Tag Archives: Science & Football

The Science + Football Conference: Day 2

Last up in this series of reviews covers the second part of the Science + Football conference.

On day 2 of the conference I kept a low profile and stuck to my seat in the presentation theatre for most of the day. It was another day of sessions from a wide variety of speakers (as by now I had become accustomed to) including psychologists, sports scientists, statisticians, scouts and a panel session including former England manager Steve McClaren.

Dr Misia Gervis, who I noted in my earlier review of the Sports Analytics Innovation Summit, gave a presentation which really struck a chord with the post I wrote on Saturday evening. A senior lecturer in sports psychology at Brunel University, Gervis’s talk discussed positive psychology and how it can be applied at football clubs. She is actively involved in efforts to bring psychology into football clubs so that it can be used to benefit players and performance. Actually, in a follow-up to my earlier post, I had already been advised to look into the work of Jacques Crevoisier whose work with the development of psychometric tests for Liverpool and Arsenal has been well-documented (although I didn’t know of him before this tip). Gervis discussed resilience: “the ability to take hard knocks, to weather the storm and to value oneself no matter what happens” – this is affected by fear of failure, perfectionism, injury and criticism with a further impact on emotional control and decision-making. She highlighted the importance of using the concept of ‘signature strengths’ with players, where their best attributes are identified and developed to help create the right conditions for them to flourish.

We were also treated to a couple of lectures about fitness planning and training regimes by Dr Peter Krustrup of the University of Exeter and Matthew Cook, head of sports science for the MCFC academy. Both discussed how optimal fitness training for footballers involves training sessions which mimic the movements and levels of activity in a match. Krustrup included work from one of his studies, showing how yo-yo training (high intensity intermittent exercise) performance was a better indicator of match fitness than VO2 max testing – although there is a correlation for footballers. Cook explained that for academy prospects at Man City, they go so far as to look at the biological age of players vs maturation levels to try to ensure that developing players are not discriminated against in comparison to faster-growing players.

That last point links in nicely with Blake Wooster’s presentation. Wooster, business development director at Prozone, described his role as a kind of coaching scientist. His views represented the future of analysis in sport when he said that clubs should “use analytics to drive and not just inform decision-making”. Wooster’s session tied in with Rasmus Ankersen’s presentation from the day before (and to a lesser degree Cook’s reference to youth maturation) as he discussed the relative age effect in youth team football. He showed how different youth age groups are concentrated towards players born in the months directly following the cut-off point because the oldest boys are likely to be the most developed e.g. where the cut-off is 31 December, players selected in a football team are most likely to be born in January and February. He went on to describe the current Belgium national team, which has an incredibly strong first 11 at the moment, and how in recent years they overhauled their age groups to include 2 separate teams – one ‘A’ team and a development team called “the futures”. Wooster also gave an example of how Prozone calculate expected pass-success rates vs actual success rates to analyse youth players and potentially identify undervalued talent – this for me was a very satisfying use of stats to aid player appraisal. Wooster, however, did admit in the later panel session that analysis is still in an embryonic stage and that the term ‘moneyball’ in football is not particularly useful in selling analytics to clubs.

For what it’s worth, the presentation that I thought was the most interesting and well-measured throughout all of the 30-odd sessions I saw over the 4 day period was from Liverpool’s Director of Research Dr Ian Graham. Graham joined the club in the summer of 2012, following 7 years with a football analysis company. His presentation, entitled “The trouble with statistics” included the right balance of caution, care and logical proofs in answering a simple question: are clean sheets more important than scoring goals?

Graham’s regression analysis showed that one extra goal scored for a team is worth 1.02pts on average, whereas one extra clean sheet is worth an additional 2.99pts. From that piece of information alone I suppose one could be forgiven (if you want to be kind) for thinking that clean sheets are indeed more important than goals scored. But the R-squared of goals scored vs points is 77% whereas for clean sheets vs points it is 65%. The relationship with clean sheets is weaker because of volume – clean sheets are a limited resource whereas goals scored are unlimited in a match. In order to improve from an average level of goals scored (50 per season) to the top quartile you would need to score about 10 more on average (+20%). However in order to go from 11 clean sheets (average) to the top quartile level of 14 per season you need to improve by +27%.  Hence we might say it is ‘easier’ to score more goals than to improve clean sheets. Having shown this, Graham explained that the FA really was a pioneer in football in 1980 when it became the first association to introduce 3pts for a win in order to incentivise attacking football (not that it had a major long-term effect). He also discussed the path of strategies for teams at different levels – showing that clean sheets are still relatively more important for below average sides who are less likely to outscore a top team and will have a better chance of success if they restrict their opponents from scoring.

The last session I attended was the coaching panel with Steve McClaren, Paul Holder (FA national coach) and Scott Miller (first-team fitness coach at Fulham). As I noted in my previous post, McClaren began by talking about how great it was to be able to support an exhibition of innovation in football, before saying that “all I want from you science people is fitness and injury stats”! He insisted that management needs be allowed to work on instinct – which just goes to show the reality of the challenge that analytics has to overcome if it will ever become fully integrated at football clubs. He gave some useful insight into his knowledge of the differences in coaching between the Netherlands and England – in the Netherlands it seems that football-related training and fitness training with a ball are given more of an emphasis. McClaren used his experiences from Twente and Wolfsburg to argue that game intelligence in England needs to improve, giving an example of a young player at Twente who, when he was asked his opinion on team tactics for the upcoming game, gave a such a full account of player positioning and where to concentrate attack/defence with a good enough understanding to be one of the coaches.

One of McClaren’s final points was that “coaches go into a comfort zone where they don’t seek to learn more. More coaches should get out of their comfort zone and try to learn new skills and gain knowledge and experience”. Finally a positive from him that could be taken for analytics, although unfortunately he wasn’t talking about the use of performance data by coaches!

Final note

I have been quite prolific over the past 7 days in terms of writing and reviewing the conferences and this is for 2 main reasons. Firstly, I have been inspired with ideas and enthusiasm after attending the conferences – for anyone with a serious interest in sports analysis I would definitely recommend getting a ticket for either (or both) next year. Secondly, the readership of my blog has increased well beyond usual levels since I started it about 6 months ago so thank you to everyone who has taken an interest and in particular retweeted/shared the link of my blog to followers, colleagues and friends. My enthusiasm in posting the reviews quickly has meant it has all been a little unfiltered but I have tried my best to keep them as informative as possible!

 

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The Science + Football Conference: Day 1

Having never attended this conference before (this was its 3rd year) I didn’t quite know what to expect – that led me to think that the organisers could perhaps make an improvement to the way they advertise and describe what the event actually is! Fortunately the conference name ‘Science + Football’ gives a pretty clear indication of the theme of the 2 days.

The event was held at the Soccerdome in North Greenwich, London with 4 main zones: coaching area, boot room, interactive arena and presentation theatre. Although I tried to see a bit of everything, my interest was mainly in the performance analysis sessions/lectures which took place in the presentation theatre – and luckily for me that was inside rather than outside in the freezing cold! I was also a bit more selective in what I saw. But I am happy to say that the standard of presentations and speakers was of a very high standard – with, amongst many other great speakers, sports science gurus from Manchester United and Manchester City, nutritionists from Arsenal and Bolton, representatives from Prozone, Liverpool FC and even a panel session with former England manager Steve McClaren.

First up on day 1 was a minute’s silence in memory of influential performance director Nick Broad, followed by a coaching session with Tony Strudwick. Strudwick’s session, where he put some youth players through their paces, was incredibly different from his session at SALDN – indicating the contrast between the 2 conferences. The coaching sessions offered good insight into coaching/training tips (less relevant for me) and they are useful in showing how skills are being developed by particular drills. The analyst in me, and this would no doubt irritate the coaches massively, would want to know the relative benefit of each drill and how they are selected – I’m living in a bit of a dreamworld there!

Something that became apparent to me over the course of the conference is how much more of an emphasis there is on coaching 1st, fitness and injury prevention 2nd, then probably psychology and performance data analysis tied in 3rd place. There is still a palpable divide between traditional thinkers (in general driven by coaches) and the appliers of science who seek to optimise the traditional approach. A quote from Steve McClaren confirmed the scale of the divide for me during his opening speech in the Sunday panel session when he stated: “All I want from you science people is fitness and injury stats”. That is the most striking quote I lifted from his talk in which he said many other useful and interesting things about coaching in the modern game but it really does hammer home the reality of how far away Moneyball-type methods are from being integrated into coaching. I will discuss McClaren’s thoughts (or indeed my interpretation of them) in the second part of my review of the conference.

Companies like Opta and Prozone are straddling the gap between conventional wisdom and the analytical approach. They are certainly selling the concept of analytics for football, with varying success, but it is clear from the difference in language used by performance data analysts and, say, sports scientists with a focus on fitness, that the performance data analysts need to heavily soften their findings and vocabulary in order to sell analytical ideas to coaches and teams.

Sometimes the analysis itself is to blame and sometimes the delivery of it misses the mark. That is particularly troublesome for sport when an analyst can easily draw spurious conclusions that undermine his research even before he undertakes the difficult task of translating analysis into something useable by coaches. Jim Hicks, head of coach education at the PFA, gave an encouraging session discussing the use of Prozone data in the Premier League. He looked at:

  1. The location of shots that result in goals
  2. The optimal passing locations that result in assists
  3. The number of touches taken by goalscorers

For me, the conclusions of this analysis could have done with a little more reasoning. I understand that Jim Hicks was using the analysis in order to frame a youth coaching session (which I didn’t watch – so I might well have missed some extra depth) and in that sense the analysis is perhaps more effective if it is short, simple and to the point. But with regards to the position of shots that result in goals it uncovered nothing new to what players and coaches should already know – that more goals are scored in central areas close to the goal than wide areas or outside the box. We can probably take some value in teaching players who consistently shoot from long range or poor angles to stop doing it so frequently. Perhaps that is a small step forward, but do we need stats to tell us? The next revelation was that the best zones for creating an assist are again central but this time just outside the area. Not exactly rocket science, I can imagine that it would be quite patronising for a coach to be told by an analyst to get their players to have more possession in and around the penalty area – particularly in central positions – they will score more goals! The third point was more interesting: the highest proportion of goals scored in the Premier League are those where the scorer has only taken one touch. Even this is heavily influenced by tap-ins but I would suggest that superior technical ability will still enable certain strikers to score more if they are able to make a higher proportion of 1 or 2 touch goals – assuming the volume of goals under pressure is high enough.

Nevertheless, the questions asked of data and indeed the analysis itself has to go much further to be significant. How do we develop strategies to get players into the right positions on the field (with the ball) so that they penetrate the danger zones? Simply encouraging players to get on the ball near the penalty spot in order to score more goals is based on a brief observation of where goals are scored from, with not enough attention paid to the phases of play that most often lead to this kind of opportunity.

Garry Gelade, who has colloaborated with Chelsea and more recently PSG in player recruitment analysis, proved that in some cases there is indeed more than meets the eye in terms of analytics at top level clubs. His presentation discussed a valuation of goals scored across the top European leagues. For his research, he cross-referenced a high volume of matches in the top leagues plus games between them at Champions League and Europa League level to infer rankings (a bit like the UEFA coefficient) for defence and attacking ability. From this he was able to make a judgement on the average level of defensive and offensive strength in each league and also how many goals a striker could be expected to score in the Premier League (on average) if they have scored say 15 in a season in the Eredivisie. That kind of a question, although subject to the same old criticism of the use a mean value where the variation in individual cases can be large, still serves as a great example of the use of analytics to hone player recruitment strategy. It also gives a nod and a wink to the kind of research that does happen at top football clubs – despite the veils of secrecy in place. How much it is applied is another question, however as outside observers we can all recognise the probable application of a player recruitment strategy at Newcastle United today – where they are clearly uncovering value in Ligue 1 in particular. There is little question in my mind that this is the result of an analysis-informed approach.

Rasmus Ankersen, apart from trying to sell his book (The Gold Mine Effect, sounds quite interesting actually!) told us about the pitfalls of talent identification and scouting. His prime example was Simon Kjaer, who even at 15 years old was not recognised for his talent and high potential by any of his coaches at the time (including Ankersen himself). Ankersen discussed many hidden factors that can be missed when we look purely at qualifications or conventional wisdom in evaluating talent. He used many examples, including one from Jamaican national team sprint coach Stephen Francis who identified 2 sprinters, 1 who runs 100m in 10.2secs and another who can run 10.6secs. Which sprinter would you prefer to train? Of course, it should depend on the circumstances in getting those times: if the 10.2s runner trains in world class facilities to strict regimes then perhaps his potential is much lower than a 10.6s runner who has developed his own style with indisciplined training. Francis would likely select the 10.6s runner who is slower on paper but has the potential – the runner in this anecdote being former world record holder Asafa Powell. The main theme of Ankersen’s work looks at the environmental, geographical and unique factors that breed success in particular ‘gold mines’ throughout the world, like the Jamaican sprint team and Ethiopian long distance sprinters, many of whom come from the same small town of Bekoji. I guess I’ll have to buy the book to find out if Ankersen offers further guidance on how to spot these hidden talents!

All in all it was a very enlightening day 1 of the conference with both encouragement and discouragement for the use of analytics in sport in equal measure. Obviously I am a little behind in posting this considering the conference came and went at the weekend – but for all those interested I expect to have another review for day 2 written up in the next couple of days.