Rugby as a sport has a vast variety of demands from a physiological point of view. It could be said that rugby is an aerobic sport based on the long distances covered by players over the pitch. On the other hand, the start-stop nature of the game indicates a big usage of anaerobic energy. In this write up the energy systems providing energy for our bodies and their ways of functioning will be looked at. Furthermore, as rugby is played by big strong men, power and strength training regimes will be discussed. Finally, speed and agility are known to impact the performance of rugby players and will be looked at suggesting some methods of practice and training programs.
Our body requires energy for every function from breathing to running. In our body, there are 3 main systems (ATP-PCr, glycolytic and oxidative systems) working together, but very different from one another, which produce energy molecules called ATP from ADP (Kenney, Wilmore and Costill 2012). The systems are using food and stored energy in our body to supply the muscles when exercising. The ATP-PCr system is immediate energy system that provides energy very quickly for brief period of time. An example would be a short 10 seconds all out sprint. This system is anaerobic, which means that does not need oxygen to produce energy. The glycolytic energy system is slower than ATP-PCr, but produces more ATP molecules. The system can work with and without oxygen by using glucose from the blood or glycogen from the muscle to produce pyruvic acid. If there is absence of oxygen the pyruvic acid is transformed into lactic acid (McArdle, Katch and Katch 2000). If there is enough oxygen the glycolytic energy system become the first stage for the oxidative system. The oxidative system is the slowest of all systems, but produces the most ATP molecules using three stages: aerobic glycolysis happening in the cytoplasm, Kreb cycle and the electron transport chain both happening in the mitochondria. An example would be running a marathon. This energy system uses CHO, fat or protein for fuel. In the graph below its shown how the three systems work together during exercise.
Playing rugby requires both strength and power. Strength is the ability to produce force (Finer, Simmons and Spudich 1994). In addition, the muscle fibre cross sectional area is positively related to maximal force production. The bigger the muscle is the bigger the force produced. Power on the other hand is a bit different than strength. The definition of power and the presence of more power is when the same amount of work is produced in shorter period or more work is produced for the same time (Ratamess, Alvar, Evetoch et al. 2009). Power is the product of force generation and movement velocity meaning that it is not limited to the strength of the individual, but also increase with increasing the velocity of the movement.
It is well known that resistance training (RT) increase strength, muscular fibre density and force production. However, the efficiency, safety and effectiveness of strength training programs are very important (Peterson. Rhea and Alvar 2004). Therefore, identifying optimal doses of training variables could prevent injury, overtraining and detraining. In addition, it could lead to maximum gains in muscular strength to be elicited per unit of time. A meta-analysis concluded that the maximum strength gains are elicited among athletes who train at a mean training intensity of 85% of 1RM (repetition max) 2 days per week and a mean training volume of 8 sets per muscle group (Peterson. Rhea and Alvar 2004). The results were very similar between trained and untrained individuals and between male and female showing that the training load of 85% of 1RM is more or less universal. Another study focused on investigating short (2min) versus long (5min) rest period between the sets in hypertrophic resistance training and found that there is no significant difference in muscle strength, size and hormonal adaptations between the two groups (Ahtiainen, Pakarinen, Alen et al. 2005). In addition, the study concludes that the length of the rest periods between sets may not be crucial factor in hypertrophic types as long as the muscles are overloaded with several sets to the concentric failure. This means that resistance training will enhance growth of muscle and increase strength when training with the optimal load of 85% of 1RM and allowing the body to rest from 1 to 2 days’ minimum so adaptation can take place.
Many studies have shown improved power performance using a standard resistance training (Ratamess, Alvar, Evetoch et al. 2009). However, programs consisting of movements with high power output using light loads have shown greater improvements in vertical jump ability when compared to a standard resistance training. When taking into account that power is the product of force and velocity, it is noticeable that heavy resistance training with slow velocities improves force production whereas power training with lighter loads and higher velocities improve the force production at higher velocities. Heavy RT could decease power output unless done with explosive movements (Ratamess, Alvar, Evetoch et al. 2009). Ballistic resistance exercise, which uses lighter loads and higher velocities have been found to limit the problem when the load for upper body training is between 15% and 50% of 1RM and for lower body between 0% and 60% of 1RM. This could be useful in rugby, because of the start-stop nature of the game and the very rapid changing environment. A study compared the effect of high-load versus high-repetition training on endurance performance (Ebben, Kindler, Chirdon et al. 2004). The results of the study show that both H-load and H-rep improve endurance performance however, after 8 weeks of training the high-load resistance training showed better adaptation in athletes with high pretraining status whereas, the high-repetition training showed greater effect on athletes with lower pretraining status. Taking this into account the high-repetition training could be more suitable for a beginner and the high-load training for an athlete that is already fit to some level to enhance endurance performance.
In Rugby, the players have to sprint from short to medium distances and be able to stop as quickly as possible or change direction. To improve their speed and agility normal training for endurance and long distance running could not be the best method. “SIT” is a sprint interval training, which has been proven to be very powerful when comes to improving speed, agility and cardiorespiratory fitness. Investigation on four weeks of running sprint interval training was made by a study (Willioughby, Thomas, Schmale et al. 2016). The study had 28 participants, 14 aged from 20 to 30 years of age and 14 aged from 40 to 50 years of age. The results between the young and older participants were compared by the study to get a better understanding. The participants completed 4 to 6, 30 seconds all-out sprints on a curved treadmill, separated by 4 minutes of active recovery, 3 times a week. The results of the study showed improvement in relative VO2max and the average sprint speed in both young and old participants. The study demonstrated that 4 weeks of “SIT” training improved aerobic and anaerobic fitness in younger and middle aged adults. Those results are backed up by a systematic review and meta-analyses (Gist, Fedewa, Dishman et al. 2014). The meta analyses found that SIT significantly improve skeletal muscle oxidative capacity, maximum oxygen uptake and endurance performance in healthy young people. Furthermore, SIT is an equally effective alternative when compared to continues endurance training of moderate intensity, but with lower volume of activity. In addition, results found by another study indicate that with proper planning and implementation HIT and RSA (High intensity interval training and Repeated sprint ability) could not only enhance athletes performance, but also can help reduce training time and carry a greater degree of specificity for field-based sports such as rugby (Hoffmann, Reed, Leiting et al. 2014). The literature shows that practising SIT for at least 3 to 4 times a week will improve performance and general health in young healthy individuals. In addition, the greater degree of specificity of the training will have a direct impact on the performance of the athlete in game.
To conclude, rugby as a sport is very dynamic and have many demands from physiological point of view. Having to compete with very fast, strong and heavy men and survive requires becoming one. Resistance training would help building muscle and being more stable as well as gaining more weight if done correctly. When combined with lighter weights and faster repetitions at higher velocities, resistance training will lead to greater improvements of power output in shorted durations. Furthermore, endurance training with weights would be beneficial for the player as the game require a lot of stamina. Sprint interval training will improve a very big side of the performance of the athlete as it will increase cardiorespiratory fitness and sprint ability. The workouts are essential for becoming a semi-pro rugby player and must be well managed.
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References
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