Monday, March 17, 2014

Random Thoughts

Random Thoughts

I was in UK for last couple of days, and today I’ve visited Leicester City FC on the Performance and Injury conference (#LCFC_PIC). It was great to be in the great LCFC gym with same/similar-minded professionals and listen to their troubles and solutions.

I am not planning to provide an overview of the seminar besides mentioning data by Jan Ekstrand (@JanEkstrand) on injuries and providing some of my random thoughts and rationale.

Player rotation as a way of reducing injuries

There was a mention that bigger clubs (with bigger athletes/player pool) could potentially use player rotation strategies to reduce injury risk in key players and potentially save them for more important game during congested game periods. This sounds like a good plan, but not without troubles.

Here is one simple hypothetical example. First four clubs play playoffs. There is one game left to play-offs. Our team is first and decide to ‘rotate’ certain key players , to rest them for play-off. The game we are about to play is against team ranked 5th that has one point difference from 4th team, and hence a chance to qualify to play off. At the same time 4th team is playing against the team from the bottom of the table that wants to avoid relegation, or a least play-out.

If our team employs player rotation strategies and play with less than the best team, that doesn’t represent ‘level playing field’ for the team ranked 4th. Not sure how ‘moral’ is this to other teams, especially the ones that are left with a lot to fight for.  Carl Valle mentioned similar scenario happening in NBA in an awesome article Money ball Madness.

The point to be taken home is that these strategies should be discussed and some policies should be made at the league level. Hope that the above example shows why. Player rotation is simply more complex.

Coaches the cause of injury? 

Jan Ekstrand showed VERY impressive data showing injury tendencies in club with same manager/head coach – or in other way, certain injury history tend to follow the coaches whenever they go. This data is not yet available, but the UEFA has it and I think it is very interesting.

What it is interesting is that there is correlation between player availability and prizes won by these coaches regardless of the club.

Everybody is trying to bring to the attention injuries problems to the managers and educated them (or showing them the economical and performance cost of injured player and a single day missed). Maybe the solution is to add an injury history to their CV along with performance improvements and competitions won? Maybe the CEO and board should track this as well – this data might be very revealing. At the same time, maybe when this is implemented the managers/head coaches will not have the last saying in return to play protocols (“We need this guy on this game – it is the risk of re-injury we need to take. It is in the nature of our sport”). This simple tracking metric might change this culture over night. Let’s hope that this data sees the day soon, but I doubt it.

Injuries and club performance

I wrote about this interesting correlation study before (click HERE), but it is worth repeating. Apparently there is a CORRELATION (not causation) link between injuries and team performance, where teams with less injuries (time/game loss and/or occurrence)  showed higher league ranking at the end of the season.  Chicken or the egg problem IMO, even it is a common sense.

One could say that to improve team ranking one of the important goals might be to reduce injuries. This is just common sense, but it CANNOT be concluded from a study like this. The other way around could be said as well: to reduce injuries start winning games.

It is well known that overall stress reduces the coping and adaptation of athletes. Hence a losing streak is a hell of a stress and can impair adaptability and recovery of the players to the usual loads. Opposite might be true as well. If the team wins, everybody is a bit more optimistic, the hormones in the body might be better, body is coping with stress better and hence there is less injuries.

I might dig into some simple data once I get the chance – we have collected wellness questionnaire (not in a great frequency that would allow confident inferences) and I might look at the differences in scoring after a game won or game loss. We all know that wellness status might predict overtraining, illness and potentially injury (research to back up this bold claim Mladen?), but if a overall climate affect wellness, that also means it affect coping with training loads as sleep, nutrition, or coach/manager as showed by Jan Ekstrand.

Again, things are not that simple and cheesy as It sound, correlation doesn’t apply causation.

Ferrari in the traffic jam – or how to make use of physical match performance data to make erroneous conclusions

This is, I think, great analogy to explain why game physical performance data might be misleading. Data such as total distance run, high-intensity running distance or percent decrement in a last 20min of a game might not mean that the player is not able or willing to run, or even worse a proof of him be tired.

Suppose you are a proud owner of Ferrari. One day you go with your Ferrari to work. The usual distance is 10km both ways. On the way back,  at around 16:30 o’clock you got stuck in the traffic jam, so it took you 30min to come from work to home. In mathematical sense that’ s on average 20km/h. On the better days is takes 15min top and that’s around 40 km/h.  So, that day it took you double the time to cover the same distance ~ there is something definitely wrong with the Ferrari (since it cannot be ‘tired’), right?

This is pretty much the same logic we employ with match physical data. We cannot make any claims without knowing the potential and expression of that potential or in other words the contexts (tactical situation at hand). To really check if something is wrong with our Ferarri we would need to take it to the raceway where there is no (or at least minimized) constraints, so it can express his maximum potential. If things are different here (everything else being equal), then and only then this might reveal us something. Comparing the average speed it took from home to work in 12:00, 16:30 and 1:00 might just tell us about the constraints of the traffic and not much, or at all, about the car potential. It might take same time to Toyota, Fiat, Ferrari and Formula 1 to cover same distance during the rush hour.

Anyway, in physical preparation worlds, the “raceway” represent certain tests, and sometimes not always ‘sport specific’  (read more HERE). We  need to assess the potential in at least constrained and reliable environment.

If you have any comments please leave them down below.


  1. Coaches as a cause of injury wouldn't really surprise me. Everyone of us may have encountered some Head Coaches that just want to play certain players, do a certain drill or something like matter what the cost is. Most of the time it's a new phase of physical therapy and lower Training volume for this guy in the next week, just like in the week before, so you're in a vicious cycle. I also feel like some teams always have the same issues with injuries, like the Hamburger SV this year. It feels like every second player on their roster is out with a strain in the hamstrings or knee problems. But i think another factor is that you have to teach athletes to monitor their own body. Most of the guys want to get back as soon as possible, but only reinjure themselves because the were flatout lying about their own pain and problems. Often players don't even know if they are really hurt or just in a little bit of pain due to some excercises and feel like these things are the same...on both sides: beeing able to play through it or not being able to play through it.

    Speaking of Injuries and club performance: I'd love to get to read the study on it. There are a lot of teams that are struggeling due to injuries and it would be nice to know to which degree a series of injuries may prevent a team from having success. Borussia Dortmund had tons of injuries and struggled to cath up with Bayern München...when their team was healthy in the last seasons, they were an equal opponent to them. Same thing goes for the Detroit Red Wings in the NHL this year, who have all starting Centres injured. But i also feel like my injured players always get re-injured and my healthy players just stay healthy. The healthier ones approach each drill as a challenge, the injury-prones more as a they often really lose their body controll, stability, etc. just because they are afraid to reinjure themselves. The outcome of this is a lack of concentration and self-esteem that leads to a suboptimal jump, squat or sprint, with the effect of a re-injury.

    Just my 2 cents that are more subjective point of view and some experience.

  2. Thanks a lot for chiming in Nicolai. Sound points.

    As for injuries and performance correlation ~ it is a common sense, yet the causality (direction) cannot be concluded from a study design. Not sure if it ever be possible to design a study to show it though....