Why Mourinho must swallow a bitter pill to save United season

After Carnerio controversy at Chelsea, the Portuguese needs his club medics to help battle fixture pile-up

Having negotiated nine games in April, Manchester United travel to Arsenal today for their second match in four days with Jose Mourinho intent on resting several key players from the team who beat Celta Vigo on Thursday.

If United reach the Europa League final, they will face five more games – and the likelihood of an increasingly busy treatment room at their Carrington training centre – before their season is done.

Mourinho’s men have already run further than most this season, with five of their players featuring in the Premier League’s top 10 for minutes played. The chase for a top-four place and Europa Cup triumph will only add to the cumulative workload, both individually and across the playing squad.

Not surprisingly, significant pressure is being placed on the club’s vastly experienced medical department, and more injuries are certain. The key internal performance indicator in most clubs now is player availability for both training and matches. The target is 90 per cent squad availability, but 80 per cent is more often observed as the season wears on.

Injuries are a potential consequence of both the players’ previous fitness history and acute spikes in the workload associated with more games in a shorter period of time. United now face five games in 15 days, bereft of Zlatan Ibrahimovic, Marcus Rojo and Luke Shaw who have recently suffered season-ending ligament damage.

Scientifically, there is evidence to show fixture congestion brings increased muscle injury rates although, paradoxically, team performance is not usually affected.

This research was undertaken by the Football Research Group, which has been running the Champions League Elite Club Injury Study for over 15 years, with 22,000 injuries recorded and categorised.

In 2014 it investigated injury rates and team match performances, comparing them with the focus on the number of recovery days between matches. The data showed specifically that total injury rates and muscle injury rates, specifically hamstring and quadriceps injuries, increased in league matches played within four days. But team performance was linked to matchload only when teams played in the Europa League. Specifically, more matches were lost following recovery periods of three days or fewer.

Mourinho’s leadership could be crucial over the next couple of weeks. Historically he has been closest to his fitness coach, Rui Faria, but his relationship with Dr Steve McNally, the head of sports medicine and science, may well determine how many treatment couches are filled.

A FRG study over the past four seasons at elite European level focused on the power of internal communication in preventing injuries and maximising player availability at training and for matches.

It found that high-quality internal communication translated into increased player availability. The survey also suggested that the most important relationship for preventing injuries and positively impacting onfield performance was between manager and the head of medical department.

Of course, Mourinho has an unfortunate history with medical staff, particularly Eva Carneiro at Chelsea. The club eventually agreed to a humiliating pay-off.

At this critical moment in United’s season, Mourinho must show he has learned from his past mistakes.