ArticlePDF AvailableLiterature Review

The Transition Period in Soccer: A Window of Opportunity

Authors:
  • Center of Research Education Innovation and Intervention in Sport (CIFI2D)
  • Portuguese Football Federation

Abstract and Figures

The aim of this paper is to describe the physiological changes that occur during the transition period in soccer players. A secondary aim is to address the issue of utilizing the transition period to lay the foundation for the succeeding season. We reviewed published peer-reviewed studies if they met the following three selection criteria: (1) the studied population comprised adult soccer players (aged >18 years), (2) time points of physiological and performance assessments were provided, and (3) appropriate statistics for the calculation of effect sizes were reported. Following two selection phases, 12 scientific publications were considered, involving a total sample of 252 players. The transition period elicits small to moderate negative changes in body composition, a moderate decline in sprint performance with and without changes of direction, and small to moderate decrements in muscle power. Detraining effects are also evident for endurance-related physiological and performance outcomes: large decrements in maximal oxygen consumption (\( \dot{V} \)O2max) and time to exhaustion, and moderate to very large impairments have been observed in intermittent-running performance. Off-season programs should be characterized by clear training objectives, a low frequency of training sessions, and simple training tools in order to facilitate compliance. The program suggested here may constitute the ‘minimum effective dose’ to maintain or at least attenuate the decay of endurance- and neuromuscular-related performance parameters, as well as restore an adequate strength profile (reduce muscle strength imbalances). This periodization strategy may improve the ability of players to cope with the elevated training demands of pre-season training and therefore reduce the risk of injury. Moreover, this strategy will favor a more efficient development of other relevant facets of performance during the pre-competition phase (e.g., tactical organization). We contend that the transition period needs to be perceived as a ‘window of opportunity’ for players to both recover and ‘rebuild’ for the following season.
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CURRENT OPINION
The Transition Period in Soccer: A Window of Opportunity
Joao Renato Silva
1,2
Joao Brito
3
Richard Akenhead
1
George P. Nassis
1
Published online: 3 November 2015
ÓSpringer International Publishing Switzerland 2015
Abstract The aim of this paper is to describe the
physiological changes that occur during the transition
period in soccer players. A secondary aim is to address
the issue of utilizing the transition period to lay the
foundation for the succeeding season. We reviewed pub-
lished peer-reviewed studies if they met the following
three selection criteria: (1) the studied population com-
prised adult soccer players (aged [18 years), (2) time
points of physiological and performance assessments were
provided, and (3) appropriate statistics for the calculation
of effect sizes were reported. Following two selection
phases, 12 scientific publications were considered,
involving a total sample of 252 players. The transition
period elicits small to moderate negative changes in body
composition, a moderate decline in sprint performance
with and without changes of direction, and small to
moderate decrements in muscle power. Detraining effects
are also evident for endurance-related physiological and
performance outcomes: large decrements in maximal
oxygen consumption (
_
VO
2max
) and time to exhaustion,
and moderate to very large impairments have been
observed in intermittent-running performance. Off-season
programs should be characterized by clear training
objectives, a low frequency of training sessions, and
simple training tools in order to facilitate compliance. The
program suggested here may constitute the ‘minimum
effective dose’ to maintain or at least attenuate the decay
of endurance- and neuromuscular-related performance
parameters, as well as restore an adequate strength profile
(reduce muscle strength imbalances). This periodization
strategy may improve the ability of players to cope with
the elevated training demands of pre-season training and
therefore reduce the risk of injury. Moreover, this strategy
will favor a more efficient development of other relevant
facets of performance during the pre-competition phase
(e.g., tactical organization). We contend that the transition
period needs to be perceived as a ‘window of opportunity’
for players to both recover and ‘rebuild’ for the following
season.
Key Points
The transition period should be viewed as a ‘window
of opportunity’ for players to recover and to ‘rebuild’
for the following season.
Coaches should adopt a holistic view (e.g., social
factors, training background) when defining the
individual training variables (e.g., frequency,
volume, intensity) and modality of the exercise
intervention.
An individualized training program during the off
season may represent an adequate methodological
and physiological strategy favoring a more efficient
periodization of the subsequent pre-season phase.
&Joao Renato Silva
jm_silv@hotmail.com; joao.silva@aspetar.com
1
National Sports Medicine Programme, Excellence in Football
Project, Aspetar-Qatar Orthopaedic and Sports Medicine
Hospital, PO Box 29222, Doha, Qatar
2
Center of Research, Education, Innovation and Intervention
in Sport (CIFI2D), Porto, Portugal
3
Health and Performance Unit, Portuguese Football
Federation, Lisbon, Portugal
123
Sports Med (2016) 46:305–313
DOI 10.1007/s40279-015-0419-3
1 Introduction
The soccer season is commonly planned in three distinct
periods: the pre-competition, competition, and transition
periods. The duration of each period is influenced by
intrinsic (e.g., environmental conditions) and extrinsic
factors (e.g., international competitions). For instance,
some leagues comprise two distinct cycles of pre-compe-
tition, competition, and transition periods. Nevertheless,
the most frequent scenario is that after 10–11 months of
training and competition [1], players undertake a period of
rest typically lasting 4–6 weeks; the so-called transition or
off-season period.
Despite the general increase of training and competition
demands over time, the transition period is generally
characterized by a complete cessation of, or substantial
reduction in, training [2,3]. In some cases, players might
be involved in sport activities and/or voluntary non-peri-
odized training. The duration of the cessation period, the
magnitude of decrement in training impulses, and the
players’ fitness levels will modulate the kinetics of alter-
ations to body composition and physiological functions;
ultimately, this may lead to a partial or complete loss of
some training-induced adaptations [2,3].
According to Mujika et al. [2], detraining can be divided
into short term (\4 weeks) and long term ([4 weeks).
Importantly, detraining effects may influence how players
prepare during pre-competition and potentially affect their
performance levels in the first matches of the competition
period [4]. In fact, pre-competition periodization is affected
by players’ physical performance and physiological status
at the start of the season. For instance, following significant
detraining during the transition period, additional physical
training may be required, which may be detrimental to
other dimensions of performance (e.g., team tactical
organization). Furthermore, the pre-competition period is
commonly characterized by a high frequency of training
sessions. Players are typically exposed to friendly games
after a short period of returning to training (7–10 days) and
are subjected to more rapid increases in training load
compared with other periods [5,6]. Moreover, clubs’
commercial obligations may see many players travelling
and competing frequently within the pre-season, limiting
structured training and recovery opportunities within this
important period; all these factors contribute to substan-
tially increasing the psychological and physiological stress
of the pre-season period [79]. The development of fatigue
during such intensified phases impacts players’ responses
to training demands (e.g., how players understand the
tactical tasks within the global team organization). More-
over, excessive fatigue may also compromise the capacity
of players to tolerate and recover from the typically higher
training loads, and consequently affect the odds of injury. It
should be noted that rapid increases in training load (e.g.,
training load =rating of perceived exertion 9training
duration), particularly during pre-season training, have
been associated with increased risk of injury [10]. More-
over, training intensity [e.g., accumulated time spent
[85 % of maximal heart rate (HR
max
)] and volume (ac-
cumulated training hours) are key variables in character-
izing players’ training load and have been recently
associated with injury incidence in professional football
players [6]. Assuming complete cessation of training dur-
ing the transition period, the pre-season period represents a
triad of risk factors: high training volumes, high training
intensity, and a rapid increase in training load relative to
recent exposure [6,11].
Despite the consensus that ‘optimal’ fitness develop-
ment requires variability in training stimuli, elite players
may be persistently exposed to high training loads during
pre-competition; internal and external load variables have
been reported as being constant within the different pre-
competition microcycles during pre-season periodization
[12]. Notwithstanding these data, the transition period
remains the least examined and understood phase of the
soccer season. Here, we discuss the physical, physiological,
biochemical, and performance alterations that occur during
transition periods. We contend that the transition period
should be viewed as a window of opportunity for players to
recover and to ‘rebuild’ for the following season. A com-
plete cessation or near absence of training stimuli might not
be beneficial or appropriate for all players. We begin by
examining the magnitude of decrements in physical per-
formance and physiological parameters observed from pre-
to post-transition. Following this, we present evidence-
based guidelines for a periodized transition program.
2 Methods
2.1 Search Strategy: Databases and Inclusion
Criteria
We selected studies in two consecutive screening phases.
The first phase consisted of identifying articles through a
systematic search using the US National Library of Med-
icine (PubMed), MEDLINE, and SPORTDiscus databases.
Literature searches comprised scientific publications from
April 2000 to January 2015. The following keywords were
used in combination: ‘elite soccer’, ‘professional soccer’,
‘highly trained players’, ‘seasonal alterations’, ‘perfor-
mance analysis’, ‘soccer physiology’, ‘football’, ‘detrain-
ing’, and ‘training cessation’. We further searched the
relevant literature using the ‘related citations’ function of
306 J. R. Silva et al.
123
PubMed and by scanning reference lists. In the second
phase, we reviewed published peer-reviewed studies if they
met the following three selection criteria: (1) the studied
population comprised adult soccer players (aged
[18 years), (2) time points of physiological and perfor-
mance assessments were provided, and (3) appropriate
statistics for the calculation of effect sizes were reported.
Following the two selection phases, 12 scientific publica-
tions (ten journal articles, one PhD thesis, and one con-
ference communication) were considered, involving a total
sample of 252 adult soccer players.
2.2 Data Extraction and Presentation
Data related to the players’ physiological parameters
(e.g., % body fat) and performance parameters (e.g., soc-
cer-specific endurance tests and jump tests) were extracted
and presented as the percentage of change (PC) =(post-
test mean -pretest mean)/pretest mean 9100. We
assessed the magnitude of the changes using effect sizes
(ES) =(post-test mean -pretest mean)/pretest standard
deviation [13]. We obtained 52 ESs, threshold values for
which were ‘trivial’ (\0.2), ‘small’ (0.2–0.6), ‘moderate’
(0.6–1.2), ‘large’ (1.2–2.0), and ‘very large’ ([2.0) [14].
3 Physiological and Performance Changes
3.1 Body Composition
It is common that the off-season break negatively influ-
ences players’ body composition. Trivial to small increases
in the percentage of body fat (%BF) in professional
(PC =0.8–3.0 %; ES =0.2–0.5; Fig. 1)[1518] and in
semi-professional (PC =0.6 %; ES =0.2) [19] players
have been reported. Moreover, moderate decreases in lean
body mass (LBM; PC =-3%; ES=-0.5) [15] and
large decrements in fat-free mass (FFM) were detected in
professional players (PC =-6.6 %; ES =-1.3) [20].
However, the ability of off-season training programs to
prevent these changes has received little attention. A
4-week off-season multi-component training program
comprising 22 sessions of general strength training and
gymnastic exercises, low-intensity running, and stretching
routines might prevent negative changes in body compo-
sition compared with no structured training program [16].
Body mass increased from 78.1 ±4.8 to 78.7 ±5.0 kg
(PC =0.8 %; ES =0.1) in the training group, but greater
increases were detected in the control group (from
76.5 ±2.7 to 77.9 ±2.8 kg; PC =1.9 %; ES =0.5)
[16]. Similarly, %BF increased by 0.3 % (ES =0.2) in the
training group and by 0.8 % (ES =0.5) in the control
group [16].
3.2 Neuromuscular Performance
In terms of long-term neuromuscular detraining, trivial to
small changes in force production at low and moderate
angular velocities occur after 4 weeks of detraining
(30 min jogging at approximately 60 % HR
max
, three times
a week) in professional players [21]. Nevertheless, the
deleterious effects may be more pronounced at higher
shortening velocities (60°s
-1
and 180°s
-1
;PC=0.1 %
and ES =0.01 vs. PC =–3.4 % and ES =-0.3, respec-
tively) [21]. This position is further supported when con-
sidering other reports tracking seasonal alterations in force
production capacity of professional players [22]. Trivial
changes in jumping ability evaluated by the counter-
movement and squat jump tests have also been reported
(PC =-0.3 % and ES =-0.03 vs. PC =1 % and
ES =0.1, respectively) [21]. Nevertheless, 6–8 weeks of
detraining was associated with moderate reductions in
countermovement jump (PC =-4.6 to -6.3 %; ES =
-0.5 to -0.8) and squat jump height (PC =-6.1 to
-7.1 %; ES =-0.7 to -0.9) in professional players [17].
Short distance (10-m sprint time: PC =2.9 %;
ES =0.7–0.8; 20-m sprint time: PC =1.3–1.7 %,
ES =0.7–0.8) [17] and long-distance sprint performance
(50-m sprint time: PC =7.4 %, ES =1.0) [18] seem to be
moderately impaired after 3–6 weeks of detraining in
professional players. Similar trends were also observed in
semi-professional players after 8 weeks’ detraining (15-m
sprint time: PC =3.3 %; ES =0.9) [19]. Additionally,
assessment of change of direction ability using the Illinois
agility test revealed moderate performance declines in
semi-professional players (PC =1.6 %; ES =0.7) [19].
3.3 Aerobic Fitness
Detraining during the off-season period is also detrimental
to other physiological and performance measures (Fig. 1).
The transition period leads to a decrease in maximal oxy-
gen consumption (
_
VO
2max
;PC=-3.5 to -6.1 %;
ES =-0.5 to -3.0) [16,17,19,23]. Sotiropoulos et al.
[16] reported that a 4-week transition period training pro-
gram undertaken by professional players did not prevent
decreases in
_
VO
2max
. However, players who did not per-
form any structured training during the transition period
had a greater decline in
_
VO
2max
than those who followed
the structured training (PC =-6.1 % and ES =-1.4 vs.
PC =-1.4 % and ES =-0.3, respectively). In contrast,
Slettalokken et al. [24] recently showed that the off-season
decline in aerobic fitness can be prevented by adding a low-
frequency high-intensity training stimulus (five bouts
of 4 min at 87–97 % of peak heart rate) during a 6-week
off-season period in semi-professional players. One
Detraining in Soccer 307
123
high-intensity training (HIT) session every second week
(PC =1%, ES=0.1) or one HIT session per week
(PC =-2%,ES=-0.6) effectively prevented a signif-
icant decrease in
_
VO
2max
in soccer players [24]. Off-season
deconditioning is also reflected in decreased time to
exhaustion during incremental tests (PC =-3.9 %;
ES =-1.2) [23], as well as a reduced ability to perform at
sub-maximal intensity. Christensen et al. [25] observed that
only 2 weeks of inactivity during the off-season period
resulted in lower
_
VO
2
kinetics (at 75 % maximal aerobic
speed) as evidenced by an increased time constant (s)
(PC =10.7 %; ES =0.9). This general attenuation of the
_
VO
2
response dynamic reduces the contribution of oxida-
tive phosphorylation for adenosine triphosphate (ATP)
resynthesis [26] and increases the accumulation of fatigue-
related metabolites (H
?
and P
i
)[27]. In addition, Mohr
et al. [23] observed that the off-season resulted in an
increased heart rate at running speeds of 10, 14, and
17 kmh
-1
(PC =6.1 % and ES =2.0; PC =4.4 % and
ES =1.4; and PC =2.8 % and ES =1.7, respectively).
Therefore, coaches should expect an altered external:
internal load ratio when players return to training, which
has obvious consequences in the high-loading phase of pre-
competition (e.g., reduced economy, increased fatigue and
psychophysiological responses to a given training load).
For this purpose, HIT impulses during the off-season
period might be needed to counteract decrements in soccer-
specific fitness. Long-term detraining impairs performance
during soccer-specific endurance tests such as the Yo–Yo
Intermittent Recovery Test—level 2 (YYIR2, PC =
10.7 %; ES =-2.2) [28] and the Yo–Yo Intermittent
Endurance Test—level 2 (YYIE2, PC =28 %; ES =
-1.0) [29]. In fact, a short-term 2-week detraining period
significantly impaired YYIR2 performance (PC =-23 %,
Fig. 1 a The effect of
detraining (3–8 weeks)
presented as mean percentage of
change and/or average weighted
mean percentage of change. b
Overall effect sizes (mean) for
body mass (BM) [1517];
percentage body fat (%BF) [15
17,19]; lean body mass (LBM)
[15,20]; 10-m [17], 15-m [19],
20-m [17], and 50-m sprint
times (T10–T50) [18]; change
of direction ability (COD) [19];
countermovement jump without
(CMJ) [17,21] and with arm-
swing (CMJWAS) [19]; squat
jump (SJ) [17,21]; maximal
oxygen consumption (
_
VO
2
max)
[16,17,19,23]; time to
exhaustion (TE) [23]; Yo–Yo
Intermittent Recovery Test—
level 2 (YYIR2) [28]; Yo–Yo
Intermittent Endurance Test—
Level 2 (YYIE2) [29]
308 J. R. Silva et al.
123
ES =-1.2) and total time to perform a repeated sprint
(RS) test (10 920 m/15-s recovery; PC =2.1 %;
ES =0.7) [25]. This decreased ability to perform high- to
very high-intensity exercise (e.g., RS) may result from the
aforementioned impairments in some neuromuscular (e.g.,
sprint speed) and endurance determinants of high-intensity
exercise (e.g.,
_
VO
2
kinetics) [30]. Given the established
associations between physical match performance and Yo–
Yo tests, it is assumed that the reduction in Yo–Yo test
performance translates into lower match running perfor-
mance [31].
The benefits of performing an off-season organized
training plan is indirectly supported by a study by Boullosa
et al. [32]. During the final 5 weeks of the transition period,
after 18 days’ rest, players performed 21 individualized
conditioning sessions (strength, endurance, and proprio-
ceptive-based exercises). After 8 weeks of pre-season
training, no pre- to post-preseason improvements were
observed in either specific (YYIR1: 2475 vs. 2600 m;
PC =5.1 %; ES =0.3) and non-soccer-specific [maximal
aerobic speed (MAS); 18.1 vs. 18.2 kmh
-1
;PC=0.6 %;
ES =0.1) endurance performance. Therefore, it can be
concluded that organized, individualized conditioning ses-
sions were as key to enabling players to maintain their ability
to perform intermittent endurance exercise as their physio-
logical determinants (e.g.,
_
VO
2max
and running economy). In
fact, players started the season with high levels of soccer-
specific endurance (YYIR1, 2475 ±421 m); pre-season
values of professional players have been reported to range
from 1510 to 2000 m [3335] and from 15.9 to 16.1 kmh
-1
[35,36] for YYIR1 and MAS, respectively.
4 Biochemical Changes
Detraining can lead to changes in the cellular and blood
biochemical milieu. Short-term detraining (2 weeks)
decreased muscle oxidative capacity, via reduced muscle
pyruvate dehydrogenase activity (17 %), and maximal
activities of citrate synthase (12 %) and 3-hydroxyacyl-
CoA (18 %) [25]. A decrease in muscle oxidative capacity
may have a detrimental effect on players’ ability to perform
and recover from intense exercise via reduction in phos-
phocreatine (PCr) resynthesis rate and increasing the con-
tribution from anaerobic sources [2527,30]. Alterations in
blood redox states indicative of a decrease in antioxidant
status capacity have also been observed; a decrease in the
first line of antioxidant enzymatic defense against super-
oxide radicals (superoxide dismutase activity) has also been
reported after a 6-week off-season period [37].
Biochemical monitoring has shown that long-term
detraining resulted in lower concentrations of biomarkers
of tissue damage (e.g., creatine kinase, malondialdehyde)
[37]. This may not be surprising given that the kinetics of
these bio-markers have been associated with the metabolic
and mechanical demands associated with eccentric muscle
contractions, ischemia-reperfusion events during power-
related actions, excessive trauma (e.g., contact actions),
and increased
_
VO
2
, which are all typical of soccer
activities. No changes in C-reactive protein have been
reported [15,37], but increases in creatinine, granulo-
cytes, total interleukin-8, serum nitrate, ferritin, and
bilirubin have been reported during the off-season phase
[15]. This apparent increase in catabolism observed after
long-term detraining periods [15] is also partially sup-
ported by an increase in cortisol levels and a decrease in
testosterone/cortisol ratio during the off-season [37].
Accordingly, Reinke et al. [15] observed that the transi-
tion period induced significant decrements in tissue-level
stress, but that periods longer than 4 weeks may be
required before full recovery is achieved. Nevertheless,
training exposure throughout the off-season was not
recorded, particularly during the final weeks of the tran-
sition period. Thus, a stress reaction related to physical
loads before the start of pre-season cannot be excluded as
a factor that may have influenced results [37]. However,
players with higher match exposure during the season
(starters vs. non-starters) may be prone to higher catabolic
states as evidenced by the kinetics of hormonal-related
parameters (increased cortisol) and their association with
match exposure [4,37]. Being so, this further reinforces
the need for a holistic approach when defining the indi-
vidual training variables of the exercise intervention (e.g.,
frequency and intensity).
Long-term detraining did not affect sex steroid levels
at rest. Non-significant changes have been reported in
sex steroid concentration, as total testosterone [17,37],
free testosterone, dehydroepiandrosterone-sulfate, D4-an-
drostenedione, estradiol, luteinizing hormone, follicle-
stimulating hormone, and prolactin [17]. However, it is
clear that the scarcity of studies examining the multi-fac-
torial nature of physiology and performance hamper
extensive conclusions on the biochemical changes
observed during transition periods. Moreover, difficulties
interpreting the meaningfulness of alterations in biological
markers due to the complexity of the network of biological
interactions (e.g., spontaneous oscillations) and the lack of
clear control of the activity of players during transition
periods all increase the complexity of drawing precise
conclusions.
Detraining in Soccer 309
123
5 How to Alleviate the Changes Due to Reduced
Training
As previously discussed, the transition period is commonly
devoted to recovery from the physiological and psycho-
logical stress of the competitive season [37,38]. Therefore,
off-season programs should be characterized by clear
training objectives, a low frequency of training sessions,
and simple training tools in order to increase compliance.
The practitioner should adopt a holistic view (e.g., social
factors, family obligations, a need for mental regeneration)
when defining the individual training variables (e.g., fre-
quency, volume, intensity) and modalities of the exercise
intervention. Player training background, accumulated
training and match exposure, injury history, player’s per-
sonality and preferences, and off-season length, among
others, are all factors that must be carefully considered
during training prescription. The best exercise intervention
is one that fits a player’s specific needs. At the end of the
season, individual members within a squad will likely
occupy a broad range of different physical and physio-
logical states (e.g., from detraining to over-reaching) [4,
3844]. Therefore, individualized training programs may
be warranted, with consideration of the aforementioned
factors. As a practical guideline, to avoid a substantial
decrement in endurance- and neuromuscular-related per-
formance, we believe that off-season structured training
programs should involve a minimum of two sessions per
week, separated by 48–72 h [16,24,45,46]. We believe
that the design presented here constitutes a ‘minimal
effective dose’ to allow maintenance, or a reduced decay of
physical and physiological features relevant to football
performance [16,24,45,46].
Our proposal includes one HIT session per week (e.g.,
594 mins at 87–97 % peak heart rate) [24]. Distinct HIT
formats have been shown as a time-efficient stimulus;
positive effects on cardiopulmonary and neuromuscular
function can be achieved with a low volume of training
[4750]. Moreover, evidence suggest that a lower volume
of high-intensity exercise is required to maintain key
physiological features (
_
VO
2max
)[51]. In addition, the hor-
monal responses associated with low-volume HIT (e.g.,
testosterone, androstanediol glucuronide, growth hormone)
favors the anabolic processes to a greater degree than high-
volume protocols [5256] and so may at least partly
counteract the negative changes in body composition pro-
file that occur during the transition period (e.g., increa-
sed %BF and decreased LBM).
The selection of the off-season HIT session should
consider an acute physiological response/strain effect [49].
Overall, the physical and physiological changes observed
during the transition period (Fig. 1) recommend HIT
sessions that combine high metabolic requirements from
the O
2
transport and utilization systems with a substantial
anaerobic glycolytic contribution whilst also considering
the desired neuromuscular load. Individualized HIT ses-
sions should be prioritized, and these sessions should take
into account the physiological and neuromuscular profile of
each player since the acute impact of HIT is highly variable
and population dependent (age, sex, training status, and
background) [49]. Moreover, the practitioner should con-
sider that manipulation of the different HIT variables (e.g.,
bout duration and intensity and duration of recovery,
number of intervals) will affect the acute physiological
responses and so model the short- to long-term training
adaptations [57].
The second training session should focus on muscle
strength and power. A combination of resistance exercises,
plyometric, and sport-specific strength exercises (e.g.,
accelerations and deceleration drills) is recommended to
target a broad range of the force–velocity spectrum [58].
The aim is to maintain the essential aspects of intra- and
inter-muscular coordination during soccer-specific motor
tasks where force production is a key factor. As an
example, the injury-prevention training program proposed
by the Fe
´de
´ration Internationale de Football Association
(FIFA) Medical Assessment and Research Centre, the
‘11?’, may represent a practical and feasible strategy [59,
60]. It is easy to implement, requiring only simple tools and
few resources. The program is focused on injury preven-
tion, but we believe the ‘11?’ has the necessary compo-
nents to also serve as a detraining prevention program. We
recommend adding a multi-joint exercise such as the squat
[e.g., [80–95 % 1 repetition maximum (1RM), 3–4 sets,
4–8 reps] to the ‘11?’ training program to address the
basic requirements of the high-force low-velocity rela-
tionship of the neuromuscular system. The plyometric
section of the ‘11?’ will provide a complementary stim-
ulus to address other parts of the force–velocity spectrum
(low-force high-velocity relationship). This training struc-
ture may partially counteract the reported negative effects
that long-term detraining (4 weeks) has on some morpho-
logical (muscle cross-sectional area) and mechanical fac-
tors (tendon stiffness), which are important in force
production and application [61]. We believe this design
may reduce the observed detraining effect in important
muscle power abilities (e.g., sprint ability). Interestingly,
one strength training session per week involving squats
(3 94RM) during the competition period may be suffi-
cient to maintain strength, jump, and sprint performance in
professional players [45]. However, a lower training
stimulus (single set vs. multiple sets) may also be effective
for maintaining strength levels during the initial stage of
the transition period [62,63]. Again, the practitioner must
310 J. R. Silva et al.
123
consider each player (e.g., single set programs prescribed
for players exposed to high training loads at the end of the
season). Nevertheless, we believe the relatively high neu-
romuscular stress imposed during training sessions and
games throughout the competitive season also provides a
meaningful stimulus and contributes to preserving a play-
er’s neuromuscular performance [39,64]. This supports our
proposal of combining HIT sessions with strength/power
training as a strategy to maintain high neuromuscular
involvement during the transition period.
The transition period also represents a window of
opportunity to intervene on modifiable risk factors associ-
ated with injury occurrence. In terms of injury prevention,
off-season training should focus on reducing the risk of the
most common injuries (e.g., hamstring strains). Players
with untreated strength imbalances may be four- to fivefold
more susceptible to sustaining a hamstring injury than
players showing normal strength profiles [65], therefore
off-season interventions should target the restoration of
normal strength profiles. Eccentric muscle loading has been
recommended for the prevention of hamstring injuries [66,
67]. Training interventions might have a time-dependent
effect on promoting eccentric strength and reducing the
negative influence of fatigue observed during matches [68].
Although scarcely investigated [69], we believe that vari-
ation is key: strength exercises and proprioception exer-
cises should be performed at both the start and the end of
training sessions to expose players to non-fatigued and
fatigued conditions, respectively. This might help condi-
tion players to cope with high-intensity periods in the final
stages of the training sessions and/or friendly matches
during pre-season. Similarly, although the mechanisms of
adaptation are currently not fully understood, eccentric
exercise elicits a protective adaptation often referred to as
the ‘repeated-bout effect’. Inducing this protective effect
via eccentric exercise might reduce the magnitude of
subsequent muscle soreness that is frequently reported
during the pre-competition period. As well as the clear
physiological benefits, this approach may also provide
psychological benefits such as a reduced perception of
effort and increased perceived tolerance and so favor
players’ commitment during training practices [70,71].
An appropriate off-season training program may con-
stitute, at least in part, a superior methodological and
physiological strategy favoring a more efficient periodiza-
tion of the subsequent pre-season phase. For instance,
given the detrimental effect of high endurance loading on
power development, a periodized program during the
transition period may avoid or reduce the interference
effect between power and endurance adaptations during
pre-season in professional players, allowing practitioners to
focus more on a certain component of a player’s perfor-
mance (e.g., muscle power) due to a greater ‘baseline’ of
aerobic fitness [72]. Indeed, the role of the different
training variables in the interference effect should be
considered [73]. The frequency, duration, and volume of
endurance training are key determinants of the develop-
ment and maintenance of strength and power [74,75]. This
provides support for the adoption of an HIT format for the
purposes of maintaining endurance qualities due to the low
frequency and volume of training required. Moreover,
strength, power, and HIT are characterized by brief and
intense muscle contractions [58] and provide synergistic
contributions to the overall training stimulus [74].
We recommend that the scientific community engage in
active collaboration with applied practitioners and coaches
to examine in detail the periodization during the transition
period. For instance, which assessments of pre- and post-
transition adaptation are the most useful: physical, physio-
logical, psychological, or a combination [7678]? Moreover,
examining the effect of different off-season periodization
programs on subsequent injury incidence, match perfor-
mance, physical fitness, and psychometric markers
throughout the season is warranted. We believe that
addressing these questions may help practitioners develop
more effective periodization models in the future, and ulti-
mately result in tangible benefits for players and teams.
6 Conclusion
Overall, detraining during the transition period results in
meaningful performance impairments in a range of physi-
ological and performance measures. Both short- and long-
term detraining leads to small-to-moderate negative chan-
ges in body composition profile and moderate changes in
sprint ability. In addition, small-to-moderate decrements in
muscle power might occur. The effect of detraining may be
more evident in the ability to produce force at high angular
velocities. Dynamic, multi-joint actions can be affected,
primarily those requiring high levels of motor coordination.
The detraining effects are also extended to endurance-
related physiological and performance outcomes. Large
reductions in
_
VO
2max
and time to exhaustion, and moderate
to very large impairments in soccer-specific endurance,
have been described. The resultant reductions in training
status may negatively affect periodization during the pre-
season, compromising performance levels during the initial
stages of the competition phase.
We believe that the transition period needs to be per-
ceived as a window of opportunity for players to recover
and ‘rebuild’ for the start of the following season. This
does not necessarily imply a complete or near cessation of
training. On the contrary, cessation of training may nega-
tively impact performance and increase susceptibility to
injury when restarting structured training. We recommend
Detraining in Soccer 311
123
that clubs, coaches, and clinical departments should con-
sider the points discussed when prescribing individualized
training programs for the transition period.
Compliance with Ethical Standards
Funding No sources of funding were used to assist in the prepa-
ration of this article.
Conflicts of interest Joao Renato Silva, Joao Brito, Richard
Akenhead, and George P. Nassis declare that they have no conflicts of
interest relevant to the content of this review.
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Detraining in Soccer 313
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... During off-season, lot of players try to retain their fitness by participating in other sport activities or following special individualized training programs. This allows them quicker adaptation during the upcoming pre-season phase [10]. However, this is really important because in preparation for the upcoming season, there are typically a high number of training sessions and friendly matches held shortly after returning to training. . ...
... In the off-season, de-training can result from meaningful reductions in training volume, intensity, and frequency, which may adversely affect performance and body composition. Additionally, the players are reported to have reduced endurance performance along-with the moderate changes in BC (inclusive of fat gain and loss of lean body mass) as a consequence of detraining [10]. ...
... For this reason, it is important to understand the influence of detraining on body composition parameters. Some previous studies, indicate that off-season (detraining period) negatively influences the body composition of soccer players [10], with a simultaneous decrease in cardiovascular and neuromuscular activity [17] and significant loss of performance (strength, speed, endurance, and flexibility) [18]. ...
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The aim of the study was to examine the effects of five weeks detraining period on body composition changes in elite professional Indonesian male soccer players. The body composition of 24 top-level male soccer players (age: 26.33 ± 4.06 years) competing in First League of Indonesia was measured before and after the 5-weeks detraining period. Body composition variables, including body mass, body fat percentage, fat-free mass, and total body water percentage, were measured using the bioelectrical impedance method. The paired samples T-test showed significant changes in the means of body composition variables for body fat percentage, fat-free mass, and total body water percentage. Mean values for body fat percentage increased during the detraining period from 10.87 ± 2.47% to 11.98 ± 2.75% (10.3%). A decrease in mean values for fat-free mass (61.34 ± 5.74 kg to 59.80 ± 6.22; 2.49%) and total body water percentage (from 65.13 ± 1.84% to 64.40 ± 1.99%; 1.12%) was observed. No significant changes occurred in body mass (from 69.05 ± 8.07 kg to 69.05 ± 8.48 kg; 0.04%) from initial to final testing. Since there was a significant difference in body fat percentage, fat-free mass, and total body water percentage % before and after detraining period. It is suggested that 5 weeks of detraining period for the professional soccer players may not be necessary, and the duration should be shortened to maintain body composition status.
... The transition period is characterized by a complete cessation or significant reduction in participation in training. During this period, athletes may be involved in recreational sports activities or a significant reduction in training participation [11]. This period should be viewed by athletes as an opportunity to recuperate before the next season. ...
... Athletes who consume more energy than their bodies need may have a rise in body fat, whereas those who consume too little and in the wrong proportions of macronutrients may experience greater muscle catabolism and a loss of mass. Inadequate body fat and muscle mass in elite football players can have a negative impact on performance and health [11,33]. ...
... The increase in body mass resulting from an improper diet affects the athletes' performance and fitness. Decreased muscle mass caused by a lack of training stimulus can result in decreased strength and endurance, and thus, an increased risk of injury when numerous and intense training units are reintroduced during the preparation period [11], which also showed an increase in lean body mass and fat mass in all body segments analyzed. ...
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Body composition is an important indicator of the overall health and fitness of team sports athletes, including in football, and therefore, anthropometric profiling of elite football players is useful as part of determining their skills, strengths, and weaknesses to develop effective strength and conditioning programs. One of the tools available to coaches to track correlates of performance and health is routine body composition assessment. The purpose of this study is to describe and compare the body composition and anthropometric profiles of players using the Direct Segmental Multi-Frequency Bio-Electrical Impedance Analysis method, and to manage body composition throughout the round in the 2020–2021 season. The investigation was carried out during the Polish football league, PKO BP Ekstraklasa, spring round of the football season 2020–2021, in which male football players participated. Athletes between the ages of 18 and 25 (n = 16) made up the younger age group, while those between the ages of 26 and 31 (n = 22) made up the older age group. This manuscript is a continuation of the presentation of the results of the study, which was conducted between 7 January and 23 July 2021. At different stages of the macrocycle, participants underwent six different body composition analyses. The younger and older groups of athletes were compared, as well as measurements of time points 1–6. The dominant extremities, assisting extremities, and trunk had larger fat-free mass contents in the older age group. In the study groups, there was a difference in the fat-free mass content between measures 1–6 that was statistically significant. In the younger group, there was a statistically significant difference in the amount of fat mass content between measurements 1–6. In the older age group, no statistically significant changes were found. The study showed changes in fat-free mass and fat mass in body segments; differences were observed between age groups and between different moments of measurement. Age is an important factor in determining body composition and is also related to an athlete’s experience and seniority. Anthropometric profiling and comprehensive body composition analysis are important tools used in preparing athletes for competition.
... Soccer is classified as a high-intensity/high-risk sport that mandates anaerobic power such as jumping, sprinting, change of direction, acceleration, and deceleration in great frequency throughout both training and competitive play (9,10,12). Furthermore, the annual training cycle (ATC) is intended to incorporate seasonal transitions with periodized variation to prepare athletes to withstand the exhausting nature of the competitive season (5,24,26). Anaerobic performance measures such as vertical power, horizontal power, and anaerobic capacity (resistance to fatigue) can be used to predict competitive success in soccer athletes (6,9,10,12,21). A successfully periodized training program can improve or maintain anaerobic power, capacity, and skill development while facilitating adequate recovery and reducing injury predisposition across the ATC (5,20,24,26). ...
... Anaerobic performance measures such as vertical power, horizontal power, and anaerobic capacity (resistance to fatigue) can be used to predict competitive success in soccer athletes (6,9,10,12,21). A successfully periodized training program can improve or maintain anaerobic power, capacity, and skill development while facilitating adequate recovery and reducing injury predisposition across the ATC (5,20,24,26). Therefore, timing appropriate training stimuli and preplanning adequate recovery (rest periods) throughout the ATC are necessary to improve performance while avoiding the negative implications of overtraining (1,22,26). ...
... A successfully periodized training program can improve or maintain anaerobic power, capacity, and skill development while facilitating adequate recovery and reducing injury predisposition across the ATC (5,20,24,26). Therefore, timing appropriate training stimuli and preplanning adequate recovery (rest periods) throughout the ATC are necessary to improve performance while avoiding the negative implications of overtraining (1,22,26). ...
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... Moreover, high-intensity running distance and actions increased by ~ 30% and ~ 50%, respectively, and sprint distance and the number of sprints increased by ~ 35% and ~ 85%, respectively, within specific time frames [12][13][14]. These changes had the burden of raising the psychological and physiological stresses placed on the athletes [15][16][17]. Therefore, clubs and federations evolved to greater levels of specialization to support players' performance and health (Fig. 1). ...
... Adopting a personal staff may also arise from the bond a player develops with a coach or practitioner when absent from club-organized training activities. Players usually require external services during the off-season period (e.g., to avoid detraining or performing additional rehabilitation work) [17]. During this period, the player may develop professional confidence (perhaps even some dependence) in the personal staff and may wish to extend this relationship throughout a complete season or even across significant periods of their career. ...
... It is unclear whether the interests of the two parties are aligned. Although the player's proactive action has several positive aspects in individual preparation [17], it also may have negative consequences if the stimulus received during this period is not considered at the club level when planning the precompetitive period [17,20]. Another scenario where the absence of communication may strongly impact a player's training load management is during the competitive microcycle. ...
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The increase in the economic value of soccer occurred in parallel with an increase in competing demands. Therefore, clubs and federations evolved to greater specialization (e.g., state-of-the-art facilities and high-profile expertise staff) to support players’ performance and health. Currently, player preparation is far from exclusively club or national team centered, and the lack of control in each player’s environment can be more prevalent than expected. For example, an elite group of professional players faces disruptions in the season club-oriented planification due to involvement in national teams. Moreover, as elite players’ financial resources grow, it is common for them to employ specialized personal staff (e.g., strength and conditioning, nutritionist, and sports psychologist) to assist in their preparation, resulting in complex three-fold relationships (i.e., club, player’s staff, national team). Although efforts have been made to improve communication with and transition from the club to the national team supervision, this new reality (club-players’ staff) may generate serious compound role-related problems and difficulties in monitoring load and training adaptation and having a unified message. Therefore, efforts must be implemented to ensure a more informed management of the players’ performance environment, where the existence and impact of these various personal staff are considered to avoid a long-term non-zero sum for all intervening parties. If left unchecked, current professional thinking may collide or overlap, potentially triggering conflict escalation and impairing athletic performance or health, especially if effective communication routes are not adequately established. Moreover, diluted personal responsibility regarding performance may ensue, resulting in decreased productivity from all involved, which may cause more harm than benefits for the player’s overall health and performance. This emerging reality calls for developing a joint working framework (i.e., between the player’s personalized support team and the clubs’ team) and better managing of a player-centered process.
... The annual macrocycle lasts about 45 weeks (Malone et al., 2015) and is usually divided into three distinct periods (Silva, Brito, Akenhead, & Nassis, 2016): the approximately 8-week preparation (Buchheit, Cholley, & Lambert, 2016) which it is the most important (Campos, Toscano, Mora, & Suarez, 2017), the competitve of about 35 weeks (Selmi, Gonçalves, Ouergui, Sampaio, & Bouassida, 2018) and the transition period. In preparation, soccer players train 7-10 times a week for 90-120 minutes per training session, while in the competitive season usually 6 times with 1 day of rest (Mylonis, 2015) and 1 or possibly 2 official games (Bekris et al., 2020). ...
... Detraining effects of the transition period are accompanied by impairments in both physical and skill * performance, which may be more pronounced if there is no individualized training program during this period (Silva et al. 2016;. The continued improvement in this parameter, until the middle of the season may be due to both the weekly training program followed and the adjustments from participation in the matches. ...
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The objective of this study was to examine long-term variations in the physical condition and performance indices of male soccer players. Eighteen Greek male semi-professional soccer players aged 25 (±5.05) years, height 180.77 (±5.93) cm, weight 78.51 (±5.25) kg and body fat 10.5 (±1.67) with training experience of 7.22 ± 3.63 (y participated in the study and these players were actively engaged in the 3rd National Division of the Greek Championship. Three ergometric assessments were conducted at key intervals during the team's competitive season specifically at the start of preparation (SPR), end of preparation (EPR) and mid-season-MS) and without changing the training and competition schedule. The testing procedures were conducted in a standardized laboratory environment and the participants visited the laboratory twice in the first examination period, familiarized first with the protocol while on the second visit, the main protocol was performed. All tests were performed during the same time of the day to avoid any chronobiological effecτ. Significant differences in physical abilities were reflected in the mean value of body composition (decrease 2 nd & 3 rd vs 1 st), maximal oxygen uptake VO2max (increase 2 nd & 3 rd vs 1 st), velocity at maximal oxygen uptake vVO2max (increase 2 nd & 3 rd vs 1 st), velocity at anaerobic threshold (increase 2 nd & 3 rd vs 1 st), vertical jump (increase 3 rd vs 1 st) and % drop in speed (decrease 2 nd & 3 rd vs 1 st). In conclusion, this study provides reference data for the evaluation of Greek semi-professional soccer players and the variation in the levels of large parameters can be observed during the competitive season. In this context, future research should expand the database and time period to draw even more secure conclusions.
... The articles featured in this research compilation underscore the intricate relationships among these specific parameters through a combination of longitudinal and cross-sectional experimental designs, as well as systematic literature reviews. Contemporary researchers have made valuable contributions to the field of health improvement and sports performance enhancement by introducing novel measurement techniques for evaluating body composition and devising training strategies to optimize body composition and sports-related achievements [5,6]. ...
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Assessing hydration status and monitoring body composition represent crucial aspects when discussing the advantages of embracing a healthy lifestyle, given its significant impact on both health and sports performance [...]
... Despite the fact that players were asked to perform individualized home training, 1,11 this transition period could have led to transiently decreased fitness, which, consequently, could increase injury risk. 20,21 Contrary to what one could expect, our findings showed that the COVID-19 lockdown period did not increase injury risk; indeed, no differences were found in overall-, training-or match-injury incidence between the post-COVID-19 lockdown period and the aggregate of the preceding seasons as a reference. ...
... At the point when a competitive league ends under typical conditions players go on siestas for around a month; still, wellness level may be kept up with part of the way by clinging to individual training programs (Mohr et al., 2020). Focusing on a constricting the rot of perseverance and neuromuscular-related performance parameters (Silva et al., 2016). Following the off season duration, clubs may ordinarily assign around a month and a half to preseason group training including training games. ...
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Team preparation in soccer is a dynamic process that should not be interrupted by third parties. During a busy season, the performance of any team is a risky procedure due to recovery limitations and a packed schedule. Any similar load without precise arrangement and organization is preparation for injuries and a drop in mental and physical performance. Busy events management requires high concentration on feeling the responsibility, leadership, philosophy, long-term sustainability, meritocracy ideology, constructivism, and physical/tactical periodization plans. Preparing players requires transformational leadership, forming, storming, norming, performing, adjourning, interpersonal relations, group relations, coaches’ feedback collection, self-preservation, and team support. Creativity and organized methods as periodization plans, can help put details ahead of time. Players should acquire mental preparation, arousal characteristics, group tasks, team tasks, the principles of play, neuroplasticity enhancement, fight/flight/freeze procedures, mental toughness, fatigue-related error, role-specific preparation, cross-role preparation, self-control, and player-centered management to face mental fatigue and physical demands. Communication is an essential process that employs components to create a unified perspective. It involves verbal and nonverbal tools as well as interpersonal communication skills. Decreasing challenges and disruptions that hinder performance from progressing can help players understand their role and feel responsible. Traditional leadership characteristics could jeopardize player-centered in all levels and especially within professional soccer teams. Vertical leadership utilization can boost leadership status over players and staff and make their efforts to accomplish goals. Leadership should stem from an organized environment. Many adult and young athletes have benefited from biofeedback, memorization enhancement, perceptual behavior, subconscious behavior, and intrinsic learning motivation. Mental and physical preparations need management to anticipate self-efficacy and better results. A crowded and busy seasonal schedule means more high-intense activities. A lack of recovery time and preparation time is an obstacle that can challenge the overall management to enhance performance. Periodization plans can control team management and various problems handling during pre-season or in-season programs. Periodization plans can also manage strategies, tactical situations, and physical adaptabilities. The aim of this project is a walk-through information that covers many aspects that need attention in soccer management and planning. Tactical management of creating attacking styles, defending styles, transitions, and the mentality that copes with the information. What a challenge and most vulnerable aspect when coaches have less time to prepare their team in a busy schedule. The discussion of this research also covers a side effect of playing high-intense games managed without any form of physical assessment utilization to prevent sudden cardiac death or injuries due to training and intense games. An adequate plan can help establish a philosophy and lead a team to satisfying performance results in full calendar seasons.
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