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ABSTRACT: Gabbett, TJ, Sheppard, JM, Pritchard-Peschek, KR, Leveritt, MD, and Aldred, MJ. Influence of closed skill and open skill warm-ups on the performance of speed, change of direction speed, vertical jump, and reactive agility in team sports athletes. J Strength Cond Res 22(5): 1413-1415, 2008-In this study, we evaluated the efficacy of two different dynamic warm-up conditions, one that was inclusive of open skills (i.e., reactive movements) and one that included only preplanned dynamic activities (i.e., closed skills) on the performance of speed, change of direction speed, vertical jump, and reactive agility in team sport athletes. Fourteen (six male, eight female) junior (mean ± SD age, 16.3 ± 0.7 year) basketball players participated in this study. Testing was conducted on 2 separate days using a within-subjects cross-over study design. Each athlete performed a standardized 7-minute warm-up consisting of general dynamic movements and stretching. After the general warm-up, athletes were randomly allocated into one of two groups that performed a dynamic 15-minute warm-up consisting entirely of open or closed skills. Each of the warm-up conditions consisted of five activities of 3 minute duration. At the completion of the warm-up protocol, players completed assessments of reactive agility, speed (5-, 10-, and 20-m sprints), change of direction speed (T-test), and vertical jump. No significant differences (p > 0.05) were detected among warm-up conditions for speed, vertical jump, change of direction speed, and reactive agility performances. The results of this study demonstrate that either open skill or closed skill warm-ups can be used effectively for team sport athletes without compromising performance on open skill and closed skill tasks. Yes Yes
The Journal of Strength and Conditioning Research 05/2013; · 1.83 Impact Factor
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ABSTRACT: OBJECTIVES: The aim of this study was to assess the physiological responses to an intensified rugby league competition and explore the relationships between fatigue and match performance. DESIGN: Prospective cohort study. METHODS: Fifteen junior rugby league players (n=8 forwards, 7 backs; mean±SE, age 16.6±0.2 years; body mass 81.6±3.0kg; and height 178.9±1.8cm) competed in five 40min games over 5 days (two games each on days 1 and 2, one game on day 4, and no games on days 3 and 5). Over the competition, players performed a countermovement jump to assess neuromuscular fatigue, provided a fingertip blood sample to measure blood creatine kinase, and completed a questionnaire to monitor perceived wellbeing; ratings of perceived effort were recorded following each game. Global positioning system and video analysis of each game were used to assess match performance. RESULTS: Over the first 3 days, there were progressive and large increases in neuromuscular fatigue which peaked 12h after game 4 (forwards ES=4.45, p=0.014; backs ES=3.62, p=0.029), and muscle damage which peaked 1h post game 4 (forwards ES=4.45, p=0.004; backs ES=3.94 p=0.012), as well as reductions in perceived wellbeing. These measures gradually recovered over the final 2 days of the competition. Compared to the backs, the forwards experienced greater increases in creatine kinase following game 2 (ES=1.30) and game 4 (ES=1.24) and reductions in perceived wellbeing (ES=0.25-0.46). Match intensity, high-speed running, and repeated-high intensity effort bouts decreased in games 4 and 5 of the competition. Small to large associations were observed between the changes in fatigue, muscle damage and match performance, with significant correlations between creatine kinase and repeated high-intensity effort bout number (r=-0.70, p=0.031) and frequency (r=0.74, p=0.002) and low-speed activity (r=-0.56, p=0.029). CONCLUSIONS: Fatigue and muscle damage accumulate over an intensified competition, which is likely to contribute to reductions in high-intensity activities and work rates during competition.
Journal of science and medicine in sport / Sports Medicine Australia. 12/2012;
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ABSTRACT: Abstract We investigated the effect of increases in task complexity on the dual-task draw-and-pass performance of professional rugby league players. Moreover, we determined the relationship between dual-task draw-and-pass proficiency measured in isolation and draw-and-pass performances as they occurred in actual competitive matches. In Study 1, 12 rugby league players performed 2-on-1 and 3-on-2 attacking drills under single (primary skill) and dual-task (primary skill performed in conjunction with secondary-task) conditions. Reductions in draw-and-pass performance occurred when task complexity was increased from the 2-on-1 to the 3-on-2 situation. In Study 2, 58 rugby league players undertook the dual-task draw-and-pass assessment. Players then competed in National Rugby League matches with video footage coded for the number of tries scored and the activities that led to the try. A total of 303 tries were scored with 150 (49.5%) tries scored from a draw-and-pass situation. Significant associations were detected between 2-on-1 dual-task draw-and-pass performance in the isolated test condition and draw-and-pass performances in competition. These studies provide evidence of (i) the greater attentional demands of the skill of drawing-and-passing in elite team sport athletes when more players are involved and (ii) the practical utility of off-field dual-task testing in supplying information predictive of skills performance in competition.
Journal of Sports Sciences 08/2012; · 1.93 Impact Factor
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ABSTRACT: BACKGROUND: Injuries are often recurrent, with subsequent injuries influenced by previous occurrences and hence correlation between events needs to be taken into account when analysing such data. OBJECTIVE: This paper compares five different survival models (Cox proportional hazards (CoxPH) model and the following generalisations to recurrent event data: Andersen-Gill (A-G), frailty, Wei-Lin-Weissfeld total time (WLW-TT) marginal, Prentice-Williams-Peterson gap time (PWP-GT) conditional models) for the analysis of recurrent injury data. METHODS: Empirical evaluation and comparison of different models were performed using model selection criteria and goodness-of-fit statistics. Simulation studies assessed the size and power of each model fit. RESULTS: The modelling approach is demonstrated through direct application to Australian National Rugby League recurrent injury data collected over the 2008 playing season. Of the 35 players analysed, 14 (40%) players had more than 1 injury and 47 contact injuries were sustained over 29 matches. The CoxPH model provided the poorest fit to the recurrent sports injury data. The fit was improved with the A-G and frailty models, compared to WLW-TT and PWP-GT models. CONCLUSIONS: Despite little difference in model fit between the A-G and frailty models, in the interest of fewer statistical assumptions it is recommended that, where relevant, future studies involving modelling of recurrent sports injury data use the frailty model in preference to the CoxPH model or its other generalisations. The paper provides a rationale for future statistical modelling approaches for recurrent sports injury.
British journal of sports medicine 08/2012; · 2.55 Impact Factor
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ABSTRACT: Abstract We investigated the relationship between skill qualities and contact injury risk in professional rugby league players. Sixty-six professional rugby league players aged 23 ± 4 years (mean ± s) participated in this three-year prospective study. Players underwent assessments of tackling proficiency, dual-task draw-and-pass proficiency, reactive agility, pattern recall, and pattern prediction. The frailty model was applied to calculate the adjusted risk ratios of injury. When the players' age and playing position were adjusted in the frailty model, the risk ratios showed that reactive agility was a predictor for the risk of injury. Players with reactive agility decision times of >80 ms had a lower incidence (relative risk = 0.68, 95% CI 0.47-0.98, P = 0.04) of injuries than players with reactive agility decision times of ≤80 ms. Although there was no relationship between injury and the majority of skill qualities (P = 0.47-0.93), players with poor reactive agility performances (specifically longer decision times) had a lower risk of injury, suggesting that poor perceptual skill is protective against contact injuries in professional rugby league players. These players might inadvertently avoid the heavy collisions that result in injury, or at best result in partial contact that does not result in exposure to the full force of a tackle.
Journal of Sports Sciences 07/2012; 30(13):1421-7. · 1.93 Impact Factor
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ABSTRACT: Well-developed physical qualities may protect against contact injuries. However, the potential contribution of physical qualities as risk or protective factors to contact injury risk is yet to be determined for rugby league. This study applied a frailty survival model that accounts for recurrent injury to identify risk factors for all physiotherapist-reported contact injury in professional rugby league players.
Prospective cohort study.
Sixty-six professional rugby league players participated in this three successive year prospective study. At the start of each season, all players underwent measurements of standard anthropometry (height, body mass, and sum of seven skinfolds), speed (10m and 40m sprint), muscular strength (1 repetition maximum [RM] bench press, 1RM squat, 1RM weighted chin-ups), power (vertical jump, bench throw, 1RM power clean, jump squat), and endurance (maximum repetition bench press with 60kg resistance), repeated-sprint ability (12×20m sprints performed on a 20s cycle), prolonged high-intensity intermittent running ability (8×12s maximal effort shuttles performed on a 48s cycle), and maximal aerobic power (multi-stage fitness test). Data was used to demonstrate the application of the frailty model extension of the Cox proportional regression model for recurrent events to identify factors associated with a high hazard ratio (HR) of injury.
Heavier (body mass, HR=2.6, 95% CI=1.2-5.7), and faster (40m sprint, HR=2.1, 95% CI=1.0-4.2) players, and those with poorly developed prolonged high-intensity intermittent running ability (HR=2.9, 95% CI=1.7-5.0) and upper-body strength (chin-up, HR=2.2, 95% CI=1.3-3.7) had a higher incidence of contact injuries.
This study demonstrates application of a novel statistical approach for the analysis of injury data that is recurrent in nature. This approach identified that the greater impact forces generated from heavier players with faster speed may result in an increase in recurrent contact injury rates. However, the development of prolonged high-intensity intermittent running ability and upper-body strength and power may assist to reduce the risk of contact injury in professional rugby league players.
Journal of science and medicine in sport / Sports Medicine Australia. 06/2012; 15(6):496-504.
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ABSTRACT: The purpose of the present study was to examine the reliability and sensitivity of three ecologically valid repeated high intensity exercise (RHIE) tests for professional rugby league and rugby union players. A further purpose was to investigate the relationship between RHIE performance and measures of speed (20m sprint) and high-intensity intermittent running ability (yo-yo intermittent recovery test). Thirty six rugby union and rugby league players were separated into three equal groups based on playing position: backs, rugby league (RL) forwards and rugby union (RU) forwards. Test-retest reliability was assessed by comparing total sprint time over nine sprints during two identical testing sessions. The intra-class correlation coefficients (ICC) for total sprint time were moderate to high (0.82, 0.97 and 0.94) and coefficient of variation (CV) low (4.2%, 1.4%, and 0.6%) for the backs, RL forwards and RU forwards tests, respectively. However, sprint performance decrement scores were poorer, with ICC and CV of 0.78, 0.86 and 0.88 and 49.5%, 48.2%, and 35.8% for the backs, RL forwards and RU forwards, respectively. Total sprint times for the backs, RL forwards, and RU forwards decreased over the three tests by 0.54 s, 0.53 s and 2.09 s respectively. Changes in RHIE total sprint time were moderately related to changes in 20 m sprint times (T1 to T2; r = 0.63, T2 to T3; r = 0.69 and T1 to T3; r = 0.63; all p < 0.05), but not yo-yo intermittent recovery test performances. The present study has shown that the designed rugby league and rugby union RHIE tests have moderate to high reliability and produce significant improvements over a training period when total sprint times are compared.
The Journal of Strength and Conditioning Research 05/2012; · 1.83 Impact Factor
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ABSTRACT: The purpose of this study was to investigate the effect of changes in field size on the physiological and skill demands of small-sided games in elite junior and senior rugby league players. Sixteen elite senior rugby league players ([mean ± SE] age, 23.6 ± 0.5 years) and 16 elite junior rugby league players ([mean ± SE] age, 17.3 ± 0.3 years) participated in this study. On day 1, 2 teams played an 8-minute small-sided game on a small field (10-m width × 40-m length), whereas the remaining 2 teams played the small-sided game on a larger sized field (40-m width × 70-m length). On day 2, the groups were crossed over. Movement was recorded by a global positioning system unit sampling at 5 Hz. Games were filmed to count the number of possessions and the number and quality of disposals. The games played on a larger field resulted in a greater (p < 0.05) total distance covered, and distances covered in moderate, high, and very-high velocity movement intensities. Senior players covered more distance at moderate, high, and very-high intensities, and less distance at low and very-low intensities during small-sided games than junior players. Although increasing field size had no significant influence (p > 0.05) over the duration of recovery periods for junior players, larger field size significantly reduced (p < 0.05) the amount of short-, moderate-, and long-duration recovery periods in senior players. No significant between-group differences (p > 0.05) were detected for games played on a small or large field for the number or quality of skill involvements. These results suggest that increases in field size serve to increase the physiological demands of small-sided games but have minimal influence over the volume or quality of skill executions in elite rugby league players.
The Journal of Strength and Conditioning Research 02/2012; 26(2):487-91. · 1.83 Impact Factor
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ABSTRACT: This study investigated the influence of wrestling on the physiological and skill demands of small-sided games. Twenty-eight elite rugby league players ([mean ± SE] age, 21.6 ± 0.5 years) participated in this within-subject crossover study. On day 1, 14 players played 2, 8-minute small-sided games, whereas the remaining 14 players played identical games with intermittent wrestling throughout. Each game was separated by 90 seconds. On day 2, the groups were crossed over. Movement was recorded by a global positioning system unit (miniMaxX, Catapult Innovations, Melbourne, Australia), sampling at 5 Hz. Each small-sided game was filmed to track the number of possessions and the number and quality of disposals. The games without wrestling resulted in a greater (p < 0.05) total distance covered (2,475 ± 31 vs. 1,964 ± 27 m) and greater distance covered in low (930 ± 19 vs. 842 ± 19 m), moderate (1,120 ± 28 vs. 752 ± 26 m), high (332 ± 16 vs. 240 ± 12 m), and very-high (24 ± 4 vs. 15 ± 3 m) velocity movement intensities. Conversely, the games with wrestling resulted in a significantly greater (p < 0.05) distance covered in mild, moderate, and maximal accelerations and a greater number of repeated high-intensity effort bouts (2.1 ± 0.2 bouts vs. 0.2 ± 0.1 bouts). No significant differences (p > 0.05) were detected between games with and without wrestling for the total number of involvements, receives, passes, effective passes, ineffective passes, and disposal efficiency. The results of this study demonstrate that intermittent wrestling reduces the running demands but increases the repeated high-intensity effort demands of small-side games. Furthermore, these physiological changes occur without compromising the volume of skill executions, the number of errors, or disposal efficiency. From a practical perspective, these results suggest that intermittent wrestling may be a useful supplement to small-sided games to concurrently train repeated-effort ability and skills under game-specific fatigue.
The Journal of Strength and Conditioning Research 01/2012; 26(1):113-20. · 1.83 Impact Factor
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Tim J Gabbett
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ABSTRACT: The purpose of this study was to investigate the sprinting demands of National Rugby League (NRL) competition and characterize the sprinting patterns of different rugby league playing positions. Thirty-seven elite rugby league players (mean ± SE age: 23.6 ± 0.5 years) underwent global positioning satellite analysis during 104 NRL appearances. The majority (67.5%) of sprint efforts were across distances of <20 m. The most common sprint distance for hit-up forwards was 6-10 m (46.3%). Outside backs had a greater proportion (33.7%) of sprint efforts over distances of ≥21 m. The proportion of sprint efforts over 40 m or greater for hit-up forwards, wide running forwards, adjustables, and outside backs was 5.0, 7.4, 5.0, and 9.7%, respectively. Of the sprints performed, approximately 48.0% involved contact, approximately 58.0% were preceded by forward locomotion (forward walking, jogging, or striding), whereas over 24.0% occurred from a standing start. Hit-up forwards more commonly sprinted from a standing start, or after lateral movement, whereas forward striding activities more commonly preceded sprint efforts for the adjustables and outside backs. The majority of sprint efforts were performed without the ball (78.7 vs. 21.3%). Most sprint efforts (67.5%) were followed by a long recovery (i.e., ≥5 minutes). Outside backs had the greatest proportion (76.1%) of long duration recovery periods and the smallest proportion (1.8%) of short duration recovery periods (i.e., <60 seconds) between sprints. The results of this study demonstrate differences among rugby league playing positions for the nature of sprint efforts and the typical distances covered during these efforts. Furthermore, the activities preceding and the recovery periods after sprint efforts were different among playing positions. These findings suggest that rugby league sprint training should be tailored to meet the individual demands of specific playing positions.
The Journal of Strength and Conditioning Research 12/2011; 26(1):121-30. · 1.83 Impact Factor
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ABSTRACT: In this study, we investigated the relationship between physiological, anthropometric, and skill qualities and playing performance in professional rugby league players. Fifty-eight high-performance rugby league players underwent measurements for anthropometry (height, body mass, sum of seven skinfolds), physiological (speed, change of direction speed, lower body muscular power, repeated-sprint ability, prolonged high-intensity intermittent running ability, and estimated maximal aerobic power), technical skill (tackling proficiency, draw and pass proficiency), and perceptual skill (reactive agility, pattern recall, pattern prediction) qualities. National Rugby League matches were coded for attacking (e.g. line breaks, try assists, etc.) and defensive (e.g. missed tackles, tackling efficiency, etc.) statistics commonly used to assess rugby league playing performance. The number of line break assists was significantly associated (P < 0.05) with greater playing experience (r = 0.36), dual-task draw and pass proficiency (r = 0.54), reactive agility (r = 0.29), and pattern recall (r = 0.32) and prediction (r = 0.28) ability, while faster speed over 40 m (r = -0.42) was associated (P < 0.05) with a higher number of tries scored. Greater age and playing experience, better lower body muscular power, and faster 10 m and 40 m speed were significantly associated (P < 0.05) with the number of tackle attempts (positive), tackles completed (positive), and proportion of missed tackles (negative). These findings demonstrate that well-developed physical and skill qualities are associated with effective playing performance in National Rugby League players.
Journal of Sports Sciences 11/2011; 29(15):1655-64. · 1.93 Impact Factor
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Tim J Gabbett
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ABSTRACT: Examination of ball-in-play periods (i.e., match activity cycles) is a method used to provide insight into the physical demands of team sport competition. However, to date, no study has investigated the ball-in-play time of rugby league matches. This study investigated the activity cycles (i.e., ball-in-play periods) of elite National Rugby League (NRL) and National Youth Competition (NYC) matches. Video recordings of 393 NRL matches and 388 NYC matches were coded for activity and recovery cycles. Time when the ball was continuously in play was considered activity, whereas any stoppages during the match (e.g., for scrums, penalties, line drop-outs, tries, and video referee decisions) were considered recovery. The total time the ball was in play for NRL and NYC matches was approximately 55 minutes and 50 minutes, respectively. In comparison with NYC matches, NRL matches had longer average activity cycles (81.2 ± 16.1 vs. 72.0 ± 14.7 seconds, effect size [ES] = 0.60). The average longest activity cycle was also higher (ES = 0.48) in NRL (318.3 ± 65.4 seconds) than in NYC (288.9 ± 57.5 seconds) matches. The longest activity cycle from any match was 667 and 701 seconds for NRL and NYC matches, respectively. The NRL matches had a smaller proportion of short duration (<45 seconds) activity cycles and a greater proportion of longer duration (>91-600 seconds) activity cycles. In conclusion, meaningful differences in activity cycles were observed between NRL and NYC matches, with NRL competition demonstrating longer ball-in-play periods, a smaller proportion of short duration activity cycles, and a larger proportion of longer duration activity cycles. These findings suggest that the ability to perform prolonged high-intensity exercise, coupled with the capacity to recover during brief stoppages in play, is a critical requirement of professional rugby league match play.
The Journal of Strength and Conditioning Research 09/2011; 26(6):1517-23. · 1.83 Impact Factor
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ABSTRACT: The aim of this study was to (a) investigate the influence of tackling on repeated-sprint performance; (b) determine whether repeated-sprint ability (RSA) and repeated-effort ability (REA) are 2 distinct qualities; and (c) assess the test-retest reliability of repeated-sprint and repeated-effort tests in rugby league. Twelve rugby league players performed a repeated-sprint (12 × 20-m sprints performed on a 20-second cycle) and a repeated-effort (12 × 20-m sprints with intermittent tackling, performed on a 20-second cycle) test 7 days apart. The test-retest reliability of these tests was also established. Heart rate and rating of perceived exertion were recorded throughout the tests. There was a significantly greater (p ≤ 0.05) and large effect size (ES) differences for total sprint time (ES = 1.19), average heart rate (ES = 1.64), peak heart rate (ES = 1.35), and perceived exertion (ES = 3.39) for the repeated-effort test compared with the repeated-sprint test. A large difference (ES = 1.02, p = 0.06) was detected for percentage decrement between the 2 tests. No significant relationship was found between the repeated-sprint and repeated-effort tests for any of the dependent variables. Both tests proved reliable, with total sprint time being the most reliable method of assessing performance. This study demonstrates that the addition of tackling significantly increases the physiological response to repeated-sprint exercise and reduces repeated-sprint performance in rugby league players. Furthermore, RSA and REA appear to be 2 distinct qualities that can be reliably assessed with total time being the most reliable measure of performance.
The Journal of Strength and Conditioning Research 09/2011; 25(10):2789-95. · 1.83 Impact Factor
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ABSTRACT: This study investigated the relative importance of physiological, anthropometric, and skill qualities to team selection in professional rugby league. Eighty-six high performance rugby league players underwent measurements of anthropometric (height, body mass, sum of seven skinfolds), physiological (speed, change of direction speed, lower body muscular power, repeated-sprint ability, prolonged high-intensity intermittent running ability, and maximal aerobic power), technical skill (tackling proficiency, draw and pass proficiency), and perceptual skill (reactive agility, pattern recall, pattern prediction) qualities. A linear discriminant analysis was also conducted comparing those players successful in gaining selection into the professional National Rugby League team with those not selected to determine which, if any, of these qualities could predict selection. Players selected to play in the first National Rugby League game of the season were older, more experienced, leaner, had faster 10 m and 40 m sprint times, and superior vertical jump performances, maximal aerobic power, tackling proficiency and dual-task draw and pass ability than non-selected players. Skinfold thickness and dual-task draw and pass proficiency were the only variables that contributed significantly (P < 0.05) to the discriminant analysis of selected and non-selected players. These findings suggest that selected physiological, anthropometric, and skill qualities may influence team selection in professional rugby league.
Journal of Sports Sciences 08/2011; 29(13):1453-61. · 1.93 Impact Factor
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ABSTRACT: To investigate the physical demands of professional rugby league match-play using microtechnology, and to compare these demands with typical training activities used to prepare players for competition.
Prospective cohort study.
Thirty elite rugby league players participated in this study. Seven hundred and eighty-six. training data sets and 104 data sets from National Rugby League matches were collected over one playing season. Movement was recorded using a commercially available microtechnology unit (minimaxX, Catapult Innovations), which provided information on speeds, distances, accelerations, physical collisions and repeated high-intensity efforts.
Mean distances covered during match-play by the hit-up forwards, wide-running forwards, adjustables, and outside backs were 3,569 m, 5,561 m, 6,411 m, and 6,819 m, respectively. Hit-up forwards and wide-running forwards were engaged in a greater number of moderate and heavy collisions than the adjustables and outside backs, and more repeated high-intensity effort bouts per minute of play (1 bout every 4.8-6.3 min). The physical demands of traditional conditioning, repeated high-intensity effort exercise, and skill training activities were all lower than the physical demands of competition.
These results demonstrate that absolute distances covered during professional rugby league matches are greater for outside backs, while the collision and repeated high-intensity effort demands are higher for hit-up forwards and wide-running forwards. The specific physical demands of competitive play, especially those demands associated with collisions and repeated high-intensity efforts, were not well matched by those observed in traditional conditioning, repeated high-intensity effort exercise, and skills training activities. Further research is required to investigate whether modifications need to be made to these training activities to better prepare players for the demands of National Rugby League competition.
Journal of science and medicine in sport / Sports Medicine Australia. 08/2011; 15(1):80-6.
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ABSTRACT: The primary aim of this study was to identify and describe the frequency and duration of repeated high-intensity exercise (RHIE) bouts in Australian professional rugby league (National Rugby League) and whether these occurred at critical times during a game. Time motion analysis was used during 5 competition matches; 1 player from 3 positional groups (hit-up forward, adjustable, and outside back) was analyzed in each match. The ranges of RHIE bouts for the 3 positional groups were hit-up forwards 9-17, adjustables 2-8, and outside backs 3-7. Hit-up forwards were involved in a significantly greater number of RHIE bouts (p < 0.05) and had the shortest average recovery (376 ± 205 seconds) between RHIE bouts. The single overall maximum durations of RHIE bouts for the hit-up forwards, the adjustables, and the outside backs were 64, 64, and 49 seconds. For all groups, 70% of the total RHIE bouts occurred within 5 minutes prior of a try being scored. The present data show that the nature of RHIE bouts was specific to playing position and occurred frequently at critical times during the game. These results can be used to develop training programs that mimic the 'worst case scenarios' that elite rugby league players are likely to encounter.
The Journal of Strength and Conditioning Research 07/2011; 25(7):1898-904. · 1.83 Impact Factor
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ABSTRACT: To document the frequency of physical collisions and incidence of contact injury in professional rugby league match-play.
Prospective cohort study.
Video recordings of 77 National Rugby League (NRL) matches were coded for the number and type of physical collisions in which players were involved. Each match was analysed and coded for defensive (i.e. tackles, missed tackles, and ineffective tackles) and attacking collisions (i.e. tackled in possession, broken tackles, offloads, support runs, and decoy runs). Injuries that occurred as a result of a physical collision were also recorded.
The total number of physical collisions performed per game was greatest in the wide running forwards (47 [95% CI, 42-52]), and was significantly greater (P<0.05) than the hit-up forwards (36 [95% CI, 32-40]), adjustables (29 [95% CI, 26-32]), and outside backs (24 [95% CI, 22-27]) positional groups. A total of 48 collision injuries were sustained, resulting in an overall injury incidence of 10.6 (95% CI, 7.6-13.6) per 10,000 collisions. Injuries resulting from attacking collisions were consistently higher than injuries sustained in defensive collisions. Wide running forwards had the lowest incidence of injury, and the adjustables and outside backs had the highest incidence of injury.
These results highlight the physical demands associated with collisions and tackles in professional rugby league. Furthermore, the results of this study suggest that playing position and the type of collision sustained have a greater influence over contact injury risk in rugby league than the number of physical collisions performed.
Journal of science and medicine in sport / Sports Medicine Australia. 02/2011; 14(3):210-5.
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ABSTRACT: This study investigated the tackling ability of high-performance rugby league players and determined the relationship between physiological and anthropometric qualities and tackling ability in these athletes. Twenty professional (National Rugby League) and 17 semiprofessional (Queensland Cup) rugby league players underwent a standardized 1-on-1 tackling drill in a 10-m grid. Video footage was taken from the rear, side, and front of the defending player. Tackling proficiency was assessed using standardized technical criteria. In addition, all players underwent measurements of standard anthropometry (height, body mass, and sum of 7 skinfolds), acceleration (10-m sprint), change of direction speed (505 test), and lower body muscular power (vertical jump). Professional players had significantly greater (p ≤ 0.05) tackling proficiency than semiprofessional players (87.5 ± 2.0 vs. 75.0 ± 2.3%). Professional players were significantly (p ≤ 0.05) older, more experienced, leaner, and had greater acceleration than semiprofessional players. The strongest individual correlates of tackling ability were age (r = 0.41, p ≤ 0.05), playing experience (r = 0.70, p ≤ 0.01), skinfold thickness (r = -0.59, p ≤ 0.01), acceleration (r = 0.41, p ≤ 0.05), and lower body muscular power (r = 0.38, p ≤ 0.05). When hierarchical multiple regression analysis was performed to determine which of the variables predicted tackling ability, playing experience and lower body muscular power were the only variables that contributed significantly (r2 = 0.60, p ≤ 0.01) to the predictive model. From a practical perspective, strength and conditioning coaches should emphasize the development of acceleration, lower body muscular power, and lean muscle mass to improve tackling ability in high-performance rugby league players.
The Journal of Strength and Conditioning Research 01/2011; 25(1):72-9. · 1.83 Impact Factor
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ABSTRACT: To investigate the relationship between training load and injury in professional rugby league players;
Prospective cohort study;
Seventy-nine professional rugby league players (mean±SD age, 23.3±3.8 years) participated in this four-year study. A periodized field, strength, and power training program was implemented, with training loads progressively increased in the general preparatory phase of the season and reduced during the competitive phase of the season. Training loads and injuries were recorded for each training session.
Training load was significantly related (P<0.05) to overall injury (r=0.82), non-contact field injury (r=0.82), and contact field injury (r=0.80) rates. Significant relationships were also observed between the field training load and overall field injury (r=0.68), non-contact field injury (r=0.65), and contact field injury (r=0.63) rates. Strength and power training loads were significantly related to the incidence of strength and power injuries (r=0.63). There was no significant relationship between field training loads and the incidence of strength and power injuries. However, strength and power training loads were significantly (P<0.01) associated with the incidence of contact (r=0.75) and non-contact (r=0.82) field training injuries.
These findings suggest that the harder rugby league players train, the more injuries they will sustain, and that high strength and power training loads may contribute indirectly to field injuries. Monitoring of training loads and careful scheduling of field and gymnasium sessions to avoid residual fatigue is warranted to minimize the effect of training-related injuries on professional rugby league players.
Journal of science and medicine in sport / Sports Medicine Australia. 01/2011; 14(3):204-9.
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ABSTRACT: 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.
The Journal of Strength and Conditioning Research 10/2010; 24(11):2979-83. · 1.83 Impact Factor
