JOURNAL OF SPORTS SCIENCE & MEDICINE
A REVIEW OF STATURE, BODY MASS AND MAXIMAL OXYGEN UPTAKE PROFILES OF U17, U20 AND FIRST DIVISION PLAYERS IN BRAZILIAN SOCCER
Cristiano Diniz Da Silva1, Jonathan Bloomfield2 and João Carlos Bouzas Marins1
1Federal University of Viçosa, Department of Physical Education, Viçosa, Minas Gerais, Brazil
2Sports Institute of Northern Ireland, University of Ulster, Northern Ireland, UK
© Journal of Sports Science and Medicine (2008) 7, 309 - 319
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|Investigations in the physiological demands of soccer have identified
that a significant percentage of energy production in match performance
is provided through the aerobic pathways. It is therefore important to assess
maximal oxygen uptake (VO2Max) of players in order to evaluate
their aerobic fitness status and optimize their physical conditioning. However,
it is also important to consider the variation of (VO2Max) profiles
for soccer players, with differences having been identified in terms of
playing position as well as playing style. This paper reviews the academic
literature between 1996 and 2006 and reports on the methodologies employed
and the values obtained for stature, body mass and (VO2Max) profiles
of soccer players of different positions in professional Brazilian clubs
at U-17, U-20 and First Division levels. Indirect measurements accounted
for the majority of tests conducted at U-17 (70%) and U-20 (84.6%) levels
whereas at First Division level almost half of the (VO2Max) evaluations
were performed by direct measurements (47.8%). The mean (VO2Max)
profiles obtained for outfield players in U-17 was 56.95 ± 3.60 ml·kg-1·min-1,
58.13 ± 3.21 ml·kg-1·min-1 for U-20 players and 56.58 ± 5.03
ml·kg-1·min-1 for First Division players. In Brazil, the U-20
players appear to have highest VO2Max values, however the profiles
reported for all outfield positions in U-17 and First Division levels are
often lower than those reported for the same category of players from other
countries. This may be a reflection of the style of play used in Brazilian
soccer. This is further emphasized by the fact that the playing position
with the highest VO2Max values was the external defenders whereas
most findings from studies performed in European soccer indicate that midfielders
require the highest VO2Max values.
Key words: Soccer, maximal oxygen uptake, playing positions.
|The exercise pattern of soccer can be described as dynamic, random
and intermittent (Bloomfield et al., 2007)
to an extent which makes physical conditioning of players a complex process.
This pattern involves a myriad of physiological processes which act in random
sequences throughout match-play and this provides a huge challenge for coaches
to condition players for the specific requirements of the game. However,
it has been established that in order to advance in playing level, players
must develop their aerobic capacity to tolerate the physiological load at
higher levels of play (Helgerud et al., 2001;
Stølen et al., 2005;
Wisløff et al., 1998).
The total mean distance covered by the top-level players during match-play
has been reported to be between approximately 10,000m to 13,500m with distinct
differences observed between each playing position (Bangsbo et al., 2006;
Barros et al., 2007;
Di Salvo et al., 2007).
Other researchers using sophisticated time-motion analysis techniques have
suggested a higher mean distance of 13,746m for players in Champions League
matches (Di Salvo et al., 2007).
This could be otherwise represented as an exercise protocol of running ~150m
every minute for 90mins, having a 15min rest period after the first 45mins.
In order to achieve this, even at moderate intensity, a high demand is placed
on the player's aerobic energy system. Also, when considering the anaerobic
requirement for match-play, the necessity of a well developed aerobic system
is vital in order to recover quickly between repeated bouts of high intensity
anaerobic activity (Stølen et al., 2005).
It is well documented that higher levels of aerobic fitness provides a player
with greater involvement potential during a match (in European studies),
with significant relationships reported between VO2Max and the
total distance covered as well as the frequency of sprints made in a match
(Bangsbo et al., 1991;
Helgerud et al., 2001;
Wisløff et al., 1998),
with time spent in high intensity activity as well as the number of involvements
with the ball by the player (Helgerud et al., 2001)
and ultimately, the final classification of the team in competitions (Wisløff
et al., 1998).
These improvements in performance have been associated with a greater ability
to offset fatigue through an enhanced oxidization of lipids as well as sparing
of glycogen and lower lactate production (Henriksson & Hickner, 1996).
To establish a profile of the aerobic capacity of soccer players, it is critical to consider many different independent factors which include chronological age, biological maturity, training age, morphology and anthropometry as well as preferred playing position. In order to establish normative data, profiles should be categorized against a range of levels of performance, as it appears that higher performance levels require higher physical and physiological demands (Rienzi et al., 2000). In addition, the measurement process for aerobic capacity must be considered as many different protocols have been suggested which ultimately fall into two categories, namely direct evaluation through online gas analysis techniques under laboratory conditions or indirect protocols using field testing methods or ergometers such as treadmills. Finally, it is of extreme importance to recognize the time of season that the testing has been performed, the mental and physical state of the players, the conditioning regimen the players have been through and the immediate period leading up to the testing. Due to a myriad of these variables, a wide range of VO2Max and estimated total energy expenditure (Kcal) have been reported in the literature.
The aerobic capacity (VO2Max) represents the metabolic parameter that quantifies the maximal oxygen uptake of an individual and is an important performance indicator in soccer. Mean heart rate values for university level players in the first and second half have been converted to a VO2 of 51.1 and 46.2 ml·kg-1·min-1 respectively (Bangsbo, 1994). However, it has been established that these values of VO2 are unlikely to be a true reflection of aerobic energy requirements through the HR-VO2 regression calculation and provide an overestimation of energy expenditure (Reilly, 1997). In general, for high level soccer players the reference values obtained from laboratories in peer-reviewed articles appear to range between 55 - 70 ml·kg-1·min-1 (Bangsbo et al., 1991; Casajús, 2001; Kemi et al., 2003; Stølen et al., 2005), with some individual values reported as superior to 73 ml·kg-1·min-1 (Silva et al., 1999). Also, direct VO2 measurements from match-play have been measured although the method is limited due to the inhibition of full involvement in soccer performance due to the restrictions from the equipment needed (Kawakami et al., 1992; Reilly, 1997). Therefore, it is suggested that players should have VO2Max values superior to 60 ml·kg-1·min-1 in order to be competitive at the highest levels in soccer (Reilly et al., 2000), although it is important to note that this is not a limiting factor to successful performance. Determining VO2Max of soccer players is therefore useful when assessing talent, in selection of players, in the design of physical conditioning programmes, predicting and monitoring physical match performance. Therefore, establishing reference parameters in high performance can assist in making important informed decisions, particularly for the strength & conditioning staff at soccer clubs and National teams to manipulate physical training to optimize the regimes.
Several recent studies have reported data of VO2Max values from First Division soccer players of high level teams from the European soccer league (Casajús, 2001; Dupont et al., 2005; Edwards et al., 2003; Kemi et al., 2003;Wisløff et al., 1998). From these data, it appears that players have increased aerobic capacity in these European studies in recent years. There may be several reasons for this increase which may include a higher number of sport science and conditioning practitioners appointed in top-level European clubs performing sophisticated profiling, prescription and monitoring of training as well as the increased use of technologies to analyze and performance (Carling et al., 2008). However, the development of aerobic capacity of soccer players playing in Brazil has not been collated and reported which is surprising when considering the success of Brazilian National Teams in recent years in international competitions, including winning the FIFA World Cup in 1994 and 2002, the Copa America in 1997, 1999, 2004 and 2007 and the Confederations Cup in 2005. Thus, this present study aims to report on the stature, body mass and VO2Max profiles of Brazilian soccer players reported since 1996, draw some comparisons with other playing nations and provide contemporary data for players identified by age category and playing position, in particular to provide reference for coaches and practitioners in Brazil and in Europe, where many Brazilian players are signed to European clubs.
|In order to track the physical and physiological development of Brazilian soccer players, a review of International and Brazilian sport science journal publications between 1996 and 2006 was undertaken. Inclusion categories for this study included each publication had to have been subjected to peer-review and contain the provision of data concerning the biographic, anthropometric and maximal oxygen uptake (VO2Max) values from high level male Brazilian soccer players in any of the First Division, U-17 (under 17 years old), U-20 (under 20 years old) categories and First Division State and National clubs. Internet sources where utilized to access electronic journal databases including Medline, Scielo and SportDiscus in order to identify and, where possible, access appropriate papers to be included in this review. Articles that were not available in an online format were accessed through a university library and in proceedings of congresses and scientific encounters. In particular, the methods of aerobic capacity assessments were compiled and reviewed as well as biographical data, body mass, stature and VO2Max data for the following positions: goalkeepers, central defenders, external defenders (also known in Europe as wing-backs or full-backs), midfielders and forwards.|
total of 32 research papers involving 49 experimental studies were considered
for this review. Each study provided data on playing level, number of
subjects, measurement process and VO2Max values. Of these,
17 studies provided full details of age, body mass and stature and 15
studies provided full or partial details of these parameters. Only 7 of
these studies provided full details of VO2Max values for the
5 positional categories and a further 7 studies provided details for only
some of the positional categories. Tables 1
and 2 illustrate the full profile
of studies according to the inclusion criteria and the values for U-17,
U-20 and First Division players.
Brazil, a country with more than 180 million inhabitants, soccer is regarded
as the national sport with a reported more than 30 million recreational
players and 12,000 players with professional registrations in clubs all
over the world (CBF, 2008).
At an elite level, there however appears to be distinct physical and physiological
differences between Brazilian players and their European counterparts.
In this respect, it appears that although players in Brazil are shorter
in stature, they are similar in body mass. In addition, the talent selection
process in Brazil is regarded as different to Europe due the Brazilian
style of play which prioritizes player selection through the technical
aspects of the game rather than recruiting through physical size (Drubsky,
p. 187). In contrast, the stature and body mass of players has been suggested
to be an important policy for player recruitment in major European Leagues
(England, Italy, Spain, Germany) in order to suit the style of the play
and the specific physical demands of each playing position (Bloomfield
et al., 2005). In this respect, the top leagues in Spain and Italy
had a much higher number of players from South America and on average,
shorter and lighter players compared to those in England and Germany,
particularly in midfield and forward positions (Bloomfield et al., 2005).
These authors also postulated that this phenomenon could additionally
be attributed to cultural and climatic reasons for adaptation to lifestyle
in a European country when migrating from South America, rather than simply
for the style of play adapted by teams in these respective leagues. Of
course, other criteria for success include tactical awareness, teamwork
abilities, fitness and psychological variables.
|There appear to be physical and physiological differences between
Brazilian soccer and European soccer in terms of the anthropometric values
and VO2Max profiles of players. In Brazil, there seems to be
a development phase for players at U-20 level which prepares them for the
demands at First Division level. VO2Max assessments have been
performed by a wide range of test protocols with more sophisticated methods
used with players at higher playing levels, however, different positional
data and methodological information have been lacked consistency making
it difficult to make sound comparisons between studies.
For coaches and physical trainers, special attention should perhaps be provided to improving the VO2Max values for Brazilian players which could provide the players with an even greater ability to become more involved in the match as well as increasing further their chances of securing a transfer to a financially lucrative European club.
|We would like to thank CAPES for providing the necessary funding and resources to make this review possible. We would also like to thank the Course of Specialization in Soccer of the Federal University of Viçosa for their financial support.|
Cristiano Diniz DA SILVA
Employment: Master student, Department of Physical Education, Federal University of Viçosa, Viçosa/MG, Brazil.
Degree: Physical Education.
Research interests: Science and football, exercise physiology.
Employment: Sport Science Officer, Sports Institute of Northern Ireland, University of Ulster, Northern Ireland.
Research interests: Science and football, time-motion analysis, performance analysis, kinanthropometry, physiology, strength and conditioning.
João Carlos Bouzas MARINS
Employment: Lecturer, Department of Physical Education, Federal University of Viçosa, Viçosa/MG, Brazil.
Research interests: Science and football, sports nutrition.