Rugby Sevens (Rugby 7's) was recently voted one of the new summer Olympic sports and will appear for the first time in the 2016 Olympic Games in Rio de Janeiro (8). Since its inclusion into the Olympic Games program, the popularity of Rugby 7's has attracted increased global attention converting it into one of the fastest growing sports (8). Although several studies have investigated the match-play demands of rugby union (4,6,11), to our knowledge, only one peer-reviewed research study has described the match activity profiles of Rugby 7's players (14). However, the results of this study are difficult to interpret because the activity profile categorization was based on qualitative criteria (14). In addition, no data are available as yet in women.
This rugby code (i.e., Rugby 7's) is played with teams of 7 players with a limited number of substitutions in matches played over two 7-minute halves, with the exception of the finals that are usually extended up to 2 halves of 10 minutes each. This allows players to play several matches in 1 day, and entire tournaments in a day or 2. The scoring and all the laws of the game are similar for both rugby codes (i.e., 15-a side and 7-a side), which combined with the fewer players and a pitch of the same dimensions, produces a far more dynamic and continuous sport (8). Despite the international popularity of female Rugby 7's, there is a clear lack of understanding of the physical and physiological requirements of the sport. A description of the physical and physiological match-play demands of female Rugby 7's will provide relevant data on the specific requirements of female Rugby 7's competition and might assist in the development of rugby-specific fitness training programs and testing protocols. Therefore, the aim of this study was to examine for the first time the match running demands and exercise intensity associated with elite women Rugby 7's.
Experimental Approach to the Problem
In this investigation, an observational design was used to examine the match running demands and exercise intensity during a Rugby 7's competitive tournament. Twelve elite female players belonging to the same national team were investigated during 5 competitive matches in a 2-day international tournament previous to the 2010 European Rugby Sevens Championship. The tournament investigated was contested in June at the end of Rugby 7's competitive season, 3 weeks before the 2010 European Rugby Sevens Championship. All the players investigated in this study were part of the team, which later on claimed the Women's Rugby Sevens European Championship. Portable global positioning system (GPS) technology and heart rate (HR) responses were used to assess match running physical demands and exercise intensity, respectively. All the players were provided with pre-exercise and post-exercise nutrition and the hydration plan developed by the medical staff to ensure adequate nutrient and fluid intake between all matches. Identification of player movement patterns and the associated physiological responses during match play is important for optimizing training prescription and managing player preparation for competition.
Time-motion analysis of running activity was collected from 12 elite female Rugby 7's players (age, 27.8 ± 4.0 years; body mass, 63.7 ± 4.8 kg; height, 165.5 ± 6.2 kg cm; maximal oxygen uptake [V[Combining Dot Above]O2max], 51.1 ± 3.6 ml·kg−1·min− 1; mean ± SD) from the same national team. All the players participated on average in 16 hours of combined rugby (4–5 sessions), strength (3 sessions), and conditioning (2–3 sessions) training and competitive play (4–5 games per weekend) per week. All the players had a minimum of 5 years of rugby-specific training. Written informed consent was obtained from all the players before the investigation. The experimental protocol was approved by the Institutional Ethics Committee.
Match analyses were performed 1–2 times on each player during a total of 5 national team level matches played over a period of 2 days during an international tournament. All the matches were played on the same standard outdoor natural grass fields with 7 players per side. Playing time was 2 halves of 7 minutes each. Three weeks before the tournament, the players undertook an incremental treadmill test. Pulmonary gas exchange (Oxycon Delta de Jaeger, Hoechberg, Germany) and HR (Polar Team System, Polar Electro, Kempele, Finland) was continuously recorded during the test to determine maximal oxygen uptake (V[Combining Dot Above]O2max) and maximal HR (HRmax). The protocol began with 4 minutes of running speed at 8 km·h− 1 followed by stepwise 1-km·h− 1 speed increments every 1 minute until exhaustion. V[Combining Dot Above]O2max was defined as the highest 15-second average recorded during the incremental treadmill test. The HRmax was defined as the highest 5-second average recorded during the incremental treadmill test.
Activity Pattern Measurements
A GPS unit capturing data at 1 Hz (SPI Elite, GPSports, Canberra, Australia) was fitted to the upper back of each player using an adjustable neoprene harness. This GPS system uses signals from at least 3 Earth-orbiting satellites to determine the player's position at a given time and therefore allow the calculation of movement speeds and distance traveled (7,10). Despite a possible underestimation of high-intensity running distance with the time resolution of 1 Hz, a good accuracy (r = 0.97) (1) and reliability (coefficient of variation = 1.7%  and 2.3%) (2) have been reported for the assessment of peak sprinting speed for this GPS device compared with that of an infrared timing system. Moreover, in the absence of a “gold standard” method, the current system has been reported to be capable of measuring individual movement patterns in other team sports (13).
Match Running Demands Analysis
Time-motion data of all the players who participated in the entire first and second halves were retained (n = 17 files from 12 different players). After collection, all match data were analyzed with the software provided by the manufacturer (Team AMS; GPSports, V1.2, Canberra, Australia) designed to provide objective measures of physical match performance. Players' activities were coded into the following categories and speed thresholds: standing and walking (0–6.0 km·h− 1), jogging (6.1–12.0 km·h− 1), cruising (12.1–14.0 km·h− 1), striding (14.1–18.0 km·h− 1), high-intensity running (18.1–20.0 km·h− 1), and sprinting (>20.1 km·h− 1). The speed thresholds for each category were the same to those reported previously by Cunniffe et al. (3) using the GPS technology. Similar to the findings of Cunniffe et al. (3), the above categories were divided into further locomotor categories to provide an estimation of player work-to-rest ratios: (a) low-intensity activity (0–6.0 km·h− 1) and (b) moderate-and-high-intensity activity (>8.0 km·h− 1). The frequency of high-speed zone entries (sprints > 20 km·h− 1) and the highest speed recorded during the game were also collected. Average speed (kilometers per hour) was also calculated from the total distance covered in each half divided by the time spent on the ground for each individual player.
Match exercise intensity was quantified by monitoring the HR during each match. The HR was continuously measured (every 1 second) with short-range telemetry (SPI Elite, GPSports, Canberra, Australia) and was expressed in relation to the individual HRmax reached during the incremental treadmill test. In those players in whom HRs were higher in the course of the match than that determined during the incremental treadmill test, the HRmax values obtained during the game were retained and used in the analysis. The HR data were classified based on percentage of total playing time spent in each of the following 6 HR zones: zone 1 (<60% HRmax), zone 2 (61–70% HRmax), zone 3 (71–80% HRmax), zone 4 (81–90% HRmax), zone 5 (91–95% HRmax), and zone 6 (>96% HRmax).
Data are presented as mean ± SD. Differences between the first and second halves were determined using Student's dependent t-test. Differences between distance covered at different running intensities and time spent at different HR intensities were analyzed using a one-way analysis of variance with repeated measures. When a significant interaction was found, Bonferroni's adjusted post hoc tests were applied. All analyses were carried out with SPSS 15.0 (SPSS Inc., Chicago, IL, USA) software with the level of significance set at p ≤ 0.05.
Match Running Demands
Mean total distance (±SD) covered over the whole match by all the players was 1,556.2 ± 189.3 m, ranging from 1,364.5 to 1,724.1 m. Figure 1 shows the match running profile during each half. There were no significant differences in match running performance between the 2 halves. The players spent longer standing, walking, and jogging (i.e., running speeds between 0 and 12 km·h− 1) than at any other running speed (p < 0.05). Low-intensity activities represented 62.9% of total time, which consisted of 29.7% (462.6 ± 94.6 m) standing and walking and 33.2% (515.9 ± 88.6 m) jogging. Cruising, striding, high-intensity running, and sprinting represented 11.6% (181.0 ± 61.4 m), 16.4% (255.7 ± 88.3 m), 3.7% (57.1 ± 40.8 m), 5.4% (84.0 ± 64.8 m) of the total time, respectively. The player's work-to-rest ratio was 1:0.4 (i.e., for every 1 minute of work, there were 0.4 minutes of rest). The average speed obtained throughout the game was 6.2 ± 0.6 km·h− 1, with no significant differences between the first and second halves (6.3 ± 0.7 and 6.2 ± 0.4 km·h− 1, respectively).
Table 1 displays sprinting performance results obtained during matches. Maximum speed obtained by a player during a match corresponded to 28.3 km·h− 1, and the longest sprint recorded (>20 km·h− 1) was 54.6 m.
The average HR in the first and second halves was 167 ± 9 and 169 ± 10 b·min−1, respectively, with no significant differences observed. HRmax was 188 ± 12 for the first half and 190 ± 10 for the second half with no differences between halves observed. Figure 2 shows the percentage of the playing time spent in each exercise intensity zone expressed as percentage of HRmax. The players spent most of their playing time at HR intensities between 81 and 90% HRmax, with no significant differences observed between halves.
To the authors' knowledge, this is the first study to examine the physical and physiological demands of women 7's match play. The only comprehensive peer-reviewed study on the activity profile of (male) Rugby 7's during competitive matches used notational analysis based on qualitative data and objective running performance (e.g., distance covered) was not provided (14); therefore, comparison of our results is not possible. The results of this study show that, during a Rugby 7's match, a female rugby player covers 1,556 ± 189 m at various speeds, resulting in an average running speed of 6.2 km·h− 1. With the same technology used in this study (i.e., GPS), it was found that male rugby union (15-a side) players covered a total match distance of 6,953 m and exercised at an average running speed of approximately 4.2 km·h− 1 (3). Using different technologies (i.e., video analysis), previous studies have reported that elite, male rugby union players covered average distances ranging from 5,408 to 6,265 m (9,15). Extrapolating the women Rugby 7's playing time to the 15-a side male rugby match duration (∼83 minute), the resulting figure is a game coverage of approximately 8,950 m. Thus, the overall running demands appear to be much higher in female Rugby 7's than in the male a-15 rugby code.
Sprints and high-intensity running actions are important in rugby because these actions are likely to influence the aspects of match play that determine the outcome of a match (15). During a Rugby 7's match in women, 9.1% of the time was spent in high-intensity activities (18–20 km·h− 1) or sprint (>20 km·h− 1), which was slightly lower than the 10.5% previously reported in male rugby union players (3). The average number of sprints (>20 km·h− 1) reported in this study was approximately 3 per half (Table 1). On average, these sprints corresponded to an average distance of approximately 17 m, which falls within the range previously reported in different rugby codes with male players (3–5). Data for maximum sprint distance reveal that Rugby 7's players are also required to sprint over distances around and over 30 m. This implies that specific sprint training should reflect these demands and both short sprints (≤20 m) and long sprints (∼30–40 m) to mimic the demands of the game.
The work-to-rest ratio in this study was 1:0.4, indicating that for every 1 minute of running, there was 0.4 minutes of lower intensity activity. Making comparisons between previous studies on time-motion analysis in rugby is difficult because analysis systems and criteria to classify motion categories have differed across studies (3,4,9,11,14,15). Nevertheless, the work-to-rest ratio values reported in this study are substantially higher than any of those previously reported in other rugby union codes (ranging from 1:2 to 1:4) (3,9,12). This provides further support to the notion that Rugby 7's is played at a much faster running tempo than are the other rugby codes.
Stoppages in play for injury and kicks are responsible for the prolonged rest periods in the 15-aside rugby code (9). Thus, this suggests that stoppages in play are less frequent in Rugby 7's in comparison with other rugby codes. In addition, differences in the number or frequency of other game-related nonlocomotive activities such as pushing and pulling in rucks or scrums can account for this higher work-to-rest ratio reported in this study. These nonlocomotive activities are registered as low running speed activities using the current GPS technology despite the highly intense nature of those static actions (3). Thus, although the work-to-rest ratio reflects total high running speed exercise vs. total low running speed exercise time, it does not accurately reflect the overall exercise intensity associated with the game. In this regard, the average percentage of the total playing time that the players spent at HR intensities >90% HRmax was 30.8%. These values were lower than those previously reported in male, rugby union players where the backs and forwards spent 41.4 and 51.1% of the total time at HR intensities >90% of HRmax, respectively (3). Further studies that combine objective GPS data with qualitative analysis of time spent in nonrunning activities are required to elicit more specific demands of the Rugby 7's game.
The assessment of the external (i.e., running demands) and internal (HR responses) loads imposed during the actual competition is the first step preceding the design of specific conditioning programs and physical fitness testing protocols in Rugby 7's. To the author's knowledge, this study is the first to show that Rugby 7's is characterized by relatively high running demands interspersed with short periods of recovery. This study also suggests that the physical demands of Rugby 7's are quite different from those encountered in other rugby codes. Collectively, these findings provide important information for prescription of training aimed at developing physiological qualities specific to the demands of competitive elite female Rugby 7's. Specifically, contemporary training regimes for Rugby 7's need to meet the apparent increased overall running demands, including high-intensity running training and an emphasis on reduced work-to-rest ratios. In this regard, data on the duration of work and rest periods from this study can be used as a reference value to adapt conditioning training programs to the temporal work demands of Rugby 7's competition and may prove useful for specific conditioning.
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