The measurement of body composition is now a fun- damental component of sport science support in elite- level soccer. Indeed, regular assessments of body com- position are often used to determine suitability for competition as well as to monitor the effectiveness of dietary and training interventions (Sutton, Scott, Wallace, & Reilly, 2009).

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Body composition assessment of English Premier
League soccer players: a comparative DXA analysis of
first team, U21 and U18 squads
Jordan Milsom
a
, Robert Naughton
b
, Andy O’Boyle
a
, Zafar Iqbal
ab
, Ryland Morgans
a
, Barry
Drust
ab
& James P. Morton
ab
a
Liverpool Football Club, Melwood Training Ground, Liverpool, UK
b
Research Institute for Sport and Exercise Sciences, Liverpool John Moores University,
Liverpool, UK
Published online: 16 Feb 2015.
To cite this article: Jordan Milsom, Robert Naughton, Andy O’Boyle, Zafar Iqbal, Ryland Morgans, Barry Drust & James P.
Morton (2015): Body composition assessment of English Premier League soccer players: a comparative DXA analysis of first
team, U21 and U18 squads, Journal of Sports Sciences, DOI: 10.1080/02640414.2015.1012101
To link to this article: http://dx.doi.org/10.1080/02640414.2015.1012101
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2. Body composition assessment of English Premier League soccer
players: a comparative DXA analysis of first team, U21 and U18 squads
JORDAN MILSOM1
, ROBERT NAUGHTON2
, ANDY O’BOYLE1
, ZAFAR IQBAL1,2
,
RYLAND MORGANS1
, BARRY DRUST1,2
& JAMES P. MORTON1,2
1
Liverpool Football Club, Melwood Training Ground, Liverpool, UK and 2
Research Institute for Sport and Exercise Sciences,
Liverpool John Moores University, Liverpool, UK
(Accepted 22 January 2015)
Abstract
Professional soccer players from the first team (1st team, n = 27), under twenty-one (U21, n = 21) and under eighteen
(U18, n = 35) squads of an English Premier League soccer team were assessed for whole body and regional estimates of
body composition using dual-energy X-ray absorptiometry (DXA). Per cent body fat was lower in 1st team (10.0 ± 1.6)
compared with both U21 (11.6 ± 2.5, P = 0.02) and U18 (11.4 ± 2.6, P = 0.01) players. However, this difference was not
due to variations (P = 0.23) in fat mass between squads (7.8 ± 1.6 v 8.8 ± 2.1 v 8.2 ± 2.4 kg, respectively) but rather the
presence of more lean mass in 1st team (66.9 ± 7.1 kg, P < 0.01) and U21 (64.6 ± 6.5 kg, P = 0.02) compared with U18
(60.6 ± 6.3 kg) players. Accordingly, fat mass index was not different (P = 0.138) between squads, whereas lean mass index
was greater (P < 0.01) in 1st team players (20.0 ± 1.1 kg · m−2
) compared with U18 players (18.8 ± 1.4 kg · m−2
).
Differences in lean mass were also reflective of higher lean tissue mass in all regions, for example, upper limbs/lower limbs
and trunk. Data suggest that training and nutritional interventions for younger players should therefore be targeted to lean
mass growth as opposed to body fat loss.
Keywords: DXA, lean mass, fat mass, soccer
Introduction
The measurement of body composition is now a fun-
damental component of sport science support in elite-
level soccer. Indeed, regular assessments of body com-
position are often used to determine suitability for
competition as well as to monitor the effectiveness of
dietary and training interventions (Sutton, Scott,
Wallace, & Reilly, 2009). For practical reasons (e.g.
ease of administration and low cost), the conventional
approach of assessment is to measure skinfold thick-
ness at multiple sites and subsequently report sum of
skinfold thickness and/or estimate per cent body fat
according to common prediction equations (e.g.
Durnin & Womersley, 1974; Reilly et al., 2009;
Withers et al., 1998). However, despite the obvious
advantages of skinfold measurement, its use in the
latter context is often critiqued given that the assump-
tions associated with hydrodensitometry (the means by
which many prediction equations were validated) may
not hold true for elite athletes who exhibit marked
variations in body composition and fat distribution
(Reilly et al., 2009).
As such, the use of DXA is becoming increasingly
popular in elite sport and is used by both practi-
tioners and researchers (Nana, Slater, Hopkins, &
Burke, 2012, 2013; Santos et al., 2014). The use of
DXA is particularly advantageous given that it pro-
duces a three-compartment model of body composi-
tion incorporating bone mineral content and both fat
and lean mass. Moreover, DXA is also beneficial for
athletic populations given that it can assess both
whole body and regional estimates of fat and fat-
free mass, variables that are highly responsive to
training, nutritional interventions and long-term
injury (Milsom, Barreria, Burgess, Iqbal, &
Morton, 2014). Furthermore, given that body com-
position varies with age (Mott et al., 1999), DXA
may be particularly beneficial when comparing
indices of body composition across playing squads
of different age and training history. For example,
where a young soccer player may report with what is
perceived as high per cent body fat, the underlying
cause may be due to low absolute levels of lean mass
and not high levels of fat mass per se. In contrast, a
Correspondence: James Morton, Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Tom Reilly Building, Byrom St
Campus, Liverpool, L3 3AF, UK. E-mail: J.P.Morton@ljmu.ac.uk
Journal of Sports Sciences, 2015
http://dx.doi.org/10.1080/02640414.2015.1012101
© 2015 Taylor & Francis
Downloadedby[UniversiteLaval]at19:4403March2015

3. senior player may present with high per cent body fat
that may be largely attributable to increased fat mass
as opposed to a lack of lean mass.
In accordance with this hypothesis, recent data
from other team sport athletes (Australian football)
confirm that elite senior players exhibit marked
increases in both whole body and regional estimates
of lean mass compared with junior players, as well as
displaying superior absolute (and relative) muscle
strength and power (Bilsborough, Greenway, Opar,
Livingstone, Cordy, Bird, et al., 2014). As such, the
use of DXA assessments as a diagnostic tool may
therefore allow for a more accurate dietary and train-
ing prescription that is more readily aligned with
optimising body composition to maximise markers
of physical performance. To the authors’ knowledge,
however, no data are currently available that have
simultaneously assessed both whole body and regio-
nal estimates of fat-free and fat mass in professional
soccer players of differing age and level of playing
squad.
Accordingly, the aim of the present study was to
therefore assess both whole body and regional esti-
mates of lean and fat mass in professional soccer
players of the English Premier League. We con-
ducted a comparative analysis of those players
from the first team (1st team), under twenty-one
(U21) and under eighteen (U18) playing squads.
We specifically hypothesised that U18 players
would present with higher per cent body fat than
their senior counterparts, but that this effect would
be largely attributable to lower absolute levels of
lean mass as opposed to higher levels of fat mass.
Although estimates of body composition (using
DXA) in elite-level soccer players have been pre-
sented previously (e.g. Egan, Wallace, Reilly,
Chantler, & Lawlor, 2006; Sutton et al., 2009), we
hereby provide the first report of body composition
values for three tiers of elite-level soccer players for
estimates of both whole body and regional lean and
fat mass.
Methods
Participants
Eighty-three male professional soccer players from
one English Premier League soccer club provided
informed consent to participate in this study.
Players were subsequently categorised as 1st team
(n = 27), U21 (n = 21) and U18 (n = 35) depending
on their age and/or the playing squad from which
they were predominantly playing in at the time of
assessment. Each player was required to provide a
single DXA assessment as part of their roles and
responsibilities (i.e. medical screening) associated
with their duties of employment, and hence, the
study conformed to the principles of both the ethical
committee of Liverpool John Moores University and
the Journal of Sports Sciences (Winter & Maughan,
2009). Scans were conducted during the period of
2010–2013 depending on each player’s duration of
employment. Although the dates of scans were not
consistent, all scans were conducted in the in-season
period between the periods of August–October (40%
of sample), November–January (41% of sample) and
February–May (19% of sample). Whilst we acknowl-
edge that body composition of individual players’
within specific squads may have changed as the sea-
son progressed (Egan, Wallace, et al., 2006), we
considered that the magnitude of such changes
were unlikely to preclude detectable differences of
much larger magnitudes when comparing between
squads. The mean (±s) age, body mass and height of
each squad are displayed in Table I. An overview of
typical weekly training frequency during this time-
scale for both field-based (i.e. soccer-specific condi-
tioning) and gym-based (i.e. resistance) sessions is
shown in Table II.
Procedures
Participants wore shorts only and removed any metal
and jewellery prior to assessment. Height (deter-
mined by stadiometry) and scale mass (Seca,
Hamburg, Germany) were recorded to the nearest
0.5 cm and 0.1 kg, respectively. Each participant
underwent a whole-body fan-beam DXA scan
(Hologic QDR Series Discovery A, Hologic,
Bedford, MA) where the effective radiation dose
was 0.01 mSv per person. All scans were performed
by the same trained operator in accordance with
standardised testing protocols that are recognised
as best practice (Nana et al., 2012, 2013, 2014;
Rodriguez-Sanchez & Galloway, 2014). Data
included for analysis included per cent body fat
and both whole-body and regional estimates of fat
and lean mass. In addition to playing squad, partici-
pants were also subcategorised for comparative ana-
lysis according to playing position and included
goalkeepers (GK), defenders (DEF, inclusive of
Table I. A comparison of age, body mass and height between
professional soccer players from the English Premier League
from the 1st team, U21 and U18 squads.
Team Age (years) Body mass (kg) Height (cm)
1st Team 24.1 ± 3.9 81.4 ± 8.2 182.5 ± 7.1
U21 s 18.4 ± 1.0* 80.2 ± 6.9 181.8 ± 6.9
U18 s 16.6 ± 0.6+ 75.1 ± 8.3+ 179.4 ± 6.0
Notes: *denotes significant difference from 1st team, P < 0.05.
+ denotes significant difference from both 1st team and U21,
P < 0.05.
2 J. Milsom et al.
Downloadedby[UniversiteLaval]at19:4403March2015

4. both central defenders and full backs), midfielders
(MID, inclusive of both central and wide mid-
fielders) and strikers (STKR). The test–retest relia-
bility of DXA-related variables in our laboratory
whilst using this specific scanner (also assessed on
professional male soccer players, n = 36) has been
published previously (Egan, Reilly, Chantler, &
Lawlor, 2006). In brief, the coefficient of variation
(CV) and absolute technical error of measurement
(TEM) for whole body fat mass, lean mass and per
cent body fat were as follows: 1.9% and 0.37 kg,
1.0% and 0.44 kg and 1.9% and 0.41%, respectively.
Regional reliability estimates (CV and TEM, respec-
tively) are also reported in the subsequent text:
upper limb fat mass (2.8%, 0.06 kg), lower limb fat
mass (2%, 0.15 kg), trunk fat mass (1.9%, 0.42 kg),
upper limb lean mass (4.5%, 0.05 kg), lower limb
lean mass (2.8%, 0.11 kg) and trunk lean mass
(3.2%, 0.26 kg). More recent reliability statistics on
body composition variables (as assessed from DXA)
from team sport athletes is also provided by
Bilsborough, Greenway, Opar, Livingstone, Cordy,
& Coutts, (2014)
Statistical analyses
All data were initially assessed for normality of dis-
tribution according to the Shapiro–Wilk’s test.
Statistical comparisons between playing squads
were subsequently performed according to a one-
way between-groups analysis of variance (ANOVA)
or the Kruskal–Wallis test. Similarly, comparisons
between playing positions within each squad were
also made according to ANOVA or Kruskal–Wallis,
where appropriate. Where significant main effects
were present, Bonferroni post hoc analysis was con-
ducted to locate specific differences, and 95% con-
fidence intervals (95% CI) for the differences are
also presented. Additionally, effect sizes (ES) were
also calculated as the difference between the means
divided by the pooled standard deviation, with the
following quantitative criteria for ES used to explain
the practical significance of the findings: trivial <0.2,
small 0.21–0.6, moderate 0.61–1.2, large 1.21–1.99,
and very large ≥2.0 (Hopkins, 2006). All analyses
were completed using SPSS for Windows (version
20, SPSS Inc., Chicago, IL) where P < 0.05 is
indicative of statistical significance.
Results
Between-squad comparisons
Body mass (P < 0.01) was significantly different
between squads, though no main effect (P = 0.12) of
height was observed (see Table I). Body mass was not
different between 1st team and U21 players (P = 1.0)
although body mass of U18 players was significantly
lower than that of both 1st team (95% CI = −11.6 to
−1.6, ES = −0.79, P < 0.01) and U21 players (95%
CI = −10.7 to 0.03, ES = −0.7, P = 0.05). As
expected, age was significantly different between
squads (P < 0.01) with significance detected between
all pairwise comparisons (P < 0.01).
A comparison of per cent body fat, lean mass and
fat mass between playing squads are shown in
Figure 1. Per cent body fat was significantly different
(P = 0.03) between squads (see Figure 1A); 1st team
players have significantly lower values than both U21
(95% CI = −2.8 to −0.3, ES = −0.76, P = 0.02) and
U18 players (95% CI = −2.5 to −0.4, ES = −0.65,
P = 0.01). However, no difference was observed
between U21 and U18 players (P = 0.89). Despite
differences in per cent body fat, no differences
(P = 0.23) were observed when comparing fat mass
between playing squads (see Figure 1B). Accordingly,
lean mass displayed significant main differences
between squads (P < 0.01) where U18 players pre-
sented with values approximately 4 and 6 kg lower
than that of both U21 (95% CI = −6.1 to −7.8,
ES = −0.62, P = 0.02) and 1st team players (95%
CI = −3.1 to −10.1, ES = −0.94, P < 0.01), respec-
tively (see Figure 1C). No differences were apparent,
however, in lean mass between 1st team and U21
squads (P = 0.24).
In accordance with absolute data, both body mass
index and lean mass index exhibited significant dif-
ferences between teams (P = 0.03 and P < 0.01,
respectively), whereas fat mass index was not
Table II. An overview of typical weekly training frequency for the 1st team, U21 and U18 squads for both field-based (i.e. soccer-specific
conditioning) and gym-based (i.e. resistance) sessions.
1st Team U21 s U18 s
Field-Based Training 5 (60–80 min) 5 (80–100 min) 5 (80–100 min)
Resistance Training 3 (2 UB + 1 LB) 2 (WB) 2 (WB)
Notes: Typical durations of field-based training are shown in parentheses. UB denotes upper-body resistance session. LB denotes lower-
body session. WB denotes whole-body session incorporating both UB and LB exercises. Resistance training sessions typically consisted of
4–6 exercises, 3–5 sets and 4–8 repetitions depending on the specific training goal of the individual. Note that because 1st team players
performed sessions dedicated solely to UB or LB, whereas U18 players performed WB sessions incorporating both UB and LB, overall
training volume per muscle was higher in the 1st team players.
Body composition, age and soccer 3
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5. different (P = 0.138) (see Figure 2). Specific differ-
ences in body mass index (95% CI = 0.3 to 1.9,
ES = 0.72) and lean mass index (95% CI = 0.4 to
2.1, ES = 0.95) were apparent between 1st team and
U18 players (P < 0.01), whereas no differences were
evident between 1st team and U21 squads (P = 0.75
and 0.58, respectively). Similarly, both body mass
index (P = 0.06) and lean mass index (P = 0.20)
were not different between U21 and U18 squads.
Regional differences in fat mass and lean mass
between playing squads are presented in Tables III
and IV, respectively. Given that no differences were
apparent in whole body fat mass between squads, it
Table III. A comparison of regional fat mass (kg) between profes-
sional soccer players from the English Premier League from the
1st team, U21 and U18 squads.
1st Team U21 s U18 s
Left arm 0.50 ± 0.09 0.55 ± 0.11 0.53 ± 0.15
Right arm 0.56 ± 0.14 0.59 ± 0.14 0.57 ± 0.15
Trunk 3.58 ± 0.74 3.94 ± 1.04 3.58 ± 0.94
Left leg* 1.52 ± 0.37a
1.87 ± 0.50 1.75 ± 0.60
Right leg 1.62 ± 0.39 1.89 ± 0.48 1.80 ± 0.60
Notes: *denotes main effect of between-squad differences,
P = 0.05.
a
denotes significant difference from both U21 and U18 squads,
P < 0.05.
Figure 1. A comparison of (A) body fat (%), (B) fat mass and (C)
lean mass between professional soccer players from the English
Premier League from the 1st team, U21 and U18 squads.
*denotes significant difference from both U21 and U18,
P < 0.05. + denotes significant difference from both 1st team
and U21, P < 0.05.
Figure 2. A comparison of (A) body mass index (BMI), (B) fat
mass index (FMI) and (C) lean mass index (LMI) between pro-
fessional soccer players from the English Premier League from the
1st team, U21 and U18 squads. *denotes significant difference
from 1st team, P < 0.05.
4 J. Milsom et al.
Downloadedby[UniversiteLaval]at19:4403March2015

6. is unsurprising that fat mass in the left arm (P =
0.41), right arm (P = 0.73), trunk (P = 0.54) and
right leg (P = 0.22) also displayed no differences
between squads. Subtle differences in left leg fat
mass (P = 0.05) were apparent, however, where 1st
team players displayed smaller values than U21
(95% CI = −0.6 to −0.08, ES = −0.88, P = 0.01)
and U18 players (95% CI = −0.5 to 0.02,
ES = −0.58, P = 0.07).
Differences in whole body lean mass between
squads were attributable to differences in all regions
including left arm (P < 0.01), right arm (P = 0.01),
trunk (P < 0.01), left leg (P = 0.01) and right leg
(P = 0.02). Left arm lean mass was specifically dif-
ferent between 1st team and U18 players (95%
CI = 0.1 to 0.8, ES = 0.83, P = 0.01), whereas
differences in right arm lean mass were located
between U18 players and both U21 (95%
CI = −0.8 to −0.02, ES = −0.72, P = 0.04) and
1st team squads (95% CI = −0.8 to −0.06,
ES = −0.72, P = 0.02). Differences in trunk lean
mass were only significant between 1st team and
U18 players (95% CI = 1.3 to 5.8, ES = 0.88,
P < 0.01). Differences in lower limb lean mass
were apparent for both right (95% CI = 0.4 to 1.7,
ES = 0.75) and left legs (95% CI = 0.4 to 1.7,
ES = 0.83) between 1st team and U18 squads
(P < 0.01).
Influence of playing position
1st team squad. Position-specific differences within
the 1st team squad were evident for body mass
(P = 0.04), height (P = 0.01) and lean mass
(P = 0.04), whereas per cent body fat (P = 0.90)
and fat mass (P = 0.33) did not exhibit any differ-
ence (see Table V). Within this squad, GK were
Table IV. A comparison of regional lean mass (kg) between pro-
fessional soccer players from the English Premier League from the
1st team, U21 and U18 squads.
1st team U21 s U18 s
Left arm* 4.09 ± 0.57 3.99 ± 0.57 3.63 ± 0.59a
Right arm* 4.39 ± 0.56 4.37 ± 0.56 4.00 ± 0.53ab
Trunk* 35.05 ± 3.90 33.57 ± 3.01 31.66 ± 3.58a
Left leg* 11.44 ± 1.21 11.11 ± 1.59 10.44 ± 1.17a
Right leg* 11.84 ± 1.32 11.50 ± 1.64 10.88 ± 1.34a
Notes: *denotes main effect of between-squad differences,
P < 0.05.
a
denotes significant difference from 1st team, P < 0.05.
b
denotes significant difference from U21, P < 0.05.
Table V. A comparison of position-specific values for body mass, height, per cent body fat, lean mass and fat mass in professional soccer
players from the English Premier League from the 1st team, U21 and U18 squads.
GK DEF MID STKR
Body mass (kg)
1st team* 89.1 ± 4.5a
(n = 4)
83.0 ± 6.6
(n = 10)
75.9 ± 7.2
(n = 9)
82.4 ± 10.5
(n = 4)
U21 85.0 ± 8.7
(n = 3)
81.5 ± 6.3
(n = 7)
79.0 ± 7.4
(n = 7)
76.1 ± 5.5
(n = 4)
U18* 88.5 ± 8.8b
(n = 4)
77.1 ± 6.4
(n = 11)
71.2 ± 5.9
(n = 15)
71.2 ± 5.9
(n = 4)
Height (cm)
1st team* 189.8 ± 3.2a
184.6 ± 5.4 177 ± 6.9 182.5 ± 6.2
U21 186.5 ± 3.3 180.8 ± 7.4 179.7 ± 7.4 184.0 ± 6.7
U18* 187.4 ± 2.8c
183.3 ± 3.5c
175.1 ± 4.2 176.8 ± 5.1
Body fat (%)
1st team 9.9 ± 0.9 10.2 ± 1.8 9.7 ± 1.7 10.3 ± 2.1
U21 12.4 ± 4.3 10.5 ± 2.1 12.0 ± 1.5 12.1 ± 3.2
U18 13.1 ± 2.7 11.1 ± 1.5 11.5 ± 3.2 10.5 ± 2.6
Lean mass (kg)
1st team* 73.5 ± 3.6a
68.2 ± 5.9 62.3 ± 6.5 67.4 ± 8.6
U21 68.2 ± 6.0 66.7 ± 6.5 62.8 ± 7.0 61.1 ± 5.4
U18* 69.8 ± 6.5d
62.3 ± 5.3 57.7 ± 4.8 58.0 ± 4.6
Fat mass (kg)
1st team 8.4 ± 1.1 8.1 ± 1.6 7.0 ± 1.4 8.1 ± 2.0
U21 10.3 ± 4.6 8.1 ± 1.3 9.0 ± 1.0 8.7 ± 2.3
U18+
11.1 ± 2.8 8.2 ± 1.6 7.8 ± 2.4 7.1 ± 2.1
Notes: *denotes main effect of between-squad differences, P < 0.05. +
denotes tendency for main effect of between-squad differences,
P = 0.06.
a
denotes significant difference from midfielders (MID).
b
denotes significant difference from defenders (DEF), MID and strikers (STKR).
c
denotes significant difference from MID and STKR.
d
denotes significant difference from MID and STKR, all P < 0.05.
Body composition, age and soccer 5
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7. heavier (95% CI = 0.6 to 25.7, ES = 2.2, P = 0.04),
taller (95% CI = 2.6 to 22.9, ES = 2.4, P = 0.01)
and possessed more lean mass than MID (95%
CI = 0.2 to 22.1, ES = 2.1, P = 0.04) (see
Table V). However, despite position-specific differ-
ences in absolute body composition variables, no
differences were apparent in anthropometric profile
when considering body mass index (P = 0.38), lean
mass index (P = 0.40) and fat mass index (P = 0.34)
(see Table VI).
U21 squad. In contrast to the 1st team squad, no
positional differences were observed in the U21
players for body mass (P = 0.37), height
(P = 0.48), per cent fat (P = 0.58), fat mass
(P = 0.53) and lean mass (P = 0.21).
U18 squad. Similar to 1st team players, position-
specific differences within the U18 squad were also
evident for body mass, height and lean mass (all
P < 0.01). Furthermore, although per cent body fat
was not significantly different (P = 0.53), absolute fat
mass tended towards statistical significance
(P = 0.06). GK were heavier than DEF (95%
CI = 0.9 to 21.9, ES = 1.5, P < 0.05), MID (95%
CI = 7.1 to 27.4, ES = 2.3, P < 0.05) and STKR
(95% CI = 4.6 to 30.0, ES = 2.3, P < 0.05).
Additionally, both GK and DEF were also taller
than MID (95% CI = 6.0 to 18.6, ES = 3.4 and
95% CI = 3.8 to 12.7, ES = 2.1, respectively) and
STKR (95% CI = 2.7 to 18.5, ES = 2.6 and 95%
CI = −0.01 to 13.1, ES = 1.5, respectively) (all
P < 0.05). GK also possessed more lean mass than
MID (95% CI = 3.9 to 20.2, ES = 2.1, P < 0.01)
and STKR (95% CI = 1.8 to 22.2, ES = 2.1,
P = 0.01). Similar to 1st team position-specific dif-
ferences, such differences were not apparent when
expressed as body mass index (P = 0.17), lean mass
index (P = 0.43) and fat mass index (P = 0.29)
(Table VI).
Discussion
The aim of the present study was to conduct a
comparative analysis of both whole-body and regio-
nal estimates of lean and fat mass in professional
soccer players with differing age and training history.
Accordingly, we studied male soccer players from
the 1st team, U21 and U18 playing squads from an
English Premier League soccer club. Confirming our
hypothesis, we provide novel data by demonstrating
that although U18 players present with higher per
cent body fat than their senior counterparts in both
the U21 and 1st team squads, this effect is largely
attributable to lower absolute levels of whole body
lean mass (approximately 4–6 kg) as opposed to
increased fat mass per se. Importantly, such differ-
ences in absolute lean mass were also apparent when
expressed as lean mass index. Our data therefore
suggest that training and nutritional interventions
for young professional soccer players should be
more closely aligned to the goal of promoting lean
mass gain as opposed to those targeting reduced fat
mass.
Although we acknowledge that our data are based
on a sample of participants from one professional
English Premier League club only (hence may not
be considered representative of a larger sample of
professional players), it is noteworthy that our data
agree well with previous observations from 1st team
professional players from the English Premier
League that were also assessed by DXA. For exam-
ple, Sutton et al. (2009) reported per cent body fat
values of 10.6 ± 2.1% in a cohort of players (n = 64)
recruited from four different English Premier League
teams. Similarly, Reilly et al. (2009) observed values
of 11.2 ± 1.8% when studying professional players
(n = 45) from three English Premier League clubs.
Given the similar values of per cent body fat
observed here (10.0 ± 1.6%) and also that training
loads and organisation are relatively similar amongst
English Premier League clubs, we therefore consider
our data to be representative of professional players
from the English Premier League in general (espe-
cially outfield players) as opposed to the specific
training and nutritional philosophies of the present
club.
Although we observed significant differences in
per cent body fat when comparing 1st team squad
players with the U21 and U18 squads, no statistically
significant differences in fat mass (or fat mass index)
were apparent between squads, where comparable
values of approximately 8 kg were evident.
Accordingly, the observed differences in per cent
body fat were attributable to significant differences
Table VI. A comparison of position-specific values for body mass
index (BMI), lean mass index (LMI) and fat mass index (FMI) in
professional soccer players from the English Premier League from
the 1st team, U21 and U18 squads.
GK DEF MID STKR
BMI (kg · m−2
)
1st team 24.8 ± 1.9 24.3 ± 1.4 24.2 ± 0.6 24.6 ± 1.5
U21 24.5 ± 3.3 24.9 ± 1.2 24.4 ± 1.0 22.5 ± 1.4
U18 25.2 ± 2.4 22.9 ± 1.7 23.2 ± 1.5 22.8 ± 2.4
LMI (kg · m−2
)
1st team 20.4 ± 1.4 20.0 ± 1.3 19.8 ± 0.6 20.2 ± 1.3
U21 19.7 ± 2.3 20.4 ± 1.1 19.4 ± 1.2 18.0 ± 1.0
U18 19.9 ± 1.9 18.5 ± 1.4 18.8 ± 1.3 18.5 ± 1.7
FMI (kg · m−2
)
1st team 2.4 ± 0.4 2.4 ± 0.4 2.2 ± 0.4 2.4 ± 0.5
U21 3.0 ± 1.4 2.5 ± 0.5 2.8 ± 0.3 2.6 ± 0.8
U18 3.1 ± 0.7 2.4 ± 0.5 2.5 ± 0.8 2.3 ± 0.8
6 J. Milsom et al.
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8. in whole body lean mass (and lean mass index) given
that U18 players typically presented with values that
were 4–6 kg less than those of the U21 and 1st team
players, respectively. This decrement in whole body
lean mass also appeared to be due to detectable
differences in all regions including the trunk (≈2–
3.5 kg), arms (≈0.5 kg) and legs (≈0.5–1 kg). It is
difficult to precisely ascertain whether the observed
differences in lean mass between U18 and senior
players is due, in part, to growth and maturation
(Lloyd et al., 2014; Malina et al., 2000), reduced
training history (Lloyd et al., 2014; Wrigley, Drust,
Stratton, Atkinson, & Gregson, 2014), inadequate
nutrition (Camera et al., 2014) or, more likely, a
combination of all of the aforementioned parameters
(especially considering differences in resistance
training volume between squads, see Table II).
Nevertheless, from a practical perspective, the pre-
sent data suggest that where an U18 player presents
with what is perceived as high per cent body fat
(usually on the basis of skinfold measurements),
the most suitable strategy may be interventions tar-
geted to stimulate lean mass growth such as
increased resistance training and dietary protein
intake (Phillips, 2014), as opposed to strategies
designed to promote body fat loss per se, for exam-
ple, energy restriction and increased aerobic exercise
(Langan-Evans, Close, & Morton, 2011; Morton,
Robertson, Sutton, & MacLaren, 2010). In this
way, such players are more likely to achieve a body
composition that is more representative of the phy-
sical attributes of 1st team players and, hence, may
therefore be more able to potentially cope with the
physical demands of elite-level English Premier
League competition.
In addition to squad differences, we also observed
position-specific differences in body composition,
within both the 1st team and U18 squads. In gen-
eral, we observed that GK tended to be taller, hea-
vier and possessed more lean mass than outfield
players, an effect that was especially prevalent when
comparing with midfield players. Our observation of
positional differences between GK and outfield
players is also in agreement with the data reported
by Sutton et al. (2009). However, unlike the latter
authors, we reported similar per cent body fat and fat
mass in 1st team GK and 1st team outfield players, a
finding that may be due to the specific nutritional
philosophy and culture of the study club in question.
It is noteworthy, however, that GK in the U18 squad
tended to possess more fat mass than outfield
players, therefore in support the traditional posi-
tion-specific anthropometrical profiles (Arnason
et al., 2004; Matković et al., 2003). Despite posi-
tion-specific differences in absolute body composi-
tion variables, no differences were apparent when
considering body mass index, lean mass index and
fat mass index. Such data therefore suggest that
differences between lean body mass are largely
reflective of changes in stature.
In contrast to 1st team and U18 squads, we
observed no statistically significant differences
between playing positions in the U21 squad. These
data may simply be reflective of sampling size issues
(given that our U21 cohort was a smaller sample)
and, hence, the inability to detect statistical differ-
ences. Support for this hypothesis is evident when
examining the mean height and lean mass between
positions where physiological differences do indeed
appear evident. Alternatively, these data may be
underpinned by the fact that individuals at U18
level are, in part, initially suited for specific positions
due to differences in anthropometrical profiles asso-
ciated with their biological age, but yet, these profiles
may become obsolete when players progress to
adulthood, that is, U21 level. In turn, the position-
specific differences evident in the 1st team squad
may therefore be subsequently due to genuine differ-
ences in the anthropometrical profile required to
complete the positional role as opposed to differ-
ences in maturation status within the sample cohort.
Future studies using larger sample sizes from multi-
ple teams would be required to directly test this
hypothesis.
In summary, we provide novel data by reporting
significant differences in both whole body and regio-
nal aspects of body composition in professional soc-
cer players from the English Premier League with
different age and training history. Specifically, we
observed that U18 players present with higher per
cent body fat than their senior counterparts in both
the U21 and 1st team squads, an effect attributable
to lower absolute levels of whole body lean mass as
opposed to increased fat mass per se. In addition to
the effects of growth and maturation, our data sug-
gest that training and nutritional interventions for
young professional soccer players should therefore
be aligned with the goal of promoting lean mass
gain (e.g. resistance training, increased dietary pro-
tein intake) as opposed to those targeting reduced fat
mass (e.g. energy restriction and increased aerobic
exercise). Future longitudinal studies should assess
the changes in body composition of young soccer
players as they progress from youth team level to
senior professionals.
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