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Heart Rate Responses and Technical Comparison Between Small- vs. Large-Sided Games in Elite Professional Soccer

Owen, Adam L1; Wong, Del P2; McKenna, Michael1; Dellal, Alexandre3,4

Journal of Strength and Conditioning Research: August 2011 - Volume 25 - Issue 8 - p 2104-2110
doi: 10.1519/JSC.0b013e3181f0a8a3
Original Research
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Owen, AL, Wong, DP, McKenna, M, and Dellal, A. Heart rate responses and technical comparison between small- vs. large-sided games in elite professional soccer. J Strength Cond Res 25(8): 2104-2110, 2011—This study aims to examine the difference in heart rate (HR) responses and technical activities placed upon European elite players when exposed to 2-sided games differing in the number of players and playing area. Fifteen male soccer players from a Scottish Premier League team (26.3 ± 4.85 years, 182.4 ± 6.99 cm, 79.5 ± 8.05 kg, O2max of 54.36 ± 5.45 ml·kg−1·min−1) performed both small (3 vs. 3 plus goalkeepers) and large (9 vs. 9 plus goalkeepers) sided games each lasting for 3 × 5 minutes interspersed with 4-minute passive recovery during the 2009-2010 season. The HR responses and players' technical actions were recorded throughout all sided games. Results show that small-sided games (SSG) induced significantly (p < 0.05, large effect) higher HR responses as compared to large-sided games. Furthermore, during SSGs, players spent significantly longer time in the >85% maximal HR zone (p < 0.05, large effect) as compared to large-sided games. Technical analysis revealed a large practical difference (effect size ranged from 1.5 to 21.2) between small- and large-sided games: less number of blocks, headers, interceptions, passes, and receives but more dribbles, shots, and tackles in SSG. Furthermore, SSG induced significantly lesser total ball contacts per game (p < 0.05, large effect) but significantly greater ball contacts per individual (p < 0.05, large effect) when compared to larger-sided games. The different technical requirements also enable coaches to carry out training games more suitable to specific playing positions such as SSG for midfielders (more dribbles, tackles, and ball contacts per player) strikers (more shots), and large-sided games for defender (more blocks, headers, and interceptions).

1Sports Science Department, Rangers Football Club, Glasgow, Scotland; 2Department of Health and Physical Education, The Hong Kong Institute of Education, Hong Kong; 3Department of Sports Science and Exercise, Strasbourg University, Strasbourg, France; and 4Tunisian Research Laboratory “Sport Performance Optimization,” National Center of Medicine and Science in Sport (CNMSS), El Menzah, Tunisia

Address correspondence to Adam Owen, adamleeowen@rangers.co.uk.

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Introduction

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.

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Methods

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.

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Subjects

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.

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Sided Games

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.

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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).

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Technical Analysis

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.

Table 1

Table 1

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Statistical Analyses

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).

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Results

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.

Figure 1

Figure 1

Figure 2

Figure 2

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%.

Table 2

Table 2

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Discussion

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.

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Practical Applications

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.

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Acknowledgment

Competing interests: none declared.

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Keywords:

football; aerobic; technical actions; fitness training; cardiac load

© 2011 National Strength and Conditioning Association