The author is with the School of Exercise Science, Australian Catholic. University, Brisbane .... in rugby league is the technical and tactical performance of teams.
International Journal of Sports Physiology and Performance, 2014, 9, 680-688 http://dx.doi.org/10.1123/IJSPP.2013-0253 © 2014 Human Kinetics, Inc.
www.IJSPP-Journal.com ORIGINAL INVESTIGATION
Effects of Physical, Technical, and Tactical Factors on Final Ladder Position in Semiprofessional Rugby League Tim J. Gabbett Purpose: A limitation of most rugby league time–motion studies is that researchers have examined the demands of single teams, with no investigations of all teams in an entire competition. This study investigated the activity profiles and technical and tactical performances of successful and less-successful teams throughout an entire rugby league competition. Methods: In total, 185 rugby league players representing 11 teams from a semiprofessional competition participated in this study. Global positioning system analysis was completed across the entire season. Video footage from individual matches was also coded via notational analysis for technical and tactical performance of teams. Results: Trivial to small differences were found among Top 4, Middle 4, and Bottom 4 teams for absolute and relative total distances covered and distances covered at low speeds. Small, nonsignificant differences (P = .054, ES = 0.31) were found between groups for the distance covered sprinting, with Top 4 teams covering greater sprinting distances than Bottom 4 teams. Top 4 teams made more meters in attack and conceded fewer meters in defense than Bottom 4 teams. Bottom 4 teams had a greater percentage of slow play-the-balls in defense than Top 4 teams (74.8% ± 7.3% vs 67.2% ± 8.3%). Middle 4 teams showed the greatest reduction in high-speed running from the first to the second half (–20.4%), while Bottom 4 teams completed 14.3% more high-speed running in the second half than in the first half. Conclusion: These findings demonstrate that a combination of activity profiles and technical and tactical performance are associated with playing success in semiprofessional rugby league players. Keywords: time–motion analysis, repeated effort, physical demands, training, team sports Since the early soccer time–motion analysis studies,1 sport scientists have attempted to understand the physical demands and movement patterns of high-intensity, intermittent team sports (eg, hockey, Australian football, rugby league). In general, these team sports consist of short bursts of high-intensity activity (eg, striding and sprinting) separated by bouts of low-intensity activity (eg, standing, walking, jogging).2–4 Mohr et al2 first demonstrated that elite-level soccer players covered greater distances and performed more high-intensity running than their subelite counterparts. These findings have been confirmed in studies from a wide range of sports including women’s soccer,4–6 women’s hockey,7 Australian football,3 and rugby league.8–10 Recently, researchers have also studied the physical demands of entire soccer competitions,11 investigating the influence of ladder position on the physical and technical demands of soccer match play.12,13 Rampinini et al13 reported that the Top 5 teams from the Italian-Serie A league performed a greater number of technical actions and more high-intensity running while in possession of the ball than the Bottom 5 teams. However, Bottom 5 teams performed more high-intensity running without the ball. In a subsequent study, Di Salvo et al12 showed that Bottom 4 and Middle 4 teams covered greater distances at high speeds than Top 4 teams. Others have studied the playing performance of a single team over a 3-year period and shown reductions in the distances covered at intermediate intensities (low, moderate, and high-intensity running), despite improving ball possession and the number of points won.14 Those authors suggested that technical and tactical effectiveness was more important than high levels of physical performance in deterThe author is with the School of Exercise Science, Australian Catholic University, Brisbane, Australia. Address correspondence to tim_gabbett@ yahoo.com.au. 680
mining success in soccer.12 Similar findings have been reported from studies of the English Premier and Championship soccer leagues.15 Championship League players covered total match distance (11.1 ± 0.9 km) similar to that of Premiership players (10.8 ± 1.0 km). Championship players also covered greater distances during jogging, running, high-speed running, and sprinting. These findings suggest that factors in addition to, or other than, physical activity profiles may explain the superiority of Premiership players over Championship players in soccer. Although rugby league requires competitors to perform highintensity running, unlike most other high-intensity intermittent team sports (such as soccer and hockey) the physical demands are increased through the large amounts of tackling, wrestling, and grappling that players are required to perform during match play. While several researchers have investigated the physical demands of rugby league match play,16–18 few studies have documented the influence of different playing levels on these physical demands. Sirotic et al10 compared the physical and technical demands of rugby league players competing at elite and semielite levels. The mean playing intensity and number of support runs in elite match play were significantly greater than in semielite match play. Similar findings have been reported8 when comparing the physical demands of senior National Rugby League (NRL) and junior elite National Youth Competition (NYC) matches with and NRL fixture and trial matches; higher playing standards were associated with greater physical demands. In the only study to investigate the influence of winning and losing on the physical demands of rugby league matches, higher match intensity was reported in winning teams.9 While no differences were found between winning and losing teams for distances covered in high-speed running, winning teams covered greater distances at low speeds. Although these studies have enhanced our understanding of the demands of rugby league
Rugby League Performance Analysis 681
match play, a consistent limitation associated with most rugby league time–motion studies is that researchers have studied the demands of single teams, with no investigations of all teams in an entire competition. A separate but equally important question governing success in rugby league is the technical and tactical performance of teams. Anecdotally, ball possession and field position, along with effective defensive performances (eg, controlling play-the-ball speed), are widely acknowledged as important determinants of rugby league competition success.8,19,20 While global positioning system (GPS) technology can provide sport scientists and coaches with information on the physical demands of match play, including the numbers of collisions and repeated high-intensity-effort bouts, information on the technical and tactical performance of teams requires notational analysis from video footage. Combining game-specific GPS information with key team performance indicators would allow coaches to determine whether the exercise performed in competition results in efficient team outcomes. To date, no study has concurrently assessed the physical demands of rugby league match play and analyzed the technical and tactical performance of successful and less-successful teams throughout an entire competition. With this in mind, the purpose of this study was to investigate the physical demands and technical and tactical performance of rugby league teams and determine which, if any, variables discriminated successful from less-successful teams in semiprofessional rugby league match play.
Methods Subjects At the beginning of the 2012 rugby league season, the 12 teams competing in the Queensland Cup rugby league competition were invited to participate in a study of the physical demands of semiprofessional rugby league. All teams but 1 agreed to participate in the study. The final sample included 185 male rugby league players (mean age 24.3 ± 3.3 y) from the remaining 11 teams competing in the competition. 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.
Procedures GPS analysis was completed during 26 matches (totaling 386 appearances). The total number of fixture matches played over the course of the season was 132. The 26 analyzed matches represented 20% of the total matches played across the season. Each team was studied on a minimum of 3 occasions, with data obtained from matches played early (first 8 competition rounds), midway (second 8 competition rounds), and toward the end (final 8 competition rounds) of the season. Up to 34 players (17 players from each team) wore a GPS unit during any given match. The mean ± SD number of GPS files collected from each team in each match was 9 ± 3 (range 4–17). GPS units were assigned to players from each of 4 positional groups (hit-up forwards, wide-running forwards, adjustables, and outside backs),21 and the same positions were also chosen for the opposition team. The positional distribution of samples from Top 4, Middle 4, and Bottom 4 teams is shown in Table 1. Movement was recorded by a minimaxX GPS unit (Catapult Innovations, Melbourne, Australia) sampling at 10 Hz. The GPS signal provided information on speed, distance, position, and accel-
Table 1 Positional Distribution of Samples From Top 4, Middle 4, and Bottom 4 Teams, Mean ± SD Hit-up forwards
Wide-Running forwards
Adjustables
Outside backs
Top 4
2±2
2±1
3±1
2±1
Middle 4
1±1
2±1
3±1
2±1
Bottom 4
2±1
3±2
3±2
2±2
eration. It 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 player’s upper back. Data were categorized into (1) low (0–5 m/s) and high (>5 m/s) movement-speed bands,22 (2) collisions, and (3) repeated high-intensity-effort bouts. A repeated high-intensity-effort bout was defined as 3 or more high-acceleration (≥2.79 m/s2),23 highspeed, or contact efforts with less than 21 seconds recovery between efforts.21 The 10-Hz minimaxX units have been shown to have acceptable validity and reliability for measuring high-speed (bias = –0.2%, coefficient of variation = 2.0%) and acceleration (bias = –2.1%, coefficient of variation = 1.9%) efforts.24 In addition, the minimaxX units have been shown to offer a valid measurement of the collisions that commonly occur in rugby league, with the standard error of the estimate between collisions recorded by the minimaxX units and those coded from video recordings of the actual collision events reported to be 4.7%.19 The intraclass correlation coefficient for test–retest reliability and coefficient of variation for the detection of collisions were .95 and 3.0%, respectively. Finally, the validity of the minimaxX units to quantify repeated high-intensity-effort bouts was determined by having players perform 2 to 4 bouts of 6 tackles, with each tackle separated by ~10 seconds of low-intensity activity. The standard error of the estimate between repeated highintensity efforts recorded by the minimaxX units and those coded from video recordings of the actual repeated high-intensity-effort bouts was 5.6%. All matches were filmed from an elevated position on the halfway line. Video footage from matches was coded via notational analysis for the teams’ technical and tactical performance. Both attacking and defensive performances were coded. A single experienced coder analyzed the technical performances of all matches. The coder had >10 years of experience analyzing the technical performances of rugby league teams. Video footage was coded using the Rugby League Analyzer (Fair Play Pty Ltd, Queensland, Australia) performance-analysis software. Matches were coded for meters gained and the total number of sets each team had possession of the ball, including the number of sets in poor (“coming-out sets,” defined as sets that started inside the attacking teams’ 30-m zone) and good (“going-in sets,” defined as sets that started outside the attacking teams’ 30-m zone) field position. Total errors while in possession of the ball were also recorded. Defensive performance statistics included the number of times teams were able to force the opposition to start their set inside the 10-m zone and restrict the opposition to kick from within their 40-m zone. All tackles were analyzed for play-the-ball speed. The tackle was defined as the period from when defenders first gained control of the ball carrier (including the ball) until the moment the ball carrier stood and placed his foot on the ball. A play-the-ball >4 seconds in duration was considered a slow play-the-ball. Each half of 10 matches was analyzed twice, at least 1 month apart, to assess intraobserver reliability. In addition, 10 matches
682 Gabbett
were analyzed by a second experienced coder (>5 y of experience analyzing the technical performances of rugby league teams) to assess interobserver reliability. The intraobserver and interobserver reliability, expressed as a coefficient of variation, for the coding of attacking and defensive performances (including play-the-ball speed) were 4 s to complete the tackle and play the ball. Fast play-the-ball: tackle completed and play-the-ball performed in
