Rabu, 05 September 2012

What are Performance Analysis and Match Analysis?


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
Strength
·         Cheap
·         Accurate (fully defined and used correctly)
·         Game is represented in its entirely and store in ROM which forms a database
·         Immediate feedback (i.e. short time)
·         Lead to the development of  predictive models
·         Indication of areas requiring improvement
·         Search video recording
·         Learning time required can be reduced considerably (e.g. keyboards, pads, graphical user interfaces, voice interactive systems)
·         Good presentation because of computer graphics, word-processing, database and multi-media  packages
Weakness
·         Time required for data processing can be very long
·         For complex game such as soccer, learning and training time is long in order to ensure accuracy and reliability of the operator
·         Expensive
·         Less accurate unless very carefully designed and validated

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.
Conclusion
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.

References

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

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