The role of motion analysis in elite soccer: contemporary performance measurement techniques and work rate data.

TL;DR: This review critically appraises various motion analysis methods currently employed in elite soccer and explores research conducted using these methods, identifying areas that require further exploration and identifying practical implications of the established body of knowledge.

Abstract: The optimal physical preparation of elite soccer (association football) players has become an indispensable part of the professional game, especially due to the increased physical demands of match-play. The monitoring of players' work rate profiles during competition is now feasible through computer-aided motion analysis. Traditional methods of motion analysis were extremely labour intensive and were largely restricted to university-based research projects. Recent technological developments have meant that sophisticated systems, capable of quickly recording and processing the data of all players' physical contributions throughout an entire match, are now being used in elite club environments. In recognition of the important role that motion analysis now plays as a tool for measuring the physical performance of soccer players, this review critically appraises various motion analysis methods currently employed in elite soccer and explores research conducted using these methods. This review therefore aims to increase the awareness of both practitioners and researchers of the various motion analysis systems available, and identify practical implications of the established body of knowledge, while highlighting areas that require further exploration.

Summary

Introduction

• A significant body of research into the host of factors contributing towards optimal performance in sport has emerged over the past two decades. [1].
• Physiological demands of contemporary professional soccer implicate an increased work-rate, a higher frequency of competition, and as a consequence, players are obliged to work harder than in previous decades. [9, 10].
• Throughout, the authors highlight that many of the latest computerised systems now are not only logistically practical, but also offer a greater breadth of analysis when compared to the more traditional labour-intensive methods.

1. Contemporary techniques for work-rate analysis

• A further technological advancement in this field has been the development of the software "Trakperformance" which provides a means of mechanically following a single player using a conventional computer pen and commercially available drawing tablet on a scaled version of the specific playing field.
• The Trakperformance system functions by using ground markings around the pitch which are employed as reference points for tracking the players.
• This computerised system has demonstrated acceptable levels of accuracy and intra-and inter-observer reliability.
• A further advantage is that movements can also be tracked in real-time (although operator skill does need to be very high and a sustained training period is needed for familiarisation with the technique) and cost is significantly reduced in comparison to other commercially available tracking systems.
• Finally, the portability of this system means it can be readily employed to analyse work-rates of players within training contexts.

1.2 Multiple player analysis

• The latest systems are advancing the analysis of sports performance through a superior level of co-ordinated biofeedback to accompany the traditional physical feedback.
• The SPI Elite GPS is capable of monitoring heart rate and recording information on the frequency and intensity of impacts such as tackles and collisions by means of a built in tri-axis accelerometer which also depicts three direction types (forwards, sideways and backwards).
• The accuracy and reliability of GPS receivers are relatively high as results of a test of accuracy showed a 4.8% error rate in measuring total distance covered and a test of intra-tester reliability reported a technical error of measurement (TEM) of 5.5%. [24].
• Recent technological developments have also led to increased miniaturisation and increased portability. [47].
• It therefore becomes the challenge for developers and researchers to investigate the optimal measurement frequency to provide appropriate data.

2.2 Interpretation of Results

• Preliminary investigation of pattern complexity between player positions suggests that a higher number of different patterns and pattern occurrences are detected for defenders than forwards and midfielders. [54].
• The same also seems to apply for length of patterns.
• These findings, and their significance, need further examination, although they could be very useful for creating specific training programmes according to individual positional requirements.

3.1 Analysis of data on overall work-rate

• Recent studies have shown that the intensity of play in professional futsal [63] was higher compared to elite players competing in the Australian National league [30] .
• The futsal players covered on average 117 meters per minute compared to 111 meters per minute for the Australian players indicating that the intensity of the game of futsal is higher than that for traditional soccer games.

3.2 Categories of movements

• The activity profile of players may be influenced by the style of play used by individual clubs and by regional differences.
• Such regional differences in performance are important as players moving between countries will probably need time to adapt both physically as well as tactically to the particular style of the different leagues.
• Nevertheless, there is still a lack of studies attempting to address either cultural or geographical differences in the work-rate pattern [27] especially at international level or between various professional leagues.
• Similarly, motion-analysis research on the work-rate performance characteristics of female and in particular younger players is still relatively limited in the literature.
• The age of players should therefore be a relevant factor when evaluating work-rate profiles.

3.4 Use of motion-analysis in studies of fatigue

• Once a susceptibility to fatigue is identified in individual players, the possible reasons for its occurrence should be explored.
• A fall in activity has been identified at the beginning of the second compared to the first half. [56].
• During the break, players tend to rest leading to a drop in muscle temperature and subsequently to reduced performance levels.
• Therefore, adequate attention to nutritional preparation (before, during and after matches) for competition is necessary.
• Monitoring efforts during training by means of heart rate monitors may also help coaches to avoid over-exerting players before matches and lowering their energy stores.

3.5 Other uses of motion analysis research

• Motion analysis data drawn from match-play have also been employed to help design laboratory based protocols to simulate soccer specific intermittent exercise and examine factors such as the effects of training interventions (Sari-Sarraf et al., 2006), [88] nutritional strategies (Clarke et al., 2005), [89] temperature (Drust et al., 2000) [90] and fatigue on performance.
• In the application to fatigue, an intermittent-exercise protocol was designed to simulate the exercise intensities associated with playing a match in order to monitor the functional characteristics of lower limb muscles at half-time and at the end of the 90 minutes. [91].
• Findings therefore had implications for competitive performance and further understanding of the reported increased risk of injury towards the end of the game.
• Motion analysis techniques could be employed to examine whether players are more at risk of injury after intense periods of high-intensity exercise.

Figures

Figure I. An example of a T-pattern incorporating regularity of movements by a centreforward in a F.A. Premiership match.

Table III. Comparison of distances covered by elite soccer players during the first and second halves of competitive match-play.

Full text

Article
The role of motion analysis in elite soccer
Carling, C., Bloomeld, J., Nelsen, L., and Reilly, T.
Available at http://clok.uclan.ac.uk/12265/
Carling, C. ORCID: 0000-0002-7456-3493, Bloomeld, J., Nelsen, L., and Reilly,
T. (2008) The role of motion analysis in elite soccer. Sports Medicine, 38 (10).
pp. 839-862. ISSN 0112-1642
It is advisable to refer to the publisher’s version if you intend to cite from the work.
http://dx.doi.org/10.2165/00007256-200838100-00004
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This is a pre-proof corrected manuscript, as accepted for publication, of an article published
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by Springer International Publishing in Sports Medicine in October 2008. The final
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publication is available at link.springer.com:
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http://link.springer.com/article/10.2165/00007256-200838100-00004
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PLEASE REFER TO THE PUBLISHED VERSION FOR CITING PURPOSES
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The role of motion analysis in elite soccer
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Christopher Carling
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, Jonathan Bloomfield
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, Lee Nelsen
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, Thomas Reilly
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LOSC Lille Métropole Football Club, Centre de Formation, Stadium Lille Métropole 30 Av.
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de la Chatellenie, 59650 Villeneuve d'Ascq, France
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Sports Institute of Northern Ireland, University of Ulster, Jordanstown, Northern Ireland,
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BT37 0QB, UK
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School of Sport and Exercise Sciences, Loughborough University, Leicestershire, LE11
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3TU, UK
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Research Institute for Sport and Exercise Sciences, Liverpool John Moores University,
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Henry Cotton Campus, Webster Street, Liverpool L3 2ET, United Kingdom
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Correspondance: Christopher Carling, LOSC Lille Métropole, Centre de Formation, Stadium
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Lille Métropole 30 Av. de la Chatellenie, 59650 Villeneuve d'Ascq, France
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Phone: 00.33.1.4891 0793
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Fax: 00.33.1.4891 0793
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Email: chris.carling@free.fr
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Word Count: 12814
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Abstract
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The optimal physical preparation of elite soccer (association football) players has
2
become an indispensable part of the professional game especially due to the increased
3
physical demands of match-play. The monitoring of players’ work-rate profiles during
4
competition is now feasible through computer-aided motion analysis. Traditional methods of
5
motion analysis were extremely labour intensive and were largely restricted to university-
6
based research projects. Recent technological developments have meant that sophisticated
7
systems, capable of quickly recording and processing the data of all players’ physical
8
contributions throughout an entire match, are now being used in elite club environments. In
9
recognition of the important role motion analysis now plays as a tool for measuring the
10
physical performance of soccer players, this review critically appraises various motion
11
analysis methods currently employed in elite soccer and explores research conducted using
12
these methods. This review therefore aims to increase the awareness of both practitioners and
13
researchers of the various motion analysis systems available, identify practical implications of
14
the established body of knowledge, while highlighting areas that require further exploration.
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Key terms: fatigue, global positioning systems, match analysis, positional role
17

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Introduction
1
A significant body of research into the host of factors contributing towards optimal
2
performance in sport has emerged over the past two decades.
[1]
This increased research
3
activity has been particularly evident in soccer (association football), where the importance of
4
scientific research and applied work has become increasingly accepted in the professional
5
game.
[2]
Over this period, comprehensive reviews have been published on the physiology,
[3,4]
6
psychology,
[1,5]
biomechanics
[6]
and interdisciplinary
[7]
aspects of soccer. This growing
7
acceptance of sports science is unsurprising considering the performance-enhancing role that
8
it can offer elite soccer coaches continually searching for a competitive edge against rival
9
teams.
[8]
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Among the traditional sport science disciplines, exercise physiology has arguably had
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the greatest impact upon practices within professional soccer. The optimisation of physical
12
fitness is now an integral facet of player and team preparation. Physiological demands of
13
contemporary professional soccer implicate an increased work-rate, a higher frequency of
14
competition, and as a consequence, players are obliged to work harder than in previous
15
decades.
[9,10]
The monitoring of players’ work-rate profiles during competition was originally
16
achieved using manual video-based motion analysis techniques such as that developed by
17
Reilly and Thomas.
[11]
The employment of such methods elicited essential scientific
18
observations but the perceived complexity and consumption of time required for coding,
19
analysing and interpreting the output formed barriers to their adoption by performance
20
analysts.
[12]
The original techniques were also extremely time-consuming and restricted to the
21
analysis of a single player and therefore were limited to university based research projects.
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Over the past decade, technological advances have included the introduction of
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increasingly sophisticated motion analysis systems that have begun to be utilised in elite
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soccer. These systems enable the simultaneous analysis of all players to be completed in a
25

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relatively short period of time, and provide a valuable pool of data that can inform and
1
influence the daily practices of coaches. The utilisation of these advanced approaches furthers
2
our understanding of position-specific work-rate profiles of soccer players and their fitness
3
requirements, the intensities of discrete activities during match play and the occurrence of a
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reduced work-rate among players.
[13,14]
Moreover, these contemporary methods employed by
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elite clubs can be used to make objective decisions for structuring the conditioning elements
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of training and subsequent match preparation.
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In recognition of the important role that motion analysis now plays as a tool for
8
measuring the physical performance of soccer players, we begin by critically appraising the
9
various methods of motion analysis available to researchers and practitioners in soccer.
10
Throughout, we highlight that many of the latest computerised systems now are not only
11
logistically practical, but also offer a greater breadth of analysis when compared to the more
12
traditional labour-intensive methods. However, many of these systems still require scientific
13
validation to ensure that data derived from these methods are both accurate and reliable. A
14
presentation and critical appraisal of various validation protocols used for assessing
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contemporary motion analysis technologies are provided in an attempt to prompt further
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research into this area of investigation. Also considered are various issues concerning the
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interpretation of the data obtained through techniques of motion-analysis. In the remainder of
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this review, motion analysis research into work-rate profiles within competitive games,
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exercise patterns, positional demands, fatigue and other uses, is considered. Collectively this
20
review should serve to increase awareness of practitioners and researchers concerning the
21
various motion analysis systems and the body of accumulated knowledge acquired through
22
using this approach, whilst identifying areas that require further exploration.
23
24
1. Contemporary techniques for work-rate analysis
25

Frequently asked questions

Q1. What is the use of motion-analysis in studies of fatigue?

Use of motion-analysis in studies of fatigue 11 In motion-analyses of soccer, data may be split into distinct time frames to help 12 establish if work-rate varies with time or task. 

Q2. How many meters per minute can be analysed?

When evaluating performance, the 19 frequency of each type of movement and the time spent or distance run in each movement can 20 be analysed. 

Q3. How much error did the authors report for reconstructing the distance between two 24 individual coordinates?

the 23 authors reported an error of less than 2% for reconstructing the distance between two 24 individual coordinates. 

Q4. How has the method of T-patterning been used to establish playing patterns in soccer?

15 The method of T-patterning has already been employed to establish playing patterns in soccer 16 by identifying complex intra- and inter-individual patterns for both individuals and teams 17using the detected behavioural patterns in combination with elementary statistics.[55] 

Q5. What is the way to study the relationship between physical performance and playing conditions?

As soccer is 14 often played across all four seasons of the year, a future study to examine the relationship 15 between physical performance and playing conditions is recommended.