Influence of the Opposing Team on the Physical Demands of Elite Rugby League Match Play : The Journal of Strength & Conditioning Research

Secondary Logo

Journal Logo

Original Research

Influence of the Opposing Team on the Physical Demands of Elite Rugby League Match Play

Gabbett, Tim J.1,2

Author Information
Journal of Strength and Conditioning Research 27(6):p 1629-1635, June 2013. | DOI: 10.1519/JSC.0b013e318274f30e
  • Free

Abstract

Introduction

Time-motion analysis has been used extensively to study the physical demands and movement patterns of team sports (1,5,8). However, despite the popularity of the sport, studies describing the physical demands of rugby league are limited, with time-motion analyses restricted to a few studies spanning for a period of 20 years. In the early 1990s, Meir et al. (17) performed the first time-motion analysis of professional rugby league players. Describing a total of 20 movements and game-specific events, these authors reported that players covered between 6,500 and 7,900 m during the course of a game, depending on the playing position. More recently, researchers have studied the high-intensity running (14,22,23), sprinting (13), tackling (4,14), ball-in-play (12), and repeated high-intensity effort demands (3,13,14) of elite rugby league competitions. Results of time-motion analysis studies have provided important information to applied sport scientists and strength and conditioning coaches to assist in the development of game-specific conditioning programs.

Previous studies of team sport athletes (e.g., soccer) have shown that elite players typically (but not always) perform more high-intensity running than sub-elite competitors (18), when the demands of competition are greatest (1). Rampinini et al. (21) investigated the physical demands of the most and least successful teams competing in the Italian Serie A league and found that the most successful teams covered greater total distances with the ball, and more high-intensity and very high–intensity running with the ball. Andersson et al. (1) showed that the amount of high-intensity running performed by female soccer players was greater in international than domestic matches. These findings have been confirmed by others (15) who demonstrated that female soccer players performed more repeated-sprint bouts in international matches (4.8 bouts per match) than national (1.0 bout per match) and domestic (1.4 bouts per match) matches. However, although the physical demands of team sport competition have been shown to increase with playing standard, results are equivocal with some studies demonstrating lower playing intensity as the competitive standard increases (8).

One method of investigating the physical demands of different playing standards is to study the movement patterns of the best and worst teams in the same competition (8,20). Di Salvo et al. (8) investigated the high-intensity running activity of elite soccer players competing in the English Premier League and found that teams finishing in the bottom 5 (919 ± 128 m) and middle 10 (917 ± 143 m) league positions completed significantly more total high-intensity running than teams in the top 5 league positions (885 ± 113 m) (8). Using a slightly different approach, Rampinini et al. (20) studied the physical demands of one professional soccer team and analyzed the influence of the opposing team on match performance. In direct contrast to the findings of Di Salvo et al. (8), the total distance covered and distance covered in high-intensity running was higher when competing against the best teams compared with the worst teams. Clearly, further studies are required to better understand the relationship between physical match performance and playing standard.

The Australian National Rugby League (NRL) competition is widely regarded as the best rugby league competition in the world. Anecdotal evidence suggests that the competitive advantage of the best NRL teams is closely linked to their ability to maintain a higher playing intensity than less successful teams. However, to date, no study has investigated if matches involving the best NRL teams are associated with higher playing intensities than matches involving the worst NRL teams and whether winning is associated with higher or lower physical demands than losing. With this in mind, the purpose of this study was to investigate if higher standard NRL matches were associated with greater physical demands than lower standard NRL matches. The influence of playing standard and winning and losing on the physical demands of competition were analyzed by comparing (a) the activity profiles of players competing against high-ranked (Top 4) and low-ranked (Bottom 4) teams and (b) the activity profiles of players when their team either won or lost.

Methods

Experimental Approach to the Problem

The physical demands of elite rugby league matches were investigated using a prospective case series experimental design. Global positioning system (GPS) data were collected over an NRL season and were analyzed by comparing the activity profiles of players competing against high-ranked (Top 4) and low-ranked (Bottom 4) teams, and when their team either won or lost. Differences among the matches of various competitive standing were compared using Cohen's effect size (ES) statistic (7). It was hypothesized that meaningful differences in activity profiles would exist among the best and worst teams, with the physical demands being greatest when playing higher ranked teams. Furthermore, it was hypothesized that the intensity of matches would be greater in winning than losing teams.

Subjects

Twenty-two NRL players (mean ± SE, aged 23.6 ± 0.5 years) participated in this study. All participants received a clear explanation of the study, including information on the risks and benefits, and written consent was obtained. All experimental procedures were approved by the Institutional Review Board for Human Investigation.

Global Positioning System Analysis

Global positioning system analysis was completed during 16 NRL matches. Movement was recorded by a minimaxX GPS unit (Team 2.5; Catapult Innovations, Melbourne, Australia) sampling at 5 Hz (Figure 1). The GPS signal provided information on speed, distance, position, and acceleration. The GPS unit also included triaxial accelerometers and gyroscopes sampling at 100 Hz, to provide information on physical collisions and repeated high-intensity efforts. The unit was worn in a small vest on the upper back of the players (Figure 2).

F1-23
Figure 1:
MinimaxX global positioning system unit used in this study.
F2-23
Figure 2:
Rugby league player wearing the minimaxX global positioning system unit.

Data were categorized into (a) movement speed bands, corresponding to low (0–5 m·s−1) and high (> 5 m·s−1) speeds (14); (b) maximal accelerations (≥2.79 m·s−2) (2); (c) mild, moderate, and heavy collisions (11); and (d) repeated high-intensity effort bouts (14). A repeated high-intensity effort bout was defined as 3 or more maximal acceleration, high speed, or contact efforts with <21 seconds recovery between efforts (13,14). The minimaxX units have been shown to have acceptable validity and reliability (19). In addition, the minimaxX units have been shown to offer a valid measurement of tackles and repeated efforts commonly observed in collision sports (11).

Players also provided a rating of their perceived effort during individual matches using a modified rating of perceived exertion scale (10). Perceptions of effort estimates were obtained 30 minutes after completing the match.

Statistical Analyses

Differences in the physical demands between high-ranked (i.e., Top 4) and low-ranked (Bottom 4), and winning and losing teams were compared using statistical significance testing and by using a practical approach based on the real-world relevance of the results (6). First, differences in the physical demands (i.e., distance covered at low and high speeds; mild, moderate, and heavy collisions; and repeated high-intensity effort activity) between Top 4 and Bottom 4 teams, and winning and losing teams were compared using an independent t-test. The level of significance was set at p ≤ 0.05, and all data are reported as mean ± SE. Second, given the practical nature of the study, differences in the demands between Top 4 and Bottom 4 teams, and winning and losing teams were also analyzed using Cohen's ES statistic (7). Effect sizes of <0.09, 0.10–0.49, 0.50–0.79, and >0.80 were considered trivial, small, moderate, and large, respectively (7).

Results

The physical demands of elite rugby league match play when competing against Top 4 and Bottom 4 teams are shown in Table 1. Players covered significantly greater (p ≤ 0.05, ES = 0.55–0.57) absolute and relative distance at high speeds when playing against Bottom 4 teams than when competing against Top 4 teams. The number of mild, moderate, and heavy collisions were similar (p > 0.05, ES = 0.00–0.28) whether competing against Top 4 or Bottom 4 teams.

T1-23
Table 1:
Physical and perceptual demands of elite rugby league match play when competing against Top 4 and Bottom 4 teams.*

The physical demands of competition were greatest when matches were won (Table 2). Players covered significantly greater (p ≤ 0.05) total distance per minute of match play (ES = 0.40) and greater relative distance at low speeds (ES = 0.46) when matches were won. In addition, a greater absolute (ES = 0.54) and relative (ES = 0.50) number of maximal accelerations, and repeated high-intensity effort bouts were performed when players were competing in winning teams than in losing teams. The mean and maximum number of efforts in a repeated high-intensity effort bout was also higher in winning teams (ES = 0.40–0.51), although the recovery between efforts was significantly shorter (p ≤ 0.05, ES = 0.50) in losing teams. No significant differences (p > 0.05, ES = 0.00–0.23) were found between winning and losing teams for the number of mild, moderate, and heavy collisions.

T2-23
Table 2:
Influence of winning and losing on the physical and perceptual demands of elite rugby league match play.*

Moderate (7–17 points) and large (≥18 points) winning margins were associated with greater relative distances covered and distances covered at low speeds than small winning margins. Ratings of perceived exertion were lower when teams won by large margins and higher when teams lost by large margins (Figure 3).

F3-23
Figure 3:
Physical and perceptual demands of elite rugby league match play with a small (≤6 points), moderate (7–17 points), and large (≥18 points) winning or losing margin. Data are mean ± SE. Effect sizes (ES) represent the magnitude of difference between the smallest and largest values. Effect sizes of <0.09, 0.10–0.49, 0.50–0.79, and >0.80 considered trivial, small, moderate, and large, respectively.

Discussion

This study investigated the influence of playing standard and winning and losing on the physical demands of elite rugby league match play. The results of this study demonstrate that the physical demands of rugby league are greater when winning than when losing and when competing against lower ranked teams. Furthermore, larger winning margins are associated with greater physical demands than small and moderate winning margins, with these physical demands, in turn, greater than losing margins of any magnitude. These findings suggest that the competitive advantage of successful NRL teams is closely linked to their ability to maintain a higher playing intensity than their less successful counterparts.

This study found greater physical demands in winning than losing teams. Players from winning teams covered greater total distances per minute of match play, including greater distances at low speeds. However, no significant differences were found between winning and losing teams for the amount of high-speed running performed. These findings demonstrate that although winning and losing teams are equally able to perform the high-intensity running demands of competition, winning teams are better able to maintain a higher intensity during recovery from these high-speed efforts.

Players from winning teams performed more maximal accelerations and a greater number and intensity of repeated-effort bouts. Although the distances covered at low and high speeds are important to elite rugby league players, previous studies have emphasized the importance of repeated high-intensity effort ability to competitive success in this sport (3,13,14,16). We have recently shown that players perform, on average, 9 ± 1 repeated high-intensity effort bouts per game (13). Furthermore, recent evidence has shown that the majority (approximately 70%) of the tries scored occur in close proximity to a repeated high-intensity effort bout (3), lending support to the suggestion that the ability (or inability) to perform these activities could prove critical to the outcome of the game. These findings have also received support from the work of others (16) who demonstrated that repeated high-intensity effort exercise (involving sprinting and tackling) was associated with higher heart rate and perceived exertion, and greater reductions in sprinting performance than repeated sprinting in isolation. Collectively, the present and previous (3,13,16) findings demonstrate the importance of repeated high-intensity effort ability to both performance and fatigue tolerance in elite rugby league players. Perhaps more importantly, this study is the first to demonstrate the importance of repeated high-intensity effort ability to competitive success in elite rugby league.

While few differences in physical demands existed between Top 4 and Bottom 4 teams, in contrast to our hypothesis, this study found greater absolute and relative amounts of high-speed running when players were competing against lower ranked teams. A possible confounding influence in this finding is that the physical demands were greater when teams were winning, and by nature of their ladder position, lower ranked teams lose more regularly. Although it is possible that low-ranked teams may be required to increase playing intensity when competing against higher ranked teams, we are more circumspect in our interpretation of this finding. Indeed, losing teams are likely to be required to perform more defense, and cover-defend against a greater number of line breaks and tackle breaks. It is plausible that the poorer match performance of losing teams results in a greater amount of scrambling in defense, which in turn, increases the amount of high-speed running performed in competition.

Players covered greater total distance when the team won by large margins; however, this increased total distance was accomplished predominantly through increases in the amount of low-intensity activity performed. There were only small differences (ES = 0.38) in high-speed running when matches were won by small (≤6 points), moderate (7–17 points), or large (≥18 points) margins. However, although insignificant differences were found between small, moderate, and large losing margins for total distance and distance covered at low speeds, greater distance was covered at high speeds when teams lost by large margins. These findings provide further support for the suggestion that performing large amounts of defense may increase the high-speed running demands of elite rugby league match play. To date, only one study has documented the physical demands of attack and defense in elite rugby league players, with this study finding higher work rates in the majority of positions when attacking than defending (23). Clearly, further studies examining the physical demands of rugby league attack and defensive play, with particular reference to field position, may provide important data to inform rugby league strength and conditioning programs.

Although the physical demands were greater when winning than losing, and when competing against lower ranked teams, player's perceptions of those demands were greatest when competing against higher ranked teams. Furthermore, although larger winning margins were associated with greater physical demands than small and moderate winning margins, the perceptions of effort were greater with smaller winning margins and larger losing margins. Collectively, these results suggest an uncoupling of the physical and perceptual demands of elite rugby league match play. In addition, these findings suggest that matches against Top 4 teams, and with small winning margins and large losing margins, provide greater psychological stress than matches against lower ranked teams, or when winning by a large margin and losing by a small margin.

Previous investigations of professional rugby league match play have shown an association between the number of collisions performed and the amount of muscle soreness, muscle damage (as estimated from creatine kinase concentration), perceptual fatigue, and neuromuscular fatigue (as measured via a counter movement jump) experienced by players (24). Although the degree of muscle damage sustained in competition was not a specific purpose of this study, it is possible that losing teams sustained greater muscle damage as a consequence of the physical dominance of winning teams. Further studies investigating the influence of winning and losing on markers of perceptual fatigue, muscle soreness, muscle damage, and neuromuscular fatigue are warranted.

In conclusion, this study investigated the influence of playing standard and winning and losing on the physical demands of elite rugby league match play. The results of this study demonstrate that the physical demands of rugby league are greater when winning than losing and when competing against lower ranked teams. Furthermore, larger winning margins are associated with greater physical demands than small and moderate winning margins, with these physical demands, in turn, greater than losing margins of any magnitude. These findings suggest that the competitive advantage of successful NRL teams is closely linked to their ability to maintain a higher playing intensity than their less successful counterparts.

Practical Applications

This study provides important information that can be applied by sport scientists and strength and conditioning coaches involved in the physical preparation of elite rugby league teams.

First, the physical demands (e.g., distance covered, maximal accelerations, and repeated high-intensity effort performance) of the winning teams were significantly greater than losing teams, and also greater than previously reported for professional rugby league players (14,25). These findings suggest that the physical conditioning programs designed to prepare players to compete in elite rugby league matches may differ from programs designed to win elite rugby league matches. It is likely that preparing players for the average demands of competition may result in players being under-prepared for the most demanding passages of play (14). Equally, given the differences in physical demands between winning and losing teams, preparing players for the average demands of competition may result in them being unable to perform the greater demands associated with winning matches.

Second, whereas repeated high-intensity effort activity (in the form of sprinting and tackling) has been shown to result in greater physiological stress and fatigue than repeated sprinting in isolation (16), this study also demonstrates the important contribution that this quality makes to competitive success. The use of game-specific repeated-effort conditioning that involves rapid accelerations, sprinting, and collisions, and short recovery periods, is likely to improve repeated high-intensity effort ability and ultimately competitive performances.

Third, winning teams were better able to maintain intensity in the recovery periods between high-speed running efforts. Whereas previous studies have shown that the use of active recovery between high-intensity training efforts results in reduced training performance than passive recovery (9), these findings suggest that conditioning coaches may benefit from manipulating the intensity of recovery in training. The use of high-intensity interval (e.g., maximal aerobic speed) training that involves a moderate-intensity recovery period between high-intensity efforts may condition players to maintain a higher pacing strategy during competition than if passive recovery alone was used between efforts.

Finally, player's perceptions of the competitive demands were greatest when competing against Top 4 teams and when winning by small margins and losing by large margins. From a practical perspective, these findings could be used by applied sport scientists and strength and conditioning staff to provide insight into subsequent physical conditioning and recovery practices. It is likely that after matches against higher ranked teams, players will experience greater perceptual fatigue, and therefore require greater recovery than when competing against lower ranked teams. Similarly, larger winning margins and smaller losing margins were associated with lower perceptions of effort, and presumably reduced perceptual fatigue. If adequate recovery time between matches is available, additional conditioning may be beneficial following these matches associated with lower psychological stress.

References

1. Andersson HA, Randers MB, Heiner-Moller A, Krustrup P, Mohr M. Elite female soccer players perform more high-intensity running when playing in international games compared with domestic league games. J Srength Cond Res 24: 912–919, 2010.
2. Aughey RJ. Australian football player work-rate: Evidence of fatigue and pacing? Int J Sports Physiol Perform 5: 394–405, 2010.
3. Austin D, Gabbett T, Jenkins D. Repeated high-intensity exercise in professional rugby league. J Strength Cond Res 25: 1898–1904, 2010.
4. Austin D, Gabbett T, Jenkins D. Tackling in professional rugby league. J Strength Cond Res 25: 1659–1663, 2011.
5. Bangsbo J, Norregaard L, Thorso F. Activity profile of competition soccer. Can J Sport Sci 16: 110–116, 1991.
6. Batterham AM, Hopkins WG. Making meaningful inferences about magnitudes. Int J Sports Physiol Perform 1: 50–57, 2006.
7. Cohen J. Statistical Power Analysis for the Behavioural Sciences (2nd ed.). New York, NY: Academic Press, 1988.
8. Di Salvo V, Gregson W, Atkinson G, Tordoff P, Drust B. Analysis of high intensity activity in Premier League soccer. Int J Sports Med 30: 205–212, 2009.
9. Dupont G, Moalla W, Guinhouya C, Ahmaidi S, Berthoin S. Effects of passive versus active recovery during high-intensity intermittent exercise. Med Sci Sports Exerc 36: 302–308, 2004.
10. Foster C, Florhaug JA, Franklin J, Gottschall L, Hrovatin LA, Parker S, Doleshal P, Dodge C. A new approach to monitoring exercise training. J Strength Cond Res 15: 109–115, 2001.
11. Gabbett T, Jenkins D, Abernethy B. Physical collisions and injury during professional rugby league skills training. J Sci Med Sport 13: 578–583, 2010.
12. Gabbett TJ. Activity cycles of National Rugby League and National Youth Competition matches. J Strength Cond Res 26: 1517–1523, 2012.
13. Gabbett TJ. Sprinting patterns of National Rugby League competition. J Strength Cond Res 26: 121–130, 2012.
14. Gabbett TJ, Jenkins DG, Abernethy B. Physical demands of professional rugby league training and competition using microtechnology. J Sci Med Sport 15: 80–86, 2012.
15. Gabbett TJ, 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.
16. Johnston R, Gabbett TJ. Repeated-sprint and effort ability in rugby league players. J Strength Cond Res 25: 2789–2795, 2011.
17. Meir R, Arthur D, Forrest M. Time motion analysis of professional rugby league: A case study. Strength Cond Coach 1: 24–29, 1993.
18. Mohr M, Krustrup P, Andersson H, Kirkendal D, Bangsbo J. Match activities of elite women soccer players at different performance levels. J Strength Cond Res 22: 341–349, 2008.
19. Petersen C, Pyne D, Portus M, Dawson B. Validity and reliability of GPS units to monitor cricket-specific movement patterns. Int J Sports Physiol Perform 4: 381–393, 2009.
20. Rampinini E, Coutts AJ, Castagna C, Sassi R, Impellizzeri FM. Variation in top level soccer match performance. Int J Sports Med 28: 1018–1024, 2007.
21. Rampinini E, Impellizzeri FM, Castagna C, Coutts AJ, Wisloff U. Technical performance during soccer matches of the Italian Serie A league: Effect of fatigue and competitive level. J Sci Med Sport 12: 227–233, 2009.
22. Sirotic AC, Coutts AJ, Knowles H, Catterick C. A comparison of match demands between elite and semi-elite rugby league competition. J Sports Sci 27: 203–211, 2009.
23. Sykes D, Twist C, Hall S, Nicholas C, Lamb K. Semi-automated time-motion analysis of senior elite rugby league. Int J Perform Anal Sport 9: 47–59, 2009.
24. Twist C, Waldron M, Highton J, Burt D, Daniels M. Neuromuscular, biochemical, and perceptual post-match fatigue in professional rugby league forwards and backs. J Sports Sci 30: 359–367, 2012.
25. Waldron M, Twist C, Highton J, Worsfold P, Daniels M. Movement and physiological match demands of elite rugby league using portable global positioning systems. J Sports Sci 29: 1223–1230, 2011.
Keywords:

playing standard; activity profiles; GPS; physical preparation

Copyright © 2013 by the National Strength & Conditioning Association.