The physical demands of elite English rugby union

TLDR: The results show the differing physical demands between forwards and backs with no evident deterioration in high-intensity activity performed during match-play.

Abstract: The aim of this study was to assess the physical demands of elite English rugby union match-play. Player movements were captured by five distributed video cameras and then reconstructed on a two-dimensional plane representing the pitch. Movements based on speeds were categorized as standing, walking, jogging, and medium-intensity running (low-intensity activity), and high-intensity running, sprinting, and static exertion (scrummaging, rucking, mauling, and tackling) (high-intensity activity). Position groups were defined as forwards (tight and loose) and backs (inside and outside). Backs travelled more total distance than forwards (6127 m, s = 724 vs. 5581 m, s = 692; P < 0.05) and greater distances in walking (2351 m, s = 287 vs. 1928 m, s = 2342; P < 0.001) and high-intensity running (448 m, s = 149 vs. 298 m, s = 107; P < 0.05). Forwards performed more high-intensity activity than backs (9:09 min:s, s = 1:39 vs. 3:04 min:s, s = 1:01; P < 0.001), which was attributable to more time spent in sta...

Figures

Table 3. Frequency and mean duration (seconds) of activity bouts in work categories 2 (mean ± s). 3 4

Figure 1. Camera locations around playing area perimeter. 4 5 6 7 8 9

Figure 4. Time spent performing work activities during each 10-min period of match-play (n = 10).

Table 1. Total distance (m) travelled in each activity category (mean ± s). 2 3

Table 2. Total time (min:s) spent in each movement speed range (mean ± s) 11 12

Full text

Citation for published version:
Roberts, SP, Trewartha, G, Higgitt, RJ, El-Abd, J & Stokes, KA 2008, 'The physical demands of elite English
rugby union', Journal of Sports Sciences, vol. 26, no. 8, pp. 825-833.
https://doi.org/10.1080/02640410801942122
DOI:
10.1080/02640410801942122
Publication date:
2008
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Early version, also known as pre-print
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Download date: 09. Aug. 2022

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Title:
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The physical demands of English elite level rugby union
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Running title:
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Physical demands of rugby union
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Key words:
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Time-motion, performance, physiology, high-intensity exercise
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Submission type:
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Original investigation
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Authors:
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Simon P. Roberts, Grant Trewartha, Rob J. Higgitt, Joe El-Abd and Keith A. Stokes
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Institutions:
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School for Health, University of Bath, Claverton Down, Bath, BA2 7AY, UK
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Corresponding Author:
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Keith A. Stokes
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School for Health
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University of Bath
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Claverton Down
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Bath
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BA2 7AY
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Tel: (+44) (0)1225 384190
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Fax: (+44) (0)1225 383275
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Email: k.stokes@bath.ac.uk
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2
Abstract
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2
The aim of this study was to assess the physical demands of English elite level rugby
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union match-play. Player movements were captured by five distributed video cameras
4
and then reconstructed on a two-dimensional plane representing the pitch. Movements
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based on speeds were categorised as standing, walking, jogging, medium (Low Intensity
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Activity: LIA) and high-intensity running, sprinting and static exertion (scrummaging,
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rucking, mauling and tackling) (High Intensity Activity: HIA). Position groups were
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defined as forwards (tight and loose) and backs (inside and outside). Backs travelled
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more total distance than forwards (6127 ± 724 m vs 5581 ± 692; P < 0.05) and greater
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distances walking (2351 ± 287 vs 1928 ± 2342 m, P < 0.001) and high-intensity running
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(448 ± 149
vs 298 ± 107 m, P < 0.05). Forwards performed more HIA than backs (9:09
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± 1:39 vs 3:04 ± 1:01 min:s, P < 0.001) attributable to more time in static exertion (7:56
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± 1:56 vs 1:18 ± 0:30 min:s, P < 0.001) although backs spent more time high-intensity
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running (0:52 ± 0:19 vs 1:19 ± 0:26 min:s. P = 0.004). Players travelled a greater
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distance in the first 10-min period compared to 50-60 and 70-80min but there was no
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difference in the amount of HIA performed during consecutive 10-min periods during
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match-play. These results show the differing physical demands between forwards and
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backs with no evident deterioration in HIA performed during match-play.
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Introduction
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In order to optimise the training regimes of players, the physical demands of rugby
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union need to be properly understood. In this sport however, the frequent bouts of
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physical contact make physiological data especially difficult to collect given the
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intrusive nature of blood sampling and the problems associated with players carrying
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instrumentation. Therefore, one of the most effective methods with which to quantify to
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activity in rugby union is through the use of time-motion analysis. This technique can
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be used by the researcher to quantify the type, duration and frequency of discrete
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movements making up the intermittent activity patterns in team sports. In addition to
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using time-motion data to improve training specificity, there is also a need to accurately
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quantify match demands for the purposes of designing more specific exercise protocols
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that allow the investigation of issues specific to rugby union.
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Traditionally, time-motion analysis data has been presented in terms of mode, frequency
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and duration of activity. These activities are most often classified as standing, walking,
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jogging, cruising, sprinting and static intense activity (McLean, 1992; Deutsch, Maw,
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Jenkins, & Reaburn , 1998; Duthie, Pyne, & Hooper, 2005). Using these classifications,
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the investigator must decide which activity the player is performing and the duration of
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the activity based on observation of each player’s running characteristics. Recent studies
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from elite southern hemisphere rugby have used this technique to provide insight into
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the relative work performed in different physical activities, but did not measure
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distances travelled or speeds attained by the players (Duthie et al., 2005; Deutsch,
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Kearney, & Rehrer, 2007). Quantification of the distances travelled by players over half
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a match has been performed in under-19 age-group rugby (Deutsch et al., 1998).
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However, players at this age are unlikely to have the same physical capabilities of those
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performing at elite senior level, thus potentially impacting on the amount of work
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performed during match-play. Furthermore, distances were calculated as the product of
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time spent performing the activity and an assigned speed determined outside of match-
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play, rather than the actual speed achieved. Alternative time-motion techniques have
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been presented for soccer (Ohashi, Miyagi, Nagahama, Ogushi, & Ohashi, 1988;
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Castagna & D’Ottavio, 2001; Mallo, Navarro, Garcia-Aranda, Gilis, & Helsen, 2007)
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and handball (Pers, Bon, Kovacic, Sibila, & Dezman, 2002) which utilise automatic and
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semi-automatic player tracking techniques to provide speed and distance over the course
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of a match. More recently an objective time-motion analysis method for team sports
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was found to be both accurate and reliable for estimating speeds and distances travelled
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during rugby union (Roberts, Trewartha, & Stokes, 2006).
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Only one study has reported detailed player movement data in the professional era in
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English rugby union (Eaton & George, 2006). This study provided detailed analyses of
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average work performed via a multi-camera, player coding technique but data on the
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accuracy and reliability of the analysis technique was not available. Therefore the
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principal aim of this study is to provide an assessment of the physical demands of
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English elite level rugby union using an accurate and reliable objective time-motion
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analysis technique in order to provide data for enhancing training practices and for the
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development of research tools specific to rugby union. Fatigue experienced during
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match-play may be manifested in terms of the amount of high-intensity activity
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performed by the players during progressive time-periods of the match. For example, in
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soccer, fatigue has been shown to occur both temporarily during, and towards the end of
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a match (Mohr, Krustrup, & Bangsbo, 2003). To date, the patterns of fatigue during
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Frequently asked questions

Q1. What activity categories were used to quantify the time spent by players in a scrum?

1112 In order to quantify the time spent by players in low and high-intensity exercise, the 13 activity categories were grouped as Low Intensity Activity (LIA) (standing, walking, 14 jogging and medium-intensity running) and High Intensity Activity (HIA) (high-15 intensity running, sprinting and static exertion). 

Q2. How many periods of exercise would be applicable to assess the performance of a player?

In order to assess 21 parameters of match specific performance, it would be most applicable to simulate 22 periods of match-play with the highest exercise intensity, appropriately weighted for 23 static exertion and running. 

Q3. How long does the current study take to capture the data?

The data 16 capture rate of 1Hz in the current study may account for a shorter estimated sprint time 17 compared to previous studies due to the fact that speeds greater than 6.7 m·s-1 are not 18 detectable if attained for a duration of less than 1 second. 

Q4. What was the time-code display on the video 2 footage?

Periods of rucking and mauling were timed from when the player 25were recorded manually by the operator referring to the time-code display on the video 2 footage during the digitising process. 

Q5. How many bouts of high intensity running were performed after the first five?

When the number of high-19 intensity running bouts performed within 20 s after each scrum were totalled for the 20 forwards, out of twenty-five scrums (5 players x 5 scrums) more bouts of high intensity 21 running were performed after the first five (12 bouts) compared to the last five scrums 22 (3 bouts) during match-play. 

Q6. Why were Scrum halves excluded from the analysis?

Scrum halves were 13 excluded from the analysis due to the limited sample and unique physical demands of 14 that position (Duthie et al., 2005; Deutsch et al., 2007). 

Q7. What is the reason why the current study used the latter method?

It is possible that when using the latter method, the player 14 may be judged to be performing at maximal intensity whilst accelerating and therefore 15 not moving at a defined sprint speed such as that used in the present study. 

Q8. What was the difference in distance between the backs and forwards?

Backs 17 spent more time walking than forwards (46.0 ± 4.6 vs 35.0 ± 4.3%, respectively; P < 18 0.001), while outside backs walked for a greater proportion of the match than inside 19 backs (48.9 ± 3.9 vs 42.5 ± 2.5%, respectively, P = 0.01). 

Q9. How many cameras were used to record the positions of the four poles?

78 INSERT FIGURE 1 HERE 910 Camera calibration and recording procedure 11 Prior to each match, a calibration of each camera view was performed by recording 12 sequences of four calibration poles (height = 1.0 m) positioned on the playing surface in 13 known locations. 

Q10. What are the common types of activities that are classified as time-motion analysis?

These activities are most often classified as standing, walking, 16 jogging, cruising, sprinting and static intense activity (McLean, 1992; Deutsch, Maw, 17 Jenkins, & Reaburn , 1998; Duthie, Pyne, & Hooper, 2005). 

Q11. What was the difference in HIA between the forwards and backs?

Although the backs spent more time 11 performing high intensity running than the forwards (1.6 ± 0.5 vs 1.1 ± 0.4%, 12 respectively; P = 0.004), the difference in HIA was mainly attributable to the forwards 13 spending a greater proportion of time in static exertion than backs (9.9 ± 2.4 vs 1.6 ± 14 0.6%, respectively; P < 0.001). 

Q12. How many minutes of activity were derived for each player?

56 For each player the following data were derived for 40 min of match-play (20-60 min) 7 and then summarised according to positional group: total distance travelled, total 8 distance travelled in each activity mode, total and % time spent in each activity mode, 9 frequency of activities in each activity mode, and mean and maximum duration of 10 activity modes.