Aerobic endurance is important for soccer players because of them covering between ∼10 and 12 km during a match (7,9). It has also been suggested that 98% of total energy used by players during a game is derived from aerobic metabolism (3,4). To improve aerobic endurance capacity, continuous exercises (2,3,5) have been traditionally used. However, Dellal et al. (7) have shown the importance of the high-intensity actions such sprinting in elite soccer. Previous research has indicated that coaches favor the high-intensity interval training because it allows significant improvements in both aerobic and anaerobic capacities (8,19,28,32,33). Likewise, previous studies have shown that small-sided games (SSGs) induce aerobic endurance training effects comparable to the aforementioned high-intensity training levels (6). Specifically, the physiological responses of adult soccer players suggest that SSG can elicit heart rate (HR) responses around 85-95% of maximal HR (HRmax) (6,19) and lead to improvements of both the aerobic fitness and physical match performance of players (12,19,20,32). Small-sided games have been reported to increase players' motivation when compared to generic running intervals eliciting the same overall HR response (15). There is emerging evidence highlighting the benefits of using SSG as part of soccer training regimens for different playing levels (5,6,13,17,20,22,29,31). Recent research has revealed that various formats of SSG (2 vs. 2, 4 vs. 4, and 6 vs. 6) provide reliable internal responses (HR, perceived exertion, and blood lactate concentration) and external loads (i.e., total distance covered) and therefore represents a viable alternative to traditional interval training for developing and maintaining aerobic fitness in soccer players (6,8,13) used to simultaneously improve the technical, tactical, and physical components of soccer (6,8,11), whereas the multifunctional benefits of SSG among youth soccer players have also been observed (17). Furthermore, soccer performance is suggested to be dependent on the successful interaction of the technical, tactical, and physical aspects of the game (2,25). In using SSG, coaches have the opportunity to maximize their contact time with players, increase the efficiency of training, and subsequently reduce the total training time because of their multifunctional nature (6,29). It is believed that this type of training is particularly beneficial for those elite players who have limited training time as a result of intense fixture periods.
Moreover, coaches can influence the intensity of SSG through altering the playing area (16,24), number of players (15,16,26,29), or game rules (7,14,15). Although the specific skill frequency of the player may also influence the training intensity (7), previous studies investigating SSG have primarily focused on the distance covered at various running speeds (13,14), leaving the technical analysis of SSG limited (22,23). In addition, no previous physical and technical comparative studies of SSG have been examined within elite soccer.
Therefore, this study aims to examine the difference in HR responses and technical skills placed upon elite players when exposed to 2 SSGs differing in the number of players and playing area (3 vs. 3 and 9 vs. 9). It is hypothesized that the 3 vs. 3 induces a higher training intensity and elicit appropriate intensity (90-95% HRmax) for aerobic endurance training (18). It is also hypothesized that the 3 vs. 3 SSGs elicit different technical demands when compared to the 9 vs. 9 larger-sided games.
Experimental Approach to the Problem
In this within-player repeated-measures study, all players were tested during 2-training sessions 3 days apart with the 3-day period between testing days consisting of 2-low intensity training days followed by 1 rest day, for 3 consecutive weeks. The study took place in January during the short 3-week period of the midseason 2009-2010 phase as to reflect players' in-season skill and physical level; hence, the players should be at peak condition. Subjects were allowed to take part in testing if they presented no signs of injury, illness, or severe fatigue; otherwise exercise was deferred to the following day. Before this, the players had been training intensively for a 6-month period, carrying out soccer-specific training lasting between 60 and 90 minutes, 3-4 times a week with 1-2 matches a week. During the first testing day, the players performed 3 vs. 3 with 2 goalkeepers, and during the second testing day, they performed 9 vs. 9 sided games with 2 goalkeepers. Therefore, there were 3 3 vs. 3 and 3 9 vs. 9 sided games being examined in this study. The HR response and technical variables were recorded throughout all sided games to examine and compare the activities of the players during the 3 vs. 3 and the 9 vs. 9 SSG.
Fifteen elite male professional soccer players from a Scottish Premier League team and who were at the time competing at UEFA Champions League level volunteered for the investigation. All subjects had been playing soccer for a minimum of 10 years. The team had been among the most successful teams in Scotland for the last 5 years, culminating in a European competition final. Ten of the players were members of their respected national teams. Players' age, height, body mass, maximal aerobic capacity, and sum of 8 skinfold sites (taken at the biceps, triceps, subscapular, iliac crest, supraspinale, abdominal, midthigh, and calf) were 26.3 ± 4.85 years, 182.4 ± 6.99 cm, 79.5 ± 8.05 kg, 54.36 ± 5.45 ml kg−1 min−1, and 57.66 ± 17.59 mm, respectively. The testing sessions took place at the same time of the day as to eradicate the potential effects of any circadian variation on the participants. The players were only informed how to perform the physical test; no information was given about the video analysis during the games, and they were truly unaware of the tested hypothesis. During the study course, players were instructed to maintain normal daily food and water intake, and no dietary interventions were undertaken. All players were fully familiarized with the experimental procedures and the requirements of the games before this study through wearing HR monitors and participating in both small- and large-sided games on a daily basis. The players had refrained from vigorous high-intensity exercise 24 hours before the testing sessions.
Written informed consent was received from all players after a brief but detailed explanation about the aims, benefits, and risks involved with this investigation. Players were told they were free to withdraw from the study at any time without penalty. The study was conducted according to the Declaration of Helsinki and the protocol was fully approved by the Sports Science Department at Rangers Football Club before the commencement of the assessments.
All games were carried out on an outdoor grass field with an average temperature of 4° C and a relative humidity of 82%. Both small- and large-sided games had the same duration and lasted for 3 × 5 minutes with a 4-minute passive recovery between games. The SSG consisted of 3 players aside (3 outfield players plus a goalkeeper) played on a 30 × 25-m pitch (22), whereas the large-sided game consisted of 9 players aside (9 outfield players plus a goalkeeper) played on a 60 × 50-m pitch. The pitch ratios per player were 125 m2 in the 3 vs. 3 (surface of the pitch per number of players) and 166.6 m2 in the 9 vs. 9. All games were preceded by a standardized warm-up period of 12 minutes followed by a 3-minute passive recovery. During this period, players were informed to only consume water if needed. Both small- and large-sided games involved normal match rules with no other added conditions. No specific tactical conditions were placed on players within the games. A large number of soccer balls were placed in each net with play always starting with the goalkeepers when the ball went out of play to aid in a rapid continuation of play.
Heart Rate Responses
A maximal incremental laboratory-based test was carried out before the training intervention with the use of a computer treadmill (Medgraphics UK, Gloucester, United Kingdom) to determine the precise individual maximal oxygen uptake (o2max) and HRmax according to the previous study analyzing SSG (24). The protocol used is commonly used for testing endurance performance in professional football players (28) and involved participants running on a treadmill inclined at 3° (Technogym, Run 500 model, Gambettola, Italy) with a precise speed increase of 1 km·h−1 every minute until exhaustion.
The HR was continuously monitored on outfield players throughout the sided games (3 vs. 3, and 9 vs. 9) and recorded at 5-second intervals by lightweight and portable HR monitor (Polar Team System, Polar Electro OY, Kempele, Finland) (6). After each testing session, all HR data were downloaded to a computer using the dedicated software (Polar Precision S-Series Software SW 3.0; Polar Electro) and stored. The mean and HRmax achieved during each game was calculated for each player, and each player's total time spent in specific HR zones as used by a previous study (20): <50% HRmax; 51-60% HRmax; 61-70% HRmax; 71-84% HRmax; and >85% HRmax (HRH). The time spent within each intensity zone was calculated for each sided game to allow an additional indication of the associated physiological stress. The coefficient of variation of HR responses (%HRmax) during soccer sided games has been reported as 1.3-4.8% (26,31).
Players were filmed for the entire duration of the sided games using a video camera (SHARP Viewcam, VL-AH131H, Media Hi8, Osaka, Japan) to determine the technical demands placed upon them. The video camera was positioned on an elevated position on the half way line of each analyzed pitch and set back 10 m from the sideline. The videos tapes were then formatted onto a digital video recorder and replayed on a standardized computer (Fujitsu, Siemens, Berlin, Germany) for analysis. The mean technical actions performed during each of the sided games were recorded using a hand notation system following the technical definitions set by Owen et al. (29) and shown in Table 1. The total technical actions during the 3 × 5-minute period were averaged over the 3 consecutive weeks and used for analysis.
Data are expressed as and mean ± SD. The normal distribution of the data was checked using the Kolmogorov-Smirnov test. After confirming normal distribution, paired sample t-test was used to compare the difference in HR responses and technical demands between the 2-sided games (3 vs. 3 and 9 vs. 9). Significant level was defined as p ≤ 0.05. Effect size (Coden's d) was calculated to determine the practical difference between small- and large-sided games. Effect size values of 0-0.19, 0.20-0.49, 0.50-0.79, and 0.8 and above were considered to represent trivial, small, medium, and large differences, respectively (4).
The SSG induced significantly higher HR responses when compared to large-sided games (90 ± 2.4 vs. 81 ± 5.5% HRmax, p < 0.05; large effect: 2.12) and peak HR (94 ± 2.7 vs. 89 ± 4.8% HRmax, p < 0.05; large effect: 1.28) HR values (Figure 1). Furthermore, the 2-sided games resulted in different amounts of time spent in the HR zones (Figure 2). Specifically, during SSG, players had significantly shorter time in the 71-84% HRmax zone (0.9 ± 0.5 vs. 8.3 ± 1.3 minutes, p < 0.05; large effect: 7.51) and longer time in the >85% HRmax zone (13.4 ± 0.64 vs. 4.8 ± 1.5 minutes, p < 0.05; large effect: 7.46) as compared to large-sided games.
The technical analysis data (Table 2) showed a large practical difference between the small- and large-sided games (effect size ranged from 1.5 to 21.2). Specifically, during SSG, there were fewer number of blocks (4 ± 2 vs. 13 ± 2; large effect: 4.6), headers (6 ± 1 vs. 15 ± 1; large effect: 15.8), interceptions (6 ± 1 vs. 27 ± 1; large effect: 21.2), passes (193 ± 6 vs. 283 ± 2; large effect: 19.9), and receives (185 ± 4 vs. 267 ± 4; large effect: 21.0) when compared to the large-sided games. However, SSG induced a higher number of dribbles (28 ± 3 vs. 11 ± 1; large effect: 8.8), shots (53 ± 3 vs. 33 ± 2; large effect: 8.2), and tackles (14 ± 1 vs. 12 ± 1; large effect: 1.5) than the large-sided games. Furthermore, SSG induced lower total ball contacts per game (443 ± 94 vs. 625 ± 137, p < 0.05; large effect: 1.6) but significantly greater ball contacts per individual (111 ± 23 vs. 63 ± 14, p < 0.05; large effect: 2.5) as compared to large-sided games (Table 2). The coefficient of variation of technical actions during the games was ranged from 0.1 to 17.2%.
The aim of this study was to compare the HR responses and technical requirements during small- (3 vs. 3 on 30 × 25 m) and large- (9 vs. 9 on 60 × 50 m) sided games in European elite soccer players. The major findings of this study supported the first hypothesis in that the SSG elicited significantly higher exercise intensity in terms of rather responses (Figure 1), and a greater amount of time spent in intense HRH zones (Figure 2), as compared to large-sided games. Furthermore, technical analysis supported the second hypothesis that there was a large practical difference (effect size ranged from 1.5 to 21.2) between small- and larger-sided games with fewer blocks, headers, interceptions, passes, receives, and total ball contacts per game but more dribbles, shots, tackles, and ball contacts per individual in SSG. Therefore, careful organization of practice is crucial if the technical development of players is one of the foci in training sessions.
This study found that SSG induced ∼90% of HRmax and peak HR of 94% of HRmax (Figure 1). This is in agreement with previous studies of SSG that observed an intensity of 90% HRmax among professional soccer players (6,7,18,26). It has been suggested that factors, such as emotion, high tensile strain, and intermittent activity, may lead to HR representing a higher intensity than the actual workload (2,26); however, recent studies investigating o2-HR relationships have been performed under laboratory conditions on an incremental treadmill test and during 5-aside soccer games (19) and a soccer-specific circuit (10,28) have revealed that HR monitoring is a valid indicator of metabolic demands placed upon professional soccer players. In this study, the intensity of small- and large-sided games both fall well within the typical training session recommended guidelines (65-90% HRmax) identified by the American College of Sports Medicine for improving and maintaining cardiovascular fitness (1). However, unlike recreationally trained and untrained individuals, it has been reported that further improvements in aerobic fitness for trained individuals can only be achieved through high-intensity training (27).
Previous studies have shown that training at intensities around 90-95% of HRmax can lead to improvements in aerobic fitness, which can facilitate subsequent improvement in competitive soccer performance at professional level (12,19,20). In addition, several longitudinal studies have shown that the use of SSG as interval training has comparable training effects on aerobic fitness when compared to traditional running interval training (6,8,20). Hill-Haas et al. (15) found that after 7 weeks of training (twice a week each lasted for 30-45 minutes) in elite youth soccer players, both the SSG and short duration interval training groups improved their performances in high-intensity intermittent running test (i.e., Yo-Yo intermittent Recovery Test-level 1). Impellizzeri et al. (20) found that both SSG and intermittent exercise could be used as high-intensity training in junior soccer players (i.e., 90-95% HRmax). After 4 weeks of training (twice a week each for 4 3 4 minutes with 3-minute active rest), both groups showed significant improvement in aerobic fitness and match performance (21). Furthermore, it has been reported that the time spent at higher HRH is important for improving aerobic fitness in soccer players (14,19,20), and in this study, SSG induced long training durations at the highest intensity HRH zone as compared with large-sided games (89 vs. 32% of the total time, i.e., 3 × 5 minutes, Figure 2). Therefore, the 3 vs. 3 SSG employed in this study seems to be a better training game than large-sided game (9 vs. 9) when high training intensity and aerobic fitness is the main foci among senior professional soccer players.
Despite the advantage of producing a higher training intensity, the SSG induces a higher number of ball contacts per individual and different technical actions when compared to larger-sided games (Table 2). The inclusion of frequent match-specific activities in SSG makes the training stimulus more specific to the demands of the sport (31) and hence increases the efficiency of training and technical performance. This study partially agreed with the previous study examining the technical actions of young soccer players during sided games, that is, 3 vs. 3 and 6 vs. 6 (23). Katis and Kellis (23) demonstrated that there were significantly more dribbles, shots, and tackles but less headers during a 3 vs. 3 SSG when compared to 6 vs. 6 SSG. Based on the results of this study, coaches can carry out training games suitable to each specific playing position for professional players. For example, at the elite level, defenders are not required to have extremely high levels of aerobic fitness because of their role within the team not requiring them to cover huge distances (7,30). Therefore, it appears that 9 vs. 9-sided games are most suited to the development of defender, because they require a greater number of blocks, headers, and interceptions (Table 2). Midfield players on the other hand, require very high levels of aerobic fitness because of the vast distances they need to cover in a match (7,30). Therefore, 3 vs. 3 SSG seems more beneficial for midfielders because of the higher training intensity (Figures 1 and 2) and a higher number of dribbles, shots, tackles, and ball contacts per individual (Table 2). Lastly, when taking into account the fact that the majority of strikers are judged on the number of goals scored and the intensity of play needed in a forward position, 3 vs. 3 SSG present more shooting opportunities (Table 2) than larger-sided games and therefore is more position specific.
In this study, SSGs (3 vs. 3) induced significantly higher exercise intensities in comparison to the larger-sided games (9 vs. 9). Subsequently, coaches will be able to manipulate the intensity of training sessions. For example, during the competitive soccer season at an elite professional level, small-sided training games may be implemented to maintain and develop players' aerobic capacity and increase the efficiency of training sessions through simultaneously developing more than one fundamental component of the game (2,6,7,19).
Furthermore, this study revealed that large practical differences were found (effect size ranged from 1.5 to 21.2) between small- and large-sided games: less blocks, headers, interceptions, passes, receives, and total ball contacts per game but more dribbles, shots, tackles, and ball contacts per individual in SSGs. This enables coaches to carry out training games suitable to specific playing positions. For example, defenders can be exposed to more headers, blocks, and interceptions by training within larger training games (9 vs. 9), whereas midfield players are more exposed to increased numbers of dribbles, shots, tackles, and ball contacts per individual during the small-sided 3 vs. 3 games. In addition, SSGs present more shooting opportunities and so could be more suitable for strikers. It has been shown that this study highlights the need for coaches to fully understand the physical and technical demands placed on players exposed to either small or large training games and that the organization of the numbers of players within the sessions to maximize the efficiency of their training sessions and target an outcome from their session (e.g., technical, tactical, or physical) is of paramount importance.
Competing interests: none declared.
1. American College of Sports Medicine Position Stand. The recommended quantity and quality of exercise for developing and maintaining cardiorespiratory and muscular fitness, and flexibility in healthy adults. Med Sci Sports Exerc
30: 975-991, 1998.
2. Bangsbo, J. The physiology of soccer-with special reference to intense intermittent exercise. Acta Physiol Scand Suppl
619: 1-155, 1994.
3. Christmass, MA, Dawson, B, Passeretto, P, and Arthur, PG. A comparison of skeletal muscle oxygenation and fuel use in sustained continuous and intermittent exercise. Eur J Appl Physiol
80: 423-435, 1999.
4. Cohen, J. Statistical Power Analysis for the Behavioral Sciences
. Hillsdale, NJ: Erlbaum Associates, 1988. pp. 567.
5. Coutts, A, Rampinini, E, Marcora, SM, Castagna, C, and Impellizzeri, FM. Heart rate and blood lactate correlates of perceived exertion during small-sided soccer games. J Sci Med Sport
12: 79-84, 2009.
6. Dellal, A, Chamari, K, Pintus, A, Girard, O, Cotte, T, and Keller, D. Heart rate responses during small-sided games and short intermittent running training in elite soccer players: A comparative study. J Strength Cond Res
22: 1449-1457, 2008.
7. Dellal, A, Chamari, C, Wong, DP, Ahmaidi, S, Keller, D, Barros, MLR, Bisciotti, GN, and Carling, C. Comparison of physical and technical performance in European professional soccer match-play: The FA Premier League and La LIGA. Eur J Sport Sci
2010, 25: 25, 93-100.
8. Dellal, A, Keller, D, Carling, C, Chaouachi, A, Wong, DP, and, Chamari, K. Physiological effects of directional changes in intermittent exercise in soccer players. J Strength Cond Res
9. Di Salvo, V, Baron, R, Tschan, H, Calderon Montero, FJ, Bachl, N, and Pigozzi, F. Performance characteristics according to playing position in elite soccer. Int J Sports Med
28: 222-227, 2007.
10. Esposito, F, Impellizzeri, FM, Margonato, V, Vanni, R, Pizzini, G, and Veicsteinas, A. Validity of heart rate as an indicator of aerobic
demand during soccer activities in amateur soccer players. Eur J Appl Physiol
93: 167-172, 2004.
11. Gabbett, TJ and Mulvey, MJ. Time-motion analysis of small-sided training games and competition in elite women soccer players. J Strength Cond Res
22: 543-552, 2008.
12. Helgerud, J, Engen, LC, Wisloff, U, and Hoff, J. Aerobic
endurance training improves soccer performance. Med Sci Sports Exerc
33: 1925-1931, 2001.
13. Hill-Haas, S, Coutts, A, Rowsell, G, and Dawson, B. Variability of acute physiological responses and performance profiles of youth soccer players in small-sided games. J Sci Med Sport
11: 487-490, 2008.
14. Hill-Haas, SV, Coutts, AJ, Dawson, BT, and Rowsell, GJ. Time-motion characteristics and physiological responses of small-sided games in elite youth players: The influence of player number and rule changes. J Strength Cond Res
24: 2149-2156, 2010.
15. Hill-Haas, SV, Coutts, AJ, Rowsell, GJ, and Dawson, BT. Generic versus small-sided game training in soccer. Int J Sports Med
30: 636-642, 2009.
16. Hill-Haas, SV, Dawson, BT, Coutts, AJ, and Rowsell, GJ. Physiological responses and time-motion characteristics of various small-sided soccer games in youth players. J Sports Sci
27: 1-8, 2009.
17. Hill-Haas, SV, Rowsell, GJ, Dawson, BT, and Coutts, AJ. Acute physiological responses and time-motion characteristics of two small-sided training regimes in youth soccer players. J Strength Cond Res
23: 111-115, 2009.
18. Hoff, J. Training and testing physical capacities for elite soccer players. J Sports Sci
23: 573-582, 2005.
19. Hoff, J, Wisloff, U, Engen, LC, Kemi, OJ, and Helgerud, J. Soccer specific aerobic
endurance training. Br J Sports Med
36: 218-221, 2002.
20. Impellizzeri, FM, Marcora, SM, Castagna, C, Reilly, T, Sassi, A, Iaia, FM, and Rampinini, E. Physiological and performance effects of generic versus specific aerobic
training in soccer players. Int J Sports Med
27: 483-492, 2006.
21. Jones, AM and Carter, H. The effect of endurance training on parameters of aerobic
fitness. Sports Med
29: 373-386, 2000.
22. Jones, S and Drust, B. Physiological and technical demands of 4 vs. 4 and 8 vs.8 in elite youth soccer players. Kinesiology
39: 150-156, 2007.
23. Katis, A and Kellis, E. Effects of small-sided games on physical conditioning and performance in young soccer players. J Sports Sci Med
8: 374-380, 2009.
24. Kelly, DM and Drust, B. The effects of pitch dimensions on heart rate responses and technical demands of small-sided soccer games in elite players. J Sci Med Sport
12: 475-479, 2009.
25. Little, T and Williams, AG. Suitability of soccer training drills for endurance training. J Strength Cond Res
20: 316-319, 2006.
26. Little, T and Williams, AG. Measures of exercise intensity during soccer training drills with professional soccer players. J Strength Cond Res
21: 367-371, 2007.
27. Londeree, BR. Effect of training on lactate/ventilatory thresholds: A meta-analysis. Med Sci Sports Exerc
29: 837-843, 1997.
28. McMillan, K, Helgerud, J, Macdonald, R, and Hoff, J. Physiological adaptations to soccer specific endurance training in professional youth soccer players. Br J Sports Med
39: 273-277, 2005.
29. Owen, A, Twist, C, and Ford, P. The physiological and technical effect of altering pitch size and player numbers. F.A. Coach Assoc J
7: 50-53, 2004.
30. Rampinini, E, Coutts, AJ, Castagna, C, Sassi, R, and Impellizzeri, FM. Variation in top level soccer match performance. Int J Sports Med
28: 1018-1024, 2007.
31. Rampinini, E, Impellizzeri, FM, Castagna, C, Abt, G, Chamari, K, Sassi, A, and Marcora, SM. Factors influencing physiological responses to small-sided soccer games. J Sports Sci
25: 659-666, 2007.
32. Stone, NM and Kilding, AE. Aerobic
conditioning for team sport athletes. Sports Med
39: 615-642, 2009.
33. Wong, P, Chaouachi, A, Chamari, K, Dellal, A, and Wisloff, U. Effect of pre-season concurrent muscular strength and high-intensity interval training in professional soccer players. J Strength Cond Res
24: 653-660, 2010.
Keywords:© 2011 National Strength and Conditioning Association
football; aerobic; technical actions; fitness training; cardiac load