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Activity Cycles of National Rugby League and National Youth Competition Matches
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.
... high-speed running and sprinting) separated by short bouts of lower-intensity activities (e.g. standing, walking and jogging) [1][2][3][4][5][6][7][8]. In addition to the numerous bouts of high-speed running, players also frequently engage in physically demanding collisions and wrestling bouts [9][10][11]. ...
... While this study provides some information on the most demanding 5 min periods of play in adjustables, only using 5 min periods may not capture, and therefore underestimate, the most demanding passages of play. Indeed, the longest time the ball is in play for in NRL and NYC matches has been reported as over 11 min [1]. The average longest activity cycle is greater in the NRL (318.3 ± 65.4 s vs. 288.9 ...
... The average longest activity cycle is greater in the NRL (318.3 ± 65.4 s vs. 288.9 ± 57.5 s) and there is a smaller proportion of shortduration activity cycles (\45 s) than longer activity cycles ([91-600 s) than in NYC matches [1]. Furthermore, Top 4 NRL teams have a greater proportion of long activity cycles than Bottom 4 NRL teams [48]. ...
Rugby league is a team sport in which players engage in repeated high-intensity exercise involving frequent collisions. Recent research, much of which has involved global positioning system (GPS) technology, has provided coaches and sport scientists with a deeper understanding of match demands, particularly at the elite level. This has allowed for the development of training programmes that prepare players for the most intense contact and running demands likely to be experienced in competition. At the elite level, rugby league players have well-developed aerobic and anaerobic endurance, muscular strength and power, reactive agility, and speed. Upper- and lower-body strength and aerobic power are associated with a broad range of technical and sport-specific skills, in addition to a lower risk of injury. Significant muscle damage (as estimated from creatine kinase concentrations) and fatigue occurs as a result of match-play; while muscle function and perceptual fatigue generally return to baseline 48 h following competition, increases in plasma concentrations of creatine kinase can last for up to 5 days post-match. Well-developed physical qualities may minimise post-match fatigue and facilitate recovery. Ultimately, the literature highlights that players require a broad range of physical and technical skills developed through specific training. This review evaluates the demands of the modern game, drawing on research that has used GPS technology. These findings highlight that preparing players based on the average demands of competition is likely to leave them underprepared for the most demanding passages of play. As such, coaches should incorporate drills that replicate the most intense repeated high-intensity demands of competition in order to prepare players for the worst-case scenarios expected during match-play.
... Hence, rugby league matches are physically demanding, requiring players to draw upon a variety of physical qualities including muscular strength and power, endurance, speed, and agility (5). 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 (6). ...
... 6 2.0%) (8). Collectively, these findings suggest 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 (6,(8)(9)(10). ...
... The maximum and total ball-in-play time was also greater at higher playing levels. Although these results may intuitively be expected, this study extends upon the findings of others (6,8) by quantifying the difference in physical demands across matches of different competitive standards and providing empirical data on the most demanding passages of elite rugby league match-play. These results demonstrate that during State-of-Origin match-play, and NRL fixture matches where representative players are both available and unavailable for selection, the total ball-in-play time is 54.2, 54.8, and 52.8 minutes, respectively. ...
State-of-Origin is the highest standard of rugby league competition played anywhere in the world. This study investigated the activity profiles of State-of-Origin and compared them against regular National Rugby League (NRL) fixture matches. Video footage from State-of-Origin and NRL matches were coded for activity and recovery cycles. Time when the ball was continuously in play was considered activity, while any stoppages during matches were considered recovery. Ball-in-play periods in matches of different playing standards were analyzed by comparing State-of-Origin matches, NRL matches (with representative players available), and NRL matches (with representative players unavailable). The mean, maximum, and total ball-in-play time of State-of-Origin matches were longer than NRL matches (ES=≥0.75), with and without the availability of representative players. State-of-Origin matches were associated with a greater proportion (ES=≥1.54) of long duration (46 to 300 s) ball-in-play periods, and a smaller proportion (ES=≥1.69) of short duration (<45 s) ball-in-play periods than NRL matches when representative players were both available and unavailable for selection. When representative players were available for club selection, NRL matches were associated with a smaller proportion of short duration ball-in-play periods (ES=1.14) and a larger proportion of long duration ball-in-play periods (ES=0.89), compared to NRL matches when representative players were unavailable. The results of this study provide empirical support for the higher playing intensity of State-of-Origin matches in comparison to regular NRL fixture matches. Furthermore, these findings demonstrate the lower quality of NRL matches during the State-of-Origin period, when representative players are unavailable for selection for their club team. From a practical perspective, these results quantify the difference in activity profiles between State-of-Origin and NRL competitions, and demonstrate the need to prepare rugby league players to perform prolonged passages of high-intensity exercise during match-play.
... Due to salary cap constraints, each NRL club can only have a limited number of established first grade players within their 25-player squad, with the vast majority of playing rosters being comprised of less established NYC and "fringe" first-grade players. Despite the relative success of the NYC, studies investigating the physical demands of these matches are limited (Gabbett, 2012a). Without an understanding of the physical demands of NYC competition relative to NRL competition, it is impossible to determine the extent to which NYC players are prepared to meet the physical demands of NRL match-play. ...
... The repeated high-intensity effort demands of the two competitions were not reported. Previously studies of ball-in-play demands have shown that in comparison to NRL competition, NYC matches are associated with a significantly greater proportion of short duration activity periods and significantly fewer long duration activity periods (Gabbett, 2012a). These findings, taken with the present finding of lower repeated high-intensity effort demands in NYC match-play confirm the marked differences in playing intensity between NRL and NYC matches. ...
... These findings, taken with the present finding of lower repeated high-intensity effort demands in NYC match-play confirm the marked differences in playing intensity between NRL and NYC matches. In addition, the present data, in combination with the findings of others (Gabbett, 2012a), demonstrate that NYC players do not compete for prolonged periods of high-intensity activity, and that the highintensity activity performed in NYC matches is more likely to be single than repeated efforts. Indeed, NRL players engaged in~35% more repeated highintensity effort bouts, with these differences most pronounced in the first half of matches, while few meaningful differences were detected between playing groups for the number of high speed efforts. ...
Abstract In this paper we report on two studies that investigated the physical demands of professional rugby league match-play. Instudy one, National Rugby League (NRL) and National Youth Competition (NYC) players underwent global positioning system (GPS) analysis during competitive matches. No differences (P > 0.05) were observed between playing standards for minutes played, total distance covered, or the distances covered at low and high speeds. However, NRL players engaged in significantly more repeated high-intensity effort bouts than NYC players (13.1 ± 0.8 bouts vs. 9.7 ± 1.1 bouts). Reductions in physical performance occurred from the first to second half for both NRL and NYC players. In study two, we investigated, in the same players, the physical demands of professional rugby league match-play when players were competing in trial and regular fixture matches. The locomotor demands of trial matches were lower than fixture matches, with players covering less distance per minute of match-play, including less distance at low and high speeds. Players were also less likely to engage in repeated high-intensity effort bouts in trial matches than fixtures. These findings demonstrate that neither NYC matches nor NRL trial matches adequately reflect the intense physical demands of NRL fixture matches.
... League (Gabbett, 2012a) and have assessed the total duration demands of competition and further analysed the time that the ball is in-play and out-of-play. However, the one hurling study that assessed the duration demands was published in 2010 and only focused on the senior level. ...
... It must be noted that all sports can vary in the overall match duration. In addition, the duration of the BIP time fluctuates between games due to the unpredictability of time stoppages for scores, fouls, injuries and substitutions (Collins, Doran and Reilly, 2010;Gabbett, 2012aGabbett, , 2015bPollard et al., 2018). This makes it difficult to compare the TD figure between sports and among players who may not have completed the same training or match duration. ...
... In addition, the match duration is a significant differentiator among team sports and even within the same sport. An investigation of the duration demands of competition has been used to provide further insight into the physical demands of competition (Gabbett, 2012a(Gabbett, , 2015b(Gabbett, , 2015aSiegle and Lames, 2012a;Pollard et al., 2018). Although the match duration is guided by the playing rules, previous research has shown that the total match duration is a poor indicator of the actual match playing time (Collins, Doran and Reilly, 2010;Pollard et al., 2018). ...
Hurling is one of the national sports played in Ireland. With 15 players on each team, the objective of this stick and ball game is to outscore your opponents. The demands of this sport are not well known. Time-motion analysis of the activity cycles of elite hurling was carried out using SportsCode analysis software, where the ball-in-play (BIP) and ball-out-of-play (BOP) cycles, the number and type of stoppage were analysed. The running variables (total distance, relative distance, distance covered at each intensity, number and length of sprints, number of entries and maximal relative intensities) were collected using GPS. Heart rate (HR) (peak [HRpeak] and mean [HRmean]) were recorded. The ball is only in play for 40%, 43% and 44% of the playing time in senior, U21 and U17 matches’ respectively. Senior matches were 11 min longer in actual match duration but no difference in the total BIP time was observed across all levels. A Shot at Goal and Free Attempted are the most frequent and longest stoppage type respectively at all levels. Elite players covered greater relative distance and relative walking distance and experienced a higher HRmean than sub-elite players. There was no difference between levels in relative jogging, high-speed running (HSR) and sprint distance (SD) and the number of entries HSR and sprinting. Elite senior hurlers covered greater total distance (TD), HSR and SD compared to U21s, U17s and sub-elite seniors. However, the number of sprints, the mean length of sprint, the maximal speed, HRmean and HRpeak were similar at all levels. In elite senior, the majority of sprints are < 20 m and occur between 22 km·h-1 and 80% of the players’ peak speed. Players at elite senior level are exposed to higher relative maximal intensities in TD, HSR and SD compared to data expressed per half and full game. Positional differences occur in TD, relative distance, HSR, SD between metrics. In addition, there were no positional differences in HRmean and HRpeak at each level, except at elite senior, where half-backs had a lower HRpeak than full-backs. Second half temporal decrements in TD, relative distance, HSR, HRmean and HRpeak are observed at all levels. The findings from the seven studies showed that hurling matches consist of a large number of short (< 30 s) BIP and BOP cycles. The similarity in the total BIP, the number and duration of stoppages, highlight the commonality among hurling matches at all levels. However, when transitioning to elite senior level, players are required to cover greater TD, relative distance, HSR and SD. The number and mean length of sprint are similar in elite senior, U21 and U17 matches, which emphasises the importance of sprinting no matter what the level. Even though the relative maximal intensities (TD, HSR and SD) only occur once in a game, players need to undertake these in training to prepare for the worst-case scenario in matches. Half-backs, midfielders and half-forwards may need additional conditioning as they cover greater TD and relative distance compared to full-backs and full-forwards at senior, U21 and U17. All positions can perform similar sprint training, as there were only minimal differences between positions at each level. No matter what the level (elite senior, U21 and U17 and sub-elite), the majority of metrics decreased in the second half compared to the first. Nutritional, tactical positional changes and substitutions strategies could be implemented to help minimise this decrement. The results of this thesis provide essential information about the match-play demands of sub-elite senior, elite senior, U21 and U17 competitions. The knowledge can be used to highlight the gaps between sub-elite and elite senior matches and between elite U17, U21 and senior matches. The findings can be used by coaches to benchmark their own team’s performances against these norms and help in the design of appropriate training programmes to help maximise the players’ match-play performances.
... Although time-motion analysis has been used to quantify the physical demands in team sports [15][16][17][18], GPS has been the most popular method of choice in hurling [1-3, 12, 13, 19]. The game of hurling is physically demanding with highintensity running performances (e.g. ...
... Another method that has been used to provide an insight into the physical demands of team sports is the examination of the ball-in-play (BIP) periods [12,15,16,25,26]. The total game duration is a poor indicator of the actual matchplaying time, as the ball was only in-play for 41% of the overall match time in senior hurling [12], 63% in Rugby League [15], and 44% in International Rugby Union [27]. ...
... Another method that has been used to provide an insight into the physical demands of team sports is the examination of the ball-in-play (BIP) periods [12,15,16,25,26]. The total game duration is a poor indicator of the actual matchplaying time, as the ball was only in-play for 41% of the overall match time in senior hurling [12], 63% in Rugby League [15], and 44% in International Rugby Union [27]. Consequently, the match-play demands which include the ball-out-play (BOP) stoppage duration may underestimate the true intensity of competition [26]. ...
Purpose
The current study aimed to investigate the ball-in-play (BIP) and ball-out-of-play (BOP) differences between U17, U21 and senior hurling matches.
Methods
Video recordings of matches (n = 36) were coded and analysed for BIP and BOP. Time when the ball was continuously in-play was considered BIP, whereas any stoppages were considered BOP.
Results
The total and mean BIP cycle duration showed no difference between levels. The number of BIP cycles were higher in senior matches compared to U17 (ES = 1.80: large) and U21 (ES = 1.27: large). U17 matches had a lower frequency of BIP cycles between 16 and 30 s (ES = − 1.75: large) compared to senior. Total BOP duration was longer in senior (45:30 ± 4:13 min) matches compared to U17 (36:31 ± 2:30 min, ES = 2.59: very large) and U21 (36:48 ± 2:53 min, ES = 2.40: very large). Senior matches had a longer BOP duration and greater number of BOP cycles than U17 (ES = 0.17: trivial, ES = 2.20: very large, respectively) and U21 (ES = 0.17: trivial, ES = 0.99: moderate, respectively). U17 matches had a lower frequency of BOP cycles > 60 s (ES = − 1.33: large) compared to senior.
Conclusion
Although there was a difference in the total match duration, U17 and U21 matches have similar BIP time as seniors, suggesting that U17 and U21 players should be conditioned to withstand the elite senior BIP duration. In training practice, high-intensity short-duration games are suggested for repeating the duration demands of competition.
... When utilised prior to land-based sprint activities no effect was reported (Gibson et al., 2013); however, the intervention was found to be beneficial on measures of acute and chronic recovery when used between tasks requiring maximal force generation (Beaven et al., 2012). This may in part be due to enhanced muscle recruitment via a desensitising of the afferent groups III and IV, increased neural drive and force output (Noakes, 2011) Interestingly, it has been suggested that IPC is less beneficial in female populations (Beaven et al., 2012;Gibson et al., 2013) Whilst a number of individual events are characterised by short but intense single efforts, team invasion sports require the performance of multiple bouts of maximal and at times supra-maximal activity (Dwyer & Gabbett, 2012;Gabbett, 2012a;Impellizzeri et al., 2006;Spencer et al., 2005). The importance of these repeated sprint efforts to successful performance has been illustrated within rugby league (Gabbett, 2012b). ...
... Results would suggest that for events requiring short (<6 s) maximal efforts IPC is not a suitable pre-exercise intervention for performance enhancement. The finding that post-exercise blood lactate levels may be reduced, especially in a female cohort, combined with non-significant changes in total power and percentage decrement warrants further investigation into the effect of IPC on activities requiring repeated forceful yet sub-maximal efforts, such as those occurring in team sports (Dwyer & Gabbett, 2012;Gabbett, 2012aGabbett, , 2012bImpellizzeri et al., 2006; ...
This study investigated whether ischemic preconditioning (IPC) in a trained population affected repeated sprint performance. A secondary aim was to assess responses according to gender. Sixteen (nine females and seven males) well trained team sport athletes took part in a randomised crossover study design. Participants underwent an IPC and placebo treatment involving three periods of 5 min occlusion applied unilaterally (3 × 5 min occlusion to each leg) at either 220 mmHg or 50 mmHg. Each period of occlusion was followed by 5 min reperfusion. Following treatment 5 × 6 s maximal effort sprints were undertaken on a cycle ergometer against 7.5% body mass, each interspersed by 24 s recovery. Measured parameters included peak power, total power, percentage decrement, post-exercise blood lactate and ratings of perceived exertion. Nor within subject main effect for IPC was observed, neither was there an interaction effect with gender. Effect sizes were trivial (ES < 0.2) with the exception of a moderate (ES < 1.2) change in post-exercise blood lactate in the female cohort (1.6 ± 0.4 mmol−1 lower following IPC). Results suggest no benefit to team sport players in utilising IPC as a means of enhancing repeated sprint performance. A lower blood lactate response in female participants following IPC may suggest improved blood flow through vasodilation.
... video referee decisions, scrums, penalties). 27 Given that the ball is in play for (on average) 55 min in an elite National Rugby League match, 27 basing training programmes on the intensity of matches that include ball out of play periods is likely to severely underestimate the true 'physical' demands of rugby league match-play. However, inclusion of ball out-of play periods in analyses, including the shortest recovery periods, may provide a better reflection of the actual work:rest ratios and worst case scenarios expected during an entire match. ...
... video referee decisions, scrums, penalties). 27 Given that the ball is in play for (on average) 55 min in an elite National Rugby League match, 27 basing training programmes on the intensity of matches that include ball out of play periods is likely to severely underestimate the true 'physical' demands of rugby league match-play. However, inclusion of ball out-of play periods in analyses, including the shortest recovery periods, may provide a better reflection of the actual work:rest ratios and worst case scenarios expected during an entire match. ...
No study has investigated the influence of field position and phase of play on the physical demands of match-play in professional rugby league forwards. We investigated the physical demands placed on forwards in elite rugby league matches, with special reference to how these demands differed between attack and defence, and in different field positions.
Cohort study.
Twenty-two rugby league players (26±3 years) from the same professional club participated in this study. Global positioning system (GPS) analysis was completed during 23 matches. Video footage was synchronised with the GPS files and coded for the time spent in attack and defence, and in one of three different field positions (0-30m, 31-70m, 71-100m).
The physical demands of defence were consistently greater than attack. Moderate to large differences (ES=0.62-1.41) were found between defence and attack for distance covered (109±16m/min vs. 82±12m/min), low speed distance (104±15m/min vs. 78±11m/min), frequency of collisions (1.9±0.7/min vs. 0.8±0.3/min), and repeated high-intensity effort bouts (1 every 4.9±5.1min vs. 1 every 9.4±6.1min). The running demands and frequency of repeated high-intensity effort bouts were greater when defending in the opposition's 30m zone (i.e. 71-100m), with repeated high-intensity effort bouts also occurring more frequently when defending the team's own try-line and when attacking the opposition's try-line.
Specific training drills designed to replicate the attacking and defensive demands of different field positional zones are likely to be effective in preparing players for the most demanding activities that occur in professional rugby league match-play.
... Recently, the activity cycles (i.e., ball-in-play) of National Rugby League matches were investigated (6,7). The average longest ball-in-play period was 318 seconds, and the longest ball-in-play period from any match was approximately 11 minutes (6). ...
... Recently, the activity cycles (i.e., ball-in-play) of National Rugby League matches were investigated (6,7). The average longest ball-in-play period was 318 seconds, and the longest ball-in-play period from any match was approximately 11 minutes (6). Of interest was the finding that across an 80 minute game, the ball was in play for an average of 55 minutes, demonstrating that over 30% of match time comprises stoppages (i.e., for scrums, penalties, line drop-outs, tries, and video referee decisions). ...
Most investigations of the activity profiles of rugby league match-play have reported the physical demands across the entire match, irrespective of stoppages in play. This study investigated the activity profiles of rugby league match-play, accounting for time when the ball was "in" and "out-of-play". One-hundred and four players (mean age, 24.0 ± 3.0 yr) from eleven semi-professional rugby league teams underwent global positioning system analysis during 22 matches. 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, and tries) were considered recovery. The relative distance (125.1 ± 16.1 m/min vs. 86.7 ± 9.8 m/min), low-speed activity (115.3 ± 15.7 m/min vs. 81.7 ± 9.8 m/min), and high-speed running (9.5 ± 2.9 m/min vs. 5.0 ± 1.8 m/min) demands were significantly (p<0.0001) higher when accounting for ball-in-play time. The frequency of collisions (0.67 ± 0.28 per minute vs. 0.41 ± 0.17 per minute) and repeated high-intensity effort bouts (1 every 6.1 ± 4.7 minutes vs. 1 every 10.7 ± 8.3 minutes) were also higher when stoppage time was excluded. Large negative correlations (p≤0.001) were found between total ball-in-play time and relative measures of total distance (r = -0.67) and low-speed activity (r = -0.60). These results demonstrate the greater movement, contact, and repeated high-intensity effort demands when rugby league time-motion data is expressed relative to ball-in-play time. Furthermore, the reduction in relative intensity with longer total ball-in-play time suggests that during prolonged passages of play, players adopt a pacing strategy in order to maintain high-intensity performance and manage fatigue.
... This is consistent with recent findings 25 in ice-hockey (Deaner, Lowen & Cobley, 2013) and rugby union (McCarthy & Collins, 26 2014) and supports reductions in relative age biases into adult professional rugby , tactical and psychological skills to progress in the longer-term if they 5 can persist within developmental programmes (Cobley et al., 2009; Deaner et al.position, significant ORs were found between the Pivots and Props, with 8 Pivots approximately three times more likely to attain professional status. This finding 9 supports previous research (Till et al., 2010a; Till, Cobley, O'Hara, Chapman & Cooke, 10 2013) questioning whether 'Props' at 13-15 years, due to their advanced maturation and 11typical underperformance on a range of fitness assessments, are less likely to attain 12 professional status due to the increasing game demands (e.g., speed) at higher playing levels 13(Gabbett, 2012). Physiologically speaking, the lower progression rates of 'Props' questions 14 the validity of early TID in this position, and suggest that coaching interventions at younger 15 age categories should aim to develop a range of generic capabilities rather than and fitness characteristics were compared according to career 18 attainment outcomes, results identified overall significant effects for anthropometric and 19 fitness characteristics at the Under 14s and 15s annual-age categories but not at the Under 20 13s. ...
... There was no financial assistance 14 associated with this research. 15 ...
This study evaluated the influence of annual-age category, relative age, playing position, anthropometry and fitness on the career attainment outcomes of junior rugby league players originally selected for a talent identification and development (TID) programme. Junior rugby league players (N = 580) were grouped retrospectively according to their career attainment level (i.e., amateur, academy and professional). Anthropometric (height, sitting height, body mass, sum of four skinfolds), maturational (age at peak height velocity; PHV) and fitness (power, speed, change of direction speed, estimated[Formula: see text]) characteristics were assessed at the Under 13s, 14s and 15s annual-age categories. Relative age (Q2 = 8.5% vs. Q4 = 25.5%) and playing position (Pivots = 19.5% vs. Props = 5.8%) influenced the percentage of players attaining professional status. Anthropometry and fitness had a significant effect on career attainment at the Under 14 (P = 0.002, η(2) = 0.16) and 15 (P = 0.01, η(2) = 0.12) annual-age categories. Findings at the Under 14s showed future professional players were significantly later maturing compared to academy and amateur players. Findings suggest that relative age, playing position, anthropometry and fitness can influence the career attainment of junior rugby league players. TID programmes within rugby league, and other related team sports, should be aware and acknowledge the factors influencing long-term career attainment, and not delimit development opportunities during early adolescence.
... The longer the period investigated, the more likely there is to be a stoppage in play due to an error being made, a score, a stoppage of time by the referee or the ball going out of play, thus reducing the need for players to maintain a certain intensity. For example, in semi-professional rugby league, 41 ± 6 stoppages in play have been reported to occur during matches [74], with the most common reasons being for scrums, penalties and tries [75]. Furthermore, it has been reported that senior professional match-play (National Rugby League) demonstrates longer periods of ball-in-play periods, and a smaller proportion of short duration activity cycles than during junior professional matches (National Youth Competition) [75], thus suggesting the decline in intensity will also be impacted by the level of play investigated. ...
... For example, in semi-professional rugby league, 41 ± 6 stoppages in play have been reported to occur during matches [74], with the most common reasons being for scrums, penalties and tries [75]. Furthermore, it has been reported that senior professional match-play (National Rugby League) demonstrates longer periods of ball-in-play periods, and a smaller proportion of short duration activity cycles than during junior professional matches (National Youth Competition) [75], thus suggesting the decline in intensity will also be impacted by the level of play investigated. ...
Background:
Quantifying the peak match demands within the football codes is useful for the appropriate prescription of external training load. Wearable microtechnology devices can be used to identify the peak match demands, although various methodologies exist at present.
Objectives:
This systematic review aimed to identify the methodologies and microtechnology-derived variables used to determine the peak match demands, and to summarise current data on the peak match demands in the football codes.
Methods:
A systematic search of electronic databases was performed from earliest record to May 2018; keywords relating to microtechnology, peak match demands and football codes were used.
Results:
Twenty-seven studies met the eligibility criteria. Six football codes were reported: rugby league (n = 7), rugby union (n = 5), rugby sevens (n = 4), soccer (n = 6), Australian Football (n = 2) and Gaelic Football (n = 3). Three methodologies were identified: moving averages, segmental and 'ball in play'. The moving averages is the most commonly used (63%) and superior method, identifying higher peak demands than other methods. The most commonly used variables were relative distance covered (63%) and external load in specified speed zones (57%).
Conclusion:
This systematic review has identified moving averages to be the most appropriate method for identifying the peak match demands in the football codes. Practitioners and researchers should choose the most relevant duration-specific period and microtechnology-derived variable for their specific needs. The code specific peak match demands revealed can be used for the prescription of conditioning drills and training intensity.
... In collision-based sports, such PHIR activity is often punctuated by forceful tackles and highly demanding eccentric muscular activities (i.e., decelerating and jumping). For example, rugby league competition is characterised by intermittent bouts of high-intensity activity that incorporates high-intensity running (HIR), repeated accelerations, changes of direction and intense physical collisions (Sirotic et al. 2011;Gabbett 2012;Johnston et al. 2014). Since the activity profile of most team sports like rugby league are largely acyclic in nature and requires these intense activities (e.g., HIR, changes of direction) at varying speeds, the energy supply for muscular effort is derived from both aerobic and anaerobic sources (Bangsbo et al. 2006(Bangsbo et al. , 2007. ...
Purpose: This study determined differences in prolonged high-intensity running (PHIR) performance and running momentum (pIFT) between competition levels and positional groups in rugby league.
Methods: Elite Australian National Rugby League (NRL), sub-elite [state-based competition (SRL); National Youth Competition (NYC); local league (LL)] and junior-elite (U18; U16) rugby league players completed the 30–15 Intermittent Fitness Test (30–15IFT) to quantify PHIR performance. Final running momentum (pIFT; kg·m∙s⁻¹) was calculated as the product of body mass and final running velocity (VIFT; m∙s⁻¹). Effect sizes (ESs) were used to examine between-group differences.
Results: 30–15IFT performance was possibly to likely higher in NRL players (19.5 ± 1.0 km·h⁻¹; mean ± SD) when compared with SRL (ES = 0.6 ± 0.5; ES ± CI), NYC (ES = 0.6 ± 0.5) and U18 (ES = 0.8 ± 0.5) players. NRL players (537 ± 41 kg·m·s⁻¹) possessed possibly to very likely greater pIFT than SRL (ES = 0.7 ± 0.5), NYC (ES = 1.2 ± 0.5), U18 (ES = 2.3 ± 0.6), U16 (ES = 3.0 ± 0.7) and LL players (ES = 2.0 ± 0.7). Middle forwards attained a likely superior pIFT (ES = 0.5 − 1.8) to all other positional groups.
Conclusions: This study demonstrated that elite rugby league players possess superior PHIR capacities, whilst highlighting that pIFT can account for the disparities in body mass between groups.
... As such, several studies adopted coding of periods where the ball is continuously in play or during stoppages. These periods have been termed "activity" and "recovery" cycles and provide information about the normative time that the ball is in and out of play, allowing coaches to design training drills that reflect the intermittent profile of the competition (Gabbett, 2012;. Studies in professional rugby league have revealed the occurrence of continuous passages of play that exceed 6 min, which four times greater than the average time that the ball is continuously in play (Gabbett, 2015a). ...
The current study aimed to describe the distribution of physical and technical performance during the different phases of play in professional Australian Football. The phases of play (offence, defence, contested play, umpire stoppages, set shots and goal resets) were manually coded from video footage for a single team competing in 18 matches in the Australian Football League. Measures of physical performance including total distance (m), average speed (m · min⁻¹), low-speed running (LSR, <14.4 km h⁻¹), high-speed running (HSR, >14.4 km h⁻¹), accelerations (2.78 m · s⁻²) and decelerations (−2.78 m · s⁻²) were derived from each phase of play via global positioning system (GPS) devices. Technical skill data including tackles, handballs and kicks were obtained from a commercial statistics provider and derived from each phase of play. Linear mixed-effects models and effect sizes were used to assess and reflect the differences in physical and technical performance between the six phases of play. Activity and recovery cycles, defined as periods where the ball was in or out of play were also described using mean and 95% confidence intervals. The analysis showed that several similarities existed between offence and defence for physical performance metrics. Contested play involved the highest total distance, LSR, accelerations, decelerations and tackles compared to all other phases. Offence and defence involved the highest average speed and HSR running distances. Handballs and kicks were highest during offence, while tackles were highest during contested play, followed by defence. Activity and recovery cycles involved mean durations of ~110 and ~39 s and average speeds of ~160 and ~84 m · min⁻¹, respectively. The integration of video, GPS and technical skill data can be used to investigate specific phases of Australian Football match-play and subsequently guide match analysis and training design.
... Colloquially, long ball-in-play periods might be perceived as an 'arm wrestle', as team's battle for field position, in an attempt to force an error from their opponent. Gabbett (2012a) investigated the ball-in-play periods of senior elite and junior elite matches, coding time when the ball was continuously in play, and any recovery periods that occurred (e.g., for scrums, penalties, line drop-outs, tries, and video referee decisions). The total time the ball was in play was ~55 minutes and ~50 minutes for senior elite and junior elite matches, respectively. ...
... With this in mind, the purpose of this study was to investigate the influence of prior knowledge of exercise duration on the pacing strategies employed during game-based activities. Given the wide match-to-match variability in the activity profiles of team-sport players 21 and the large amount of time the ball is out of play during competition, 22 we used a small-sided game controlling for rules, verbal encouragement, pitch size, player numbers, and match duration. Based on the findings of Billaut et al, 5 we hypothesized that players would perform at higher intensities and have greater total involvements with the ball during game-based activities of an anticipated shorter duration and establish a lower pacing strategy during game-based activities of an anticipated longer duration. ...
Purpose:
To investigate the influence of prior knowledge of exercise duration on the pacing strategies employed during game-based activities.
Methods:
Twelve semiprofessional team-sport athletes (mean ± SD age 22.8 ± 2.1 y) participated in this study. Players performed 3 small-sided games in random order. In one condition (Control), players were informed that they would play the small-sided game for 12 min and then completed the 12-min game. In a 2nd condition (Deception), players were told that they would play the small-sided game for 6 minutes, but after completing the 6-min game, they were asked to complete another 6 min. In a 3rd condition (Unknown), players were not told how long they would be required to play the small-sided game, but the activity was terminated after 12 min. Movement was recorded using a GPS unit sampling at 10 Hz. Post hoc inspection of video footage was undertaken to count the number of possessions and the number and quality of disposals.
Results:
Higher initial intensities were observed in the Deception (130.6 ± 3.3 m/min) and Unknown (129.3 ± 2.4 m/min) conditions than the Control condition (123.3 ± 3.4 m/min). Greater amounts of high-speed running occurred during the initial phases of the Deception condition, and more low-speed activity occurred during the Unknown condition. A moderately greater number of total skill involvements occurred in the Unknown condition than the Control condition.
Conclusions:
These findings suggest that during game-based activities, players alter their pacing strategy based on the anticipated endpoint of the exercise bout.
... Within the United Kingdom, talented academy-aged rugby league players are recruited to train within professional clubs academy programmes between 13 and 20 years of age (28,29) for the talent development pathway within the United Kingdom). A purpose of these programmes is to develop the anthropometric and physical qualities of academy rugby league players required to meet the increasing training and game demands at progressing levels (14). Although research exploring seasonal changes in under 18 players is available (10), the expected absolute and percentage seasonal changes for anthropometric and physical characteristics within rugby league players aged between 13 and 20 years are not available. ...
Professional rugby league clubs implement training programmes for the development of anthropometric and physical characteristics within an academy programme. However, research that examines seasonal changes in these characteristics is limited. The purpose of the study was to evaluate the seasonal changes in anthropometric and physical characteristics of academy rugby league players by age category (i.e., under 14, 16, 18, 20). Data were collected on 75 players pre- and postseason over a 6-year period (resulting in a total of 195 assessments). Anthropometric (body mass, sum of 4 skinfolds) and physical (10- and 20-m sprint, vertical jump, Yo-Yo intermittent recovery test and 1 repetition maximum squat, bench press, and prone row) measures were collected. The under 14s and 16s showed greater seasonal improvements in body mass (e.g., under 14s = 7.4 ± 4.3% vs. under 20s = 1.2 ± 3.3%) and vertical jump performance than under 18s and under 20s. In contrast, under 18s and under 20s players showed greater seasonal improvements in Yo-Yo performance and 10-m sprint (e.g., under 14s = 1.3 ± 3.9% vs. under 20s = -1.9 ± 1.2%) in comparison to under 14s and under 16s. Seasonal strength improvements were greater for the under 18s compared with under 20s. This study provides comparative data for seasonal changes in anthropometric and physical characteristics within rugby league players aged 13-20 years. Coaches should be aware that seasonal improvements in speed may not exist within younger age categories, until changes in body mass stabilize and consider monitoring changes in other characteristics (e.g., momentum). Large interplayer variability suggests that player development should be considered on an individual and longitudinal basis.
... The NYC is restricted to players under 20 years of age and provides an important pathway to a potential professional career in the NRL. Recent research comparing the match activity profiles between NRL and NYC players has reported that the average length of activity cycles was shorter in NYC compared to NRL, with a higher percentage of short activity cycles and a lower percentage of long activity cycles (Gabbett, 2011). In addition, there were also a greater number of tries and scrums in NYC matches, and the authors suggested that this is associated with poorer defensive coordination, a greater number of errors and an inability to maintain concentration for prolonged periods of time. ...
Abstract This study examined the influence of match-related fatigue on physical and technical skill performance in ball playing positions at two different levels of rugby league competition. Time-motion analyses were performed using global positioning systems from 6 elite National Rugby League (NRL) and 11 junior elite National Youth Competition (NYC) players from 45 matches. A standardised 5-point technical coding criteria was used to qualitatively assess skill involvements during match-play. The distance travelled in the 0-5 and 40-45 min period were significantly higher compared to the 30-35, 35-40, 70-75 and 75-80 min periods (P < 0.001). Skill rating and involvements were higher in the 0-5 and 40-45 min compared to 70-75 and 75-80 min periods (P < 0.001 and P < 0.001, respectively).There was no significant difference in the number of physical collisions between the 5-min periods (P = 0.051). Following the peak 5-min bout of exercise intensity there were reductions in distance (P < 0.001), quality of skill involvements (P < 0.001), number of involvements (P < 0.001) and collisions (P < 0.001). Elite NRL and NYC "ball players" exhibit reductions in physical performance towards the end of matches and following brief periods of intense exercise. There also appears to be a reduction in technical performance for NRL and NYC ball players, which may be attributable to match-related fatigue.
... These short and unpredictable possession chains are in contrast to other sports such as rugby and basketball which are typically characterised by discrete attacking and defensive phases. [19][20][21] The nature of possession in AF is closer to other 'offside' sports such as soccer which fundamentally revolve around an ongoing contest for possession. 22,23 We observed that the average time 'in play' was approximately 40 s, which was interspersed with an 'out of play' period of ~20 s. ...
Contemporary analysis of physical activity in Australian Football (AF) are typically presented as a total measure and independent of game context, which is not representative of how the game is played and/or assessed by coaches. This study examines the activity profile of individual possession chains and determines the influence that field position, initial chain state, and possession phase have on these activity characteristics in men’s AF.
Global positioning system data was attained from 35 players in 13 matches across the 2019 Australian Football League season. Matches were coded into different possession phases, initial field location of the ball, and initial chain state. Mixed models were built to observe the influence of field position and initial chain state for each possession phase.
Less TD and HSR distance were covered during attacking chains in the forward 50 and attacking midfield, while defensive chains covered less TD and HSR in the defensive 50 and defensive midfield (p<0.001). Significant main effects for possession phase and initial chain state were observed for TD and HSR. TD and HSR were higher during attacking chains, while chains beginning from a stoppage were lower than intercept and kick-ins (p<0.001).
Overall, the most intense moments of the game appear similar across all possession phases when field location is accounted for and that transitioning the ball quickly from the defensive end of the field results in greater physical activity. These findings can be used for prescription and monitoring of training drills specific to AF requirements.
... 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 highintensity 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 timemotion 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. ...
This study investigated the influence of playing standard, and winning and losing on the physical demands of elite rugby league match-play. Twenty-two elite rugby league players participated in this study. Global positioning system data was collected during 16 rugby league matches. Players covered significantly greater (P≤0.05) absolute and relative distance at high speeds when playing against Bottom 4 teams than when competing against Top 4 teams. The total distance per minute of match-play, and relative distance at low speeds were greater when matches were won. In addition, a greater absolute and relative number of maximal accelerations, and repeated high-intensity effort bouts were performed when players were competing in winning teams than when competing in losing teams. The mean and maximum number of efforts in a repeated high-intensity effort bout was also higher in winning teams, although the recovery between efforts was shorter in losing teams. 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. No meaningful differences were found in the physical demands between small, moderate, and large losing margins. 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 elite rugby league teams is closely linked to their ability to maintain a higher playing intensity than their less successful counterparts.
... Hence, rugby league matches are physically demanding, requiring players to draw upon a variety of physical qualities including muscular strength and power, endurance, speed and agility (Gabbett, 2005), combined with technical and tactical skills, all of which can influence final ladder position (Gabbett, 2014). The ability to perform prolonged high-intensity exercise, coupled with the capacity to recover during brief stoppages in play, is a critical requirement of elite rugby league match-play (Gabbett, 2012a;Kempton, Sirotic, Cameron, & Coutts, 2013). ...
We investigated changes in activity and recovery cycles and skill involvements: (1) during National Rugby league (NRL) match-play from 2004 to 2014 and (2) among successful and unsuccessful teams over the same period. Teams were divided into 4 tiers according to final ladder position: (A) 1st–4th, (B) 5th–8th, (C) 9th–12th and (D) 13th–16th. Total, mean and maximum ball-in-play time decreased, while recovery time increased from 2004 to 2014. Offensive and defensive skill involvements changed differentially over time with moderate to large reductions in the number of play-the-balls, offloads and missed tackles, and moderate to large increases in the number of passes, tackles made and ineffective tackles. The gap between Tier A and Tier D decreased for mean activity time and the proportion of short (<45 s) ball-in-play periods. Conversely, the gap between Tier A and Tier D increased for skill involvements, with Tier A completing more play-the-balls, and Tier D performing a greater number of offloads, and total, missed and ineffective tackles. Our results demonstrate the decreasing ball-in-play demands of NRL competition over 11 seasons. However, our data also highlight the narrowing gap in ball-in-play demands, and increasing gap in skill involvements between the top tier and bottom tier teams.
... Tim Gabbett looks at how play-time compares to periods of non-action in National Rugby League matches and National Youth Competition matches in Australian Rugby League (Gabbett 2012). Referring to these cycles as "activity" (ball-in-play) and "recovery" (ball not in-play) cycles, he concludes that National Rugby League matches have longer activity cycles and shorter recovery cycles, suggesting that the physical demands of professional rugby are greater than those at the youth level. ...
The role of time is crucial in virtually all sports. As part of a larger presentation on the concept of time in sports, including topics such as schedules, durations and endings, this paper examines the relationship between the official time allotted to the playing of a game from the very beginning to the very end (“wall-time”), and the amount of time spent in actual play (“play-time”). After analyzing this relationship in the big four American team sports of baseball, football, basketball and ice hockey (hockey), the paper focuses on these two temporal phenomena in Association Football (soccer). It concludes that the auspiciousness of this temporal relationship in soccer bodes well for the game’s increased presence in the American sports space.
... We report metres per minute is lower for all positions in the current study when compared with previous investigations. Given the mean number of tries scores per game was 11, the mean errors per game was 28 and the ball was only "in play" for~48 minutes per game (which is considerably lower than previously reported in ESL at around 55 min (Sykes, Twist, Hall, Nicholas, & Lamb, 2009) and NRL at around 55 min (Gabbett, 2012) it is likely that the lower metres per minute observed is a direct result of the numerous stoppages in play. Contrastingly, the high-intensity distance (>5.0 m·s 1 ) covered per minute is higher in this study than those previously reported in ESL. ...
The physical match demands for a newly promoted European Super League (ESL) squad were analysed over a full season using global positioning systems. Players were classified into four positional groups: outside backs (OB), pivots (PIV), middle unit forwards (MUF) and wide running forwards (WRF). MUF covered less total distance (4318 ± 570 m) than WRF (6408 ± 629 m), PIV (6549 ± 853) and OB (7246 ± 333 m) (P < 0.05) and less sprint distance (185 ± 58 m) than WRF (296 ± 82 m), PIV (306 ± 108) and OB (421 ± 89 m; P < 0.05), likely attributable to less playing time by MUF (47.8 ± 6.6 min) compared with WRF (77.0 ± 9.0 min), PIV (72.8 ± 10.6 min) and OB (86.7 ± 3.4 min; P < 0.05). Metres per minute were greater for MUF (90.8 ± 2.2 m.min(-1)) compared with OB (83.6 ± 2.8 m.min(-1)) and WRF (83.4 ± 2.4 m.min(-1); P = 0.001) although not different from PIV (90.2 ± 3.3 m.min(-1); P > 0.05). WRF (36 ± 5) and MUF (35 ± 6) were involved in more collisions than OB (20 ± 3) and PIV (23 ± 3; P < 0.05). The high-speed running and collision demands observed here were greater than that previously reported in the ESL, which may reflect increased demands placed on the lower ranked teams. The present data may be used to inform coaches if training provides the physical stimulus to adequately prepare their players for competition which may be especially pertinent for newly promoted franchises.
... Rather, it is the relative intensity of the game, and in particular the ability to perform RHIE bouts and prolonged high-intensity exercise with the capacity to recovery during brief stoppages, that discriminates between higher and lower standard competition levels. 17,37 The coaching of RHIE ability in the form of high-intensity running, tackling and wrestling exercise should be a key emphasis of training programmes, particularly in the development of elite youth players training to compete at higher competition standards. ...
Rugby football codes have continually increased in popularity and are played professionally around the world at domestic, national and international level. Coaching professionals can use the findings of this review to guide training practices for the professional rugby football player, particularly those players that may be competing concurrently or transferring between codes. The development of repeated high-intensity exercise (RHIE) ability should be a key emphasis of training programs especially for players that are aiming to compete at higher competition standards. Importantly, there are considerable differences in RHIE demands of match-play for different positional groups. For greatest transference to match performance, training programs should replicate the frequency and duration of RHIE bouts in addition to the relative contribution of high-intensity running, tackling and physical collisions. Training programs should not neglect developing players’ prolonged high-intensity running ability as high-speed running efforts may occur separately from RHIE bouts and likely place considerable demands on rugby football players, particularly in rugby sevens competition. Rugby football players have been shown to experience transient fatigue patterns during match-play where teams may be susceptible to conceding points or sustaining injury. Improved physical conditioning strategies may reduce development of match-fatigue; however, research is yet to investigate the influence of fitness levels and team strategies. A better understanding of these factors and how they interact with match-fatigue will assist with the improvement of training practices for professional rugby football players.
... e., running and sprinting) interspersed with bouts of low-intensity activity (i. e., walking and jogging) [19,20,30,35]. Additionally, players frequently engage in physically demanding collision and wrestle bouts [2,17]. ...
The purpose of this study was to apply a time-motion model to estimate and describe the energy expenditure and metabolic power demands of playing positions in elite rugby league match-play, utilizing Global Positioning System (GPS) devices. 18 elite rugby league players participated in this study. Players' positional groups included: outside backs (n=59 files, n=4 players), adjustables (n=74 files, n=4 players), wide-running (n=104 files, n=7 players) and hit-up forwards (n=36 files, n=3 players). Outside backs expended the greatest total energy (40.1±5.0 kJ·kg(-1)) per match, equivalent to 8.1%, 26.6% and 61.9% greater energy than adjustables, wide-running and hit-up forwards, respectively. Adjustables attained an anaerobic index 7.3% higher than wide-running forwards, 19.7% higher than hit-up forwards (p=0.001) and 43.2% higher than outside backs (p<0.001). Wide-running forwards achieved an anaerobic index (0.34±0.04) 11% and 32.8% higher than hit-up forwards (p=0.001) and outside backs (p<0.001), respectively. Mean power of adjustables (10.0±0.9 W·kg(-1)) was significantly higher than all other groups (outside backs: 28.8%, 7.8±1.0; hit-up: 12.4%, 8.9±0.6; and wide-running: 8.7%, 9.2±0.7 forwards) (p<0.001). Energetics indices indicated differing metabolic demands for all positional groups, suggesting position-specific conditioning drills are required to replicate the energetic demands of match-play.
© Georg Thieme Verlag KG Stuttgart · New York.
... Differences exist between the physical demands of junior and senior rugby league matches. Gabbett [6] investigated the physical demands between National Rugby League (NRL, senior players) and National Youth Competition (NYC, elite U20s) match-play measuring the activity cycles (i.e., ball-in-play periods) during the game. NRL matches had longer ball-in-play periods, a smaller proportion of short duration activity cycles, and a larger proportion of longer duration activity cycles. ...
Rugby league is an intermittent, collision team sport played at amateur and professional levels across junior and senior age categories worldwide. A paucity of literature exists with regard to research on nutrition for junior rugby league players. This lack of research makes the development of specific nutritional recommendations for players problematic. There is a concern that players may adopt the latest fad diet or supplement to augment their performance at a risk to their performance, training adaptation, recovery, injury susceptibility and health. Youth culture, social media, socio-economic status, behavioural and educational issues may contribute to the poor dietary practices of players. To maintain health, optimise growth and enhance athletic performance and recovery, junior rugby league players need to consume an appropriate diet. Junior rugby league players should periodise their nutritional intake according to the training and competition phase. 1.5-1.7 g.kg-1 day-1 of protein is recommended with equally spaced meals throughout the day to maximise protein synthesis. During phases where skeletal muscle tissue is prioritised this recommendation should be towards the higher end, 1.7 g.kg-1 day-1. Carbohydrate ingestion between 4-8 g.kg-1 day-1 should be adjusted daily according to the daily exercise needs of the player. A food first policy should be adopted basing food intake on primarily whole and minimally processed sources from a variety of foods will help players meet their micronutrient intake. Implementation of a nutrition education programme should be undertaken with players improve the nutritional knowledge and dietary practice. This paper reviews the current scientific data related to the energy needs of junior rugby league players, special nutrient needs during training and competition and the use of supplements.
... Differences in playing time present another difficulty in comparing physical performance amongst the football codes. The unpredictability of time stoppages leads to fluctuations in the time the ball is in play both within-and between-codes, with the ball out of play for~30-40% of the match time in rugby league, soccer and Australian football (Gabbett, 2012;Myiamura, Seto, & Kobayashi, 1995;Norton, 2012). Furthermore, the time an athlete is in play differs between all codes due to the length of a game, number of periods of play and the rules regarding player substitution or interchange. ...
Abstract We compared the match activity profiles of elite footballers from Australian football (AF), rugby league (RL) and soccer (SOC), using identical movement definitions. Ninety-four elite footballers from AF, RL or SOC clubs in Australia participated in this study. Movement data were collected using a 5-Hz global positioning system from matches during the 2008-2011 competitive seasons, including measures of velocity, distance, acceleration and bouts of repeat sprints (RS). Australian footballers covered the greatest relative running distances (129 ± 17 m.min(-1)) compared to RL (97 ± 16 m.min(-1)) and SOC (104 ± 10 m.min(-1)) (effect size [ES]; 1.0-2.8). The relative distance covered (4.92 ± 2.10 m.min(-1) vs. 5.42 ± 2.49 m.min(-1); 0.74 ± 0.78 m.min(-1) vs. 0.97 ± 0.80 m.min(-1)) and the number of high-velocity running (0.4 ± 0.2 no.min(-1) vs. 0.4 ± 0.2 no.min(-1)) and sprint (0.06 ± 0.06 no.min(-1) vs. 0.08 ± 0.07 no.min(-1)) efforts between RL and SOC players were similar (ES; 0.1-0.3). Rugby league players undertook the highest relative number of accelerations (1.10 ± 0.56 no.min(-1)). RS bouts were uncommon for all codes. RL and SOC players perform less running than AF players, possibly due to limited open space as a consequence of field size and code specific rules. While training in football should be code specific, there may be some transference of conditioning drills across codes.
The purpose of the current study was to evaluate the anthropometric and physical characteristics of English academy rugby league players by annual-age category (Under 16s - Under 20s) and between backs and forwards. Data was collected on 133 academy players over a 6 year period (resulting in a total of 257 assessments). Player assessments comprised of anthropometric (height, body mass, sum of 4 skinfolds) and physical (vertical jump, 10m and 20m sprint, estimated V[Combining Dot Above]O2max via the yo-yo intermittent recovery test level 1, absolute 1-RM and relative squat, bench press and prone row) measures. Univariate analysis of variance demonstrated significant (p<0.05) increases in height, body mass, vertical jump, absolute and relative strength measures across the five annual-age categories (e.g., Body Mass - Under 16s = 75.2 ± 11.1, Under 20s = 88.9 ± 8.5kg; Vertical Jump - Under 16s = 45.7 ± 5.2, Under 20s = 52.8 ± 5.4cm; 1-RM Bench Press - Under 16s = 73.9 ± 13.2, Under 20s = 114.3 ± 15.3kg). Independent t-tests identified significant (p<0.05) differences between backs and forwards for anthropometric (e.g., Under 16s body mass - Backs = 68.4 ± 8.6, Forwards = 80.9 ± 9.7kg) and physical (e.g., Under 19s 20m sprint - Backs = 3.04 ± 0.08, Forwards = 3.14 ± 0.12s; Under 18s relative squat - Backs = 1.65 ± 0.18, Forwards = 1.51 ± 0.17kg/kg) characteristics that were dependant on the age category and measure assessed. Findings highlight that anthropometric and physical characteristics develop across annual-age categories and between backs and forwards in academy rugby league players. These findings provide comparative data for such populations and support the need to monitor player development in junior rugby league players.
Caffeine is a psycho-active stimulant that can improve physical and cognitive performance. We systematically reviewed the evidence on the effects of acute caffeine ingestion on physiological parameters, physical and technical-skill performance during high-performance team-sport match-play. Following PRISMA guidelines, studies were identified using scientific databases (PubMed, Web-of-Science, Scopus, and SPORTDiscus) in February 2021. Of 281 results, 13 studies met inclusion, totalling 213 participants. Included studies adopted the randomised double-blinded cross-over design, involving caffeine and control conditions. In studies reporting physiological variables, responses to caffeine included higher peak (n=6/ 8 [n/ total studies measuring the variable]) and mean (n=7/ 9) heart rates, increased blood glucose (n=2/ 2) and lactate (n=2/ 2) concentrations. Improvements in physical performance were widely documented with caffeine, including greater distance coverage (n=7/ 7), high-speed distance coverage (n=5/ 7) and impact frequencies (n=6/ 8). From three studies that assessed technical-skills, it appears caffeine may benefit gross-skill performance, but have no effect, or negatively confound finer technical-skill outcomes. There is compelling evidence that ingesting moderate caffeine doses (~3 to 6 mg·kg-1) ~60 minutes before exercise may improve physical performance in team-sports, whereas evidence is presently too scarce to draw confident conclusions regarding sport-specific skill performance.
A several cycles of design-verification-modification are needed during traditional design, which is very time-consuming. Topology optimization is rapidly expanding in the recent years in the field of structural mechanics. Currently it is widely applied to structural design. The combination of topology optimization and sizing and/or shape optimization has been adopted for flight vehicle structural design, which results possible better designs. In the paper, continuum structural topology optimizations as well as size optimization are combined for a folding wing structural design. A structure optimization problem is established using Solid Isotropic Material with Penalization (SIMP) method, it consists of the thickness variable of the skin and the relative element density variables of the tip part of the folding wing. The design objective is to minimize the compliance of the whole structure, and the constraints are structural mass constraints and stress constraints. The problem was solved based on commercial software package HyperWorks™. The resulting design shows that a new tip structure which satisfies the requirements of stiffness and strength was reconstructed.
Purpose:
To describe the physical and technical demands of rugby league 9s (RL9s) match play for positional groups.
Methods:
Global positioning system data were collected during 4 games from 16 players from a team competing in the Auckland RL9s tournament. Players were classified into positional groups (pivots, outside backs, and forwards). Absolute and relative physical-performance data were classified as total high-speed running (HSR; >14.4 km/h), very-high-speed running (VHSR; >19.0 km/h), and sprint (>23.0 km/h) distances. Technical-performance data were obtained from a commercial statistics provider. Activity cycles were coded by an experienced video analyst.
Results:
Forwards (1088 m, 264 m) most likely completed less overall and high-speed distances than pivots (1529 m, 371 m) and outside backs (1328 m, 312 m). The number of sprint efforts likely varied between positions, although differences in accelerations were unclear. There were no clear differences in relative total (115.6-121.3 m/min) and HSR (27.8-29.8 m/min) intensities, but forwards likely performed less VHSR (7.7 m/min) and sprint distance (1.3 m/min) per minute than other positions (10.2-11.8 m/min, 3.7-4.8 m/min). The average activity and recovery cycle lengths were ~50 and ~27 s, respectively. The average longest activity cycle was ~133 s, while the average minimum recovery time was ~5 s. Technical involvements including tackles missed, runs, tackles received, total collisions, errors, off-loads, line breaks, and involvements differed between positions.
Conclusions:
Positional differences exist for both physical and technical measures, and preparation for RL9s play should incorporate these differences.
The purpose of the present study was to evaluate the annual and long-term (i.e., 4 year) development of anthropometric and physical characteristics in academy (16-20 years) rugby league players. Players were assessed at the start of pre-season over a six year period and were required to be assessed on consecutive years to be included in the study (Under 16-17, n=35; Under 17-18, n=44; Under 18-19, n=35; Under 19-20, n=16). A subset of 15 players were assessed for long-term changes over 4 years (Under 16-19). Anthropometric (height, body mass, sum of four skinfolds) and physical (10 and 20 m sprint, 10 m momentum, vertical jump, yo-yo intermittent recovery test level 1, 1-RM squat, bench press and prone row) assessments were collected. Paired t-tests and repeated measures MANOVA demonstrated significant annual (e.g., Body mass, U16 = 76.4±8.4, U17 = 81.3±8.3 kg; p<0.001, d=0.59) and long-term (e.g., vertical jump, Under 16 = 44.1±3.8, Under 19 = 52.1±5.3 cm; p<0.001, d=1.74) changes in anthropometric and physical characteristics. Greater percentage changes were identified between the Under 16-17 age categories compared to the other ages (e.g., 1-RM squat, U16-17 = 22.5±19.5 vs U18-19 = 4.8±6.4%). Findings demonstrate the annual and long-term development of anthropometric and physical characteristics in academy rugby league players establishing greater changes occur at younger ages upon the commencement of a structured training programme within an academy. Coaches should understand the long-term development of physical characteristics and use longitudinal methods for monitoring and evaluating player performance and development.
Purpose: Rugby union referee research has reported the game demands for whole game averages and comparisons between each half and 10 minute periods. No study has reported the movement game demands for the maximum ball in play time for referees. The purpose of this study was to quantify the maximum ball in play (Max BiP) demands termed “worst case scenario” (WCS) of sub-elite rugby union referees using 10Hz Global Positioning System (GPS) units. Method: Movement demands of ten (n=10) sub-elite referees across 27 matches, played during the 2017/18 All Ireland League Division 1, was calculated using 10Hz GPS units. The total distance covered (m), relative distance (m.min-1), percentage time in 6 velocity zones, were reported across the whole match, 1st half, 2nd half, 10minute periods and the maximum ball in play time using paired sample t-tests. Cohen’s d effect sizes was reported. Results: The maximum ball in play time was reported to be 172 ± 71 sec. The relative distance during Max BiP (107.9 ± 22.54 m.min-1) was significantly higher (p < 0.005) than whole match (75.1 ± 8.6 m.min-1) and 1st half (75.4 ± 8.7 m.min-1) & 2nd half (74.8 ± 13.1 m.min-1). During the Max BiP, referees spend a significantly higher (p < 0.005) percentage of time above whole game averages for walking (0.5 - 2.0m.s-1), jogging (2.01 - 4.0m.s-1), running (4.01 - 5.5m.s-1) and lower for high speed running (5.51 - 7.00 m.s-1) and sprinting (>7.01m.s-1). Conclusion: The results of this study quantifies the Max BiP movement demands for a sub-elite rugby union referee which are higher than those reported in whole game averages, 1st & 2nd halves and some 10min periods. These results provide sports scientists with the worst case scenario demands and can allow for these demands to be replicated in training with those experienced in matches.
This study investigated the influence of ladder position on ball-in-play and recovery periods in elite National Rugby League (NRL) competitive matches. Video recordings of 192 NRL matches and 18 NRL finals matches played over two competitive seasons were coded for activity and recovery cycles. Time when the ball was continuously in play was considered activity, while any stoppages during the match (e.g., for scrums, penalties, line drop-outs, tries, and video referee decisions) were considered recovery. In comparison to matches involving lower standard teams, there was a greater proportion (effect size = 0.37-0.67) of long duration (>91 s) and a smaller proportion (effect size = 0.49-0.68) of short duration (<45 s) ball-in-play periods when Top 4 teams were competing against other Top 4 teams. No meaningful differences were found between teams of different ladder positions for the proportion of short (effect size = 0.04-0.16) and long (effect size = 0.06-0.28) recovery periods. In comparison to fixture matches involving the Top 4 teams, finals matches had a smaller proportion (effect size = 0.56) of long duration activity periods, and a greater proportion (effect size = 0.54) of short duration activity periods. Only small differences were found between finals matches and matches involving the Top 4 teams for the proportion of short (effect size = 0.42) and long (effect size = 0.41) recovery periods. These findings suggest 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. Furthermore, long ball-in-play periods in high-standard fixture matches (i.e. involving Top 4 teams) ensure that players are adequately prepared for the ball-in-play demands of finals matches.
This study investigated the tackling technique of high-performance, collision-sport athletes and documented the relationships between tackling technique and playing experience, playing level, game-specific tackling performance, and injury in these athletes. Twenty-two national rugby league (NRL) and 17 state-based rugby league (SRL) players underwent a standardized one-on-one tackling drill in a 10 m grid. Video footage was taken from the rear, side, and front of the defending player. Tackling technique was assessed using standardized technical criteria. A large difference (ES = 1.53, p <0.05) was detected between playing groups for tackling technique, with NRL players having better tackling technique than SRL players. Players who had at least 150 NRL matches experience had a significantly greater (ES = 1.1-1.6, p <0.05) tackling technique than players who had played up to 49 NRL matches, 5099 NRL matches, or 100-149 NRL matches. Significant relationships (p <0.05) were detected between tackling technique and the proportion of tackles missed each game (r = -0.74) and the proportion of dominant tackles effected each game (r = 0.78). There was no relationship between tackling technique and the incidence of tackling injuries. The results of this study demonstrate that playing level and playing experience influence tackling technique in high-performance, collision sport athletes, with greater playing experience and playing level associated with greater tackling technique. Furthermore, significant relationships were detected between tackling technique and the proportion of tackles missed each game (negative) and the proportion of dominant tackles effected each game (positive). Identifying the factors that limit tackling proficiency may assist playing performance, but may have minimal effect on injury prevention in high-performance, collision-sport athletes.
When developing a sport specific training program for a team, the strength and conditioning coach needs a detailed knowledge and understanding of the demands placed on participants during competition. Observation using time and motion analysis is a practical alternative to more sophisticated procedures that can provide details relating to the type of match play activities performed, how often they are performed, and for what period of time. In addition, the frequency and ratio of work to rest, overall distance covered, and intensity of effort—and therefore the dominant energy systems used—can be identified and estimated.
Although the potential link between running loads and soft-tissue injury is appealing, the evidence supporting or refuting this relationship in high-performance team sport athletes is nonexistent, with all published studies using subjective measures (e.g., ratings of perceived exertion) to quantify training loads. The purpose of this study was to investigate the risk of low-intensity (e.g., walking, jogging, total distances) and high-intensity (e.g., high acceleration and velocity efforts, repeated high-intensity exercise bouts) movement activities on lower body soft-tissue injury in elite team sport athletes. Thirty-four elite rugby league players participated in this study. Global positioning system data and the incidence of lower body soft-tissue injuries were monitored in 117 skill training sessions during the preseason and in-season periods. The frailty model (an extension of the Cox proportional regression model for recurrent events) was applied to calculate the relative risk of injury after controlling for all other training data. The risk of injury was 2.7 (95% confidence interval 1.2-6.5) times higher when very high-velocity running (i.e., sprinting) exceeded 9 m per session. Greater distances covered in mild, moderate, and maximum accelerations and low- and very low-intensity movement velocities were associated with a reduced risk of injury. These results demonstrate that greater amounts of very high-velocity running (i.e., sprinting) are associated with an increased risk of lower body soft-tissue injury, whereas distances covered at low and moderate speeds offer a protective effect against soft-tissue injury. From an injury prevention perspective, these findings provide empirical support for restricting the amount of sprinting performed in preparation for elite team sport competition. However, coaches should also consider the consequences of reducing training loads on the development of physical qualities and playing performance.
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.
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.
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.
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.
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.
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.
This study described the number and intensity of collisions experienced by professional rugby league players during pre-season and in-season skills training sessions using microtechnology (e.g. accelerometers, gyroscopes). Short, medium, and long recovery periods between matches were accounted for and the incidence of collision injuries sustained in the training environment was also assessed. Thirty professional rugby league players (mean±SD age, 23.6±3.8yr) participated in this study. The number and intensity of collisions and the incidence of collision injuries were monitored during 117 skills training sessions. Over the course of the season, an average of 77 collisions occurred per player, per session. The average number of mild, moderate, and heavy collisions performed by each member of the squad per session was 24, 46, and 7, respectively. A total of 37 collision injuries were recorded during training over the season, equating to an injury incidence of 6.4 per 10,000 collisions. Over half (54.1%) of all collision injuries resulted in no loss of training time, and less than 14% of collision injuries resulted in a missed match. The greatest number of collisions occurred during training sessions in the weeks with the longest recovery between matches (10 days). The incidence of collision injuries also peaked during the 10 day between match recovery cycle. These findings demonstrate that while significant physiological demands are placed on rugby league players as a result of the large number and intensity of physical collisions performed in training, these collisions are associated with minimal injury risk.
This study investigated the physiological demands of women's field hockey competition and compared these demands to those experienced during game-based training activities. Fourteen elite women field hockey players (mean +/- SD; age, 23.3 +/- 3.2 years; maximal oxygen consumption, 53.5 +/- 4.3 ml x kg(-1) x min(-1)) participated in this study. Global positioning satellite (GPS) system analysis was completed during 19 training appearances and 32 Australian Hockey League (AHL) appearances. All training sessions consisted of game-based activities (i.e., small-sided training games) that were played on a reduced-sized pitch. Movement was recorded by a global positioning satellite unit sampling at 5 Hz. Data were categorized into discreet movement velocity bands, corresponding to low-intensity (0-1 m.s(-1)), moderate-intensity (1-3 m.s(-1) and 3-5 m.s(-1)), and high-intensity (5-7 m.s(-1) and >7 m.s(-1)) activities. Players covered 6.6 km (range: 3.4-9.5 km) over the course of the match. Midfielders spent more time and covered greater distances in high-intensity running (i.e., >5 m.s(-1)) than strikers and defenders. The number of high-velocity and high-acceleration efforts over the course of a match was greater in midfielders. In comparison to competition, game-based training sessions resulted in more time spent in low-intensity (i.e., 0-1 m.s(-1)) activities and less time spent in moderate (i.e., 1-3 m.s(-1) and 3-5 m.s(-1)) and high-intensity (i.e., 5-7 m.s(-1) and >7 m.s(-1)) activities. Although game-based training is likely to be useful for improving the skill levels of players, the skill activities used in the present study did not reflect the physiological demands of competition, with players spending more time in low-intensity activities and less time in high-intensity activities than competition. Modifications in training group size and/or drill design and complexity may better simulate the physiological demands of competition.
Full-text of this article is not available in this e-prints service. This article was originally published following peer-review in International Journal of Performance Analysis in Sport, published by and copyright UWIC Press. The aims of this study were to examine the consequences of the introduction of professional playing status in 1995 on game variables in international rugby union football, and secondly to provide a longitudinal game map for use in future research. Twelve 'Five Nations' Championship games between 1988 and 1995 (pre-professional Era), sub-divided into two Periods (1988-92 and 1995-97) and twelve 'Five' and 'Six Nations' Championship games between 1997 and 2002 (professional Era), sub-divided into two Periods (1997-99 and 2000-02) were analysed using a sequential data gathering hand notation system. Initial intra- observer reliability analysis established that the level of observer agreement exceeded 97% for all game variables. Normalised profiles were also constructed for each variable. These profiles demonstrated that the data for all variables reached stables means within 6 full games. Frequency data and frequency data per unit time were assessed with the Mann-Whitney U statistic to examine Era differences and the Kruskal Wallis H tests to identify Period differences. Where Period differences were indicated, the Mann-Whitney U test was used as the appropriate post-hoc procedure. Analysis identified significant increases (P < 0.005) in the frequency of rucks, dummy/scrum half passes, open play passes and total passes, and significant decreases (P < 0.005) in the frequency of lineouts, kicks out of play, total game kicks, mauls, set possessions and activity possessions from the pre- to the professional era. No significant difference was identified for either scrums or kicks in play frequencies. Analysis of these variables normalised to ball in play time resulted in significant increases (P < 0.005 ) in the frequency of dummy/scrum half passes, rucks, lineouts, and a significant decrease (P < 0.005) in the frequency of mauls, scrums, total game kicks, kicks out of play, kicks in play, and set possessions across the Eras. Significant (P < 0.005) Period main effects were identified for the frequency of lineouts, kicks out of play, scrums, (trend decreasing across Periods) total game passes, passes from the dummy/scrum half position, rucks, activities/phases, and set possession (P = 0.01) and total game kicks (P = 0.006) (trend increasing across Periods). Analyses of these variables normalised to ball in play time resulted a significant (P < 0.05) Period main effects being identified for total game kicks, kicks out of play, kicks in play, mauls, scrums, set possessions,(trend decreasing across Periods) passes from the dummy/scrum half position (trend increasing across Periods) and offloads (no identifiable trend across Periods). It was concluded that the introduction of professional playing status in rugby union had had a marked effect on game action variables and, as a consequence the playing pattern of the game is significantly different in the professional Era and Periods compared to the pre-professional Era and Periods.
The aim of this study was to analyse movement patterns of professional rugby league players during matches played as part of Australia's National Rugby League (NRL) competition. The movement patterns of one player from each of the three positional groups (hit-up forwards, adjustables, and outside backs) during three competition matches were examined using time-motion analysis. Positional groups differed in distances covered (P = 0.001), and covered shorter distances than those described in earlier research. The mean exercise-to-rest ratio was 1:6 for the outside backs and hit-up forwards and 1:5 for the adjustables. However, such ratios did not reflect the most demanding periods of the game, which included repeated high-intensity efforts interspersed with recovery periods of short duration. These periods of repeated high-intensity exercise often occurred at crucial phases of the game, when players were either attacking or defending the try-line. Furthermore, patterns of movement during repeated high-intensity periods of play differed among positional groups. To prepare for the most highly intense periods of match-play, professional rugby league players should adopt position-specific training that includes the highest and lowest exercise-to-rest ratios likely to be experienced in competition.
The authors conducted a study to develop a repeated-effort test for international men's volleyball. The test involved jumping and movement activity that was specific to volleyball, using durations and rest periods that replicated the demands of a match.
A time-motion analysis was performed on a national team and development national team during international matches to determine the demands of competition and thereby form the basis of the rationale in designing the repeated-effort test. An evaluation of the test for reliability and validity in discriminating between elite and sub-elite players was performed.
The test jump height and movement-speed test parameters were highly reliable, with findings of high intraclass correlations (ICCs) and low typical errors of measurement (TE; ICC .93 to .95 and %TE 0.54 to 2.44). The national team's ideal and actual jump height and ideal and actual speeds, mean +/- SD, were 336.88 +/- 8.31 cm, 329.91 +/- 6.70 cm, 6.83 +/- 0.34 s, and 7.14 +/- 0.34 s, respectively. The development national team's ideal and actual jump heights and ideal and actual speeds were 330.88 +/- 9.09 cm, 323.80 +/- 7.74 cm, 7.41 +/- 0.56 s, and 7.66 +/- 0.56 s, respectively. Probabilities of differences between groups for ideal jump, actual jump, ideal time, and actual time were 82%, 95%, 92%, and 96%, respectively, with a Cohen effect-size statistic supporting large magnitudes (0.69, 0.84, 1.34, and 1.13, respectively).
The results of this study demonstrate that the developed test offers a reliable and valid method of assessing repeated-effort ability in volleyball players.
A study of a sample provides only an estimate of the true (population) value of an outcome statistic. A report of the study therefore usually includes an inference about the true value. Traditionally, a researcher makes an inference by declaring the value of the statistic statistically significant or nonsignificant on the basis of a P value derived from a null-hypothesis test. This approach is confusing and can be misleading, depending on the magnitude of the statistic, error of measurement, and sample size. The authors use a more intuitive and practical approach based directly on uncertainty in the true value of the statistic. First they express the uncertainty as confidence limits, which define the likely range of the true value. They then deal with the real-world relevance of this uncertainty by taking into account values of the statistic that are substantial in some positive and negative sense, such as beneficial or harmful. If the likely range overlaps substantially positive and negative values, they infer that the outcome is unclear; otherwise, they infer that the true value has the magnitude of the observed value: substantially positive, trivial, or substantially negative. They refine this crude inference by stating qualitatively the likelihood that the true value will have the observed magnitude (eg, very likely beneficial). Quantitative or qualitative probabilities that the true value has the other 2 magnitudes or more finely graded magnitudes (such as trivial, small, moderate, and large) can also be estimated to guide a decision about the utility of the outcome.
The aim of this study was to examine the influence of perceived intensity, duration and load of matches and training on the incidence of injury in rugby league players. The incidence of injury was prospectively studied in 79 semi-professional rugby league players during the 2001 season. All injuries sustained during matches and training sessions were recorded. Training sessions were conducted from December to September, with matches played from February to September. The intensity of individual training sessions and matches was estimated using a modified rating of perceived exertion scale. Training load was calculated by multiplying the training intensity by the duration of the training session. The match load was calculated by multiplying the match intensity by the time each player participated in the match. Training load increased from December (278.3 [95% confidence interval, CI 262.2 to 294.5] units) to February (385.5 [95% CI 362.4 to 408.5] units), followed by a decline until September (98.4 [95% CI 76.5 to 120.4] units). Match load increased from February (204.0 [95% CI 186.2 to 221.8] units) to September (356.8 [95% CI 302.5 to 411.1] units). More training injuries were sustained in the first half of the season (first vs second: 69.2% vs 30.8%, P < 0.001), whereas match injuries occurred more frequently in the latter stages of the season (53.6% vs 46.4%, P < 0.001). A significant relationship (P < 0.05) was observed between changes in training injury incidence and changes in training intensity (r = 0.83), training duration (r = 0.79) and training load (r = 0.86). In addition, changes in the incidence of match injuries were significantly correlated (P < 0.05) with changes in match intensity (r = 0.74), match duration (r = 0.86) and match load (r = 0.86). These findings suggest that as the intensity, duration and load of rugby league training sessions and matches is increased, the incidence of injury is also increased.
The purpose of this paper is to provide a comprehensive review of the science of rugby league football at all levels of competition (i.e. junior, amateur, semi-professional, professional), with special reference to all discipline-specific scientific research performed in rugby league (i.e. physiological, psychological, injury epidemiology, strength and conditioning, performance analysis). Rugby league football is played at junior and senior levels in several countries worldwide. A rugby league team consists of 13 players (6 forwards and 7 backs). The game is played over two 30 - 40 min halves (depending on the standard of competition) separated by a 10 min rest interval. Several studies have documented the physiological capacities and injury rates of rugby league players. More recently, studies have investigated the physiological demands of competition. Interestingly, the physiological capacities of players, the incidence of injury and the physiological demands of competition all increase as the playing standard is increased. Mean blood lactate concentrations of 5.2, 7.2 and 9.1 mmol . l(-1) have been reported during competition for amateur, semi-professional and professional rugby league players respectively. Mean heart rates of 152 beats . min(-1) (78% of maximal heart rate), 166 beats . min(-1) (84% of maximal heart rate) and 172 beats . min(-1) (93% of maximal heart rate) have been recorded for amateur, semi-professional and junior elite rugby league players respectively. Skill-based conditioning games have been used to develop the skill and fitness of rugby league players, with mean heart rate and blood lactate responses during these activities almost identical to those obtained during competition. In addition, recent studies have shown that most training injuries are sustained in traditional conditioning activities that involve no skill component (i.e. running without the ball), whereas the incidence of injuries while participating in skill-based conditioning games is low. Collaborative research among the various sport science disciplines is required to identify strategies to reduce the incidence of injury and enhance the performance of rugby league players. An understanding of the movement patterns and physiological demands of different positions at all standards of competition would allow the development of strength and conditioning programmes to meet the precise requirements of these positions. Finally, studies investigating the impact of improvements in physiological capacities (including the effect of different strength and conditioning programmes) on rugby league playing performance are warranted.
Rugby league football is played in several countries worldwide. A rugby league team consists of 13 players (6 forwards and 7 backs), with matches played over two 40-minute halves separated by a 10-minute rest interval. Several studies have documented the physiological capacities of rugby league players and the physiological demands of competition, with the physiological capacities of players and the physiological demands of competition increasing as the playing level is increased. However, there is also evidence to suggest that the physiological capacities of players may deteriorate as the season progresses, with reductions in muscular power and maximal aerobic power and increases in skinfold thickness occurring towards the end of the rugby league season, when training loads are lowest and match loads and injury rates are at their highest.
Player fatigue and playing intensity have been suggested to contribute to injuries in rugby league, with a recent study reporting a significant correlation (r = 0.74) between match injury rates and playing intensity in semi-professional rugby league players. Studies have also reported a higher risk of injury in players with low 10-m and 40-m speed, while players with a low maximal aerobic power had a greater risk of sustaining a contact injury. Furthermore, players who completed <18 weeks of training prior to sustaining their initial injury were at greater risk of sustaining a subsequent injury. These findings provide some explanation for the high incidence of fatigue-related injuries in rugby league players and highlight the importance of speed and endurance training to reduce the incidence of injury in rugby league players.
To date, most, but not all, studies have investigated the movement patterns and physiological demands of rugby league competition, with little emphasis on how training activities simulate the competition environment. An understanding of the movement patterns and physiological demands of specific individual positions during training and competition would allow the development of strength and conditioning programmes to meet the specific requirements of these positions. In addition, further research is required to provide information on the repeated effort demands of rugby league. A test that assesses repeated effort performance and employs distances, tackles and intensities specific to rugby league, while also simulating work-to-rest ratios similar to rugby league competition, is warranted.
This study investigated the influence of fatigue on tackling technique in rugby league players and determined the relationship between selected physiological capacities and fatigue-induced decrements in tackling technique. Eight rugby league players underwent a standardized one-on-one tackling drill in a 10-m grid. Players performed the one-on-one tackling drill before strenuous exercise and following game-specific repeated-effort exercise of progressively increasing intensities (corresponding to moderate, heavy, and very heavy intensity) in order to induce fatigue that was representative of match conditions. Video footage was taken from the rear, side, and front of the defending player. Tackling technique was objectively assessed using standardized technical criteria. In addition, all players underwent measurements of standard anthropometry (height, body mass, and sum of 7 skinfold measurements), speed (10-, 20-, and 40-m sprint), muscular power (vertical jump), agility (L run), and estimated maximal aerobic power (VO2max multistage fitness test). A progressive increase in total repeated-effort time, heart rate, blood lactate concentration, and ratings of perceived exertion occurred throughout the repeated-effort protocol, demonstrating a progressive increase in intensity and fatigue. Fatigue resulted in progressive reductions in tackling technique. Players with the best tackling technique in a nonfatigued state demonstrated the greatest decrement in tackling technique under fatigued conditions. In addition, a significant association was observed between estimated VO2max (r = -0.62) and agility (r = 0.68) and fatigue-induced decrements in tackling technique. From a practical perspective, these findings suggest that strength and conditioning programs designed to develop endurance, change of direction speed, and anticipation skills may reduce fatigue-induced decrements in tackling technique. Furthermore, any defensive drills designed to improve tackling technique should be performed before and under fatigue.
We investigated the movement patterns of small-sided training games and compared these movement patterns with domestic, national, and international standard competition in elite women soccer players. In addition, we investigated the repeated-sprint demands of women's soccer with respect to the duration of sprints, number of sprint repetitions, recovery duration, and recovery intensity. Thirteen elite women soccer players [age (mean +/- SD) 21 +/- 2 years] participated in this study. Time-motion analysis was completed during training (n = 39) consisting of small-sided (i.e., three versus three and five versus five) training games, domestic matches against male youth teams (n = 10), Australian national-league matches (n = 9), and international matches (n = 12). A repeated-sprint bout was defined as a minimum of three sprints, with recovery of less than 21 seconds between sprints. The overall exercise to rest ratios for small-sided training games (1:13) were similar to or greater than domestic competition against male youth teams (1:15) and national-league (1:16) and international (1:12) competitions. During the international matches analyzed, 4.8 +/- 2.8 repeated-sprint bouts occurred per player, per match. The number of sprints within the repeated-sprint bouts was 3.4 +/- 0.8. The sprint duration was 2.1 +/- 0.7 seconds, and the recovery time between sprints was 5.8 +/- 4.0 seconds. Most recovery between sprints was active in nature (92.6%). In contrast to international competition, repeated-sprint bouts were uncommon in small-sided training games, domestic competition against male youth teams, and national-league competition. These findings demonstrate that small-sided training games simulate the overall movement patterns of women's soccer competition but offer an insufficient training stimulus to simulate the high-intensity, repeated-sprint demands of international competition.
A methodology to assess work rate in competitive professional football was designed and validated. The technique required monitoring by observation the intensity and extent of discrete activities during match play and was found to have a measurement error of less than one percent. Performance was observed over 51 games. A complete match typically involved approximately nine hundred separate movement activities per player. The overall distance covered per game was observed to be a function of positional role, the greatest distance covered in outfield players being in mid fielders, the least in centre backs.
Many methods of assessing game intensity that are appropriate to the research scientist- including heart rate analysis (Ali and Farrally1 Carter, A. and Potter, G. (2001). The 1995 World Cup Finals. Where does all the time go In Hughes, M. (Ed.) Notational Analysis of Sport III. UWIC, Cardiff. [Google Scholar]), blood lactates (Deutsch, Maw, Jenkins and Reaburn2 Cleary, M. and Griffiths, J. (1997). Rothmans Rugby Union Yearbook 1997-98. London: Headline Book Publishing. [Google Scholar]) and time-motion analysis (Reilly and Thomas3 Garraway, W. M., Lee, A. J., Hutton, S. J., Russell, E.B.A.W. and Macleod, D. A. D. (2003). Impact of professionalism on injuries in rugby union. British Journal of Sports Medicine, 34;4, 348–351. [Google Scholar] and Withers, Maricic, Wasilewski and Kelly4 Hodges, N.J., &, I.M. (2002b). Modelling coaching practice: The role of instruction and demonstration. Journal of Sports Sciences,20, 1–19. [Google Scholar]) - may have limited application in the ‘real world’. Hence in game analysis, the relative simplicity of videotape recordings may be considered the most appropriate tool for the rugby coach in terms of applicability and reproducibility.
Anecdotal evidence would suggest that since the introduction of professional rugby union, the game has become more intense due to increases in total activity duration and speed of play. Analysis using a modified time/motion approach specifically relating to activity times may provide detailed information on the relative intensity of the game.
The purpose of this study was to compare the time and frequency of activity and ball re-cycling (using videotaped recordings) of International Rugby Union teams in four discrete periods spanning the inception of professional rugby in the mid 1990’s with particular reference to periods spanning the inception of professional status in 1995/6.
Individual activity times (initial possession to completed tackle) were recorded for twelve pre-recorded matches (1988-2002) taken from the Five and Six Nations Championships; using a standard lap split time stopwatch and hand notation system.
Intra-observer reliability analysis of ruck time indicated 0.11sec difference between observations. This represented 96% level of agreement. For activity time, intra-observer reliability was calculated as 0.18 sec difference between observations. This represented an agreement of 97%.
Repeated measure ANOVA indicated highly significant differences between periods activity times (F = 10.16, df = 3 12, p = .001). Post hoc analysis (Tukey HSD) revealed differences to be between period 1 compared to period 3 and period 1 compared with period 4. No main effect was established for ruck time. Analysis of ruck frequency revealed significant differences (F = 13.87, df = 3, 12, p < .0005) between games periods. Post hoc analysis indicated these to be between periods 4 and 2 (p = .003) and 4 and 1 (p = .0005). Repeated measures analysis for frequency of activity revealed significant main effects for period (F = 5.39, df = 3, 12, p <. 01). Results of post hoc analysis revealed differences in activity instances between periods 1 and 4 (p = .01). Analysis of ball in play time comparing pre and post 1995 revealed a significant main effect for period (F = 12.97, df = 1, 14, p = .003) with ball in play 26.5% of the time in the period pre-1995 compared to 32.1% of the time in the period post-1995. This represents a mean time difference of 4 minutes and 45 seconds of play.
It was concluded that since the inception of professional status in rugby union, the mean time players spend in game activity has been significantly reduced, whilst total game activity has been increased. Similarly the frequency of rucks has significantly increased in the post professional era, although the speed of ball recycling has been shown to be relatively consistent during 1988-2002. This indicates that the game activity patterns may have shifted towards a faster ruck dominated game which includes more phases of play. Consequently, game activity time has increased indicating a positive shift in game activity duration. Accordingly, such changes in the game need to be considered in designing training schedules for rugby union.
The purpose of this study was to examine differences in physical performance and game-specific skills between elite and semi-elite rugby league players during match-play. Time-motion analysis was used to determine physical and game-specific skill match demands in 17 elite and 22 semi-elite rugby league players. Physical performance (time, intensity of exercise, frequency, repeated-sprint ability, and speed measures) and game-specific skill measures (ball carries, supports, ball touches, play-the-balls, and tackles) were recorded per minute of playing time. The main findings were that total intensity (elite: 108.9 +/- 10.6 m . min(-1); semi-elite: 102.3 +/- 9.7 m . min(-1)), high-intensity exercise (elite: 36.7 +/- 9.8 m . min(-1); semi-elite: 29.6 +/- 7.8 m . min(-1)), mean playing speed (elite: 6.6 +/- 0.6 km . h(-1); semi-elite: 6.2 +/- 0.6 km . h(-1)), and support play (elite: 0.29 +/- 0.16 . min(-1); semi-elite: 0.15 +/- 0.09 . min(-1)) were all higher during first-half match-play in the elite than semi-elite players (P < 0.01). The elite players experienced decrements in most physical performance measures during the second-half of match-play (P < 0.01), which was not evident in the semi-elite players (P > 0.01). There were no differences in most physical performance and game-specific skill measures for the match between the two playing standards. These results show that while the two standards of competition have similar game-specific skills and physical demands during a match, there is variation within a match according to standard. Specifically, the higher physical demands placed on elite players during the first half could result in the earlier onset of physical fatigue towards the end of a match.
The aim of this study was to investigate the physical demands of international rugby union. Five games in the 1989-90 Five Nations Championship were analysed using video-recordings of live television transmissions. When the ball was in open play, the average running pace of players central to the action ranged from 5 to 8 m s-1. This together with scrum, lineout, ruck and maul was classified as high-intensity exercise. The density of work was measured by timing the work:rest ratios (W:RRs) throughout each game. The mean duration of the work periods was 19 s and the most frequent W:RRs were in the range of 1:1 to 1:1.9. On average, a scrum, lineout, ruck or maul occurred every 33 s. The ball was in play for an average of 29 min during a scheduled time of play of 80 min. To complement the time-motion analysis, blood samples were taken from six players throughout a first-class game. The highest measured blood lactate (BLa) concentrations for each individual ranged from 5.8 to 9.8 mM. Running speed, duration, BLa levels, physical confrontation and, most particularly, the density of work as illustrated by the W:RRs indicate that the game places greater demands on anaerobic glycolysis than previously reported. This has implications for the physical conditioning of rugby union players.
Risk factors for contact injury in elite collision sport athletes
- T Gabbett
- S Ullah
- C Finch
Gabbett, T, Ullah, S, and Finch, C. Risk factors for contact injury in
elite collision sport athletes. Football Sci 8(Suppl. 1): 312, 2011.
A time analysis of men's and women's soccer
- S Miyamura
- S Seto
- H Kobayashi
Miyamura, S, Seto, S, and Kobayashi, H. A time analysis of men's and
women's soccer. In: Science and Football III. T. Reilly, J. Bangsbo, and
M. Hughes, eds. London, United Kingdom: E & FN Spon, 1997.
pp. 251-257.