Fitness standards for Rugby
Followers of rugby union will recognise the varied type of physical performance qualities required for the game, including the ability to accelerate or sprint at maximal pace for short periods (e.g. three seconds), maintain a fast striding pace for the duration of the average move (e.g. eight seconds), recover during differing rest periods to repeat these types of exercises, jump, change speed and direction, use upper body muscles, and so on. In short, sports scientists use the term "high-intensity intermittent exercise" to describe this form of activity.
One method of determining what kind of demands an actual rugby match imposes on a player is to video a competitive game and later follow each player around the pitch while noting the time spent performing different activities. This has been done by researchers in Canada (Docherty and colleagues, University of Victoria, British Columbia) and revealed an average of 47% of time spent walking or jogging, 6% running or sprinting, 9% tackling or competing for the ball and 38% standing. While the low-intensity exercise periods predominate, periods that are the crucial, competitive phases of the game, and thus these should be concentrated during training on the high-intensity.
In more detail, a comparison between the centre and prop positions showed the centres to sprint for >3% of the time, but the props for <1%. In contrast, the centres spent <4% of the time competing for the ball, whereas props were involved in this activity for 16% of the time. Logically, the training structures of these players should reflect their specific demands - centres should spend more time on acceleration and sprint work, while props should concentrate more on muscle strength and size. Any coaches who still expect their entire squad to perform the same drills on training nights are sadly out-of-date. The arrival of true professionalism and any minor law changes that may be made will only emphasise fitness standards approaching those of track and field athletes.
So, what are the fitness standards?
What should the players and coaches aim for, given the known demands of the game? Several recent scientific studies help us to answer this question. These studies describe the physical attributes of current elite players, and several have appeared since organised squad sessions, and scientific support has become commonplace. Much work has focused on Welsh, English and United States players. Other early work in the UK concentrated mainly on university-level players and gave generalisations of body size and shape only. Let us, therefore, look at the recent studies of first-class players.
Although not a world rugby power, the US has an excellent national team. Besides, data about national players are usually hard to come by, and any insight is welcome. A complete presentation of information about a large number of elite players has been given by San Diego State University in California researchers. The data, in this case, was obtained during a national squad training week that involved 65 players.
Findings that forwards were taller (average 187cm), heavier (average 99kg) and more muscular than backs (average 179cm, 81kg) matched their role as competitors for the ball in both set play and loose play. The additional finding of higher body fat among forwards is common but hard to justify. A particular advantage from higher body fat may be gained in contact situations from the increased momentum (bodyweight x speed) compared to a lighter, leaner opponent. This advantage may prove decisive at lower levels of play, where body weights are generally less. However, a player of similar weight with more significant lean tissue is likely to be stronger, faster and more agile, and better able to control body temperature in hot conditions.
The answer for a forward is, therefore, to increase lean body weight at the expense of fat mass, such that body fat <10% (as opposed to the observed average of 13.5% for the US forwards) and body weight is 90-120kg, depending on the specific position. For the backs, the ability to change direction, accelerate and run at speed are the essential components of rugby fitness. In the US study, backs generally performed better on measures of speed and power relative to body weight. It is consistent with the positional demands just described.
For instance, the average 40yd sprint time was 4.8secs, compared to 5.1 seconds for the forwards. Vertical jump heights were 62cm for the backs but 58cm for forwards. Again, the body fat percentage should be in single figures (9.2% in the US study). Still, total muscle mass is less critical - the ability to use the muscle mass to move the body quickly over short distances (power and- speed movements) should be the important area for training.(Carlson et al. 1994).
Breaking down the data
A study involving the Liverpool, Waterloo and Leicester teams was carried out at Liverpool by P. Rigg and T. Reilly. Professor Reilly has been at the forefront of the application of sports science to team games in the UK. Apart from the findings reported in the US study, these researchers also broke down the data to distinguish between individual forward and back positions. Expected results were found in that second rows (usually ball-winners at the lineout) were the tallest players (average 197cm) and half-backs the shortest and lightest (in keeping with their role of gathering loose balls and evading tacklers). Front-row players were found to have the greatest upper-body strength, while all backs appeared faster than forwards in sprint tests. Outstanding on an analysis of anaerobic power and capacity were the back-row forwards, who also performed well on all other tests. It perhaps reflects their role as links between the forwards and the backs. They are required to undertake heavy physical contact during rucks, mauls and tackles while also being expected to sprint and cover large distances at speed in support of play.
Low VO2 max values for the Welsh
An analysis of Welsh Division one player gave further evidence of the power and strength necessary to compete at the highest level. Researchers at Loughborough and Cardiff collaborated to find the average height, weight and body-fat values of 186cm, 97kg and 11.3% for forwards, and 178cm, 79kg and 8% for backs. Lean tissue predominates, with substantial muscle mass observed among the forwards. A sprint shuttle run totalling 40m with two turns again showed the backs to be better sprinters and more agile than the forwards (8.4secs compared to 8.7secs).
However, the VO2 max values of 52 and 56 for forwards and backs were not as high as expected or desired. Although the most critical periods of the game of rugby are of an intensity that requires anaerobic energy production, the ability to recover sufficiently between plays will depend mainly on the ability to deliver oxygen to the muscles. However, the ability to maintain high levels of both aerobic and anaerobic fitness simultaneously is a difficult one. (Nicholas and Baker 1995).
Other researchers in Cardiff, working as part of the Sports Science Support Service, looked specifically at any physical differences between the Welsh national squads at senior (37 players) and under-21 (42 players) levels. Very few differences were found, except for the more significant bodyweight of the senior players, which could be identified as extra muscle tissue. The observation supported this finding that the two squads' average 3-Rep Max on a bench press was far more significant for the senior players. Average weights achieved for the whole squads were 83kg and 99kg for the under-21 and senior players, respectively. Also of note was the extensive range of scores within each team, with the forwards displaying greater upper-body strength in absolute terms and relative to body weight.
Fitness changes in the England squad
An exciting study on the English squad was carried out at Loughborough University, which considered any fitness variations observed throughout one year. The pre-stated aim for the players was a peak for the International season beginning in January.
Findings showed some subtle changes - aerobic power, speed (30m sprint), and body composition improved over the 12 months. It led to the effectiveness of the current training programs on these variables. Short-term changes were a selective reduction in body fat and corresponding increases in aerobic power and speed during the offseason. Speed also improved slightly during the season (end peak 4.3secs and 3.9secs for forwards and backs respectively over 30m), and a further reduction in body fat was noticed approaching the intended peak fitness time (13.3 and 11.4% respectively for forwards and backs just before the major international matches). However, the heavy match schedules and reduced training time perhaps limited the range and size of improvements that might otherwise have been possible. The closer analysis may have shown certain player positions such as props to increase other fitness qualities concentrated during the offseason - upper-body strength, for example.
Back to energy systems
One area of more theoretical debate concerning the demands and fitness requirements of rugby union is related to the energy systems used during a match. It is accepted that aerobic power is necessary to recover between intense bouts of exercise. It is also assumed that the short-term energy system, mainly the phosphocreatine system, is repeatedly stressed and should be concentrated on during training (i.e. periods of intense activity for <10 seconds). However, the extent to which the lactic acid system is used during a game is unclear. Players may well testify that extreme fatigue (classically given by a build-up of lactic acid) is felt during a competitive match (and I can vouch for this from my own experience). However, scientific observation does not seem to support the idea that the lactic-acid system is stressed significantly for most rugby players.
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