RESEARCH ARTICLE
Exposure time, running and skill-related
performance in international u20 rugby union
players during an intensified tournament
Christopher J. Carling1,2, Mathieu Lacome2*, Eamon Flanagan3, Pearse O’Doherty4,
Julien Piscione2
1 Institute of Coaching and Performance, University of Central Lancashire, Preston, United Kingdom,
2 Research Department, French Rugby Union, Marcoussis, France, 3 Irish Rugby Football Union, Fitness
Department, Dublin, Ireland, 4 Statsports Technologies™, Newry, Northern Ireland
* mathlacome@gmail.com
Abstract
Purpose
This study investigated exposure time, running and skill-related performance in two interna-
tional u20 rugby union teams during an intensified tournament: the 2015 Junior World
Rugby Championship.
Method
Both teams played 5 matches in 19 days. Analyses were conducted using global positioning
system (GPS) tracking (Viper 2™, Statsports Technologies Ltd) and event coding (Opta
Pro®).
Results
Of the 62 players monitored, 36 (57.1%) participated in 4 matches and 23 (36.5%) in all 5
matches while player availability for selection was 88%. Analyses of team running output (all
players completing >60-min play) showed that the total and peak 5-minute high metabolic
load distances covered were likely-to-very likely moderately higher in the final match com-
pared to matches 1 and 2 in back and forward players. In individual players with the highest
match-play exposure (participation in >75% of total competition playing time and >75-min in
each of the final 3 matches), comparisons of performance in matches 4 and 5 versus match
3 (three most important matches) reported moderate-to-large decreases in total and high
metabolic load distance in backs while similar magnitude reductions occurred in high-speed
distance in forwards. In contrast, skill-related performance was unchanged, albeit with trivial
and unclear changes, while there were no alterations in either total or high-speed running
distance covered at the end of matches.
Conclusions
These findings suggest that despite high availability for selection, players were not over-
exposed to match-play during an intensified u20 international tournament. They also imply
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November 14, 2017
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OPEN ACCESS
Citation: Carling CJ, Lacome M, Flanagan E,
O’Doherty P, Piscione J (2017) Exposure time,
running and skill-related performance in
international u20 rugby union players during an
intensified tournament. PLoS ONE 12(11):
e0186874. https://doi.org/10.1371/journal.
pone.0186874
Editor: Jaime Sampaio, Universidade de Tras-os-
Montes e Alto Douro, PORTUGAL
Received: April 11, 2017
Accepted: October 9, 2017
Published: November 14, 2017
Copyright: © 2017 Carling 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: All relevant data are
within the paper and its Supporting Information
files.
Funding: No specific funding was provided for this
work either by the French Rugby Union Federation,
Irish Rugby Football Union or Statsports
Technologies Ltd. These commercial entities only
provided support in the form of salaries for authors
[CC, ML, EF, PO and JP], but did not have any
additional role in the study design, data collection
that the teams coped with the running and skill-related demands. Similarly, individual play-
ers with the highest exposure to match-play were also able to maintain skill-related perfor-
mance and end-match running output (despite an overall reduction in the latter). These
results support the need for player rotation and monitoring of performance, recovery and
intervention strategies during intensified tournaments.
Introduction
Rugby union is an intermittent team sport requiring players to repeatedly perform bouts of
high-speed running interspersed with periods of low-speed activity [1]. Intense static exertions
such as scrummaging, physical collisions and tackles also occur frequently throughout play
[2]. On average, forward and back players at elite senior levels are shown to spend 14% and 8%
of their match time in highly intense activities such as sprinting and tackling and in scrums,
rucks and mauls [3]. Combined, these physical demands are shown to result in high levels of
muscle damage [4,5], neuromuscular and perceptual fatigue [6] and compromised immunity
[7] post-competition. While generally transient in nature, such disturbances typically persist
for 24–48 h following match-play although muscle damage can last for several days with large
variations in recovery kinetics reported across individuals [8]. At elite senior levels however, a
single match is generally played per week over the course of the season [9]. Therefore, the time
interval separating consecutive matches is sufficient in theory to ensure complete physical and
physiological recovery [10].
In contrast to elite senior rugby union competition, congested competition schedules
involving multiple matches played in a short time period occur in players in elite junior cate-
gories. For example, the annual World Rugby u20 World Cup schedule requires national
teams to participate in 5 matches over a 19-day period. If recovery time between successive
matches is short, residual fatigue, muscle damage and reduced immunity have the potential to
compromise ensuing match performance [11]. Yet to our knowledge, no data currently exist
on the potential effects on match performance (e.g., running, technical actions) of participa-
tion in intensified tournaments such as the u20 World Cup. Related research in junior Rugby
League players has reported a progressive accumulation of fatigue represented by a reduced
capacity to perform high-speed exercise during tournaments where multiple matches were
played over a 5-day period [12]. An investigation more representative of the u20 World Cup
schedule (cycle of 4 matches in 22 days vs. 5 matches in 19 days), albeit in professional rugby
league players demonstrated fluctuations in running activity with reductions in high-speed
and increases in low-speed distance covered in the latter matches [13]. No information was
reported on any potential changes in technical skill-related performance in either study. Thus
research investigating match-to-match running and technical skill-related performance during
the u20 World Cup is warranted.
Despite the aforementioned potential risk of fatigue accumulation and compromised com-
petitive performance associated with insufficient recovery time during intensified tourna-
ments, no information exists on the actual exposure time of players to match-play. Recent
research in a professional association football club [14] has shown that despite the frequent
occurrence of periods of match congestion across the season, squad rotation strategies were
employed by the coaching staff to ensure that players did not endure over-exposure. Thus, in
our opinion, similar data across tournaments such as the u20 World Cup are necessary to
Match performance in elite u20 rugby union
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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: The authors have no
competing interests and their commercial affiliation
(French Rugby Union Federation, Irish Rugby
Football Union or Statsports Technologies Ltd)
does not alter their adherence to PLOS ONE
policies on sharing data and materials. (as detailed
online in the journal’s guide for authors http://
journals.plos.org/plosone/s/competing-interests).
determine the actual extent of player exposure and therefore the aforementioned potential risk
of compromised match performance.
This study examined exposure time and the effects of an intensified tournament on running
and skill-related match performance in international u20 players during the 2015 World
Rugby u20 World Cup.
Materials and methods
Experimental approach to the problem
The present study was conducted during the 2015 World Rugby u20 World Cup tournament.
Participation time for each player was recorded to determine the extent of match exposure
over this intensified schedule. Global positioning systems (GPS) and match analysis software
were used to gather data related to match running and skill performance and examine the
potential effects of the congested schedule on performance notably in players with high expo-
sure time to match-play.
Participants
All players were members of the French or Irish national u20 teams. Altogether, 63 players
(age: 19.8 ± 0.5 y, body mass: 99.1 ± 9.1 kg, stature: 185.4 ± 7.0 cm) participated. Prior to par-
ticipation, all players received comprehensive verbal and written explanations of the study and
provided voluntarily signed informed consent to wear GPS in competitive matches and to par-
ticipate in the collection of performance data for the entirety of the Championship. These data
arose as a condition of selection for their national team in which player performance was rou-
tinely measured over the course of the competitive season [15]. Nevertheless, institutional
board approval for the study was obtained from the Medical Council of the Federation Fran-
c¸aise de Rugby. To ensure confidentiality, all performance data were anonymized. This study
conformed to the recommendations of the Declaration of Helsinki.
Competition
During the competition, each team played 5 matches in 19 days. A total of 4 days (94-98h) sep-
arated matches 1 and 2 and matches 2 and 3 and 5 days (118-120h) separated matches 3 and 4
and matches 4 and 5. Altogether, 226 match observations (forwards = 128 and backs = 98
matches) were collected. All participating players followed standardized recovery protocols
over the course of the competition: consumption of a minimum of 40 g carbohydrates and
20 g protein in liquid or whole food form immediately after competition. Players were also
requested to use cold bath, massages and compression garments. The day following the match,
players performed recovery protocols (hydrotherapy session, foam rolls, compression gar-
ments) and received appropriate nutritional and hydration plans.
Study design
In order to conduct the analyses, two categories of performance measures were employed:
1. Time-motion analyses of running performance.
Each player wore a 10-Hz GPS unit
(mass = 50g, size = 86x33x20mm; Viper 2™, Statsports Technologies™, Newry, Northern Ire-
land) in a bespoke pocket fitted in their playing jersey which positioned the GPS unit on the
upper thoracic spine between the scapulae. Independent testing has reported low typical error
of measurement (range: 0.7–1.7%) and coefficient of variation (2.0–2.9%) as well as low abso-
lute error (2.9–3.0%) over a range of activities including repeated 30m shuttle runs, a 132.3m
circuit simulating soccer activity and 16-minute duration small-sided matches (unpublished
Match performance in elite u20 rugby union
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data, Marathon Performance Center, 2014). All participants were familiarised with the devices
as part of their daily training and practice in the season leading up to the 2015 World Rugby
u20 World Cup.
The GPS units were turned on at least 30 minutes prior to each match to facilitate satellite
signal connection. Information on the average number of satellites to which GPS devices were
connected and values for the horizontal dilution of precision were unavailable. Following the
matches, GPS data were downloaded to a laptop and analysed with proprietary software
(STATSport Viper Rugby v2.6.1.173, STATSports Technologies Ltd., Ireland, UK). Players
whose GPS unit suffered a loss of signal for a period of time within the match were excluded
(i.e., GPS fell on the ground, spikes in the data, n = 11). Each file was cropped to ensure that
only data recorded when the player was on the field was included. A number of locomotor var-
iables were analysed: total distance run (TD) and that covered at high-running speeds (HS)
(threshold > 5.5 m.s-1). High-metabolic load distance (HI distance + distance covered while
accelerating above 2 m.s-2) [16] and the total number of high-speed activities (> 5.5 m.s-1) and
accelerations (> 2 m.s-2) were also recorded. Finally, the peak 5-min of HMLD (HMLD.Peak5-
min) was recorded for each match and player using a 5-min rolling average with step 0.1-s.
2. Match analyses of skill-related performance.
Measures of skill-related performance
defined by Opta Pro1 data provider and coded by the company’s match analysts using the
Sportscode software (Sportstec, Australia) included the total number of tackles, passes and car-
ries along with respective completion rates in these events. Effective playing time (time the ball
was in play) was also recorded. Although no data exists for elite rugby union, high levels of
Opta inter-operator reliability for coding match events in elite association football have been
demonstrated [17].
Data collection procedures
1. Participation patterns.
Exposure time was recorded for each individual player. Basic
metrics quantified from this data included total number of and percentage of the players com-
pleting: (1) 3, 4 and 5 matches respectively, (2) 3, 4 and 5 matches played successively, (3) at
least 60-min play [18] in 3, 4 and 5 matches played successively, (4) >240-min (equivalent to 3
complete matches) and >320-min (equivalent to 4 complete matches) total participation time
over the tournament. Time loss injuries and subsequent unavailability for match selection
were prospectively recorded by the team physicians respective to both teams.
2. Overall team running and skill-related performance.
To investigate accumulated
changes in overall team performance, running and skill-related performance measures were
normalised relative to each player’s participation time and compared across matches 1 to 5.
Players competing for <60-min were excluded. A total of 171 match observations were col-
lected including 77 and 94 observations for backs and forwards respectively.
3. Running and skill-related performance in “high exposure” players.
Players with high
exposure time notably during the final three matches were assessed separately. These three
matches were selected as these were considered to be the highest standard and most important
matches of the competition (e.g., semi-finals, finals or matches to determine team seeding in
the following year’s u20 world cup) and for which coaching staff habitually select their best
performers. Hence players should have been subjected to the highest physical and technical
demands in these three matches. Inclusion criteria were: (1) participation in at least 75-min in
each of the final 3 matches in the series, and (2) played more than 320-min over the course of
the competition (>75% of total playing time).
To investigate potential accumulated changes in individual match-performance, the afore-
mentioned running and skill-related measures were normalised relative to each player’s total
Match performance in elite u20 rugby union
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playing time and compared from Match 3 to Match 5. The total distance and high metabolic
load distance covered were also compared for the final 10-min period versus the mean value
(minus first and last 10-min periods) for the other 10-min periods.
Statistical analysis
Statistical analyses were performed using R statistical software (R. 3.1.0, R Foundation for Sta-
tistical Computing) using the lme4 and psychometric package. Means and standard deviations
for each group or playing time were derived from a generalized linear model, with the distribu-
tion and link function contingent upon the nature of the dependent variable. The overdis-
persed Poisson distribution was chosen for modelling the data from the match analyses and
the normal distribution was chosen for distances from the time-motion analyses. For each
analysis, the match (Match 1 to Match 5) was included as a fixed effect while players and teams
were included as random effects. The % differences between mean values with 90% confidence
intervals (CI) are reported.
A magnitude-based inferential approach was adopted [19,20]. Effect sizes (ES) were quanti-
fied to indicate the practical meaningfulness of the differences in mean values. Standardisation
was performed with the estimated marginal means and associated variance provided by the
generalized linear model. The ES was classified as trivial (0–0.19), small (0.20–0.59), moderate
(0.6–1.19), large (1.20–1.99) and very large (>2.0). If the 90% CI over-lapped small positive
and negative values, the magnitude was deemed unclear. The chances that the changes in run-
ning- or skill-related performance were greater for a group (i.e., greater than the smallest
worthwhile change, SWC (0.2 multiplied by the between-subject standard deviation, based on
Cohen’s d principle)), similar or smaller than the other group were calculated. Quantitative
chances of greater or smaller changes in performance variable were assessed qualitatively with
the following scale: 25−75%, possible; 75−95%, likely; 95−99%, very likely; >99%, almost cer-
tain. [21]
Results
Match exposure
The patterns of participation of players and exposure to periods of match congestion cycles are
presented in Table 1. Of the 62 players, 36 (57%) played 4 matches and 23 (37) played 5
matches. Of these appearances, 39, 28 and 23 players played 3, 4 and 5 matches successively
(62, 44, and 37% respectively). The proportion of backs and forwards who played 3, 4 and 5
matches successively with over 60-min of playing time was 14, 6 and 6% respectively for for-
wards and 35, 19 and 8% respectively for backs. Player availability for selection overall across
the competition was 88%.
Overall team match performance
Table 2 reports running and skill-related performance of players completing at least 60-min
in the matches while Fig 1 reports standardised changes in running and skill-related perfor-
mance in match 2 to 5 compared with match 1. Overall, unclear to likely small changes in
HSR, HMLD, sprints and accelerations were observed for backs (ES: -0.44 ±0.44 to 0.54 ±0.54)
between match 1 and the other matches. Regarding total distance covered, moderate increases
were observed for match 3 and 5 compared with match 1 (ES: 0.62 ±0.31 and 0.65 ±0.44
respectively). In forwards, unclear to small changes were reported in all running-performance
variables except for total distance covered. Regarding total distance covered, small to moderate
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increases were observed between match 3 and 5 compared to match 1 (ES: 0.40 ±0.42 and
0.89 ±0.80 respectively).
Regarding skill-related performance, unclear to small differences in the frequency of passes
and carries were observed between match 1 and the other matches. Likely moderate increases
were reported between the frequencies of tackles performed by backs between match 1 and
matches 2 to 4 (ES: 1.00 ±0.70; 1.30 ±0.53 and 1.10 ±0.80 for matches 2, 3 and 4 respectively).
Unclear to small fluctuations in pass success rates or average gain per carries were observed in
backs. Likely moderate decreases in tackles success rates occurred between match 1 and match
3 and 4 in backs (ES: 1.30 ±0.53 and 1.10 ±0.80). In forwards, there were unclear to trivial effect
size differences in the frequency and success rates of skill-related performance measures
between match 1 and the other matches except in tackling actions for which there was a mod-
erate decrease in match 1 vs match 2 and a moderate decrease in passing success rates in
match 1 vs match 4.
There was no difference in effective playing time between Match 1 and 2 but possibly mod-
erate to likely large increases were observed in Match 3, 4 and 5 compared with Match 1 (ES:
0.90 ±0.49; 1.75 ±0.51; 1.43 ±0.50 respectively).
Match performance in “high exposure” players
Table 3 reports running and skill-related performance in high exposure players. In backs, likely
moderate to large decreases in total distance covered and HLMD distance covered were
reported between match 3 versus match 4 and 5 (ES: -0.61 ±0.78 to -1.70 ±1.50). Regarding
HSR distance covered as well as sprints and acceleration frequencies, only unclear differences
were reported between match 3 versus match 4 and 5. In forwards, except for HSR distance
covered (ES: 1.20 ±0.78 and 0.69 ±0.75 for Match 4 and 5 compared to Match 3 respectively),
only unclear differences were reported in running related performance.
Table 1. Overall participation of players in the competition and exposure to match congestion cycles.
Match exposure
ALL PLAYERS (62)
FORWARDS (36)
BACKS (26)
Occurrences (n) Relative Nb
(%)
Occurrences (n) Relative Nb
(%)
Occurrences (n) Relative Nb
(%)
Matches played
Played >320 min in total
14
22%
5
14%
9
35%
Played >240 min in total
23
37%
10
28%
13
50%
Participations in 3 games (nb)
47
75%
26
72%
21
81%
Participations in 4 games (nb)
36
57%
19
53%
17
65%
Participations in 5 games (nb)
23
37%
13
36%
10
38%
Multiple match cycles
Participations in 3 successive games (nb)
39
62%
23
64%
16
62%
Participations in 3 successive games
>60-min (nb)
14
22%
5
14%
9
35%
Participations in 4 successive games (nb)
28
44%
16
44%
12
46%
Participations in 4 successive games
>60-min (nb)
7
11%
2
6%
5
19%
Participations in 5 successive games (nb)
23
37%
13
36%
10
38%
Participations in 5 successive games
>60-min (nb)
4
6%
2
6%
2
8%
Nb: Number.
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In backs and forwards, unclear differences were observed in pass and tackle success rates
and average gain per carries between match 3 versus match 4 and 5 although there was a
large increase in tackle success rates in match 3 vs match 5 in backs (ES: 1.20 ±0.99). In
backs, there were possibly moderate and likely small increases in the frequency of passes (ES:
0.77 ±0.86 and 0.41 ±0.57 respectively) along with a possibly moderate to possibly large
decrease in tackle frequency in matches 4 and 5 compared with match 3 (ES: -0.87 ±0.91 and
-1.58 ±1.04 respectively). In forwards, unclear differences were observed in the frequency of
tackles and carries between match 3 and matches 4 and 5. Possibly small to possibly moderate
increases in passing frequency were reported in match 3 compared to matches 5 and 4 (ES:
0.41 ±0.57 and 0.77 ±0.86 respectively).
Fig 2 reports differences in total distance covered and HMLD distance covered between the
mean 10-min versus the final 10-min period, from match 3 to match 5. Small to moderate
increases in total distance covered between the final 10-min and mean 10-min period were
observed in matches 4 and 5 compared to match 3 (ES: 0.33 ±0.41 and 0.95 ±1.10 respectively).
Regarding HMLD, there were large increases in match 4 and 5 compared to match 3 (ES:
1.25 ±0.83 and 1.24 ±1.30 respectively).
Table 2. Running and skill- performance in players competing at least 60-min from match 1 to match 5.
BACKS
Match 1 (13)
Match 2 (14)
Match 3 (13)
Match 4 (12)
Match 5 (12)
TD (m.min-1)
66.8 ± 6.0
64.7 ± 8.3
71.3 ± 7.9
68.0 ± 5.1
70.3 ± 3.6
HSR (m.min-1)
4.4 ± 2.0
4.1 ± 1.4
4.0 ± 1.5
4.9 ± 2.3
4.4 ± 1.8
HMLD (m.min-1)
10.5 ± 2.0
10.0 ± 1.9
11.1 ± 2.8
11.3 ± 2.4
11.3 ± 2.0
Sprints (n.min-1)
0.24 ± 0.08
0.25 ± 0.07
0.24 ± 0.08
0.29 ± 0.1
0.27 ± 0.08
Accel (n.min-1)
0.31 ± 0.08
0.27 ± 0.09
0.34 ± 0.13
0.36 ± 0.11
0.35 ± 0.11
HMLD.Peak5min (m.min-1)
25.7 ± 5.2
26.9 ± 6.0
28.3 ± 6.0
30.6 ± 9.0
30.0 ± 8.3
Tackles (n)
0.05 ± 0.03
0.09 ± 0.04
0.10 ± 0.04
0.08 ± 0.03
0.06 ± 0.03
Passes (n)
0.10 ± 0.12
0.10 ± 0.11
0.07 ± 0.09
0.12 ± 0.1
0.07 ± 0.04
Carries (n)
0.08 ± 0.04
0.05 ± 0.03
0.06 ± 0.04
0.09 ± 0.03
0.10 ± 0.06
Tackles (%)
0.82 ± 0.30
0.83 ± 0.15
0.62 ± 0.23
0.63 ± 0.18
0.74 ± 0.29
Passes (%)
0.97 ± 0.06
0.98 ± 0.05
0.93 ± 0.11
0.93 ± 0.12
0.91 ± 0.14
Average Gain/Carries (m)
5.23 ± 3.00
5.10 ± 2.28
6.59 ± 8.05
5.82 ± 2.89
4.70 ± 2.29
FORWARDS
Match 1 (12)
Match 2 (10)
Match 3 (12)
Match 4 (9)
Match 5 (10)
TD (m.min-1)
59.8 ± 4.7
53.8 ± 6.4
62.7 ± 8.2
61.3 ± 4.6
63.6 ± 3.5
HSR (m.min-1)
1.1 ± 0.8
0.6 ± 0.5
1.0 ± 0.8
1.4 ± 0.7
1.1 ± 0.8
HMLD (m.min-1)
6.5 ± 2.2
5.2 ± 1.9
7.0 ± 2.4
6.4 ± 3.0
7.2 ± 2.0
Sprints (n.min-1)
0.09 ± 0.06
0.06 ± 0.05
0.10 ± 0.07
0.10 ± 0.06
0.09 ± 0.06
Accel (n.min-1)
0.31 ± 0.16
0.19 ± 0.11
0.31 ± 0.16
0.27 ± 0.16
0.33 ± 0.11
HMLD.Peak5min (m.min-1)
15.4 ± 3.2
16.3 ± 5.4
17.4 ± 5.1
15.7 ± 6.5
19.3 ± 4.9
Tackles (n)
0.11 ± 0.06
0.15 ± 0.01
0.13 ± 0.05
0.08 ± 0.03
0.12 ± 0.06
Passes (n)
0.03 ± 0.04
0.01 ± 0.02
0.02 ± 0.03
0.04 ± 0.04
0.04 ± 0.06
Carries (n)
0.09 ± 0.06
0.05 ± 0.05
0.10 ± 0.08
0.08 ± 0.06
0.09 ± 0.06
Tackles (%)
0.96 ± 0.06
0.89 ± 0.11
0.92 ± 0.09
0.83 ± 0.19
0.94 ± 0.08
Passes (%)
0.99 ± 0.03
1.00 ± 0.00
0.98 ± 0.06
0.91 ± 0.19
0.98 ± 0.06
Average Gain/Carries (m)
1.91 ± 1.68
1.93 ± 1.51
1.88 ± 1.34
1.56 ± 1.04
1.46 ± 1.11
Effective playing time (min)
29.3 ± 2.1
29.6 ± 3.4
35.3 ± 8.5
32.2 ± 0.2
33.1 ± 2.5
TD: Total distance; HSR: High speed running; HMLD: High metabolic load distance; ES: Effect size; % chances: % chances that the true difference is +ive/
trivial/ -ive.
Number in parenthesis refers to the number of players analysed.
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Discussion
To our knowledge, this is the first study conducted in international junior rugby union players
to investigate exposure time to match-play, running and skill-related match performance dur-
ing an intensified tournament (5 matches in 19 days). The main findings were: (1) only <60%
and <40% of players participated in 4 or 5 of all matches respectively despite a substantially
higher availability rate for selection, (2) the two teams as a whole were able to maintain run-
ning- and skill-related performance throughout this intensive schedule, (3) in players with the
highest exposure time to play, overall running performance over the final two matches was
Fig 1. Standardised differences in running (panel A)- and skill (panel B)- related performance between match 1 and match 2 to 5 in
forwards and backs. Grey zone stands for trivial zone (effect size ± 0.2). TD: Total distance; HSR (High speed running); HMLD: High metabolic
load distance. Accel: Accelerations; HMLD.Peak5min: Peak 5-min of high metabolic load distance.
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affected to a certain extent although end match running output and overall skill-related perfor-
mance remained stable.
Match exposure
In elite rugby union, the exposure time of players to competition has generally received little
attention in the scientific literature [9]. No information exists for elite players in younger age
categories and especially during intensified tournaments such as the u20 World Cup. In this
tournament, teams are exposed to a demanding schedule of 5 matches over a 19-day period. In
the present study, analysis of two international u20 teams showed that only 57% and 37% of
players participated in 4 or 5 out of the 5 successive matches respectively despite player avail-
ability being nearly 90% across the tournament. These findings imply that the teams’ coaching
staff recognised the need to rotate and rest players over the course of the tournament. In
regards to participation in successive matches, almost two-thirds of players were exposed to 3
consecutive matches although only 22% (35% of backs and 14% of forwards) played over
60-mins in all three matches. While no information is available on the actual reasons of
Table 3. Running and skill-performance in “high-exposure players” from match 3 to match 5.
BACKS (5)
Match 3
Match 4
Match 5
Match 3 vs Match 4
Match 3 vs Match 5
ES
% chances
ES
% chances
TD (m.min-1)
73.7 ± 7.1
66.1 ± 4.6
69.9 ± 3.5
-1.20 ±0.80
0/2/97
-0.61 ±0.78
4/14/81
HSR (m.min-1)
4.9 ± 1.0
4.8 ± 1.7
3.8 ± 0.9
-0.05 ±0.79
29/33/37
-0.98 ±1.30
6/9/85
HMLD (m.min-1)
12.2 ± 0.6
11.2 ± 1.8
10.8 ± 0.9
-0.67 ±0.81
4/13/83
-1.70 ±1.50
2/3/95
Sprints (n.min-1)
0.29 ± 0.02
0.30 ± 0.06
0.26 ± 0.05
0.22 ±8.90
50/3/47
-0.57 ±0.94
9/17/75
Accel (n.min-1)
0.40 ± 0.10
0.40 ± 0.12
0.37 ± 0.11
-0.03 ±2.40
44/11/45
-0.30 ±0.96
19/24/57
HMLD.Peak5min (m.min-1)
31.8 ± 5.0
28.4 ± 6.3
26.9 ± 1.2
-0.53.± 1.04
12/15/72
-1.20.± 1.04
2/4/94
Tackles (n)
0.12 ± 0.05
0.08 ± 0.03
0.06 ± 0.02
-0.87 ±0.91
3/8/89
-1.58± 1.04
1/1/98
Passes (n)
0.03 ± 0.03
0.06 ± 0.04
0.06 ± 0.05
0.72 ±1.20
79/12/9
0.66 ±1.10
78/14/9
Carries (n)
0.08 ± 0.02
0.07 ± 0.02
0.08 ± 0.05
-0.15 ±1.60
35/18/48
-0.06 ±0.91
31/30/39
Tackles (%)
0.59 ± 0.19
0.59 ± 0.20
0.80 ± 0.12
0.01 ±1.00
37/27/36
1.20 ±0.99
95/4/2
Passes (%)
0.95 ± 0.11
0.86 ± 0.14
0.92 ± 0.14
-0.60 ±1.00
10/15/75
-0.24 ±1.00
22/25/53
Average Gain/Carries (m)
5.52 ± 7.35
5.71 ± 3.09
3.46 ± 1.51
0.03 ±0.88
36/32/32
-0.35 ±0.94
15/23/61
FORWARDS (5)
Match 1
Match 2
Match 3
Match 3 vs Match 4
Match 3 vs Match 5
ES
% chances
ES
% chances
TD (m.min-1)
61.4 ± 8.8
62.5 ± 3.5
64.2 ± 2.5
0.15 ±0.61
44/39/17
0.40 ±0.66
70/24/7
HSR (m.min-1)
0.5 ± 0.3
1.4 ± 0.8
1.0 ± 0.8
1.20 ±0.78
98/1/0
0.69 ±0.75
86/11/3
HMLD (m.min-1)
5.8 ± 2.0
6.5 ± 3.6
7.1 ± 1.6
0.23 ±0.69
53/32/15
0.65 ±1.10
75/15/10
Sprints (n.min-1)
0.06 ± 0.04
0.11 ± 0.07
0.08 ± 0.05
0.91 ±0.80
93/6/1
0.43 ±0.88
67/21/11
Accel (n.min-1)
0.28 ± 0.10
0.29 ± 0.19
0.34 ± 0.1
0.07 ±0.85
40/31/30
0.53 ±0.78
76/18/6
HMLD.Peak5min (m.min-1)
17.1 ± 6.1
14.6 ± 7.6
18.4 ± 5.6
-0.33.± 1.04
20/20/60
0.19.± 1.04
51/23/27
Tackles (n)
0.13 ± 0.05
0.10 ± 0.02
0.13 ± 0.05
-0.85 ±1.10
6/11/83
0.01 ±1.1
38/25/37
Passes (n)
0.03 ± 0.03
0.06 ± 0.04
0.05 ± 0.07
0.77 ±0.86
87/9/4
0.41 ±0.57
74/22/4
Carries (n)
0.10 ± 0.08
0.09 ± 0.06
0.10 ± 0.06
-0.07 ±0.72
25/37/37
-0.06 ±0.69
25/39/36
Tackles (%)
0.87 ± 0.07
0.80 ± 0.19
0.90 ± 0.09
-0.48 ±0.80
8/19/73
0.35 ±1.40
57/18/25
Passes (%)
0.97 ± 0.07
0.85 ± 0.22
0.96 ± 0.08
-0.63 ±0.95
7/14/79
-0.06 ±2.20
41/13/45
Average Gain/Carries (m)
1.35 ± 0.72
1.14 ± 0.67
1.22 ± 1.13
-0.27 ±1.40
28/18/53
-0.13 ±0.63
18/40/42
Effective playing time (min)
35.3 ± 8.5
32.2 ± 0.2
33.1 ± 2.5
-0.5± 0.74
6/18/76
-0.34± 0.74
12/25/63
TD: Total distance; HSR: High speed running; HMLD: High metabolic load distance; ES: Effect size; % chances: % chances that the true difference is +ive/
trivial/ -ive.
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Match performance in elite u20 rugby union
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practitioners for selection/non-selection or substitutions of players during the present con-
gested competition, these results again tend to suggest that rotation strategies were employed
to avoid over-exposure. Similar findings have been previously identified in an elite association
football club [14]. However, before any generalisations can be made additional work is neces-
sary to determine exposure time and identify the reasons for rotation strategies across all par-
ticipating teams and multiple u20 World Cup competitions.
Overall team performance
Analyses of running and skill related performance (excluding players competing for less than
60-min) for the two teams as a whole across the 5-match schedule reported no notable changes
from match to match. It is noteworthy that during the final match of the series, small to mod-
erate increases in values were observed for the total distance covered, HMLD, number of accel-
erations and HMLD.Peak5-min compared to those recorded in matches 1 and 2 in both backs
and forwards. The frequency of passes, successful passes and tackles and average gains per
Fig 2. Differences in total distance covered (panel A) and high metabolic load distance covered (panel
B) between the mean 10-min versus the final 10-min period, from match 3 to match 5. Grey zone stands
for trivial zone (effect size ± 0.2). Grey circles: Individual observations. Black circle and bar: Mean and
standard deviation.
https://doi.org/10.1371/journal.pone.0186874.g002
Match performance in elite u20 rugby union
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carry were lower in match 5 versus match 1 whereas the frequency of tackles and carries were
higher. However, the effect sizes for these differences ranged from trivial to small. Taken
together, these findings suggest that the two teams as a whole coped ‘physically’ and ‘techni-
cally’ with the demands of this intensive schedule. In the absence of similar data for rugby
union, comparisons can only be made with other team sports such as soccer and rugby league.
In two studies in elite soccer, neither skill nor running performance declined in two teams as a
whole over several successive matches played over a short time period [22,23]. Junior rugby
league players in contrast [12] reported an attenuation in overall distance run and that covered
in high-speeds in the final two matches during an intensified competition (5x40-minute
matches played over a 5-day period).
Several reasonable explanations may be forwarded for this lack of a reduction in match per-
formance. First, the 4-5-day interval between matches may have been sufficient to enable full
physical and/or physiological recovery and readiness for the following match [24]. Second, the
systematic monitoring by the teams of recovery responses (e.g., RPE, sleep quality and quan-
tity, muscle soreness) following competition combined with daily training load management
enables evidence-based and informed decisions on player selection policies for the forthcom-
ing match [9,25]. Third, the aforementioned standardized post-match recovery interventions
possibly also aided players to maintain match performance although contrasting evidence
exists for their effectiveness [26,27]. Finally, the highly developed physical qualities of players
at international standards could have attenuated post-match fatigue enabling a quicker recov-
ery. In rugby league, both the ability to perform high-intensity running and body strength are
shown to minimise post-match fatigue and muscle damage markers [28]. Work in elite rugby
union populations is necessary to verify this latter explanation.
Performance in “high match exposure” players
A separate analysis of the final three matches of the competition (separated by 5-days recovery
intervals) was conducted as these were considered the most demanding due to the standard of
the opposition and stakes: semi-finals, finals or matches to determine team seeding in the fol-
lowing year’s u20 world cup. In backs who participated in a minimum 75-min play in each of
these latter matches and 75% of the total team’s exposure over the entire competition, there
were moderate to large decreases in total distance covered, HMLD and HMLD.Peak5min
overall in games. Similar magnitude drops also occurred for HSR in forwards in matches 4
and 5 versus match 3.
These findings imply that running performance overall was negatively affected in high
exposure players and might be associated with a progressive accumulation of fatigue. The
decline could be associated to the cumulative perceptual, physical and physiological effects of
participation in several matches over a short time frame. These results also demonstrate the
importance of examining performance on an individual basis notably in players with greater
exposure rather than simply for the team as a whole. It is important to note however that a
reduction in effective playing time in matches 4 and 5 occurred. This drop might have partly
contributed to the lower distances covered. Research to identify potential reasons for such
match-to-match changes in running output related to effective playing time and other contex-
tual factors such as score line is necessary. Similarly, simultaneous monitoring of post-match
neuromuscular, blood creatine kinase, perceptual well-being, RPE and sleep responses [9]
would be pertinent to complement the present external analyses of match demands. In general,
work is necessary to determine the minimal time interval necessary to ensure that elite junior
players are fully recovered psychologically, physically and physiologically between consecutive
matches during the present tournament.
Match performance in elite u20 rugby union
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Interestingly, despite the decrease in overall running output in matches 4 and 5 versus
match 3, no decrements in total distance covered or HMLD were observed during the final
10-minutes of play compared to the mean distance run for all other 10-min periods. Thus it
seems that the high exposure players were able to maintain end-match running performance
even at the latter end of the congested schedule. This result contrasts with previous research
showing a general trend for reductions in running distances towards the end of matches in
elite senior rugby union [29–31]. A reasonable explanation for this lack of a decline could be
linked to players adopting a pacing strategy in order to maintain their ability to participate in
key match actions throughout the entire course of play [32].
Recent research has shown that senior international rugby union players are able to main-
tain skill-related performance over the course of match-play even when declines in running
performance occur [33]. Here, a large disparity in changes in the overall frequency and success
rates of technical actions was observed in backs and forwards across the three final matches
rendering difficult the interpretation of findings. For example, in match 5 compared to match
4 passing frequency improved in both playing positions whereas tackle frequency dropped in
backs but increased in forwards. As these patterns might only be a reflection of the present two
teams and related to the opposition teams each faced (standard, style of play, tactics), we sug-
gest there is a need for analysis of all participating u20 teams to provide a larger sample from
which more accurate conclusions can be drawn.
Limitations and research perspectives
While two national teams collaborated on this research project, larger sample-size studies are
necessary to determine exposure time and assess player rotation strategies across all participat-
ing teams and in those that are deemed to be successful or non-successful. Monitoring of the
time course of various recovery markers (perceptual, physical and physiological) is also neces-
sary to allow assessment of how a congested schedule impacts post-match recovery kinetics
and subsequent readiness for play.
Conclusions
This study shows that only <60% and <40% of players participated in 4 or 5 of all matches
respectively despite high availability for selection suggesting that coaching staff operated rota-
tion and rest strategies. It would seem that effective squad management strategies are necessary
to aid junior international teams in sustaining work rate and skill proficiency over an intensi-
fied schedule as reflected in the maintaining of running and skill-related match performance
by the present teams. However, in individual players reporting the highest exposure time to
play especially in the most important matches (final 3 in the 5 match series), running perfor-
mance over the entire match was affected to a certain extent although overall skill-related per-
formance remained stable. Similarly, running performance during the latter stages of play was
also stable. These results suggest that, while overall running performance tended to decrease in
high exposure players, coaches can generally be confident in their players’ ability to maintain
end-match physical- and skill-related performance even during congested schedules. This pos-
itive result might be linked to pacing and/or post-match recovery strategies and requires fur-
ther investigation.
Supporting information
S1 Data. Blind Global positioning system dataset.
(XLSX)
Match performance in elite u20 rugby union
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Author Contributions
Conceptualization: Christopher J. Carling, Mathieu Lacome, Eamon Flanagan, Julien
Piscione.
Data curation: Mathieu Lacome.
Formal analysis: Mathieu Lacome, Pearse O’Doherty.
Funding acquisition: Julien Piscione.
Investigation: Christopher J. Carling, Mathieu Lacome.
Methodology: Christopher J. Carling, Mathieu Lacome, Eamon Flanagan.
Project administration: Julien Piscione.
Resources: Eamon Flanagan.
Software: Pearse O’Doherty.
Supervision: Eamon Flanagan, Julien Piscione.
Validation: Christopher J. Carling, Mathieu Lacome, Eamon Flanagan, Julien Piscione.
Visualization: Pearse O’Doherty.
Writing – original draft: Christopher J. Carling.
Writing – review & editing: Christopher J. Carling, Mathieu Lacome.
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Exposure time, running and skill-related performance in international u20 rugby union players during an intensified tournament.
Carling, Christopher J,Lacome, Mathieu,Flanagan, Eamon,O'Doherty, Pearse,Piscione, Julien