RESEARCH ARTICLE
Movement Demands of Elite Under-20s and
Senior International Rugby Union Players
Daniel J. Cunningham1☯, David A. Shearer2,3☯, Scott Drawer4‡, Ben Pollard4‡,
Robin Eager4‡, Neil Taylor4, Christian J. Cook1, Liam P. Kilduff1,3☯*
1 Applied Sport Technology Exercise and Medicine Research Centre (A-STEM), College of Engineering,
Swansea University, Swansea, Wales, 2 School of Psychology and Therapeutic Studies, University of South
Wales, Rhondda Cynon Taff, Wales, 3 Welsh Institute of Performance Science, College of Engineering,
Swansea University, Swansea, Wales, 4 The Rugby Football Union, Greater London, England
☯ These authors contributed equally to this work.
‡ These authors also contributed equally to this work.
* l.kilduff@swansea.ac.uk
Abstract
This study compared the movement demands of elite international Under-20 age grade
(U20s) and senior international rugby union players during competitive tournament match
play. Forty elite professional players from an U20 and 27 elite professional senior players
from international performance squads were monitored using 10Hz global positioning sys-
tems (GPS) during 15 (U20s) and 8 (senior) international tournament matches during the
2014 and 2015 seasons. Data on distances, velocities, accelerations, decelerations, high
metabolic load (HML) distance and efforts, and number of sprints were derived. Data files
from players who played over 60 min (n = 258) were separated firstly into Forwards and
Backs, and more specifically into six positional groups; FR–Front Row (prop & hooker),
SR–Second Row, BR–Back Row (Flankers & No.8), HB–Half Backs (scrum half & outside
half), MF–Midfield (centres), B3 –Back Three (wings & full back) for match analysis. Linear
mixed models revealed significant differences between U20 and senior teams in both the
forwards and backs. In the forwards the seniors covered greater HML distance (736.4 ±
280.3 vs 701.3 ± 198.7m, p = 0.01) and severe decelerations (2.38 ± 2.2 vs 2.28 ± 1.65, p =
0.05) compared to the U20s, but performed less relative HSR (3.1 ± 1.6 vs 3.2 ± 1.5, p <
0.01), moderate (19.4 ± 10.5 vs 23.6 ± 10.5, p = 0.01) and high accelerations (2.2 ± 1.9 vs
4.3 ± 2.7, p < 0.01) and sprint•min-1 (0.11 ± 0.06 vs 0.11 ± 0.05, p < 0.01). Senior backs cov-
ered a greater relative distance (73.3 ± 8.1 vs 69.1 ± 7.6 m•min-1, p < 0.01), greater High
Metabolic Load (HML) distance (1138.0 ± 233.5 vs 1060.4 ± 218.1m, p < 0.01), HML efforts
(112.7 ± 22.2 vs 98.8 ± 21.7, p < 0.01) and heavy decelerations (9.9 ± 4.3 vs 9.5 ± 4.4, p =
0.04) than the U20s backs. However, the U20s backs performed more relative HSR (7.3 ±
2.1 vs 7.2 ± 2.1, p <0.01) and sprint•min-1 (0.26 ± 0.07 vs 0.25 ± 0.07, p < 0.01). Further
investigation highlighted differences between the 6 positional groups of the teams. The
positional groups that differed the most on the variables measured were the FR and MF
groups, with the U20s FR having higher outputs on HSR, moderate & high accelerations,
moderate, high & severe decelerations, HML distance, HML efforts, and sprints•min-1. For
the MF group the senior players produced greater values for relative distance covered,
PLOS ONE | DOI:10.1371/journal.pone.0164990
November 8, 2016
1 / 13
a11111
OPEN ACCESS
Citation: Cunningham DJ, Shearer DA, Drawer S,
Pollard B, Eager R, Taylor N, et al. (2016)
Movement Demands of Elite Under-20s and Senior
International Rugby Union Players. PLoS ONE 11
(11): e0164990. doi:10.1371/journal.
pone.0164990
Editor: Karen Hind, Leeds Beckett University,
UNITED KINGDOM
Received: March 1, 2016
Accepted: October 4, 2016
Published: November 8, 2016
Copyright: © 2016 Cunningham et al. This is an
open access article distributed under the terms of
the Creative Commons Attribution License, which
permits unrestricted use, distribution, and
reproduction in any medium, provided the original
author and source are credited.
Data Availability Statement: Data are available
from the Swansea University Ethics Committee for
researchers who meet the criteria for access to
confidential data.
Funding: The author(s) received no specific
funding for this work and no authors have any
financial or other interest in the products or
distributor of the products named in the study. The
Rugby Football Union provided support in the form
of salaries for authors Scott Drawer, Robin Eager,
Ben Pollard and Neil Taylor, but did not have any
additional role in the study design, data collection
HSR, moderate decelerations, HML distance and sprint•min-1. The BR position group was
most similar with the only differences seen on heavy accelerations (U20s higher) and mod-
erate decelerations (seniors higher). Findings demonstrate that U20s internationals appear
to be an adequate ‘stepping stone’ for preparing players for movement characteristics
found senior International rugby, however, the current study highlight for the first time that
certain positional groups may require more time to be able to match the movement
demands required at a higher playing level than others. Conditioning staff must also bear in
mind that the U20s players whilst maintaining or improving match movement capabilities
may require to gain substantial mass in some positions to match their senior counterparts.
Introduction
Rugby union is a high intensity intermittent sport, where periods of intense static exertions,
collisions and running at various intensities are interspersed with random periods of lower
intensity work and rest [1, 2]. Recent work has characterised the movement demands of senior
professional rugby union players [1, 3–7]. There is, however, a lack of literature on movement
demands, physical characteristics and match analysis at the highest level of rugby union (inter-
national), with only a few studies published on work:rest ratios [8, 9], endocrine response [10,
11], time motion analysis [12] and a recent publication on movement demands [13]. A study
by Quarrie et al., [12] reported rugby union players covered on average between 5.5 and 6.3 km
per game during 27 international matches observedin their study. Backs generally covered
greater distances compared to the forwards, conversely forwards sustained greater contact
loads from scrums, rucks and mauls. These researchers utilised video and player tracking soft-
ware to quantify distances and contact elements of the game. Unfortunately the current micro-
sensor technology appears inadequate in quantifying the collision based elements of the game
[14]. A cluster analysis revealed 5 distinct groups of players (e.g. props, second rows, back row,
wings & fullback (back 3), centres & fly half)with the authors suggesting that hookers should
be grouped with props or second rows and not back row players, which has previously been the
case in older time-motion studies [15–17]. Although positional groups covered similar dis-
tances during matches, the distances they covered at various speed zones varied considerably
and the amount of game time also varied significantly across positions due to tactical substitu-
tions [12]. They also suggested that there was a difference in the amount of high speed running
(>5m•s-1) performed at international level compared to lower levels of the game and therefore,
players hoping to compete at international level need to be conditioned for the increased inten-
sity of match play [12].
In addition, there is little in the literature about the elite development pathways (e.g. U20s
internationals). With the exception of the work by Lombard et al., [18] on the 10 year physical
evolution of South African U20s players, the research of Barr and colleagues [19] reporting
speed characteristics of U20s players from a nation outside of the top 10 (i.e. tier 2), and move-
ment characteristics in U20 players However, currently no literature exists on how these
demands map with those of their senior counterparts. This information would be useful in
order to prepare players for the movement demands of senior rugby, whilst minimising the
risk of injuries by monitoring playing/training ensuring acute:chronic workloads are appropri-
ate [20].
There has been a historical evolution of both senior and junior rugby players from a physical
perspective [18, 21] with the rate of increase in body mass particularly large in the last 30–40
Movement Demands of Elite Under-20s and Senior International Rugby Union Players
PLOS ONE | DOI:10.1371/journal.pone.0164990
November 8, 2016
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and analysis, decision to publish, or preparation of
the manuscript. The specific roles of these authors
are articulated in the ‘author contributions’ section.
Competing Interests: We have the following
interests. Scott Drawer, Robin Eager, Ben Pollard
and Neil Taylor are employed by The Rugby
Football Union. There are no patents, products in
development or marketed products to declare. This
does not alter our adherence to all the PLOS ONE
policies on sharing data and materials, as detailed
online in the guide for authors.
years [21]. For example, South African U20s players have increased in height (~2.8%), weight
(~14%), strength (~51%), muscular endurance (~50%), and improved speed times over 10m
(~7%) and 40m (~4%) but have not improved aerobic performance over a 13 year period [18].
This change is most likely due to the amount of training time available since the advent of pro-
fessionalism and the training method advances made within the domain of strength and condi-
tioning coupled with the desire for larger rugby players in order to gain the upper hand in the
collision/contact area of the game. Despite seniors and juniors showing rapid developments in
physical characteristics there still appears to be differences between these groups. For example,
at the 2015 6 Nations tournament (the highest level of international competition in the north-
ern hemisphere) the average weight of a senior English forward was 115.8 ± 8.12 kg compared
to 110.3 ± 8.14 kg for an U20s forward. Similarly for the backs 93.8 ± 6.9 vs 89.9 ± 5.7 kg for
seniors and U20s (unpublished data). Argus and co-workers [22] also found moderate to very
large differences in mass, upper and lower body strength and upper body and lower body
power between academy and senior professional southern hemisphere rugby union players.
Interestingly Barr et al., [19] found no significant differences between senior and U20s interna-
tionals for initial and maximal sprint velocity, however, when initial and maximal sprint
momentum was calculated there were significant differences between the groups. These find-
ings are further corroborated by the work of Hansen and colleagues [23] who reported signifi-
cant differences between elite senior and junior players for mass and measures of strength and
power, but not for speed times over 5, 10 and 30m.
In rugby league, significant differences in distance travelled during match play between pro-
fessional senior and elite junior players have been reported by McClellan & Lovell [24]. Specifi-
cally, the mean total distance travelled during professional games (8371 ± 897 m) was
significantly greater than that travelled during elite junior (4646 ± 978 m) match-play.
Research indicates a progression of physical characteristics between playing levels in rugby lea-
gue players, Gabbett [25] outlined the progressive improvement in the physiological capacities
(mass, speed, agility and aerobic endurance) of rugby league players as the playing level
increases from U13 right the way through to professional level. A similar progression in physi-
ological characteristics was reported in an elite English rugby union academy, when Darrall-
Jones et al., [26] undertook a comprehensive testing battery with the U16, U18 and U21 acad-
emy squads. They reported a progressive increase between the groups on mass, strength, power
and momentum, however no differences were found on aerobic endurance or speed times.
Recent work by Gannon et al [27] showed improvements in strength and power measures over
the course of a season in a professional club environment. The largest improvements were seen
in the early to mid-season period with a drop off towards the end of the season but still achiev-
ing an overall gain from the start of the season. Neither of these studies made any comparison
between age grade players and seniors.
A greater understanding of player movement patterns in senior and U20s international
rugby union, may give an indication of the positional requirements of performance (as shown
in senior professional rugby by Lindsay et al., [3]). Which may also aid in targeting qualities/
physical outputs players need to work on. This will facilitate the planning and implementation
of training programmes and development pathways that elicit the required physiological adap-
tations specific to individual player needs, whilst ensuring increases in training/playing load
are applied appropriately to minimise the risk of injury [20]. Conversely, it could help identify
outstanding performers who could be fast tracked into the senior set up. Therefore, assessing
how U20s compare to seniors and ascertaining where this development tool sits in the player
pathway to senior international honours needs to be addressed. Therefore, the aim of this
study was to compare U20s international competitions with senior international competitions
based on movement demands recorded using GPS devices.
Movement Demands of Elite Under-20s and Senior International Rugby Union Players
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Methods
Elite professional junior players from an U20s international performance squad (n = 43), and
elite professional senior players from an international performance squad (n = 27) participated
in the study. Prior to providing written informed consent, participants were given information
outlining the rationale, potential applications and procedures associated with the study. Ethics
approval was granted by the Swansea University Ethics Committee. All players were consid-
ered healthy and injury-free at the time of the study and were in full-time training. Players
were grouped broadly as forwards and backs and more specificallyin sub units within those
groups. With front row (FR), second row (SR) and back row (BR) making up the forwards.
Half backs (HB), midfield/centres (MF) and back three (B3) players making up the backs. The
U20s players (Table 1) provided a total of 161 GPS files from 15 games from two 6 Nations
tournaments (2014 and 2015) and the 2015 Junior World Cup. The senior players (Table 1)
provided a total of 97 GPS files from 8 games from the 2014 and 2015 6 Nations tournaments.
Previous studies have shown that substitute players display greater work-rates compared to
players who start the match, suggesting that these players do not pace their involvement [28].
Therefore, to be included in the analysis players had to complete 60 mins match time [5, 29].
The seniors won all 8 games (5 home, 3 away), the U20 won 8/10 (5 home, 5 away) in the 6
Nations and 4/5 at the Junior World Cup (neutral venues). The average points scored per game
was 31.3 and 36, and points conceded 15.4 and 11.4 for senior and U20 respectively. Each
player provided at least 1 GPS file with the largest number of files provided by any one player
being 11 and 8 in the U20s and seniors, respectively. A total of 79 GPS units were used during
the study, units were returned to the manufacturer at the end of each competition for mainte-
nance/repair.
Procedures
All Matches took place between January 2014 and June 2015, each player wore a GPS unit
(Viper Pod, STATSport, Belfast, UK) in a bespoke pocket incorporated into their playing jersey
on the upper thoracic spine between the scapulae to reduce movement artefacts [30]. The GPS
units captured data at a sampling frequency of 10Hz utilising the 4 best available satellites.
Recent advancements in GPS technology have made 10 Hz units commercially available,
Table 1. Anthropometric Characteristics of Position Groups.
Positional Group
Team
Age (years) M ± SD
Height (cm) M ± SD
Mass (kg) M ± SD
FR
Senior
26.1 ± 2.3
185.7 ± 4.2
119.1 ± 5.0
U20
19.5 ± 0.7
184.4 ± 3.0
111.8 ± 5.6
SR
Senior
26.4 ± 3.3
199.2 ± 1.6
116.8 ± 4.8
U20
19.7 ± 0.5
199.7 ± 2.3
115.2 ± 4.1
BR
Senior
26.0 ± 3.3
190.0 ± 2.6
117.7 ± 10.4
U20
19.9 ± 0.3
187.7 ± 2.7
101.6 ± 3.9
HB
Senior
24.2 ± 2.5
179.5 ± 6.0
88.7 ± 4.6
U20
19.6 ± 0.4
176.0 ± 2.1
84.2 ± 4.1
MF
Senior
25.7 ± 1.3
190.2 ± 4.1
102.3 ± 6.9
U20
19.5 ± 0.6
183.0 ± 4.9
96.1 ± 6.6
B3
Senior
24.6 ± 3.4
182.6 ± 4.1
91.7 ± 2.1
U20
19.6 ± 0.5
183.7 ± 4.3
89.6 ± 4.9
FR = Front Row (Prop & Hooker), SR = Second Row, BR = Back Row, HB = Half Backs, MF = Midﬁeld/Centres, B3 = Back Three (Wing & Full Back).
doi:10.1371/journal.pone.0164990.t001
Movement Demands of Elite Under-20s and Senior International Rugby Union Players
PLOS ONE | DOI:10.1371/journal.pone.0164990
November 8, 2016
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which are more accurate for quantifying movement patterns in team sports [31, 32]. For exam-
ple, Varley et al., [32] reported that a 10 Hz GPS unit was two to three times more accurate for
instantaneous velocity during tasks completed at a range of velocities compared to a criterion
measure, 6 times more reliable for measuring maximum instantaneous velocity and had a coef-
ficient of variation less than or similar to the calculated smallest worthwhile change [33] during
all phases of acceleration/deceleration.More specificallythis brand of GPS devices has been
used in team sports to assess movement demands during training and competitive matches
[13, 34–39]. In our study, all participants were already familiarized with the devices as part of
their day-to-day training and playing practices. Units were activated according to the manufac-
turer’s guidelines immediately prior to the pre-match warm-up (~30–60 minutes before kick-
off),and to avoid inter-unit variation players wore the same GPS device for each match. Post
match, timings from the game were (e.g. kick off, half time, sin binning etc) were entered into
the software the raw data files were then processed and data for distance covered, and accelera-
tion/deceleration events in pre-set zones were derived automatically by the software (Viper
PSA software, STATSports, Belfast, UK).
Locomotor Variables
The distance relative to playing time (m•min-1), high speed running (HSR) relative to playing
time >18.1km•h-1 (the threshold used in numerous rugby GPS studies in both codes; e.g. Aus-
tin & Kelly [40] & Jones et al., [4]), number of sprints relative to playing time (sprints•min-1),
moderate, high and severe intensity accelerations and decelerations (±2-3m•s-2, ±3-4m•s-2,
±>4m•s-2), high metabolic load distance (HML; defined as distance covered accelerating and
decelerating over 2 m•s-2 and/or distance covered >5 m•s-1), and high metabolic load efforts
(the number of separate movements/efforts undertaken in producing HML distance). Total
time was calculated for ‘playing time’ only, that is, the time the player was on the playing field
only, with time off the field (e.g., half time, periods on the bench/sin bin) removed from the
data analysis. Time off during match play, such as injury time or video referee, was included in
the study, because this was part of the game duration; hence ‘playing time’ may exceed the stan-
dard 80 minutes of match play.
Data Analysis
Linear mixed models were used to examine each dependent variable for the interaction
between teams in respect to positional types (forwards and backs) and groups (e.g., front rows,
second rows etc.). To allow for the nested design of the data, random intercepts were modelled
for participants (individual GPS measures), teams (i.e., U20 vs Senior) and competition (U20 6
Nations 2014, U20 6 Nations 2016, U20 Junior World Cup 2015, Senior 6 Nations 2014, Senior
6 Nations 2015). Attempts were made to also model for random slopes for the same variables
but this resulted in over-specified models. Where significant interactions were identified, dif-
ferences were interpreted using a combination of estimates of fixed effects, examination of
means and 95% confidence intervals (Tables C and D in S1 File).
Results
Examination of means and standard deviations indicated visible difference between teams as a
function of position type (Table 2). Linear mixed models indicated a significant interaction
between Team (U20 v Senior) and Positional Type (Forwards and Backs) for M•min-1 (p <
.001), HSR m•min-1 (p < .001), Accelerations 2-3m•s-2 (p < .01), Accelerations 3-4m•s-2 (p <
.001), Decelerations 3-4m•s-2 (p < .001), Decelerations >4m•s-2 (p < .01), HML Distance (m)
(p < .001), Sprint•min-1 (p < .001), and HML Efforts (p < .001). Further examination of fixed
Movement Demands of Elite Under-20s and Senior International Rugby Union Players
PLOS ONE | DOI:10.1371/journal.pone.0164990
November 8, 2016
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effects for these significant interactions revealed that U20 forwards had significantly higher
HSR m•min-1 (p < .001, CI: -3.33 to– 1.08), Accelerations 2-3m•s-2 (p < .01, CI: -9.99 to–
1.46), Accelerations 3-4m•s-2 (p < .001, CI: -4.45 to– 1.72), Decelerations 3-4m•s-2 (p < .05,
CI: -3.87 to– 0.44), Sprint•min-1 (p < .001, CI: -.12 to– 0.04), and significantly lower Accelera-
tions >4m•s-2 (p < .05, CI: 0.13 to 3.66) and HML Distance (p < .05, CI: -292.12 to– 41.40).
For backs, fixed effect revealed U20 players had significantly lower values for M•min-1 (p <
.001, CI: 4.52 to 11.34), HML Distance (p < .001, CI: 140.65 to 402.96) HML efforts (p < .001,
CI: 10.74 to 34.20) and Decelerations 3-4m•s-2 (p < .05, CI: 0.13 to 3.66), while significantly
higher values for HSR m•min-1 (p < .001, CI: 1.15 to 3.51) and Sprint•min-1 (p < .001, CI: 0.04
to 0.13). However, some other variables were close to significance also (Table C in S1 File).
Examination of means and standard deviations indicated visible difference between teams
as a function of positional groups (Table 3). Linear mixed models indicated a significant inter-
action between team (U20 v Senior) and positional groups (e.g., half-back, second rows etc.)
for M•min-1 (p < .05), Accelerations 2-3m•s-2 (p < .05), Decelerations 2-3m•s-2 (p < .001),
Decelerations 3-4m•s-2 (p> .05), HML Distance (p < .01), and HML efforts (p > .001). Esti-
mates of fixed effects were used to indicate differences between specific playing group between
teams where interactions occurred.U20 Front Rows scored significantly higher than seniors
for HSR m•min-1 (p < .001, CI: -5.15 to -1.61), Accelerations 2-3m•s-2 (p < .001, CI: -21.08 to
-8.09), Accelerations 3-4m•s-2 (p < .001, CI: -6.35 to -1.84), Decelerations 2-3m•s-2 (p < .001,
CI: -17.78 to -6.79), Decelerations 3-4m•s-2 (p < .001, CI: -7.55 to -2.20), Decelerations
>4m•s-2 (p < .01, CI: -4.04 to -0.59), HML Distance (p < .001, CI: -618.18 to -240.92), HML
efforts (p < .001, CI: -51.90 to -20.07) and Sprint•min-1 (p < .001, CI: -0.20 to -0.07). U20 Sec-
ond rows scored significantly higher for HSR m•min-1 (p < .05, CI: -3.92 to -0.13), Accelera-
tions 3-4m•s-2 (p < .01, CI: -5.72 to -0.91), however seniors performed more Sprint•min-1
(p < .001, CI: -0.20 to -0.07). U20 Back rows had significantly less Decelerations 2-3m•s-2 (p <
.01, CI: 1.74 to 11.46) but more Accelerations 3-4m•s-2 (p < .05, CI: -4.26 to -0.14). U20 Half
back had significantly lower scores for for M•min-1 (p < .001 CI: 6.48 to 17.80), Decelerations
2-3m•s-2 (p < .05, CI: 0.20 to 11.86), HML Distance (p < .05, CI: 56.47 to 503.78) and HML
efforts (p < .001, CI: 19.72 to 55.84). U20 Midfield players had significantly lower values for
Table 2. Movement Characteristics for Senior and U20s, Forwards and Backs Groups.
Position Group
Forwards
Backs
Seniors (n = 15)
U20s (n = 21)
Seniors (n = 12)
U20s (n = 22)
GPS Variable
M ± SD
M ± SD
M ± SD
M ± SD
M•min-1
66.8 ± 7.0
61.5 ± 8.0
73.3 ± 8.1*
69.1 ± 7.6
HSR m•min-1
3.1 ± 1.6
3.2 ± 1.5^
7.2 ± 2.1
7.3 ± 2.1*
HML Distance (m)
736.4 ± 280.3^
701.3 ± 198.7
1138.0 ± 233.5*
1060.4 ± 218.1
HML Efforts
84.8 ± 30.4
78.8 ± 21.5
112.7 ± 22.2*
98.8 ± 21.7
Accelerations 2-3m•s-2
19.42 ± 10.5*
23.6 ± 8.9^
26.4 ± 8.4
26.1 ± 10.1
Accelerations 3-4m•s-2
2.2 ± 1.9*
4.3 ± 2.7^
4.9 ± 3.0*
6.4 ± 4.5
Accelerations >4m•s-2
0.69 ± 0.95
0.47 ± 0.84
1.04 ± 1.22
0.89 ± 1.37
Decelerations 2-3m•s-2
24.56 ± 11.5
25.2 ± 9.3
28.4 ± 7.7*
25.3 ± 9.3
Decelerations 3-4m•s-2
6.4 ± 4.0
7.5 ± 3.5^
9.9 ± 4.3*
9.5 ± 4.4
Decelerations >4m•s-2
2.38 ± 2.2^
2.28 ± 1.65
4.39 ± 2.77
4.95 ± 3.0
Sprint•min-1
0.11 ± 0.06
0.11 ± 0.05^
0.25 ± 0.07
0.26 ± 0.07*
^ = Signiﬁcantly higher than either Senior or U20 forwards counterpart.
* = Signiﬁcantly higher than either Senior or U20 backs counterpart.
doi:10.1371/journal.pone.0164990.t002
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Table 3. Movement Characteristics Presented by Playing Groups.
Position Group
FR
SR
BR
HB
MF
B3
Team
M ± SD
Team
M ± SD
Team
M ± SD
Team
M ± SD
Team
M ± SD
Team
M ± SD
M•min-1
U20s
60.1 ± 7.2
U20s
60.8 ± 5.9
U20s
63.2 ± 9.7
U20s
67.5 ± 9.1*
U20s
70.5 ± 6.8*
U20s
68.7 ± 7.6*
Seniors
61.1 ± 7.9
Seniors
67.6 ± 6.5
Seniors
69.9 ± 4.3
Seniors
77.4 ± 5.6
Seniors
71.9 ± 10.0
Seniors
70.8 ± 7.1
HSR m•min-1
U20s
2.5 ± 1.3*
U20s
3.0 ± 1.1*
U20s
4.0 ± 1.6
U20s
5.5 ± 2.4
U20s
7.2 ± 1.7*
U20s
8.1 ± 1.7*
Seniors
1.8 ± 1.1
Seniors
2.9 ± 1.2
Seniors
4.0 ± 1.4
Seniors
6.3 ± 1.6
Seniors
8.0 ± 2.3
Seniors
7.4 ± 2.2
HML Distance (m)
U20s
584.9 ± 199.1*
U20s
673.3 ± 124.1
U20s
820.6 ± 182.5
U20s
954.8 ± 304.0*
U20s
1103.4 ± 168.6*
U20s
1069.7 ± 203.0
Seniors
452.3 ± 172.9
Seniors
747.1 ± 227.9
Seniors
911.4 ± 210.2
Seniors
1144.5 ± 175.9
Seniors
1205.4 ± 265.6
Seniors
1076.1 ± 246.0
HML Efforts
U20s
66.0 ± 22.6*
U20s
77.2 ± 14.5
U20s
90.7 ± 19.0
U20s
99.9 ± 27.2*
U20s
105.0 ± 15.9
U20s
93.4 ± 22.4
Seniors
54.6 ± 19.3
Seniors
85.8 ± 26.7
Seniors
103.4 ± 22.4
Seniors
126.3 ± 14.2
Seniors
113.9 ± 23.1
Seniors
99.7 ± 20.5
Accelerations 2-3m•s-2
U20s
17.8 ± 6.6*
U20s
22.9 ± 7.4
U20s
29.0 ± 8.5
U20s
23.5 ± 13.6
U20s
27.4 ± 10.3
U20s
26.1 ± 8.1
Seniors
10.0 ± 6.0
Seniors
21.3 ± 9.4
Seniors
24.4 ± 9.5
Seniors
26.8 ± 7.9
Seniors
28.5 ± 9.4
Seniors
24.4 ± 7.9
Accelerations 3-4m•s-2
U20s
3.5 ± 2.4*
U20s
3.8 ± 2.1*
U20s
5.5 ± 3.1*
U20s
4.3 ± 5.4
U20s
5.9 ± 2.8
U20s
7.6 ± 4.9
Seniors
1.1 ± 1.3
Seniors
1.8 ± 1.9
Seniors
3.1 ± 2.0
Seniors
4.8 ±2.9
Seniors
4.0 ± 3.0
Seniors
5.7 ± 3.0
Accelerations >4m•s-2
U20s
0.39 ± 0.75
U20s
0.25 ± 0.53*
U20s
0.71 ± 1.04
U20s
0.33 ± 0.49
U20s
0.45 ± 0.78
U20s
1.47 ± 1.73
Seniors
0.50 ± 0.65
Seniors
0.83 ± 1.19
Seniors
0.73 ± 0.98
Seniors
1.19 ± 1.22
Seniors
1.07 ± 1.44
Seniors
0.89 ± 1.08
Decelerations 2-3m•s-2
U20s
21.1 ± 9.0*
U20s
24.8 ± 9.8
U20s
28.8 ± 7.9*
U20s
24.7 ± 9.9*
U20s
28.1 ± 8.9*
U20s
23.3 ± 9.1
Seniors
13.0 ± 6.1
Seniors
24.5 ± 10.4
Seniors
32.0 ± 8.4
Seniors
31.1 ± 5.6
Seniors
31.1 ± 8.6
Seniors
23.9 ± 6.7
Decelerations 3-4m•s-2
U20s
6.2 ± 3.7*
U20s
8.0 ± 3.0
U20s
8.2 ± 3.4
U20s
6.5 ± 3.6
U20s
11.5 ± 4.1*
U20s
9.2 ± 4.3
Seniors
3.5 ± 2.4
Seniors
5.7 ± 2.4
Seniors
8.6 ± 4.3
Seniors
9.4 ± 4.8
Seniors
11.3 ± 4.2
Seniors
9.2 ± 3.9
Decelerations >4m•s-2
U20s
2.2 ± 1.9*
U20s
1.6 ± 1.3
U20s
2.9 ± 1.5
U20s
3.0 ± 2.0
U20s
5.2 ± 3.5
U20s
5.5 ± 2.6*
Seniors
1.0 ± 1.5
Seniors
2.7 ± 2.2
Seniors
3.1 ± 2.3
Seniors
3.7 ± 2.3
Seniors
4.3 ± 2.7
Seniors
5.1 ± 3.1
Sprint•min-1
U20s
0.09 ± 0.04*
U20s
0.10 ± 0.03*
U20s
0.14 ± 0.05
U20s
0.18 ± 0.06
U20s
0.27 ± 0.06*
U20s
0.29 ± 0.06*
Seniors
0.06 ± 0.04
Seniors
0.11 ± 0.04
Seniors
0.14 ± 0.05
Seniors
0.21 ± 0.06
Seniors
0.28 ± 0.07
Seniors
0.27 ± 0.08
FR = Front Row (Prop & Hooker), SR = Second Row, BR = Back Row, HB = Half Backs, MF = Midﬁeld/Centres, B3 = Back Three (Wing & Fullback).
* = signiﬁcant difference to Senior counterpart
doi:10.1371/journal.pone.0164990.t003
Movement Demands of Elite Under-20s and Senior International Rugby Union Players
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November 8, 2016
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M•min-1 (p < .05, CI: 1.27 to 12.34), HSR m•min-1 (p < .001, CI: 1.05 to 5.05), Decelerations
2-3m•s-2 (p < .05, CI: 0.21 to 11.73), HML Distance (p < .01, CI: 122.37 to 543.28) and HML
efforts (p < .01, CI: 7.07 to 41.74), Sprint•min-1 (p < .001, CI: 0.04 to 0.18), but higher values
for Decelerations 3-4m•s-2 (p < .05, CI: 0.24 to 5.99). Finally, U20 Back Three players had sig-
nificantly lower values for M•min-1 (p < .05, CI: 1.12 to 10.58), and HML Distance (p < .01,
CI: 51.45 to 399.61), but higher values for HSR m•min-1 (p < .001, CI: 0.81 to 4.09), Decelera-
tions >4m•s-2 (p < .05, CI: 0.20 to 3.39) and Sprint•min-1 (p < .001, CI: 0.04 to 0.15).
Discussion
The aim of this study was to compare the locomotor demands of senior international and age
grade international (U20) rugby union matches using GPS devices. The current study is the first
to present an analysis of movement demands of senior international competition in comparison
to the elite junior international competition. The results of the present study increase our under-
standing of the movement demands of competition experiencedby players in existing interna-
tional rugby union development pathways and determine whether the U20s competition reflects
the movement demands of senior match-play. Therefore, the results of the current study may
have implications for the design and implementation of physical conditioning programmes in
order to prepare players for the movement demands of senior international rugby.
In general, the seniors covered greater relative distance for both forwards (66.8 ± 7.1 vs
61.5 ± 8.0m•min-1) and backs (73.3 ± 8.1 vs 69.1 ± 7.6m•min-1), however this was only statisti-
cally significant for the backs. The U20s forwards performed more HSR m•min-1 accelerations
in zones 2–3 & 3-4m•s-2, decelerations 3-4m•s-2 and sprint•min-1 than the seniors, but less
HML distance. In the Backs, the senior group covered more relative distance (m•min-1) per-
formed more decelerations 3-4m•s-2, more HML distance & efforts, but the U20s performed
more HSR m•min-1 and sprint•min-1. The U20s also had significantly longer match time,
which could be due to different substitution strategies or a number of other factors (e.g. more
injury stoppages, discipline issues, third match official use). The relative distance values pre-
sented in the current study are lower than a recent publication from a southern hemisphere
club team [3] (Forwards: 77.3 ± 20.5, Backs: 84.7 ± 10.4m•min-1), and in between values pro-
duced by 2 different Pro 12 clubs [5, 7] (Forwards: 60.4 ± 7.8 & 71.6 ± 10.1, Backs: 67.8 ± 8.2 &
81.0 ± 10.2m•min-1). However, when comparing to data published from the Premiership (For-
wards: 64.6 IQR 6.3, Backs: 71.1 IQR 11.7 m•min-1) from which the current players are drawn,
it appears that U20s international competition is marginally below the movement demands of
the Premiership, while senior international competition is higher, in terms of relative distance
covered. This may indicate that U20s rugby is preparing players for movement demands in
Premiership rugby, which in turn will help prepare for full international matches. However,
given the likely variation in tactics/playing styles between the teams and the opposition faced,
care must taken when making comparisons [41, 42].
Although generally there are differences between senior and U20s backs and forwards, the
number of variables that were significantly different varied across each positional group. There
were no significant differences in relative distance covered between U20s and seniors in any
forward positional group (front row, second row, back row). There were significant differences
in relative distance covered for the half backs (77.37 ± 5.62 vs 67.47 ± 9.10m•min-1), midfield
(71.9 ± 10.0 vs 70.5 ± 6.8m•min-1) and back three (70.8 ± 7.1 vs 68.7 ± 7.6m•min-1) with
seniors covering greater distances in all cases. The U20s covered greater relative HSR distance
in the front & second rows and back three position groups, with the opposite being the case for
the midfield group. No differences between seniors and U20s were seen for back row or half
backs for HSR.
Movement Demands of Elite Under-20s and Senior International Rugby Union Players
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The front row and midfield groups had the most differences between seniors and U20s. Sig-
nificant differences were found between front row groups on HSR (relative), accelerations (2–3
and 3-4m•s-2), decelerations (2–3, 3–4 and >4m•s-2), HML distance, HML efforts, and
sprints•min-1 with the U20s having higher outputs on each variable. Conversely for the mid-
field group seniors had significantly greater values for relative distance covered, HSR (relative),
decelerations (2–3•s-2), HML distance and sprints•min-1. The back row group was most similar
with only accelerations (2–3•s-2), decelerations (2–3•s-2) being significantly different. Compar-
ing acceleration and deceleration data with previous literature is somewhat problematic as
Cunniffe et al. [6] reported no differences between backs and forwards groups, however, a very
low sample size was utilised (1 back, 1 forward during 1 game) together with different accelera-
tion zones. Jones et al., [5] reported distance covered while in various acceleration and deceler-
ation zones for both backs and forwards combined when investigating temporal fatigue in their
study, which makes comparison impossible, as the current study used number of acceleration
and deceleration events. Owen and co-workers [43] utilised comparable zones and reported
number of acceleration/deceleration events, their work supports the current finding that backs
are involved in more frequent acceleration and deceleration events. However, the current study
appears to have a slightly higher frequency for both backs and forwards, potentially as a result
of the level of competition (Super vs International rugby).
The number of sprints•min-1 performed was significantly different between U20s and
senior forwards (0.11 ± 0.05 vs 0.11 ± 0.06) and U20s and senior backs (0.26 ± 0.07 vs
0.25 ± 0.07). However, this is unlikely to be of practical significance given the low frequency.
Backs performed more sprints than the forwards (~x2.5) in both groups. The greatest differ-
ence between positional groups was the U20s front row group who performed almost double
the amount of their senior counterparts (8.73 ± 4.52 vs 4.71 ± 3.45). This could be due to U20s
players being lighter (119.1 ± 5.0 vs 111.8 ± 5.6 kg) and potentially more mobile, or simply a
reflection of their physical capabilities. The number of sprints reported in the current study is
higher than those reported by Jones and co-workers [5] most likely again to the difference in
playing standard (club vs international) or potentially style of play.
Overall there were a number of differences between the forwards and backs of the U20s and
senior teams. However, when broken down further into positional groups, variations in differ-
ences between the two teams in certain positions emerged. The positional groups that appeared
most different between the teams on the metrics measured were the front row and midfield
groups, with the U20s front row performing more than their senior counterparts on HSR,
moderate and heavy accelerations, all decelerations, HML distance HML efforts. As the senior
players tend to be heavier and stronger, the static exertions (not measureable by GPS) from
scrums have been shown to be greater in the senior international game [44]. This may result in
transient fatigue, whereby there is a reduction in high-intensity activity performed immediately
following an intense bout, with a subsequent recovery later in performance [45], and account
for their lower movement scores. The opposite was true for the midfield group with the seniors
producing higher scores for relative distance covered, HSR, moderate decelerations, HML dis-
tance and sprints•min-1. Perhaps indicating these players are used more frequently in a more
direct, gain-line based game plan.
High speed running (HSR) has previously been shown to distinguish between playing levels
in a number of sports (e.g. [12, 46, 47]), with the more elite levels covering greater distances in
this speed zone. However, in the current study overall the U20s forwards and backs groups,
performed more relative HSR than their senior counterparts. This wasn’t the case for each posi-
tional group however, both senior and U20 back row and half backs had no differences between
them for HSR. Whilst the senior midfield group outperformed the U20s. One potential reason
for these discrepancies is that the two groups used here (senior and U20) are not elite and non-
Movement Demands of Elite Under-20s and Senior International Rugby Union Players
PLOS ONE | DOI:10.1371/journal.pone.0164990
November 8, 2016
9 / 13
elite as used in studies where HSR has been a distinguishing factor. Both groups could be
viewed as ‘elite’, in support of this 8 players from the U20s cohort have already progressed to
the senior squads. It is also worth noting U20s players generally weigh less than their senior
counterparts so will need to be able to maintain the same movement work load (e.g. distance
covered, HSR distance, accelerations, decelerations) whilst increasing in mass to prepare for
senior internationals. To our knowledge this is the first study comparing movement demands
of U20 and senior International rugby union matches. The data suggests that the movement
demands in Under 20s internationals are adequate for preparing players for movement
demands reported in International rugby. However, certain positional groups might require
more work and/or time to match their senior counterparts than others. Conditioning staff
must also bear in mind that the U20s players whilst maintaining or improving match move-
ment capabilities may require to gain substantial mass in some positions to match their senior
counterparts.
Supporting Information
S1 File. Table A. Supplementary Movement Characteristicsfor Senior and U20s, Forwards
and Backs Groups. Data presented as Mean ± S.D Table B. SupplementaryMovement Char-
acteristics Presented by Playing Groups. FR = Front Row (Prop & Hooker), SR = Second
Row, BR = Back Row, HB = Half Backs, MF = Midfield/Centres,B3 = Back Three (Wing &
Fullback). Data presented as Mean ± S.D. Table C. Estimates of fixed effects for all GPS vari-
ables displaying difference for position type between U20s and Seniors Table D. Estimates
of fixed effects for all GPS variables displaying difference for position group between U20s
and Seniors
(DOCX)
Author Contributions
Conceptualization: DC LK SD RE CC DS BP NT.
Data curation: DC LK SD RE CC DS BP NT.
Formal analysis: DC LK SD RE BP.
Funding acquisition: SD LK.
Methodology:DC LK SD RE CC DS BP NT.
Project administration: DC LK SD RE CC DS BP NT.
Supervision:LK.
Writing – original draft: DC LK SD RE CC DS BP NT.
Writing – review& editing: DC LK DS.
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Movement Demands of Elite Under-20s and Senior International Rugby Union Players
PLOS ONE | DOI:10.1371/journal.pone.0164990
November 8, 2016
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Movement Demands of Elite Under-20s and Senior International Rugby Union Players.
Cunningham, Daniel J,Shearer, David A,Drawer, Scott,Pollard, Ben,Eager, Robin,Taylor, Neil,Cook, Christian J,Kilduff, Liam P