Preseason is a period of critical importance to develop high-level performance in
soccer, which is supposed to be conducted with the aim of maximizing players' participations
in team training sessions (Windt et al., 2017). In fact, the development of technical,
phycological, physical and tactical performance is particularly important to be addressed
during this period (Ostojic, 2004; Di Salvo et al., 2007; Fessi et al., 2016), when
a substantial number of new players (and sometimes coaches) are being integrated into
the team and have to adapt to a typically new and different training process.
This specific period can be defined as the moment in which the main objective is the
acquisition of individual and collective adaptations that allow starting the competition
adequately. Over the years, it has been possible to optimize its development in blocks
ranging from 4 to 6 weeks (Loturco et al., 2019). During this particular training
phase, the optimization methods seek individualized strategies and the ability to
adapt to changing training goals and workloads (Carey et al., 2018). From a conditioning
point of view, the preseason is characterized by a high volume of training and a gradually
increasing intensity (Nikolaos et al., 2015), however, team strategical and tactical
training should also be a major determinant in this period. Recent research has reported
that performance in large-sided games (8 vs. 8 with goalkeepers) has changed as an
effect of the preseason training, expressed by the lower total distance covered (from
165.5 ± 23.8 to 142.2 ± 18.4 m.min−1) and, interestingly, by the higher movement synchronization
percentages (Folgado et al., 2018). These results confirm that optimizing players'
conditioning as well as team strategical and tactical attuning during the preseason
might be a key determinant of future performances.
It is usual for teams to aim for the highest training loads during the preseason (Jeong
et al., 2011). Accordingly, the competition carried during preseason is generally
used with the purpose of progressively reaching adequate performance levels that may
be maintained over the entire season. In fact, the competition periods can be very
long (around 40 weeks) and sometimes including World and European Cups on summer or
preliminary rounds for European Cups or Intertoto challenge. Therefore, the highest
level of performance, congested fixtures are substantially increasing and requiring
adequate care. In general, the competition period is followed by the off-season, consisting
~2–5 weeks, and the cycle is repeated, with players returning to the clubs for a successive
preseason (Woods et al., 2002).
In these scenarios, a very important topic, is that the reality of modern soccer is
presenting more and more marketing-related tours with commercial interest, with the
preseason summer tournaments becoming less and less frequent. For example, in 2019,
Real Madrid reported a 10-days preseason calendar fixtures during their USA tour as
follows: July 20th played against Bayern Munich in Houston; July 23th played against
Arsenal in Maryland; July 26th played against Atletico de Madrid in New Jersey, and
finally, July 26th played against Tottenham in Berlin, Germany. Another example, in
2019, Manchester City reported an 11-days preseason calendar in China/Japan with four
matches: July 16th played against West Ham in Nanjing; July 19th played against Wolves
in Xangai; July 24 played against Kitchee in Hong Kong and, July 27th played against
Yokohama Marinos in Yokohama.
It is a fact that these games are set closer and closer to the beginning of the preseason
period, which may cause an extra pressure on the player and coaching staff, forcing
them to accelerate the conditioning process, thus skipping important steps in the
training process and implementing higher workload values than the expected for the
period (Rabelo et al., 2016), probably with unwanted consequences at different levels.
Furthermore, due to the high-level of these summer tournaments, the “need to win”
is becoming an additional stressing factor (Lee et al., 2001) It has also been reported
that competing with high-level opponents increases time-motion demands at high intensities
in tandem with intra-team movement synchronization tendencies (Folgado et al., 2014).
It has been recently revealed that training load during the pre-season (6 weeks) of
a professional elite football team may not have an effect on team physical performance
during the first five official matches of the season, since no relationship was found
between training load and injury rate, inflammation and muscle damage markers (Coppalle
et al., 2019). One of the most significant findings from an initial Football Association's
epidemiological study was the disproportionately high number of training injuries
during July, a month that corresponds to the preseason period (Woods et al., 2002).
Nevertheless, an inappropriate pre-season training period can be associated with a
higher incidence of players' injuries throughout the competitive season (Eliakim et
al., 2018).
In particular, quadriceps injuries were more frequent during preseason, whereas adductor,
hamstring, and calf injury rates increased during the competitive season (Hägglund
et al., 2013). In this sense from the institutions are considering to be able to manage
the total volume of minutes per player quantifying all competitions in a season. Therefore,
an extra effort to understand how elite players are adapting (acutely and chronically)
to these new scenarios of being exposed to preseasons with more and more competitive
matches is required.
In this sense, it seems appropriate to discuss a global phenomenon within the sports
community: are preseason friendly matches, friendly in reality? And, which are the
implications for in-season injury incidence? Bearing in mind the aforementioned arguments,
this current phenomenon in soccer implies that:
a) Understanding soccer players' match-related fatigue and recovery profiles likely
helps with developing conditioning programs that increase team performance and reduce
injuries and illnesses (Silva et al., 2018).
b) The process of understanding the training effects should be analysed overcoming
the isolated inspection of conditioning variables, thus, requiring the control of
strategic and tactical-related variables which relate to team and players' performance
(Folgado et al., 2018).
c) The resignation of the transitory period supposes that, let's not take advantage
of how as a “window of opportunity” for players to both “recover” and “rebuild” for
the following season (Silva et al., 2016).
d) Although players are under less pressure to win compared to the end-of-season (Weinberg
et al., 2006) in the recent years, preseason games are less friendly.
There are many possible reasons why players who attend more preseason training weeks
may have a higher risk of subsequent injury (Lee et al., 2001). Nevertheless, recent
studies suggest that players are at the greatest risk during the pre-competition period,
and the low preseason cumulative workloads seem to be associated with increased in-season
injury risks (Colby et al., 2017). In addition, large increments in weekly training
load seem to increase injury risk (Harrison and Johnston, 2017). In this regard, an
interesting study by Ekstrand in 2016, using a prospective design of 255 hamstring
injuries in the “UEFA Elite club injury study” concluded that the majority of the
intramuscular injuries affected muscle function (56% in grade 1 and 2 injuries), but
no difference in lay-off time was found between the different types of injuries (Ekstrand
et al., 2016).
In summary, an urgent SOS to the world of soccer is required. The preseason games
are becoming less and less friendly. An evidence-based analysis suggests that more
and more intense competitions during the consecutive seasons require to respect the
primary objective of preseasons, which is to properly prepare and conditioning the
players after a period of decreased activity. This is a crucial phase in which the
competition stress should to be moved to the background and the physical conditioning
and cognitive readiness should be the focus, to increase the chances of reaching the
important moments of the season in the peak performance, and with all players available
(or, at least, with the greatest number available). As the ability to provide multi-peak
performances over the season does not seem possible (Issurin, 2010) and this is a
real necessity in modern soccer, this issue should be further discussed.
Author Contributions
JC-G: first idea. CL, DM-J, PA, TF, and NT: review. FC, AG-D, JM, IL, XP, and IR:
design. JS: final approval. All authors contributed to the article and approved the
submitted version.
Conflict of Interest
The authors declare that this text was conducted in the absence of any conflict of
interest. Our institution did not receive payment or services from a third party for
any aspect of the submitted work and we declared no financial relationships with entities
that could be perceived to influence, or that give the appearance of potentially influencing.