Generally, performance analysis can be classified into two main categories: notational analysis and motion analysis. The two systems have different focuses. Notational analysis provides factual record about the position of the ball, the players involved, the action concerned, the time and the outcome of the activity, etc. Motion analysis focuses on raw features of an individual’s activity and movement, for example, identifying fatigue and measuring of work rate. For further details about motion analysis, please refer to my previous post. The two systems contribute for the performance analysis which has three main aims:
- Observing one’s own team’s performance to identify strengths and weakness
- Analysing opposition performance by using data and trying to counter opposing strengths and exploit weaknesses
- To evaluate whether a training programme has been effective in improving match performance
Performance analysis is not just about analysing matches and games. It is essential in the training programme to help coaches improve players’ performance. The following figure shows the coaching cycle.
Figure 1. The coaching cycle
Performance analysis plays a key role in this cycle. Starting from the top, “Performance” means the performance in the game or training. “Observation” can be from the coach or video camera. Since research indicates that coaches are able to recall fewer than half of the key incidents that arise during the game, video camera is a better way which can record all the key events (actions and movements) for further analysis. In “Analysis”, it means analysis of data which include data management. For example, using performance analysis software to code the game, editing footages from the camera, extraction of data from data provider, etc. These are the areas in which the performance analyst spent most of the time. The product of this “analysis” stage can be statistical analysis and video recordings. In “Interpretation”, it can be put in two ways according to my experience. It could be done by coach or performance analyst. Some analysts have the authorisation from coach to interpret the data and then write a report or make a presentation to the coach or team. Some coaches just want the data from performance analysts and the coaches will interpret the data by themselves. It really depends on the coaches’ preference and the partnership between the analyst and the coach. After that, “planning” means the coach plan what to do after knowing what went wrong or which part the team did well. The coaches have to evaluate the performance prior to this planning stage. Otherwise, he doesn’t know how to improve the team’s performance in the next match. In most of the cases, it means the planning of the coaching session using the result of the performance analysis. “Preparation” means the execution of those coaching session in the training so prepare the team for the coming game. It will go back to the “Performance” stage and the whole cycle keep going.
In my opinion, performance analysis plays a key role in three stages in this cycle: “observation”, “analysis” and “interpretation”.
CARLING, C. et al., 2005. Handbook of Soccer Match Analysis. Oxon: Routledge
Fifteen years ago, there may be only a few big Premier League football clubs had a performance analysis department. Nowadays, even a League 2 club like Aldershot for which I am working have set up a Performance Analysis department this season. It is a fast growing industry and I firmly believe it will keep growing for the next ten years at least.
Where does it come from?
If we want to know where it came from, sports science has to be mentioned. The first academic programmes in sports science were studied in the UK in 1975. Initially, it included biology, biochemistry, physiology, biomechanics, mathematics, psychology and sociology. Nowadays, the sports science programmes may include economics, recreation sport development, coaching and computer science also (Reilly and Williams 2003). The first Bachelor of Science degree which combined science and football together was offered at Liverpool John Moores University in 1997. Performance analysis in football was one of the core modules.
Difference between Performance Analysis and Match Analysis
You may realize both terms are used in books and articles as they are very similar. In my opinion, match analysis focuses everything about the matches, e.g. post-match analysis, opposition analysis (tactics and strategies). Performance analysis has a wider coverage and includes more disciplines. In short, match analysis is part of the performance analysis. Apart from match analysis, performance analysis includes player recruitment, player evaluation, training analysis, trend analysis and even referees analysis (Prozone 2009). However, you may realize that some of these disciplines are just the further development of match analysis, e.g. player evaluation and trend analysis. Therefore, I think match analysis is the core part of performance analysis. I will focuses on match analysis in the following paragraphs.
Why match analysis is undertaken?
Some people may argue that soccer is an art, especially if you watch the Zinadine Zidane played. I won’t deny that as I agree playing and coaching soccer are arts but I think science can be a part of soccer as well. In terms of preparation, science information is helpful for coaches and trainers to make decisions and judgement. For one’s own team, the information can be used to identify strengths and weaknesses. For opposition, we can use data to counter opposing strengths and exploit weaknesses. Moreover, match analysis can be used to evaluate whether the training programmes improve the match performance or not (Carling et al. 2005). The information is a big set of data and coach can’t remember all of it during the game. Franks and Miller (1986) found that international level soccer coaches could only recollect 30% of the key elements that determined successful soccer performance observed. Another research indicated that coaches are able to recall fewer than half of the key incidents (Carling et al. 2005). Another reason is that the coach may not be able to get the information objectively. Neisser (1982) found that the accuracy of memories of events I greatly influenced by many factors, e.g. the beliefs of the observer. In other words, coaches are active observers rather than passive perceivers of information. Their perception of events would not be a copying process but rather a selective and constructive one (Reilly 1996). Then coaches can’t provide an objective and unbiased information. Therefore, match analysis/ performance analysis is needed to provide such information and analysis.
What does match analysis include?
In my opinion, match analysis can be divided into two categories: Notational analysis and Motion analysis.
Notational analysis is a means of recording events so that there is an accurate and objective record of what actually took place (Carling et al. 2005). There should be at least five elements which should be recorded: the position (where?), the players involved (who?), the action concerned (what?), the time (when?) and the outcome of the activity (e.g. successful or unsuccessful, or on target or off target. Generally there are two ways to do it: by hand/manual or by computer. Reep and Benjamin (1968) were the early researchers in hand notation system. They collected data from 3213 matches between 1953 and 1968 and recorded actions such as passing and shooting. Their conclusions were that 80% of goals were resulted from a sequence of three passes or less and 50% of all goals came from possession gained in the final attacking quarter of the pitch. In terms of computerized notation system, Matchviewer of Prozone is a good example which provides the data of passing, heading, shooting, tackling etc. Both systems have their strengths and weaknesses. The following table summarizes part of it.
|Hand/ Manual notational system||Computerized notational system|
Table 1: Summary of the strengths and weaknesses of hand and computerized notation system
Another category of match analysis is motion analysis which focuses on raw features of an individual’s activity and movement (Carling et al. 2005). It can specify work rates of the players in different positions and distances covered in a game (Reilly and Williams 2003). This analysis is useful in identifying fatigue and differentiating between positional differences in work rate and fitness levels (e.g. ability to move backwards and sideways is important for defenders) (Carling et al. 2005). There are three elements which should be measured: intensity (walking, jogging, cruising and sprinting), duration (or distance) and frequency. Prozone3 is software of Prozone which provides this sort of data. Nowadays, most of the motion analysis would be done by computer as it is difficult for people to record how many metres a player ran in a match. However, in the old days, researchers had to do it by hand. Reilly and Thomas (1976) recorded and analyzed the intensity and extent of discrete activities. They combined hand notation with tape to analyse the movement of the players. They found that a player is in possession of the ball for less than 2% of the game.
Performance analysis is becoming more popular in lower leagues and more football clubs will set up the performance analysis department in future. There is still much room for the development of performance analysis. Match analysis is different from performance analysis but it is the core part of performance analysis. The aim of doing analysis is to provide objective information and analysis for the coach about past performance (either team or individual). The analysis can be done by hand/manual and computer as well. Both systems have their own strengths and weaknesses.
CARLING, C. et al., 2005. Handbook of Soccer Match Analysis. Oxon: Routledge
FRANKS, I.M. and MILLER, G., 1986. Eyewitness testimony in sport. Journal of Sport Behavior, 9, 38-45
NEISSER, U., 1982. Memory Observed. San Francisco: CA
PROZONE, 2009. Services [online][viewed 5 September 2012]. Available from: http://www.prozonesports.com/services.html
REEP, C., & BENJAMIN, B., 1968. Skill and chance in association football. Journal of the Royal Statistical Society A, 131, 581-585
REILLY, T., 1996. Science and Soccer. E & FN Spon
REILLY, T. and THOMAS, V., 1976. A motion analysis of work-rate in different positional roles in professional football match-play. Journal of Human Movement Studies, 2, 87-97
REILLY, T. and A., M. WILLIAMS, 2003. Science and Soccer. 2nd ed. Oxon: Routledge