Tuesday, 21 July 2015

Man Games Lost To Injury In The Premier League (2012/13 - 2014/15)

I first wrote about injury and man games lost to injury all the way back at the start of 2013. That first post on the topic of injuries was followed by this , more extensive, post on the 2012/13 season. I didn't post too much on the injury data for the 2013/14 season for I was informed, with the best of intentions, that I may want to keep any future data private for purposes that were never disclosed (money, I guess. Though I am certain there ain't no money in this!). 

Anyways, I don't want to keep data private or try and hawk any wares, be it good, bad, or any lemon in-between. Personally, I much prefer making any data, or writing, public with the intent of having folk beat the shit out of it, mock it, or make recommendations for the purposes of improving one's own work. That said, I am probably in the minority here. 

I digress, go read those linked posts for more info on method, the effect of European football on injury totals (only 1 season), and a few brisk thoughts on potential solutions to the worst of the injury problems that the league has.


Man Game Lost To Injury = the number of games missed by a single injured player. For example, imagine a player, let's call him Linvoy Primus, suffers a simple calf strain and is injured for 30 days. Linvoy's club plays 4 Premier League games during those 30 days. Linvoy Primus misses 4 man games lost to injury, his club has lost 4 man games lost to injury.
I'll try to keep things short from now on. Lots of graphs, fewer words. 


This sortable table lists each club and their man games lost to injury for each season.

Villa, Newcastle, Man United and Arsenal posted consistently high numbers by this metric. Chelsea, on the other hand, have posted consistently low numbers despite carrying a relatively small squad.

Sort away, if you like.

S 12/13 Man Games Lost  S 13/14 Man Games Lost  S 14/15 Man Games Lost 
Arsenal 12/13 138 Arsenal 13/14 211 Arsenal 14/15 231
Aston Villa 12/13 219 Aston Villa 13/14 182 Aston Villa 14/15 169
Chelsea 12/13 81 Cardiff 13/14 67 Burnley 14/15 113
Everton 12/13 82 Chelsea 13/14 79 Chelsea 14/15 53
Fulham 12/13 116 Palace 13/14 128 Palace 14/15 98
Liverpool 12/13 122 Everton 13/14 175 Everton 14/15 180
Man City 12/13 140 Fulham 13/14 120 Hull 14/15 130
Man United 12/13 148 Hull 13/14 112 Leicester 14/15 79
Newcastle 12/13 175 Liverpool 13/14 131 Liverpool 14/15 173
Norwich 12/13 109 Man City 13/14 134 Man City 14/15 86
QPR 12/13 119 Man United 13/14 135 Man United 14/15 169
Reading 12/13 94 Newcastle 13/14 157 Newcastle 14/15 253
Southampton 12/13 66 Norwich 13/14 123 QPR 14/15 140
Stoke 12/13 70 Southampton 13/14 92 Southampton 14/15 138
Sunderland 12/13 117 Stoke 13/14 71 Stoke 14/15 124
Swansea 12/13 91 Sunderland 13/14 99 Sunderland 14/15 114
Tottenham 12/13 128 Swansea 13/14 108 Swansea 14/15 88
West Brom 12/13 106 Tottenham 13/14 165 Tottenham 14/15 72
West Ham 12/13 115 West Brom 13/14 127 West Brom 14/15 82
Wigan 12/13 145 West Ham 13/14 143 West Ham 14/15 111

The above table tells us the raw man games lost to injury for each team, but it tells us nothing about injury trends throughout the season. 

Man Games Lost To Injury On A Monthly Basis

The chart below tells us the league total number of man games lost to injury on a monthly basis for each of the past three Premier League seasons. There's a pretty clear trend in this chart.

If we focus on the 3-year average for a moment we can see a gradual increase in total man game lost from August through to October. We then see a significant jump from 188 games lost in October to 297 in November. There is then another huge jump in December to 453 games lost. 

That number then cools to 313 games lost in January and 248 games lost in February. 

Those mid-winter months of November, December and January really deserve some further investigation. 

A simple question: Why does the league suffer so many injuries during these months? 

Games Per Month

Part of the answer to the question posed above is pretty simple: the number of (league) games played in each month is a pretty important reason as to the number of injuries that occur in certain months.

If we look once again at the 3-year average, we see that the Premier League has a light schedule in the months of August to October. November sees an average of 5 Premier League games, December 6 Premier League games and thereafter, more or less, we see an average of 4 Premier League games scheduled in the remaining months.

It's been over three years since I started collecting this data and I am still unsure as to why the Premier League continues to schedule so many games around November, December, and January (not to mention that clubs also have European football and domestic cup competitions to contend with). Why not redistribute some of those mid-winter games to the early season months thus flattening out the schedule? The international schedule is probably the reason why this 'flattening' out doesn't happen.

Anyway, back to the question I posed: Why does the league suffer so many injuries during these months? 

Part of the answer is the bottleneck of games in mid-winter months. There's also the graph below.

Man Games Lost To Injury On A Game Week Basis

The chart below is showing us man games lost to injury on a game week basis. If fatigue, recovery time, and rotation were unimportant things then maybe we should see a semi-random distribution of man games lost throughout the season.

Instead, we see a gentle increase in weekly games lost to injury, a peak of sorts from week 14 to week 21, and then a gentle decline to week 27. Then injuries slowly pick up again. 

Curious stuff.

The chart above shows the aforementioned steady increase in games lost to injury in the early weeks of the season. We then see a smallish peak in games lost to injury from about week 14 to week 21. Game week 14 is roughly the first week in December and game week 21 is roughly the first week in January. This is our peak of games lost to injury.

Why do we see a peak for those 35 or so days? Big squads and rotation are now the norm at nearly every Premier League club yet the intensity of the league, sheer number of games, insufficient recovery time, travel, games just 3 days apart at certain points in our 'peak', and players playing whilst in the red zone in terms of fatigue would be my guesses.

Despite all the work that goes into injury prevention and sports science I'm unsure how a team who is playing in all competitions is expected to cope with 8 PL games, 1 European game, 1 League Cup game and an FA cup game in a ~35 day period.

Two years ago I wrote the following: 

Looking over the injury total numbers for the November to January period it becomes difficult not to argue the case for a winter break. No club wants to pay a substantial wage to players who are not able to do their job. Injured players - especially crucial players - cost clubs in terms of performance and points, and thus money. Why clubs and the PFA don't push harder for a winter break in order to protect their players and assets is difficult to grasp.
A front and back loaded league schedule which avoids clashing with the bulk of the the domestic and European cups would surely be a better idea than the current setup. Games could be more evenly distributed across the months, injuries may decline due to this and teams would benefit in the ways already stated. Players may stay healthier, managers can field stronger teams and owners may not be wasting as much money paying injured players.
Seems sensible, so it probably won't happen.
My thoughts haven't changed much in two years. A flattening out of the schedule - be it front or back-loaded - whilst retaining the historic Boxing Day and New Years Day games, makes a little more sense to me than the current setup which crams a crazy amount of fixtures (all competitions)  into the months of November, December and January.

In short: 

  • Teams suffer too many injuries in the mid-winter months. 

  • This is due to the sheer number of games played in all competitions. 
  • The frequency of games played in those mid-winter months allows for little recovery time between fixtures. 
  • This leads to fatigue, minutes on the field when players are in the red zone re injury risk, and finally, actual injuries.

Fix the winter fixture list.

*Also worth noting that work on injury metrics could be improved upon if we could we had salary information available for all players. A metric along the lines of CHIP (cap hit of injured players) would be an improvement.