Rugby - Assessment of training needs
Team sports like rugby are classed as 'intermittent sprint sports' because, in the course of a match, players will alternate between sprinting, running, jogging, walking and standing. Rugby matches are like random interval workouts and include sport specific activities such as rucking, mauling and scrummaging. These are game specific tasks and like sprinting, they are high intensity activities. When rugby players perform these high intensity activities, their anaerobic systems provide the required energy, while the aerobic system predominates during the low intensity activities.
If the high intensity periods are short, less than 10 seconds, and recovery times between efforts are relatively long, 60 seconds or more, then the phosphocreatine (PC) system will be the key energy source. This is the simplest and most rapid means of energy production, in which phosphate (donated by PC) and Adenosine Diphosphate (ADP) combine to make Adenosine Triphosphate (ATP). During the low intensity periods, the aerobic system will replenish PC stores, ready for the next high intensity effort.
However, PC stores can provide energy for only about 10 seconds of activity. So, if the high intensity periods are of intermediate length, 10 to 45 seconds, or the recovery times are relatively short, 20 to 40 seconds, then the glycolytic system of anaerobic energy production, involving the breakdown of carbohydrate within muscle cells to release energy, comes into play. Similarly, short periods of high intensity work, interspersed with recovery times that are too brief for complete replenishment of PC stores, also bring the glycolytic system into play.
Demands of player position
To understand the key physiological demands on the players, so that we can help them train for top performance, there are two interesting questions about rugby:
Recent research in New Zealand analysed the time and motion of 29 top class professional rugby union players during the course of eight professional 'Super 12' matches in New Zealand.
Players were placed into one of four positional groups:
The hooker was placed in the back row group as they have a roving role at lineouts and do not push as much in the scrum as other front row forwards. The scrum half position was not analysed. One or two players from each positional group were analysed during each match.
The researchers broke down player movements as follows:
They then analysed the amount of time spent in each category of movement and the frequency and average time of each individual activity. The key data is summarised in the table below.
As you can see, both front row and back row forwards complete many more high intensity efforts per match than backs, with front row forwards performing over three times more than outside backs. While the average duration of high intensity efforts are similar, at around five seconds, across all four positional groups, the average rest periods for the forwards are significantly shorter. Since both sets of forwards only get to enjoy around 35 seconds of recovery, their PC stores will not be replenished and so the glycolytic energy system will be very important for maintaining the work rate required.
Backs, by contrast, get plenty of recovery time between high-intensity efforts, 88 to 115 seconds, which is easily enough time to replenish PC stores. The PC system will be most important for backs.
The researchers also found that the type of high intensity activity varied between positional groups. Of the different types of high intensity activity, front row forwards performed fewer sprints, while backs performed more high intensity runs and sprints. Back row forwards and inside backs completed an average of 7 sprints per match and outside backs an average of 11.
By contrast, forwards were involved in many more rucks, mauls and scrums than backs. Front row forwards, for example, were involved in an average of 75 rucks/mauls and back row forwards in 57, while inside and outside backs were involved in only 11 and 7 respectively.
This data leads to the following conclusions about the key differences between forwards and backs:
Interval training for anaerobic fitness
Clearly, forwards need to develop good anaerobic fitness, specifically targeting the glycolytic system. The best way to train this system is through interval training, making sure that work periods are sufficiently long, 20 to 40 seconds, and rest periods long enough to allow athletes to repeat the work but not recover completely, 40 to 90 seconds. For example:
However, as forwards tend to perform more high intensity 'physical work' than running, performing intervals on a rowing machine might be a better. For example:
Even more specific to the demands of match play would be interval workouts that combine 'physical work' with running. This would prepare players to work intensively and make appropriate transitions between upper body/trunk strength tasks and running. Players could work in pairs to push or wrestle with each other and then run a fixed distance, with the combination of push/wrestle and run counting as one interval repetition. For example:
This kind of workout would provide a close match of both the energy system and physical task demands of forwards' match play.
Backs, by contrast, need high anaerobic power, targeting the PC energy system. Interval training is also a very effective route to PC fitness, but the work intensity must be higher and the rest periods longer than with intervals targeting the glycolytic energy system; 5 to 8 second repetitions and rest periods lasting a minimum of 60 seconds would be highly appropriate. For example:
For backs, this sprinting workout would be highly sport specific, reflecting the amount of high intensity running they perform in matches.
Aerobic fitness is important for both backs and forwards, since the aerobic system will provide most of the energy for movement and replenishment of PC stores during all low intensity activities. Forwards will also use their aerobic systems to provide energy for the longer high intensity or shorter recovery periods, providing valuable back up for the anaerobic glycolytic system.
As far as aerobic endurance training is concerned, the rowing machine may still be the best activity choice for forwards, with running best for backs. A combination of continuous steady state training and interval workouts would be an effective approach. For example:
Workouts that are more specific could be developed by performing shuttle runs instead of straight runs as intervals to increase the agility running component for backs. In addition, sessions incorporating circuit exercises to develop pushing and wrestling strength would be useful for forward players.
The reference for this page is:
The following Sports Coach pages should be read in conjunction with this page:
The following books provide more information related to this topic: