Impact of New Managers on Player Injuries
It's one of the last scenarios a newly appointed football manager desires: just moments into their tenure, a key player is sidelined due to injury. This unexpected turn of events is hardly the ideal start, raising the question of whether it could have been prevented.
In addition to the primary goal of securing victories, maintaining a healthy squad is a top priority for any manager.
However, many experts suggest that the arrival of a new manager and coaching staff can often result in a temporary spike in injuries.
Ben Warburton, a physiotherapist and brother of Welsh rugby legend Sam Warburton, is one such expert. Having begun his career with academy players at Cardiff City and the Welsh rugby team, the Dragons, Warburton has primarily worked in rugby and served as Wales' physiotherapist during their summer tour to Japan this year.
"It is well established in the medical community that an increase in injury incidence often accompanies the arrival of a new coach," Warburton told BBC Sport. "Players strive to impress the new coach and secure a spot in the starting eleven, leading them to underreport minor injuries and push through discomfort, which can ultimately result in more serious injuries."
Changes in training methods can also play a significant role. "For instance, if a new manager prioritizes gym work, players who are unaccustomed to such a focus may face injury risks," he added.
Ben Dinnery, the founder of Premier Injuries— a website that tracks injury data for the Premier League— concurs. "Numerous factors contribute to this phenomenon," he noted. "A new manager may not be fully aware of the injury histories of players, which could lead to mismanagement. Additionally, player fatigue is a concern; a new manager typically seeks to maximize player performance, but this can lead to overexertion."
Furthermore, the psychological pressure on players to prove themselves can also lead to an uptick in injuries.
There are numerous instances where new managers have quickly lost players to injuries. For example, when Jürgen Klopp took over Liverpool in 2015, his squad experienced over 20 separate injuries within his first three months. Dutch coach Raymond Verheijen later claimed that Klopp had caused 20 hamstring injuries in 10 months, while Klopp often attributed injuries to external factors.
Following Liverpool's challenging Christmas schedule in 2016, which featured less than 48 hours between matches, Klopp remarked, "You might wonder, 'Why didn’t they perform well? Was it injuries?' Then the Dutch guy says, 'The training is not too good.'"
A growing body of research indicates that the appointment of a new manager frequently correlates with an increase in injuries. A UEFA Elite Club Injury Study published in 2023 asked 14 unnamed men's teams to report on staff changes and hamstring injuries. The findings revealed that new managers bringing in their own fitness or performance coaches led to a threefold increase in hamstring injuries. Similarly, a 2020 study of Turkish Super League clubs found that injuries more than doubled in the first two weeks following a coaching staff change.
Tracking Player Performance
Most top clubs utilize GPS technology to monitor player performance during matches and training sessions. Players wear devices that capture metrics such as distance covered and speed. "Some coaches may ease up on training during the week, but if they go too light, players can struggle during matches. Conversely, if teams train too hard, players may enter games fatigued, increasing the risk of injury. Striking the right balance is crucial," Warburton explained.
The Challenges of Analyzing Injury Data
One significant challenge in analyzing injury data is ensuring comparability. "A Premier League club competing in the Champions League under a new manager could play over 60 games a season," Dinnery noted. "Contrasting their injury rates with those of lower league clubs that play fewer matches is complex due to numerous variables. Factors such as the type of injury, the mechanism of injury, and the duration of recovery must all be considered. The timing of a new manager's appointment is also critical; if they join during the January transfer window or pre-season, they may bring in players from different leagues who are untested at this level, raising concerns about their ability to cope with the Premier League's physical demands."
'Avoid Rapid Changes'
In a results-driven sport, managers often feel compelled to implement their philosophies swiftly. However, Warburton cautions against rushing the process. "The new coaching team should assess each player's performance data and training metrics from the past 4-6 weeks before making drastic changes. It is essential to maintain a consistent training schedule during the initial weeks to mitigate significant changes in workload that players may not be accustomed to. I recommend tracking players' training volumes across various metrics and attempting to replicate those in training for the first month or two before fully implementing the new program. No one has discovered a perfect winning formula; if they had, it would be adopted by every club in Europe," he concluded.