as the Video Assistant Referee in football, is up against a change to the way analysts can gather information to improve things dramatically for sides.

For a long time, the only information that analysts had to work with was the likes of goals and assists, perhaps with others such as touches of the ball and key passes coming into the conversation over time.

In other sports, like basketball for example, that was limited to points, rebounds and assists. The information just wasn’t there for teams to accurately offer any sort of explanation of what they had going on with the side during matches. In recent years that has changed dramatically, but how is it that companies like Opta can accurately track players so well?

Optical Tracking

football tactics board formationOf all of the things that have changed the game in sports, there is nothing quite as influential as optical tracking. In simple terms, optical tracking systems use visual information gained from cameras strategically located at sporting events in order to paint a picture of what is happening.

This can include both the things that a player is doing and also what is happening to the ball at any given moment. Think of a time when you’ve watched a round of golf on television and seen the path of the ball after it’s been hit. This is thanks to tracking technologies that show where the ball is heading.

The information that is gained from the cameras is fed into a sophisticated computer algorithm to work out exactly what it happening at any given moment. Using multiple points and sensors allows for the computer system to triangulate the location and orientation of everything the camera sees, giving three-dimensional positional information.

The cameras capture images of the players and the ball at a high frame rate, typically several times per second, allowing for a complete picture of what is taking place in almost microscopic detail, which is ideal for data analysts.

Electronic Performance & Tracking Systems

sport technology concept

The majority of football clubs have in-house analysts that engage in their analysis. They do so using electronic performance and tracking systems, which track player movements and feedback data on the likes of a player’s position, their velocity, acceleration and the distance that they cover. There are three main types of EPTS systems that can be used, which are as follows:

  • Optical-based camera systems
  • Local positioning systems or LPS
  • Global navigation satellite systems or GNSS

There are also 3D motion capture systems that Arte often used to validate EPTS devices. They are incredibly accurate within small areas, able to provide sub-millimetre errors to users. The problem is that they can’t cover an entire football pitch at the same time, which is due to the weak depth of field offered by 3D motion capture cameras.

A study carried out by Dr. Robert J. Aughey and colleagues suggested that a hybrid system that combined 3D motion capture systems with a computer vision system known as VisionKit might be the way forward, with research providing accurate data from both camera types to within millimetres of deviation of data.

Why It Matters

football cartoon with question markKnowing how technology can help analysts at football clubs, baseball teams or the coaches of professional tennis players is all well and good, but the obvious question is about why it matters.

The answer is that most sports are decided on fine margins in the modern era. Whilst dinosaurs of the game like Richard Keys might mock clubs like Liverpool for working with throw-in coaches, that is the kind of small detail that can help make the difference in a football match that is often won by a single goal. Equally for tennis players, even just a couple of points can make the difference between a match being won or lost.

Being able to track players accurately isn’t just about the spectacle for people watching on television. It is also the sort of information that coaches can use to remove the possibility of players coming up with excuses for their performances. Instead of relying on a player saying what they did, accurate data tracking allows for coaches to look very specifically at what happened and work out from there what went wrong with a match or performance.

Combining data from a host of different systems paints a more accurate picture of the reality of an event than eyes alone will ever be able to do.

Tracking Fails

As much as technology has advanced to the point that the movement of players and the ball can be tracked with extreme accuracy, there have still been more than a few occasions in which it has failed. By introducing technology into aspects of sport that can be decisive for the outcome of games and matches, we have effectively removed human error and shifted the error over to computer systems.

That makes it harder to blame a specific person, but no less infuriating for the team or player that is on the wrong side of it. Here are some examples of when tracking when wrong:

The ‘Freak Occlusion’ That Saved Aston Villa

In June 2020, Aston Villa and Sheffield United were engaged in a tense battle in the Premier League that would have implications to the relegation battle. Oliver Norwood whipped the ball into the box for the Blades, which Aston Villa’s goalkeeper, Orjan Nyland, collected out of the crowd.

He carried the ball across the line but the Goal-line Technology system failed to alert the match referee, Michael Oliver, that it had done so. This was later blamed on a ‘freak occlusion’ that hadn’t been seen in more than 9,000 matches, but it resulted in Villa gaining a point, which was what kept them up over Bournemouth at the end of the season.

A Similar Failing Saw Blackpool Win

There was a similar failing of technology in a Championship match between Blackpool and Huddersfield Town in the Championship in the 2022-2023 season. This time the ball was bundled across the line by Yuta Nakayama, with replays clearly showing that it should have been a goal.

When the referee’s watch failed to buzz, however, he neglected to award it as such and Blackpool were able to cling on for a 1-0 win. At the end of the season it didn’t make a difference, with Huddersfield finishing comfortably above Blackpool in the Championship table, but it was yet another failure of technology at a crucial time.

Andy Murray v Nikoloz Basilashvili

As if to prove that it isn’t just football that can have technological errors, there was also a failure during the match between Andy Murray and Nikoloz Basilashvili during Wimbledon in 2021. It was an exciting match in which Murray went into a two set lead before seven games in a row saw Basilashvili get back into it.

When Murray went 3-1 up in the fourth set and the score being 30-30 on Basilashvili’s serve, a ball was called out and Hawk-Eye was turned to confirm. After a lengthy delay with nothing appearing to happen on the screen, the umpire stuck with the original call. In the end, Murray won 6-3 to take a 3-1 set victory.