A coaching app for tennis, created by SAP.

Sports tech: getting professionals to the top of their game

Sport is big business and these days teams, clubs, managers and players are all turning to technology for new ways of staying fit, maximising performance and outdoing rivals.

This time last year Germany won the World Cup for the first time since East and West reunified. Experts said that the Germans had the best players, the best team, maybe even the best manager. But they also had the best technology supporting them from behind the scenes.

At the 2010 World Cup and the 2012 European Championships, Germany lost out to Spain and Italy, teams that passed the ball quicker and with more purpose. Before the 2014 World Cup, Germany coach Joachim Low and his staff found technology that enables coaches to show the player the precise number of seconds he has the ball before passing to a teammate.

Measuring key performance indicators

SAP Insights is an app designed by one of Germany’s top technology companies. The software enables coaches to analyse thousands of pieces of real-time data about their players’ performance in training. This information helped the Germans devise their World Cup tactics and outwit, as well as outplay, the rest of the world.

The Insights app works on SAP’s High-performance Analytical Appliance (HANA) platform. Eight cameras surround the pitch and trace each player digitally. The software tracks the player’s movements, gathering data that helps coaches measure key performance indicators - number of touches, average possession time, distance travelled, movement speeds and directional changes. In just ten minutes, ten players with three balls can produce over seven million data points. The SAP HANA platform processes this data in real time, enabling coaches to customise training and prepare for the next game. German players reduced their average possession time to 1.1 seconds - down from 3.4 seconds at the 2010 World Cup.

In-game tennis match analysis

SAP has also developed a coaching app for women’s tennis. Since 2014, the women’s tour has allowed on-court coaching breaks during games. The SAP app enables coaches to collect and display statistics relating to aces, double-faults, first serve percentages giving the coach and their player a breakdown of what is going on in the game.

Before the Australian Open Final this January, Andy Murray complained that he was carrying a shoulder injury. Murray lost to Novak Djokovic in the final. Shoulder injuries are a common affliction for tennis players, so in 2012, Alison Sheets, then at Stanford University, now at Ohio State University, used markerless motion-capture technology to identify the relationship between different types of tennis serves and shoulder injuries.

Markerless motion-capture is widely used in the film and computer game industries, allowing analysts to record actors’ movements and use the information to animate digital characters. With it, analysts can track how a person moves without attaching markers. A computer algorithm allows the system to analyse multiple streams of optical inputs, identify human form and break it down for tracking purposes.

Sheets studied three types of tennis serves, and identified one in particular, called a kick serve, which creates the highest potential for shoulder injury. The kick serve is where the player tries to precisely time upwards and sideways racquet movements to generate spin. Sheets discovered that the kick serve generates larger forces on muscles crossing the shoulder joint than the other two serves, which could promote injury.

Using motional capture technology to prevent injuries

To discover all this, Sheets worked with seven members of the Stanford men’s varsity tennis team. Eight video cameras recorded each person’s movements at the same time, each shooting from a different angle. A computer program then combined the images to identify the 3D volume and shape of the person in each video frame. By comparing this shape to body measurements of the person under study, researchers could pinpoint the parts of the body that engage for a particular action, such as serving a tennis ball.

Sheets thinks that tennis coaches could use motion capture analysis of their players to prevent injury and improve performance.

“The potential for markerless motion capture is vast and exciting, because it can quantify how a person moves without the need to attach electronic markers or other equipment to their body,” she says. “People can move naturally, and in a natural setting outside of a laboratory.”

Traditional motion-capture technology works by attaching markers to a subject’s skin or clothing and tracking them as the subject moves. The markers emit an electronic signal or reflect light, and the associated wiring and other equipment can limit or otherwise influence people’s movement. The tracking has to take place in a laboratory setting, where lighting and background are carefully controlled.

It’s just not cricket!

The International Cricket Council uses this technology to test bowlers who have been identified by umpires as having used a suspect bowling action during an international game.

Cricket’s rule makers have never allowed bowlers to bowl with an arm that starts off bent and ends up straight. Unfair advantage, they say, as this can give them too much speed and too much spin. Studies in the 1990s and early 2000s showed that it was physically impossible to bowl without some degree of arm flexion and extension though, and in 2003 the ICC decided on a 15 degrees limit. Last year, the ICC suspended seven international bowlers for exceeding this limit - more bans than in the previous 15 years.

The ICC tells international umpires to report any bowler who looks as if they might be exceeding the limit. The naked eye can’t tell for certain if someone is breaking the rules, though, so the bowler has their action checked at one of the ICC’s six testing centres. The bowler goes through their repertoire of deliveries, the markers emit an electronic signal or reflect light, which the analysts track with motion capture cameras, high speed infra-red cameras and radar guns.

Sports technology degree courses

One of the ICC testing centres, Loughborough University, also has its own Sports Technology Institute, which runs undergraduate and postgraduate courses.

Senior lecturer, Jonathan Roberts, explains that the university’s BSc Sports Technology programme combines sports engineering and technology.

“The course is designed to equip students with the necessary skills to pursue a career in the sports equipment industry,” he says. “It covers design, manufacture, materials, mechanics, human sciences, measurement and computing.

“New technologies have transformed the way in which many people engage with sport, whether spectator or participant, amateur enthusiast or elite athlete. Sport offers great opportunities for new innovations as there are relatively few rules and regulations in place,” he adds.

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