Revealed: The Silicon Valley algorithm helping Liverpool cope with history-making quadruple assault

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Revealed: The Silicon Valley algorithm helping Liverpool cope with history-making quadruple assault
Revealed: The Silicon Valley algorithm helping Liverpool cope with history-making quadruple assault

“I always say we are a little bit like criminal detectives.” So says Dr Andreas Schlumberger, Liverpool’s head of recovery and performance, but it is hard to imagine even the most enlightened FBI agent employing anything more sophisticated than the extraordinary technology that is helping Liverpool in their quest for an unprecedented quadruple.

Invented by the artificial intelligence company Zone7, who are based in California’s Silicon Valley, Liverpool have been using cutting-edge computer algorithms that both detect injury risk and recommend preemptive action.

It all helps to explain why manager Jurgen Klopp chose to rotate nine key players in beating Southampton on Tuesday night, barely three days after needing 120 minutes to win the FA Cup.

It perhaps also helps to explain how Liverpool have slashed their number of lost days this season to injury by more than a third and retained such remarkable performance levels across 61 games.

News of the partnership can be disclosed today for the first time, as well as Liverpool’s decision to extend their use of the artificial intelligence platform by a further two seasons, as well as with both the women’s and Under-23 teams.

The Liverpool men’s first-team squad have been using Zone7’s technology since the start of this current 2021/2022 season. The platform analyses comprehensive player information, including in-game and training data, as well as biometric, strength, sleep, flexibility and stress levels to create risk signals and practical interventions, all aimed at improving performance while lowering injury rates.

That information is then directly delivered via an app to a club’s key decision-makers, ranging from the manager through to his various sports science, medical and coaching staff.

“Football has become very data rich and, if you can extract deep value from the data, then you can have a competitive advantage,” says Tal Brown, the chief executive and founder of Zone7. “This is already very well established in the area of talent identification, and it is now starting to happen in measuring and trying to optimise player wellbeing and performance.”

Brown was a first-class graduate of computer systems engineering at the University of Warwick before starting his career in the Israel Defence Force’s Intelligence Corps. His team have long been designing predictive software in other industries, ranging from cyber security to financial services, and began working in football four years ago. They duly gathered millions of hours of data from more than 30 teams worldwide, including Getafe, Glasgow Rangers and Hull City.

In its quest to identify patterns that might get missed by purely human analysis, the algorithm provides information at various levels, from football as a sport through to teams and individual players. It is designed constantly to update and improve with new data.

“The software can simulate optimal scenarios on a day-by-day basis so that the players are trending towards their peak and injury risk is minimised,” explains Brown. “Sometimes risk may mean a reduction in workload - less running of a specific type like sprinting. Sometimes a player can be undertrained and additional work may be required.”

Central to Zone7’s philosophy has been to also employ people with experience inside professional football to advise and help deliver the information in a way that is practical and accessible. “These are Premier League veterans - it’s not just a couple of people from Silicon Valley running around with spreadsheets,” says Brown. “It was a long process to create adaptations that make the software usable in a football environment. Football is not stock trading and neither is it anything else out there on a professional or human experience.”

Jordan Henderson has featured in 55 of Liverpool's games this season - PA
Jordan Henderson has featured in 55 of Liverpool's games this season - PA

At the time of the first Covid-19 lockdown in 2020, Zone7 had evolved to the point where they believed that their systems could detect 70 per cent of injuries up to seven days before they occurred. They specifically highlighted the correlation between game-load and injury, emphasising the elevated risk of six matches over a 30-day period. Liverpool have just completed their ninth match in 30 days, including the last seven back-to-back midweeks.

Brown cannot talk about the specific findings of any one club, and stresses that there “are no certainties”, but does reveal some fascinating insights.

Although there is indeed a general correlation between game-load and injury risk, this changes according to mitigations that are put in place and there are also very clear dangers associated with too much rest.

“We have found across all teams that, in about a third of cases, injury risk is attributed to under training and not overtraining,” he says. Environmental factors, such as travel and sleep, and whether a team has stayed in a hotel immediately after a fixture, are areas that are producing increasingly striking results. Zone7 also now works with teams both in the NBA and NFL, allowing their systems to identify trends which may be distinct or common to different sports.

“The algorithm is as good as the data - the more examples, the better it will become and, over time, it will have less black spots,” says Brown. Events like the condensed Covid programme and Liverpool’s current schedule have therefore provided rich opportunities to harvest new information.

According to Premier Injuries, a company which analyses injuries across England’s top-flight, Liverpool have recorded vast improvements this season.

They have so far lost 1,008 days to injury, compared to more than 1,500 in 2020-21. Crucially, the days lost to what are deemed ‘substantial injuries’, which are those lasting more than nine days, have almost halved from 1,409 to 841.

'Liverpool employ the best of the best'

Simon Brundish, who works as a consultant sports scientist for various clubs and players, believes that a change of approach became very evident early in the season. August and September is a period during which rotation is often very minimal but Liverpool were already averaging almost four changes per game.

It was a strategy that ensured key players could build gradually into the season and, crucially, that more peripheral squad players had game-time in which to establish partnerships. That would prove critical later in the season, such as against Southampton on Tuesday, when certain changes were forced upon the team.

“He kept players fresh while keeping a bigger pool of players topped up,” said Brundish, who says that Klopp’s “strategies of rotation have improved year on year” amid a schedule now that he describes as “incredible, unheard of” and “unsustainable” over any prolonged period.

“Klopp understands sports science - he uses the information and has a really collaborative team,” says Brundish. “He has developed a strategy, planned across the season, and then rotated deliberately and proactively ahead of time so that players have a specific chronic load.”

Conall Murtagh, Liverpool’s first-team fitness coach, describes Zone7 as “a helpful…innovative” resource which has been used over the last nine months “to help optimise” player care.

“It is a very exciting development for the future load management of elite football players,” he said. Brown also constantly emphasises the wider human expertise. “Liverpool employ the best of the best, in terms of data, sports medicine and staff,” he says.

“It’s a very delicate, well thought through process. Zone7 is a dashboard on the pilot’s cockpit but it is not the pilot. It is not magical software. It helps with some of the data heavy lifting but there’s a lot more that they see that the software does not - like players’ mood, their wellbeing, the tactical needs of the day. Ultimately it is human experts who are driving the show. It’s the human touch that makes that data useful and usable.”

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