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Physiological and Skill Demands of ‘On-Side’ and ‘Off-Side’ Games

Gabbett, Tim J1,2; Jenkins, David G2; Abernethy, Bruce2,3

Journal of Strength and Conditioning Research: November 2010 - Volume 24 - Issue 11 - p 2979-2983
doi: 10.1519/JSC.0b013e3181e72731
Original Research
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Gabbett, TJ, Jenkins, DG, and Abernethy, B. Physiological and skill demands of ‘on-side’ and ‘off-side’ games. J Strength Cond Res 24(11): 2979-2983, 2010-This study investigated the physiological and skill demands of ‘on-side’ and ‘off-side’ games in elite rugby league players. Sixteen male rugby league players participated in ‘on-side’ and ‘off-side’ games. Both small-sided games were played in a 40- × 40-m playing area. The ‘off-side’ game permitted players to have 3 ‘plays’ while in possession of the ball. Players were permitted to pass backward or forward (to an ‘off-side’ player). The ‘on-side’ game also permitted players to have 3 ‘plays’ while in possession of the ball. However, players were only permitted to pass backward to players in an ‘on-side’ position. Heart rate and movement patterns (via global positioning system) were recorded continuously throughout both games. Data were collected on the distance covered, number of high-acceleration and velocity efforts, and recovery between efforts. Video footage was also taken to track the performance of the players. Post hoc inspection of the footage was undertaken to count the number of possessions and the number and quality of disposals. In comparison to ‘on-side’ games, ‘off-side’ games had a greater number of involvements (“touches”), passes, and effective passes. However, the cognitive demands of ‘on-side’ games were greater than ‘off-side’ games. ‘Off-side’ games resulted in a greater total distance covered, greater distance covered in mild and moderate accelerations, and greater distance covered in low, moderate, and high-velocity efforts. There were also a greater number of short duration recovery periods between efforts in ‘off-side’ games. The results of this study demonstrate that ‘off-side’ games provide greater physiological and skill demands than ‘on-side’ games. ‘Off-side’ games may provide a practical alternative to ‘on-side’ games for the development of skill and fitness in elite rugby league players.

1Brisbane Broncos Rugby League Football Club, Queensland, Australia; 2School of Human Movement Studies, The University of Queensland, Queensland, Australia; and 3Institute of Human Performance, The University of Hong Kong, Hong Kong, China

Address correspondence to Dr. Tim Gabbett, timg@broncos.com.au.

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Introduction

Small-sided games are increasingly being used as a means of improving the skill and physical fitness levels of team sport athletes (9) because they allow the simulation of movement patterns of team sports, while maintaining a competitive environment where athletes must perform under pressure and while fatigued (6). Several researchers have investigated the physiological demands of small-sided games. Impellizzeri et al. (10) investigated the effects of game-based training and aerobic interval training on maximum oxygen consumption, lactate threshold, running economy at lactate threshold, soccer-specific endurance (measured via Ekblom's circuit test), and indices of physical performance during soccer matches (total distance covered, and time spent standing, walking, and running) in junior soccer players. The authors reported no significant differences between groups for any of the measured variables, including the soccer-specific tests. In a study of rugby league players, Gabbett (7) found a similar heart rate (152 vs. 155 b·min−1) and blood-lactate concentrations (5.2 vs. 5.2 mmol·L−1) during competition and training (that consisted entirely of small-sided games). Furthermore, in a study of elite female soccer players, no differences were reported between small-sided games and international competition for the relative amount of time spent standing, walking, jogging, striding, and sprinting (8).

More recently, researchers have investigated the effects of increasing field size (5,11,13) and decreasing player numbers (5) on physiological responses and the volume of skill executions. Increasing the field size increased the heart rate, whereas increasing the player numbers tended to decrease heart rate and the volume of skill executions (i.e., “touches”) (5). These findings have important practical implications as coaches often need to maximize the physiological benefits of small-sided games while also gaining a sufficient volume of skill executions to enhance game-specific skill.

Coaches commonly adapt training drills from a completely different sport to their sport of choice. Indeed, it is not uncommon for coaches from rugby league, rugby union, and touch football (which are all played with ‘on-side’ rules and require the ball to be passed backward) to play small-sided games and drills that are adapted from netball, Australian football, soccer, and hockey (which allow players to be ‘off-side,’ and permit backward and forward passes). The inclusion of ‘on-side’ and ‘off-side’ games within skills programs is based on the premise that exposure to a wide range of invasion sports assists the development of expert decision making (3).

Although coaches are increasingly using small-sided games to develop physical qualities, and perceptual and motor skill, information on the physiological demands of ‘on-side’ and ‘off-side’ games is currently unavailable. In addition, no study has compared the skill demands of ‘on-side’ and ‘off-side’ games. With this in mind, the purpose of this study was to investigate the physiological and skill demands of ‘on-side’ and ‘off-side’ games in elite rugby league players.

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Methods

Experimental Approach to the Problem

The physiological and skill demands of ‘on-side’ and ‘off-side’ small-sided games were investigated in elite rugby league players using a within-subjects crossover study design. We hypothesized that ‘off-side’ games would elicit greater physiological demands and a greater volume of skill executions (i.e., “touches”) than ‘on-side’ games.

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Subjects

Sixteen elite male rugby league players ([mean ± SD]) age, 17.3 ± 0.9 years) participated in this study. Players were members of a National Rugby League club high performance development squad. Testing was performed in the competitive phase of the season after the players had completed a 4-month preseason skills and conditioning program. All participants were in peak physical condition and free from injury at the time of testing. Participants were requested to abstain from strenuous physical exercise for 72 hours before testing. All participants received a clear explanation of the study, including information on the risks and benefits, and written parental or guardian consent was obtained. The Institutional Review Board for Human Investigation approved all experimental procedures.

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Small-Sided Games

This study was completed over 2 training sessions. One ‘on-side’ game and one ‘off-side’ game were played in each session, in random order. Each small-sided game was separated by 3 minutes. Both small-sided games were played in a 40- × 40-m playing area. The ‘off-side’ game permitted players to have 3 ‘plays’ while in possession of the ball. Players were permitted to pass backward or forward (to an ‘off-side’ player). The ‘on-side’ game also permitted players to have 3 ‘plays’ while in possession of the ball. However, players were only permitted to pass backward to players in an ‘on-side’ position. For each play, defending players were required to touch their opponent with 2 hands. All other rules, including the field dimensions, numbers of players (8 vs. 8), duration (8 minutes), and coach encouragement were identical between small-sided games.

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Physiological Demands

Movement was recorded by a global positioning system (GPS) unit (miniMaxX, Catapult Innovations, Melbourne, Australia) sampling at 5 Hz. The GPS signal provided information on speed, distance, position, and acceleration. The GPS unit also included triaxial accelerometers sampling at 100 Hz, to provide greater accuracy on speed and acceleration. The unit was worn inside a small vest, on the upper back of the players. Data were categorized into (a) discrete acceleration bands, corresponding to mild (0.55-1.11 m·s−2), moderate (1.12-2.78 m·s−2), and maximal (≥2.79 m·s−2) accelerations (1); (b) discreet movement velocity bands, corresponding to very low (0-1 m·s−1), low (1-3 m·s−1), moderate (3-5 m·s−1), high (5-7 m·s−1), and very high (> 7 m·s−1) velocities; and (c) recovery between efforts, corresponding to short (<30 seconds), moderate (30 seconds to 2 minutes), and long (> 2 minutes) recovery. High correlations (r = 0.99) and low coefficients of variation (1.2-1.7%) have been reported between GPS measurements of speed and actual speeds determined by chronometry (14). In addition, GPS technology has been shown to offer a valid and reliable method of detecting isolated sprints and repeated-sprints commonly observed in team sports (2).

Heart rate was recorded using Polar S610i heart rate monitors. Once the raw data were collected, they were downloaded to a computer using Polar Precision Performance software.

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Volume of Skill Executions

A 37-mm-digital video camera (Sony, DCR-TRV 950E, Nagasaki, Japan) was used to track the performance of the players. Post hoc inspection of the footage was undertaken to count the number of possessions, and the number and quality of disposals. The intraclass correlation coefficient and coefficient of variation for the coding of skill involvements ranged from 0.90-0.99 and 0.2-0.5%, respectively.

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Cognitive Load

Subjective measurements of cognitive load were collected by self-report at the completion of each game. The cognitive scale required participants to rate each game using the following questions as a guide: (a) how much mental and decision-making activity was required in this drill? (b) was the drill easy or demanding, simple or complex? The scale ranged from extremely demanding (game-like) to not demanding at all (4).

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Statistical Analyses

Differences in the physiological demands and volume of skill executions between the ‘on-side’ and ‘off-side’ games were compared using a paired t-test. The level of significance was set at p ≤ 0.05, and all data are reported as mean ± SE.

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Results

Volume of Skill Executions

The skill demands of the ‘on-side’ and ‘off-side’ games are shown in Table 1. In comparison to ‘on-side’ games, ‘off-side’ games had a significantly greater (p < 0.05) number of involvements (“touches”), passes, and effective passes. The number of players experiencing 11 or more total involvements was greater in the ‘off-side’ (N = 16) than the ‘on-side’ (N = 10) games. Almost half of participants (N = 7, 43.8%) in the ‘off-side’ games had 21 or greater total involvements, whereas only 25% (N = 4) of participants in the ‘on-side’ games experienced 21 or greater total involvements (Figure 1). The cognitive demands of ‘on-side’ games were significantly greater (p < 0.05) than ‘off-side’ games.

Table 1

Table 1

Figure 1

Figure 1

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Physiological Demands

‘Off-side’ games resulted in a greater (p < 0.05) total distance covered; greater distance covered in mild and moderate accelerations; and greater distance covered in low, moderate, and high-velocity efforts. There were also a significantly (p < 0.05) greater number of short duration recovery periods between efforts in ‘off-side’ games (Table 2).

Table 2

Table 2

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Discussion

The purpose of this study was to investigate the physiological and skill demands of ‘on-side’ and ‘off-side’ games in elite rugby league players. The results of this study demonstrate that ‘off-side’ games provide greater physiological and skill demands than ‘on-side’ games. ‘Off-side’ games may provide a practical alternative to ‘on-side’ games for the development of skill and fitness in elite rugby league players.

This study is the first to compare 2 commonly used approaches to game-based training in the rugby codes. The first game employed traditional ‘on-side’ rules, whereas the second was adapted from other invasion sports (e.g., netball, Australian football, soccer, and hockey) that employ ‘off-side’ rules. Previous studies of small-sided games have investigated the effect of changing field size (5,11,13), player numbers (5), or coach encouragement (13) on physiological responses and technical actions in team sport athletes. Studies have shown that increasing the field size, player numbers, or coach encouragement can significantly alter the physiological responses and volume of skill executions (i.e., “touches”) during small-sided games (5,11,13). This study extends the findings of others by demonstrating that simple changes to the ‘on-side’ rule results in significant changes in the physiological and skill demands of small-sided games.

‘Off-side’ games were associated with a greater volume of skill executions (“touches”) than ‘on-side’ games. In addition, the number of players experiencing 11 or more total involvements was greater in the ‘off-side’ (n = 16) than the ‘on-side’ (n = 10) games. Almost half of the participants (n = 7, 43.8%) in the ‘off-side’ games had 21 or greater total involvements, whereas only 25% (n = 4) of the participants in the ‘on-side’ games experienced 21 or greater total involvements. The greater number of “touches” in ‘off-side’ games occurred predominantly as a result of a greater number of passing opportunities. No significant differences were detected in disposal efficiency between ‘on-side’ and ‘off-side’ games although the cognitive rating of perceived exertion (RPE) was significantly higher in ‘on-side’ games. Because of the higher volume of skill executions, it is tempting to conclude that ‘off-side’ games provide a greater skill learning stimulus than ‘on-side’ games. However, high cognitive load has previously been associated with greater skill learning (12). The lower number of “touches” in ‘on-side’ games, coupled with the higher cognitive RPE may indicate that each involvement in the ‘on-side’ game presented a greater learning opportunity than those presented in ‘off-side’ games. From a skill acquisition perspective, clearly a balance must be reached between gaining an adequate number of “touches” to improve passing and catching skills, while also providing a game-specific stimulus that replicates the technical and tactical demands of the sport. Although ‘off-side’ games may prove beneficial in providing a variable training stimulus for competitors from ‘on-side’ sports, future studies investigating games that use a combination of both ‘on-side’ and ‘off-side’ rules may provide a greater insight into the practical utility of these training drills. In addition, although differences did exist between ‘on-side’ and ‘off-side’ games for cognitive load, it should be recognized that cognitive load was indirectly measured using a self-reported subjective scale. With this in mind, future studies using more objective means of measuring cognitive load (e.g., dual-task methodology) in the different game types are warranted.

Although not statistically significant, the average heart rate achieved in ‘off-side’ games was 11 b·min−1 higher than that achieved in ‘on-side’ games. Greater total distances were covered in the ‘off-side’ games, and a greater number of short duration recovery periods were observed between high-intensity efforts. In addition, ‘off-side’ games were associated with a greater number of mild and moderate acceleration efforts and low, moderate, and high-velocity efforts. Interestingly, despite the freedom to move into greater space to receive the ball from either a forward or backward pass, ‘off-side’ games had similar amounts of high-acceleration and high-velocity efforts to ‘on-side’ games, which may be a reflection of the field constraints imposed on the players. In isolation, neither the ‘on-side’ or ‘off-side’ games offered an adequate training stimulus to improve aerobic fitness, and consequently would require supplementation with a traditional conditioning program to adequately prepare players for the physical demands of rugby league competition. However, collectively these results demonstrate that ‘off-side’ small-sided games are more physiologically demanding, and offer a superior training stimulus to their ‘on-side’ equivalent.

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Practical Applications

This study investigated the physiological and skill demands of ‘on-side’ and ‘off-side’ games in elite rugby league players. The results of this study demonstrate that ‘off-side’ games provide greater physiological and skill demands than ‘on-side’ games. ‘Off-side’ games may provide a practical alternative to ‘on-side’ games for the development of skill and fitness in elite rugby league players.

Although adequate training loads are required to elicit training adaptations, an equally important consideration in the development of conditioning programs is the implementation of adequate recovery between intense bouts of training. Coaches often use low-intensity small-sided games as a means of reducing the physical and mental ‘load’ on players. Although ‘on-side’ games reduce the skill demands of training (by reducing the volume of skill executions), they also reduce the total distance covered, the number of high-acceleration and high-velocity sprint efforts, and the number of short duration recovery periods between high-intensity efforts. These results suggest that if low-intensity activity and recovery is a goal of the training session, then ‘on-side’ games are preferential to ‘off-side’ games.

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References

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Keywords:

game-based training; small-sided games; fitness; skill; rugby

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