Rugby is a multi-activity sport played over 80 minutes. The game can be described as a discontinuous, high-intensity, multi-activity sport. Each player's physique and body shape can differ dramatically and each position makes its own unique physical demands on the player. The physical fitness demands of the game include multiple acceleration and sprint efforts over distances typically up to 25 metres for players in general. The outside backs can cover greater distances at top speed whereas the forwards tend to reproduce shorter distances of explosive acceleration bursts more frequently. Multi-directional activities including weaving, running sideways, side-stepping, stepping backwards, in addition to straight line running are constantly repeated by all players. Total body encounters are frequent in the form of tackles, collisions, scrums, mauls and rucks. To cope with these demands players are required to have well-developed levels of strength, power, speed, multi-sprint endurance, agility and mobility.
In general, Rugby conditioning programmes often include aerobic or endurance training with the goal of establishing an "aerobic base". Aerobic training is generally completed in the off-season or early pre-season periods to enhance the player's ability to endure or last the game. However, training to improve a player's aerobic base may be more harmful than beneficial to the rugby player. Lets look carefully at the energy demands of rugby. This will help clarify why an emphasis on endurance training is not necessary.
Energy Requirements of the Game
High aerobic fitness levels are common in athletic events such as 5,000m, 10,000m and marathon running. The aerobic energy system contributes more and more to the energy supply of these distance events as the event distance or its duration increases. The high aerobic fitness levels noted in distance athletes are important in maintaining an unbroken, continuous speed/pace effort. Frequently aerobic fitness is measured in terms of aerobic capacity or VO2 max. The levels found in top distance runners can range from 65 ml/kg/min to 80 ml/kg/min. The average fit male adult has a VO2 max of approximately 40-45 ml/kg/min. The average VO2 max for a top class sprinter can be from 50-60 ml/kg/min. The VO2 max of Rugby players differs widely and can be from 45 ml/kg/min for heavy front row players to 65 ml/kg/min for 2nd row and back players.
How relevant is a high VO2 max to Rugby? Remember that Rugby is not a continuous unbroken or steady state activity. It consists of multiple activities which demand constant changes in pace and intensity of effort. If you ask a distance athlete who possesses a high VO2 max to repeatedly slow down or stop and then accelerate he will find this most uncomfortable. This is because he does not possess the muscular strength in the legs to change from a stationary position to a flat out pace or to repeatedly change direction while accelerating or decelerating. He lacks the strength and explosiveness to do this rather simple feat. In contrast doing this repeatedly is critical for a Rugby player. The reason that the distance runner lacks this type of Endurance conditioning is mainly twofold
1) he has completed a high volume of steady paced running which blunts his speed, strength and explosiveness and
2) he does not complete regular speed, strength or power training.
Rugby can be classified as an anaerobic sport because of the intermittent high intensity nature of the game, with speed, strength and power activities dominating (Figure 1). The high intensity fuel required for strength, speed and power efforts has to be in good supply. Having a plentiful supply of this high energy fuel in the explosive muscles is important in rugby. This fuel comes from the ATP-PC system. In order to ensure that the explosive muscles have a good supply of this high-intensity fuel they must be trained in a high-intensity manner - using speed, strength and power as the foundation of training. The muscles must get sufficient time to recover between bouts of high-intensity sets and exercises during a training session so that the fuel stores can be repleted. Good recovery strategies must also be a feature of the weekly training programme as fatigue can accumulate over a number of training sessions. Therefore a proper mix of speed, strength, power, agility training and recovery is critical to developing the energy system required to play high-intensity rugby. Interference in developing strength, power and speed can occur if the muscles are exposed to too much endurance training.
The endurance athlete in contrast relies on a different fuel store to supply energy for the endurance effort - he relies on the aerobic energy system to fuel his activity. This energy comes from a mix of carbohydrates and fats. These fuels do not supply energy fast enough to fuel a quick burst of acceleration. Figure 2 demonstrates the importance of the high-intensity fuel stores to short fast bursts of activities.
A review of the main energy systems will indicate that the anaerobic system is primarily responsible for activities that last from less than 1 second to I.5 minutes in duration. This pathway is composed of the ATP-PC and glycolysis systems. As the length of the activity increases, the aerobic system becomes increasingly responsible for supplying energy (see Figure 2). Remember, all of these systems are functioning at the same time. The intensity and the duration determines the extent to which each is used.
While it is agreed that the aerobic system plays an important role in recovery, it is not agreed that including aerobic training in the programme will improve the performance of players involved in anaerobic sports, such as rugby. A look at the adaptations to training should suggest that the use of aerobic training for this purpose is not necessary and may limit improvements in performance.
The design of any conditioning programme must be based on an analysis of the primary energy sources and mechanical movement patterns for the particular sport. As stated the energy system taxed by endurance training is different to that required by the rugby player to complete high-intensity multi activities.
It is often suggested that an enhanced aerobic endurance capacity will enable players to meet the energy demands needed in the later stages of a game. However, few sports go non-stop from beginning to end. Game activity is likely to be disrupted by a ball going out of bounds, by fouls, breaks during play, by injuries to players and the interval break.
It is not a question of whether the player can last the game rather it is a question of how well the player can reproduce over the 80 minutes the high-intensity bouts of activity that are required of him during play.
Also, it has been reported that there is little relationship between aerobic endurance and anaerobic performance. In a recent study on the relationship between aerobic power and anaerobic performance indices, Koziris et al. found little correlation between the two. Their conclusion was that since the relationship is so poor, it is not necessary to focus specifically on enhancing the aerobic system to improve performance in anaerobic type activities. back to top
Specificity - An Important Principle
The principle of specificity dictates that the mode of activity used in training will influence the adaptations seen in the energy and neuromuscular systems. The neuromuscular system refers to the muscles and nerves supplying the particular muscles. Aerobic activities of a slow and continuous nature tend to recruit primarily slow-twitch fibres. Endurance training adaptations will occur mainly within these fibers.
Activities of a start and stop nature that utilize the fast-twitch fibres depend primarily on the anaerobic system. The physiological changes due to start and stop type training such as speed and power training occur mainly within the fast-twitch fibres. Anaerobic training will also increase the ability to withstand higher levels of blood lactate, increase aerobic power, and thereby enhance recovery. Thus anaerobic training such as interval training will improve a players ability to recover between intense bouts of activity. It has previously been demonstrated in rugby players that strength training alone will maintain endurance levels as well as improving speed, power in addition to strength.
Examples of Anaerobic type training include interval training. Significant increases in aerobic fitness (i.e an increase in VO2 max) can be expected following this type of training. In addition the ability to recover from high-intensity bouts is also improved. Therefore, contrary to popular opinion it is clear that strength training in conjunction with anaerobic type training is more productive for Rugby players compared to aerobic type training.
Aerobic conditioning is generally used to help one progress to intense anaerobic training. However, due to decreases in strength and power associated with aerobic training, and the time constraints of most programmes, this may not be appropriate. By manipulating work-to-rest ratios and distances covered during interval training, one can change the intensity of the workout and still maintain the appropriate energy system adaptations and muscle fibre type recruitment patterns.
Anaerobic training is important not only for obtaining specific energy or metabolic adaptations. Activities that incorporate similar joint angles and ranges of movements, contraction modes, and speeds of contraction that are similar to the actual movement demands of the position of the player provide for essential neuromuscular development. To be prepared for Rugby competition, the player must train with Rugby specific actions and speeds. This method of training allows the gross motor adaptations gained from the strength and power portion of the programme to be refined into more applicable Rugby skills. back to top
For most programmes that follow periodisation, the training year is divided into 3 periods: Pre-season, In-season, and active rest. The pre-season is generally a time to regain or increase muscle size and strength. It is not prudent to emphasize aerobic training during a period in which the goal is increased muscle strength and size, since aerobic training is associated with decreases in muscle strength, power and size.
Using interval training to enhance anaerobic endurance would be more appropriate. Interval training can be designed to be lower in intensity than sprint training while ensuring that the appropriate neuromuscular patterns are maintained. Speed training can be completed in the early and late pre-season.
The guidelines of progression should be followed, focusing on developing the ATP and ATP-PC systems for enhanced quickness, speed, and power. Many programmes proceed from a general period of higher volume and lower intensity to a specific period of lower volume and higher intensity, which may include shorter distance sprints, agility drills, plyometrics, and specific Rugby drills and activities.
The fitness goal during the In-season is to a) recover from the demands of playing and b) to maintain the strength/power and conditioning levels that were developed during the previous pre-season periods. Due to the intense nature of team training at the professional level in Rugby, a high volume of anaerobic fitness training may not be advisable during the In-season. Rugby practices may be sufficient to provide the necessary maintenance for most players. Additionally, recovery training is important as it speeds up the recovery process thereby allowing the player to commence maintenance training. A recovery session typically would take place in the swimming pool with the emphasis on low to moderate intensity swimming and post exercise flexibility maintenance. Following this maintenance training is advisable for strength and power and typically these sessions may be cycled with 1 and 2 conditioning sessions on alternate weeks. back to top
Unloading - planned recovery periods
Unloading training or planned recovery periods between intense training periods, are important if the player is to recover and benefit from training. A planned unloading week every 3-5 weeks is recommended. The goal here is to allow the player to recover from the cumulative fatigue that will have built up over the previous weeks of intense games and recovery/maintenance training. The unloading or 'easy' week should exploit the principle of variation. This means doing different activities during training times or changing the training venue if possible but most importantly it requires a reduction in the total training volume. This will serve to ensure that the player does not overreach (a condition that precedes the debilitating state of overtraining), and this break from training will allow him to enter the next series of games and training with a renewed freshness. back to top
Aerobic training IS useful and important
One important time for aerobic conditioning is during the unloading week and during the Active rest period. A player can engage productively in non-impact steady state aerobic activity during these periods. Also, injured players will find aerobic training effective when other forms of training are limited. Active rest is a period during which activity of a non sport specific nature is recommended. It is during this period that the player should take a complete break from his sport and the sporting environment. This gives the player the opportunity for complete recovery and rejuvenation before starting the Pre-Season for the following year. Since most programmes have restrictions governing the time a player can spend in training, it is important that every effort be made to use that time effectively.
This may not be the case if aerobic training is a component of the conditioning programme as a means of progression or to provide an aerobic base. The use of aerobic or endurance exercise in this manner is not supported by current research. In fact the data and anecdotal evidence indicates that, for most players involved in anaerobic sports, aerobic exercise may be counterproductive to performance. back to top
Rugby is a multi-activity sport and involves brief high-intensity bouts interspersed with low to moderate periods of activity. Training to meet these demands should commence with a matching of training to the actual movement and energy requirements displayed during the game. The principle of Specificity needs to be applied when designing any fitness training programme. This helps the coach and player to be better prepared for the demands of the game. A periodised plan allows for all the demands to be catered for in a structured manner. Unloading and recovery are key elements in any periodised programme and often these are neglected. Aerobic training is useful but the coach and player should not overemphasise this form of training as it has been shown to be counterproductive to developing speed, power and strength. back to top