International  Journal  of
Environmental Research
and Public Health
Article
Motion Analysis of Match Play in U14 Male Soccer Players and
the Inﬂuence of Position, Competitive Level and
Contextual Variables
Erling Algroy 1,*, Halvard Grendstad 2, Amund Riiser 3, Tone Nybakken 2, Atle Hole Saeterbakken 3
,
Vidar Andersen 3 and Hilde Stokvold Gundersen 2


Citation: Algroy, E.; Grendstad, H.;
Riiser, A.; Nybakken, T.;
Saeterbakken, A.H.; Andersen, V.;
Gundersen, H.S. Motion Analysis of
Match Play in U14 Male Soccer
Players and the Inﬂuence of Position,
Competitive Level and Contextual
Variables. Int. J. Environ. Res. Public
Health 2021, 18, 7287. https://
doi.org/10.3390/ijerph18147287
Academic Editors: Filipe
Manuel Clemente, Ana Filipa Silva
and Daniele Conte
Received: 4 June 2021
Accepted: 5 July 2021
Published: 7 July 2021
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1
Campus Bergen, NLA University College, 5812 Bergen, Norway
2
Department of Sport, Food and Natural Sciences, Campus Bergen, Western Norway University of
Applied Sciences, 5020 Bergen, Norway; halvardg@nih.no (H.G.); tone.nybakken@hvl.no (T.N.);
hilde.stokvold.gundersen@hvl.no (H.S.G.)
3
Department of Sport, Food and Natural Sciences, Campus Sogndal, Western Norway University of
Applied Sciences, 6851 Sogndal, Norway; amund.riiser@hvl.no (A.R.); atle.saeterbakken@hvl.no (A.H.S.);
vidar.andersen@hvl.no (V.A.)
*
Correspondence: eaa@nla.no
Abstract: This study aimed to investigate match running performance in U14 male soccer players
in Norway, and the inﬂuence of position, competitive level and contextual factors on running
performance. Locomotion was monitored in 64 different U14 players during 23 ofﬁcial matches.
Matches were played at two different competitive levels: U14 elite level (n = 7) and U14 sub-elite level
(n = 16). The inclusion criterion was completed match halves played in the same playing position.
The variables’ inﬂuence on match running performance was assessed using mixed-effect models,
pairwise comparisons with Bonferroni correction, and effect size. The results showed that the U14
players, on average, moved 7645 ± 840 m during a match, of which 1730 ± 681 m (22.6%) included
high-intensity running (HIR, 13.5–18.5 km·h−1) and sprinting (>18.5 km·h−1). Wide midﬁelders
(WM) and fullbacks (FB) covered the greatest sprint distance (569 ± 40 m) and, in addition to the
centre midﬁeld position (CM), also covered the greatest total distance (TD) (8014 ± 140 m) and
HIR distance (1446 ± 64 m). Centre forwards (CF) performed signiﬁcantly more accelerations
(49.5 ± 3.8) compared other positions. TD (7952 ± 120 m vs. 7590 ± 94 m) and HIR (1432 ± 57 m vs.
1236 ± 43 m) were greater in U14 elite-level matches compared with sub-elite matches. Greater TD
and sprint distances were performed in home matches, but, on the other hand, more accelerations
and decelerations were performed in matches played away or in neutral locations. Signiﬁcantly
higher TD, HIR and sprinting distances were also found in lost or drawn matches. In conclusion,
physical performance during matches is highly related to playing position, and wide positions seem
to be the most physically demanding. Further, competitive level and contextual match variables are
associated with players’ running performance.
Keywords: match running performance; youth soccer; positional differences; competitive levels;
contextual variables
1. Introduction
In the last decade, several studies have described the physical demands of youth soccer [1].
Previous reports have shown that U14 players cover a total distance between 105–115 m·min−1
during a match and 11.5–14.5 m·min−1 at higher speed (13.1–19 km·h−1) [2,3] Additionally,
elite U14 players perform about 0.4 ± 0.2 sprints (speed above 25.2 km·h−1) [2] and
1.82 ± 0.33 accelerations per min during a match [2,4]. Although there is a growing body
of evidence related to the physical match characteristics of youth soccer players, very
few studies have examined running performance at the U14 level speciﬁcally in relation
to high-explosive actions like sprints, accelerations and decelerations [1,5]. Due to the
Int. J. Environ. Res. Public Health 2021, 18, 7287. https://doi.org/10.3390/ijerph18147287
https://www.mdpi.com/journal/ijerph
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increasing physical match demands with age, more knowledge about performance at
speciﬁc age levels is necessary to gain insights into the prerequisites of competing at U14
level. Additionally, the inﬂuence of competing standard and positional roles on players’
running performance seems to be an important factor in youth soccer [1] and must be
accounted for.
Although the scientiﬁc evidence is scarce, some studies have examined match running
characteristics among youth players. These have reported that U13–U18 players’ physical
match characteristics are affected by positional demands, as strikers and wide midﬁelders
demonstrated the highest peak game speeds and frequency of high-intensity actions [5,6].
Additionally, centre midﬁelders have been reported to cover the highest total distance [5,6],
whereas centre backs covered the lowest total distance [7] and the lowest amount of
high-intensity actions [6].
A current limitation in research on youth soccer is the lack of information regarding
the inﬂuence of contextual variables like match results, location and match status [1].
One previous study has shown that U14 elite level players outperform non-elite players
regarding match running performance [2], suggesting a higher external demand during
elite matches [7,8]. Studies from senior soccer have also reported greater match running
performance in games lost compared with games won [9].
To date, no study has examined the match performance characteristics of U14 soccer
players from Norway or other Scandinavian countries. Comparing data from different
countries and regions of the world would be important to enhance our understanding of
various approaches to and philosophies of talent development. Especially, more research
regarding accelerations and decelerations is necessary in youth soccer. These high-intensity
actions have been found to be crucial determinants for successful performance and to
discriminate high- and low-level adult players [10]. Accelerations and decelerations also
require high rates of force development and are therefore related to the total match load [11].
Additionally, studies on U14 players have, to the best of our knowledge, only been con-
ducted in the United Kingdom, Qatar and New Zealand [1]. Hence, the ﬁrst aim of this
study was therefore to analyse match running performance in U14 male soccer players
in Norway. A second aim was to identify how playing position, competitive level and
contextual factors inﬂuenced running performance. We hypothesise that players’ playing
positions and competitive level inﬂuenced the amount of high-intensity actions in U14
soccer matches.
2. Materials and Methods
The current study is part of a longitudinal research project, examining factors related
to talent development in youth soccer [12]. The study design in the present study is
descriptive, and match running performance data were collected during the 2018 season,
from April to October. Collection of anthropometric data was performed during 2 different
days for each player in the middle of the 2018 season. Contextual factors investigated in
the present study were match results, match location and match halves.
2.1. Participants
Sixty-four U14 male outﬁeld players (age: 14.0 ± 0.3 years, height: 166.3 ± 8.8 cm,
weight: 51.9 ± 9.7 kg, body fat: 8.7 ± 3.3%) from 4 clubs with youth soccer academies were
included. Three of the players were U13 players but were included as they played in the
U14 teams investigated. The Regional Committee for Medical and Health Research Ethics
approved the study (2017/1731), which was conducted in accordance with the Helsinki
Declaration. Since players were under the legal age of consent, both the players and their
parents gave written informed consent to participate. All results were treated anonymously.
2.2. Matches
Match running performance was obtained from 23 matches, 15 at the team’s home
location and 5 away and 3 on a neutral ﬁeld. In 17 of the matches, the teams won; 1 match
Int. J. Environ. Res. Public Health 2021, 18, 7287
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ended with a draw and 5 with a loss. All matches were ofﬁcial league or cup matches,
played outdoor on regular-sized synthetic grass soccer ﬁelds with 11 players per side.
Matches were played at 2 different competitive levels: U14 elite, national level (7 matches,
93 match halves), U14 sub-elite, the highest regional level (16 matches, 249 match halves).
Players playing in elite teams are recruited into playing at professional youth academies
and matches are played in the U14 national level league, in which youth academies from
professional Norwegian clubs participate. Some players played matches at more than
1 level.
Match playing time was 2 × 35 min in the U14 local series and 2 × 40 min for the U14
national series. All match performance outcomes were normalised to 35 min of playing
time before the analyses to allow direct comparison between matches at different competing
levels and to be comparable with other studies examining U14 players.
Because of the “rolling substitution” policy resulted in a large variation in playing
time between players, all match halves completed by 1 player in the same playing position
were included in the dataset. The dataset comprised 342 match halves, including 187 ﬁrst
halves and 155 second halves; 278 of the included halves were from complete matches
played by 1 player.
2.3. GPS Tracking
During the matches, the players wore a portable and previously validated [13] GPS
device (Apex, STATSsport, Newry, UK) monitoring their motions and position with a
sampling frequency of 18 Hz. The players wore, in most cases, the same unit in every game
to limit inter-unit reliability issues, although the present GPS system has been shown to
have excellent inter-unit reliability [14]. The units were placed in vests located between the
players’ scapulae. The raw GPS data were synchronised to the start and end of each half
match period and exported for further analysis.
2.4. Match Running Categories
Match activities were divided into different speed categories: walking (0.1–4.5 km·h−1),
low-intensity running (LIR, 4.5–8.5 km·h−1), medium-intensity running (MIR, 8.6–13.5 km·h−1),
high-intensity running (HIR, 13.6–18.5 km·h−1), sprinting (>18.5 km·h−1) and maximal
speed. The speed thresholds were age-speciﬁc [3] and adapted from previous studies on
U14 soccer players [3,15] to compare running performance with previously reports on
U14 soccer players. In addition, sprint distance with a threshold adapted from studies on
senior soccer players (25.2 km·h−1 with a duration of at least 1 s) was included to compare
sprint distance between U14 players and senior elite players [16]. Total distance included
all locomotion during the match. Data are presented both in absolute (m) and relative
(m·min−1) distances.
The number of accelerations and decelerations was also examined, and were deﬁned
as actions when speed was increased or decreased by more than 3 m·s−2 and lasted more
than 0.5 s. Only accelerations and decelerations at speeds above 13.5 km·h−1 were included.
2.5. Playing Position
Players were categorised as centre backs (CB, n = 70 match halves), fullbacks (FB,
n = 68 match halves), centre midﬁelders (CM, n = 100 match halves), wide midﬁelders
(WM, n = 65 match halves) or centre forwards (CF, n = 39 match halves). Players swapping
positions were excluded from the analysis. Goalkeepers were excluded from the study due
to their low running demands [16,17].
2.6. Statistical Analyses
Data are presented as means with the standard deviation (SD) or 95% conﬁdence inter-
val (CI). Visual inspection conﬁrmed that all data were normally distributed. Differences in
match running performance between halves were assessed by one-way ANOVA analysis.
Int. J. Environ. Res. Public Health 2021, 18, 7287
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The ﬁxed effects (E) of the independent variables on match running performance
were assessed using mixed-effect models with the player as a random effect to adjust for
multiple match observations by the same player. All independent variables were included
in the models, as they may inﬂuence match running performance in theory. The variables
analysed were playing position (5 positions), competitive level (elite vs. sub-elite), match
location (home vs. neutral/away), match results (win vs. draw/loss) and match half
(ﬁrst vs. second half). The collinearity between the continuous independent variables
was inspected by Pearson’s product moment correlations coefﬁcients and were included if
r < 0.6. Pairwise comparisons for competition level and playing position were performed
with Bonferroni correction. IBM SPSS Statistics (version 26, IBM, Armonk, NY, USA) was
used for all statistical analyses. Signiﬁcance for all analyses was accepted at p ≤ 0.05. When
signiﬁcant differences were detected, Cohen’s d effect size (ES) was calculated. An ES of
0–0.2 was considered trivial, >0.2 as small, >0.5 as medium and >0.8 as large [18].
3. Results
3.1. Match Running Performance
During a match, players covered, on average, 22% of the total distance by high-
intensity running (13.6–18.5 km·h−1) and sprinting (>18.5 km·h−1), 32% by medium-
intensity running (8.6–13.5 km·h−1), 32% by low-intensity running (4.6–8.5 km·h−1) and
16% by walking (0.1–4.5 km·h−1). More distance was covered in the ﬁrst compared with
the second half, both in metres (ES = 0.71) and metres pr minute (ES = 0.29). Total distance
and high-intensity activities for each half are presented in Table 1.
Table 1. An overview of total match distance covered and high-intensity actions in Norwegian U14 players. Data are
presented as means ± SD. Match playing time was 2 × 35 min. One-way ANOVA was used when comparing match halves
independently of whether the same players played one or both halves.
First Half (n = 187)
Second Half (n = 155)
Full Match
p-Values
ES Values
Total distance
m
3883 ± 405
3762 ± 435
7645 ± 840
0.008
0.71
m·min−1
111.0 ± 11.6
107.5 ± 12.4
109.3 ± 12.0
0.008
0.29
HIR (13.6–18.5 km·h−1)
m
618 ± 185
600 ± 199
1218 ± 398
0.365
0.09
m·min−1
17.7 ± 5.3
17.1 ± 5.7
17.4 ± 5.5
0.365
0.11
Sprint distance
>18.5 km·h−1 (m) a
242 ± 105
229 ± 116
471 ± 221
0.260
0.12
>25.2 km·h−1 (m) b
19.8 ± 31.2
20.8 ± 31.1
40.6 ± 62.3
0.767
0.03
Maximal speed (km·h−1)
27.0 ± 2.2
26.6 ± 2.2
27.0 ± 2.2
0.061
0.18
Accelerations (n)
18.9 ± 9.4
19.7 ± 8.9
38.6 ± 18.3
0.419
0.09
Declarations (n)
23.1± 11.3
24.7 ± 10.9
47.8 ± 22.2
0.194
0.14
HIR: high-speed running. a threshold adapted from previous studies on U14 soccer players, b above 25.2 km·h−1 for more than 1 s
(threshold adapted from studies on senior soccer players). Accelerations/decelerations: actions (>13.6 km·h−1) when speed was increased
or decreased by more than 3 m·s−2 and lasted more than 0.5 s. Data were not corrected for multiple match observations by the same player.
p ≤ 0.05 is statistically signiﬁcant. ES: 0–0.2 = trivial; >0.2 = small; >0.5 = medium; >0.8 = large.
3.2. Playing Position
Playing positions were associated with TD and all high-intensity parameters inves-
tigated (HIR, sprints, accelerations and decelerations). FB, WM and CM showed signiﬁ-
cantly greater total distance and HIR distance compared with CB (ESTD = 0.62–1.05 and
ESHIR = 0.91–3.06) and CF (ESTD = 0.62–1.05 and ESHIR = 0.57–2.61). Wide playing posi-
tions (WM, FB) covered the most sprint distance (ES = 0.64–1.08), and CF also covered
greater sprint distance compared with CB positions (ES = 0.90). CF performed signiﬁcantly
more accelerations compared with all other playing positions (ES = 0.48–0.96). WM and
CF had the highest number of decelerations (ES = 0.38–1.04), and CB performed signiﬁ-
Int. J. Environ. Res. Public Health 2021, 18, 7287
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cantly fewer decelerations compared with all other positions (ES = 0.53–1.18). Positional
differences according to running performance are described in Table 2.
Table 2. Positional differences (mean ± 95% CI) in match running performance during one match half (35 min).
Total Distance (m)
HIR (m) (13.6–18.5 km·h−1)
Sprints (m) (>18.5 km·h−1)
Accelerations (n)
Decelerations (n)
FB ‡
3987 [3838, 4136] (‡ > §, ∞) *
722 [653, 790] (‡ > §, ∞) *
281 [240, 322] (‡ > §, ¶) *
19.3 [16.3, 22.3]
25.2 [21.7, 28.6] (‡ > §) *
WM †
4015 [3883, 4148] († > §, ∞) *
712 [651, 774] († > §, ∞) *
288 [251, 326] († > §, ¶) *
20.0 [17.1, 22.9]
27.9 [24.5, 31.3] († > §, ¶) *
CB §
3673 [3506, 3839]
552 [475, 629]
187 [141, 233]
16.2 [13.1, 19.3]
18.0 [14.5, 21.5]
CM ¶
4020 [3887, 4153] (¶ > §, ∞) *
736 [674, 796] (¶ > §, ∞) *
217 [180, 254]
17.5 [14.9, 20.1]
23.6 [20.5, 26.6] (¶ > §) *
CF ∞
3734 [3551, 3917]
614 [529, 699]
257 [205, 309] (∞ > §) *
24.8 [20.1, 28.6]
(∞ > ‡, †, §, ¶) *
27.6 [23.2, 32.0] (∞ > §) *
HIR: high-intensity running; FB: fullback; WM: wide midﬁelder; CB: centre back; CM: centre midﬁelder; CF: centre forward. Accelera-
tions/decelerations: actions (>13.6 km·h−1) when speed was increased or decreased by more than 3 m·s−2 and lasted more than 0.5 s.
Data were corrected for multiple match observations by the same player and all independent variables. Pairwise comparisons for playing
position were performed with Bonferroni correction. * p ≤ 0.05.
3.3. Competitive Level
Players covered signiﬁcantly greater total distance (ES = 0.35) and HIR distance
(ES = 0.43) (13.6–18.5 km·h−1) in matches played at U14 elite level compared with the local
U14 sub-elite level (Table 3). No differences between groups were found regarding sprints,
accelerations and decelerations.
Table 3. Match running performance (mean ± 95% CI) in one match half (35 min) in U14 players according to competitive
level.
Total Distance (m)
HIR (m) (13.6–18.5 km·h−1)
Sprints (m) (>18.5 km·h−1)
Accelerations (n)
Decelerations (n)
U14 elite matches
3898 [3779, 4016] *
671 [616, 727] *
247 [216, 279]
17.9 [15.1, 20.6]
22.9 [19.6, 26.2]
U14 sub-elite matches
3752 [3659, 3845]
596 [554, 639]
245 [222, 267]
20.4 [18.7, 22.2]
24.4 [22.2, 26.5]
U14 elite: national U14 elite level; U14 sub-elite: highest regional U14 level. HIR: high-intensity running. Accelerations/decelerations:
actions (>13.6 km·h−1) when speed was increased or decreased by more than 3 m·s−2 and lasted more than 0.5 s. Data were corrected for
multiple match observations by the same player. Pairwise comparisons for playing position were performed with Bonferroni correction.
* p ≤ 0.05.
3.4. Contextual Factors
Signiﬁcant greater total distances (p < 0.001, ES = 0.36), HIR distances (p < 0.001,
ES = 0.32) and sprint distances (p = 0.016, ES = 0.11) were observed in matches lost or
drawn compared with matches won. Match location was also shown to have an impact on
most running variables investigated. Players performed greater TD (p = 0.043, ES = 0.13)
and sprint distance (p = 0.038, ES = 0.20) when playing at home compared with playing
away or at a neutral match location. On the other hand, the number of accelerations
(p < 0.001, ES = 0.56) and decelerations (p < 0.001, ES = 0.46) was higher when playing away
or at a neutral location compared with playing at home. Greater total distances (3883 ± 405
vs. 3762 ± 435, ES = 0.71) covered in one half were observed (p = 0.008), but we found no
other differences between match halves.
4. Discussion
This study aimed to analyse match running performance in U14 male soccer players
in Norway, and to identify how playing position, competitive level and contextual match
variables inﬂuenced running performance. Overall, 22% of the locomotion during matches
constituted high-speed running and sprinting, with the rest being performed at lower
running intensities. There were signiﬁcant differences in physical performance between
positions, in addition to greater running demands when players competed at the highest
competitive standard. Furthermore, contextual factors were associated with most running
variables investigated.
The ﬁndings of the present study showed that Norwegian male U14 soccer players
run similar distances or more during a match compared with previous reports on U14
Int. J. Environ. Res. Public Health 2021, 18, 7287
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players [1]. The group in our study covered a total distance of 109.2 m·min−1, which is
higher than that of 95.7 m·min−1 reported in New Zealand U14 male soccer players [3]
and 106.5 m·min−1 in English U14 soccer players [19]. Similarly, in our study, 22% of the
total match time was spent as high-intensity running actions (>13.6 km/h−1), whereas
reports from youth soccer in New Zealand [3], Italy [20] and England [19] have shown
total high-intensity running actions to constitute 7%, 16% and 17%, respectively, with a
similar speed threshold applied as in the present study. These results could be explained
by how the different countries approach and emphasise the game, as studies from senior
soccer highlighted that soccer philosophy, technical performance and physical performance
varied between different countries and leagues [21–23].
Across playing positions we found that CF had a greater number of accelerations
compared with all other playing positions. In contrast, a previous study on youth soccer
showed that attackers perform a high amount of accelerations, but that players in wide
positions (WM and FB) in general perform more accelerations than central players (CB, CM
and CF) [24]. However, Vigh-Larsen and colleagues [24] only examined 14 outﬁeld players
from one single team, and their ﬁndings could reﬂect the team’s formation and tactical
dispositions, or the physical capacity of the individual players [25]. Indeed, discrepancies
have been found for high-intensity physical performance between different playing forma-
tions in elite senior soccer [26]. Regardless, our ﬁnding that CB perform fewer accelerations
than other positions is in line with previous ﬁndings [24,27], and also that CB positions in
general have a lower running performance compared with other playing positions [1]. Our
results showed that wide playing positions performed the highest amount of high-intensity
work and, in general, were the most physically demanding playing positions. This was also
supported by Pettersen and colleagues (2019), who investigated a group of Norwegian U17
soccer players [27]. In senior soccer, studies have demonstrated that evolving tactics over
the last decade have especially impacted the physical demands of wide players, as this
position has shown the greatest increase in high-intensity running [17,28]. Our ﬁndings
suggest that the high running demands of wide positions found at higher age groups and
in senior soccer also seems to be evident at U14 level.
Total distance and high-intensity running were signiﬁcantly higher in matches at U14
elite level compared with sub-elite level, which is in line with ﬁndings from a previous
study [2]. However, the observed difference was small regarding effect size, and we found
no differences regarding sprint distance, or the number of accelerations and decelerations.
A possible explanation is that the sub-elite teams represented in our study were the
highest ranked sub-elite teams and included highly talented players also recruited in
the U14 national and regional teams. The observed difference in our study regarding
running performance and competitive level might been greater with a wider range of
teams included from the sub-elite group. Our ﬁnding is in contrast to what has previously
been reported in top-ranked U17 players, where the best teams outperformed players in
lower-ranked teams [29]. Contrarily, studies on senior players from teams that ﬁnished in
the top ﬁve at the end of the English Premier League season performed less sprinting than
those that ﬁnished outside of the top ﬁve [30].
Match results were associated with running performance. The players covered a
greater total distance, HIR distance and sprint distance in matches they lost or drew com-
pared with the matches they won. Previous studies in elite senior soccer have shown
conﬂicting results regarding the inﬂuence of match results, where Castellano et al. [9]
found no relationship with match results, whereas Lago et al. [31] found that players
ran less at higher intensities when winning. Playing against high-quality opposition has
been found to be associated with lower ball possession [32], and a possible explanation
could be that the lower-quality team has to cover a greater distance to regain possession
and defend important spaces. Our results also showed that match location inﬂuenced
match running performance, as greater TD and sprinting distance (>18.5 km·h−1) were
performed when playing at home, even though fewer accelerations and decelerations were
performed. Different tactical approaches to home matches versus away matches may be an
Int. J. Environ. Res. Public Health 2021, 18, 7287
7 of 9
explanation, but more research is necessary to better understand this. A limitation in the
present study according to contextual factors is the preponderance of matches ending with
a win compared with matches ending with a draw/loss. Our results showed a signiﬁcant
association between contextual factors and several running performance variables; how-
ever, these ﬁndings had, in general, a small/medium effect size. More research is necessary
in order to better understand the link between match running performance and contextual
factors in youth soccer. The inﬂuence of these multivariate factors should not be considered
in isolation.
A challenge when comparing time motion data from different studies from youth
soccer is the different methodological approach to the rolling substitution policy, resulting
in a large variety in playing time between players. In the present study, all completed
match halves were included to increase the sample size and statistical power, in contrast
to most previous studies that only included completed matches. Excluding players who
did not play full matches may bias analyses by reducing the sample size and removing
variations in running performance. This is important to take into account when interpreting
positional differences, as offensive positions are commonly substituted [33]. We observed a
signiﬁcantly lower relative total distance covered in the second half (3.9 m·min−1), but the
small difference observed between halves was argued to be of less practical meaning.
Overall, our results show that physical performance during matches is affected by
several factors and differs between leagues and countries. Running demands in soccer and
especially different positional running demands are evolving [28], and highlight the need
for updated research. This is the ﬁrst study to assess match-related physical performance
and positional differences in Scandinavian U14 youth soccer. Our results suggest that
physical performance during matches is similar or higher than in reports from other parts
of the world and are highly related to playing position. Wide playing positions seem
to be the most physically demanding positions. In addition, centre forwards perform
more accelerations than all other positions. Given the high physical demands of high-
intensity work and the impact of these actions on post-match muscle damage [34], coaches
must consider different positional match loads, and individualise training according to
positional demands. Further, our data indicate that playing at the highest U14 level was
more physically demanding, suggesting a higher external demand during elite matches
compared with sub-elite matches. This reveals important information for practitioners,
as the physical training could be tailored to the game demands, and/or players could
be moved between levels to assist in talent development. Future research should seek to
improve our understanding of positional demands related to different tactics and team
formations, and to investigate training load according to positional demands. More research
is also necessary to better understand the inﬂuence of different contextual factors in
youth soccer.
5. Conclusions
Physical performance during matches in this group of Norwegian U14 male soccer
players was similar or higher than reports from other parts of the world and are highly
related to playing position. Total distance and high-intensity running were greater in
elite matches compared with sub-elite matches, but no differences were found regarding
sprints, accelerations and decelerations. Match result and match arena also inﬂuenced
running performance.
Author Contributions: Conceptualisation, E.A., H.G. and H.S.G.; formal analysis, E.A., A.R., V.A.
and H.S.G.; investigation, E.A, T.N. and H.S.G.; methodology, E.A., A.R. and H.S.G.; project adminis-
tration, H.S.G.; supervision, H.S.G.; visualisation, E.A.; writing—original draft, E.A., H.G. and H.S.G.;
writing—review and editing, E.A., H.G., A.R., T.N., A.H.S., V.A. and H.S.G. All authors have read
and agreed to the published version of the manuscript.
Funding: This research was given ﬁnancial support by the University and College Network for
Western Norway.
Int. J. Environ. Res. Public Health 2021, 18, 7287
8 of 9
Institutional Review Board Statement: The study was conducted according to the guidelines of the
Declaration of Helsinki and approved by The Regional Committee for Medical and Health Research
Ethics, Grant number (720025).
Informed Consent Statement: Informed consent was obtained from all subjects involved in the study.
Data Availability Statement: The data presented in this study are available on request from the
corresponding author. The data are not publicly available due to ethical restrictions.
Acknowledgments: We would speciﬁcally like to thank all the participants, Knut Kvammen and
Håvard Wiersen for contributing to the data collection, and the University and College Network for
Western Norway for ﬁnancial support.
Conﬂicts of Interest: The authors declare no conﬂict of interest.
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Motion Analysis of Match Play in U14 Male Soccer Players and the Influence of Position, Competitive Level and Contextual Variables.
Algroy, Erling,Grendstad, Halvard,Riiser, Amund,Nybakken, Tone,Saeterbakken, Atle Hole,Andersen, Vidar,Gundersen, Hilde Stokvold