Training the energy systems for improved repeated sprint ability in rugby league

The activity pattern of many game sports is intermittent based, shifting between brief periods of maximal or near maximal work to periods of moderate and low intensity activity. These periods of maximal work also known as the games players repeated sprint ability (RSA) are vital as the athlete has to be able to perform short duration sprints with often, brief recovery periods (Girard, Mendez-Villanueva & Bishop, 2011).

While recent studies suggest fatigue and playing intensity contribute to injuries in rugby league (Gabbett, 2004) and a study by Gabbet and Domrow (2005) reporting players with low 10 metre and 40 metre sprint speeds have a higher risk of injury than those who are quicker, it highlights the importance of repeated sprint ability within rugby league. Taking the above findings together with reports from Bishop and Edgem (2006), who conclude athletes with greater aerobic fitness have a superior ability to resist fatigue during repeated sprint exercise, what reason do you have to not include both aerobic and anaerobic training into your programmes to improve RSA!?

The underlying principles

The two energy systems are known as the aerobic and the anaerobic systems. Gastin et al (2001) divides the anaerobic energy system in to two components named the alactic and lactic components. The alactic component refers to the processes involved in splitting Adensine triphosphate (ATP) and phosphocreatine (Pcr), with the lactic component involving nonaerobic glycolysis.  

Alactic component of the anaerobic energy system

Within the body, muscle stores of ATP are typically between 20-25 mmol/kg (Glaister, 2005) and with peak ATP turnover rates of around 15 mmol/kg stores deplete after 1-2 seconds of maximal activity (Glaister, 2005). ATP then needs to be synthesised through a variety of metabolic processes in order to provide sufficient energy to meet demands.

Phosphocreatine is important during explosive activities that demand a high release of energy, such as sprinting. Resynthesis of ATP is driven by a reaction between PCr and Adensine phosphate (ADP) which results in the formation of ATP and creatine (Glaister, 2005). Intramuscular stores of PCr are approximately 80 mmol/kg dm (dry muscle) (Gaitanos et al, 1993 & Bogdanis et al, 1998). As maximal turnover rates of PCr can reach 9mmol ATP/kg dm/sec high intensity exercise can see stores depleting within 10 seconds (Glaister, 2005). It is therefore imperative that we train the body in order to replenish these stores as quickly as possible, enabling the body to repeatedly perform at a high intensity.

Lactic component

The breakdown of muscle glycogen to glucose and then ATP is known as anaerobic glycolysis. 3 molecules of ATP along with by products of hydrogen and lactate are produced through this process, which is activated rapidly at the commencement of high intensity activity (Glaister, 2005). Anaerobic glycolysis can reach peaks of between 6-9 mmol ATP/kg dm/sec as reported by Parolin et al (1999) and Hultman & Sjoholm (1983) after approximately 5 seconds of work (Gastin, 2001)

Aerobic energy system

Aerobic metabolism involves oxygen molecules in the reactions that provide energy (ATP) (Glaister, 2005). During maximal work aerobic ATP resynthesis is predominately achieved through the oxidation of glucose (Bangsbo et al, 1992 & Bangsbo et al 2001). Glucose reacts with oxygen, ADP and inorganic phosphate ions Pi to produce 38 ATP molecules along with by-products of water and carbon dioxide (Glaister, 2005).

Which of my athletes’ energy systems should I train to gain the best results?

Both! Recent studies have shown that not one type of training can be recommended to improve repeated sprint ability of games players as it is such a complex fitness component.

Pie charts showing the contribution of aerobic metabolism (a) during the first sprint and (b) the tenth sprint. (Girard, Mendez-Villanueva, Bishop, 2011)

Work conducted by Gaitonis et al (1993) on muscle metabolism during high intensity intermittent exercise found that glycolysis accounted for 44% of total anaerobic ATP provision during the first sprint while the 10^th sprint was 16% with 4 of the 7 participant’s anaerobic provision during the 10^th sprint estimated to be 0. Presenting more evidence that training athletes repeated sprint ability needs to become smarter, by developing a training plan that can address both of the energy systems and train athletes effectively in order to meet the demands of the modern game.


The training principles

In the 2011 repeated-sprint ability part II review  by Bishop, Girard and Mendez-Villanueva the authors recommended two key points from previous literature in order to improve RSA. To include some training that improves single-sprint performance (training the anaerobic system) using occasional high-intensity training. The second key point being that it is also important to include some interval (training the aerobic system) training to improve the ability to recover between sprints. Therefore the following two plans were designed specifically tailored to rugby league in order to combat these two points.

"It is essential that training should prepare the players to cope with the most taxing elements of rugby league match-play, to ensure that the players are not under-prepared” King, Jenkins & Gabbett (2009)

Anaerobic training to improve single-sprint performance

Bishop, Girad and Mendez-Villanuvea (2011) report that high-intensity training to improve single performance sprint speed should involve repeated periods of work separated by ~ 10 minutes of recovery.

 

(Image courtesy of The Sunday Telegraph (2010))

Giving Usain Bolt a run for his money. Through gritted teeth Bolt just manages to beat the rugby league players after their successful sprint training sessions.

To make the drill rugby specific data reported by King, Jenkins and Gabbett (2009) from a study on time motion analysis from a rugby league match has been included into both of the training programmes. The authors reported that the mean work ratio of the players was 1:5 and the longest period of time players spent performing high intensity activities was 35 seconds. The programme to work on the anaerobic energy system and improving single-sprint performance is as follows:

·         6 x 35 second all-out sprints with 175 seconds of rest

There are 6 repetitions of this as 6 phases are made in one play by a team.

·         Players start on the back line and upon commencement of timing 35 seconds begin sprinting to the half way line

·         Touch half way line and sprint back to the line

·         Repeating this process till the 35 seconds is up signalled by the coaches whistle, timing of 175 seconds rest begins

·         Players stop sprinting and walk back to the starting point

·         Process is repeated a further 5 times, totalling 6 sets in all 

The evidence that supports this programme

A drop in intramuscular phosphocreatine along with a rise in Pi and adenosine monophosphate activate anaerobic glycolysis at the start of high intensity work such as sprinting (Crowther et al, 2002). It  is evident that anaerobic glycolysis plays an important role in the synthesis of ATP during sprint performance (Gaitanos et al, 1993) and improving the maximal glycolytic rate will in turn improve RSA. This is also supported by Gaitanos et al (1993) who reports that athletes with a greater glycolytic rate have also been denoted to have a greater initial sprint performance. And that there is a strong correlation between initial sprint performance (Gaitanos et al, 1993) and total sprint performance (Bishop, Lawrence & Spencer, 2003 & , Pyne et al, 2008). With more evidence in support by Bishop and Schneiker (2008) that increasing the anaerobic contribution is likely to improve both initial and mean sprint performance and consequently the athletes RSA.

Aerobic training to improve the ability to recover between sprints

Bishop, Girad and Mendez-Villanuvea (2011) report that to improve fatigue resistance, work that involves high intensity interval training broken up with rest periods that are shorter than the period worked for is efficient to increase aerobic fitness and the rate of phosphocreatine resynthesis.

High intensity work as classified by King, Jenkins and Gabbett (2009) were activities such as sprinting, striding and tackling. The following plan incorporates striding and wrestling to imitate tackling as part of the high intensity component of this programme.

• 6x(2min run & wrestle, 1 minute rest)

·         Players work in pairs. One of each pair starts back-to-back on the halfway line, facing there try line.

·         Both start striding on instruction of the coach when timing of 2 minutes begins

·         Players touch the try line and stride back to half way (faster complete the striding = more time wrestling).

·         Players meet back at the half way line and get down on knees to begin wrestling

·         The aim is to get the other players back on the ground. If successful players keep repeating this until 2 minutes is up.

·         When 2 minutes is up coach blows to signal stop and times the 1 minute rest.

·         Process is repeated a further 5 times, totalling 6 sets in all.

This type of high intensity interval training aims to combat the recovery times between sprints targeting to improve the time it takes for phosphocreatine to resynthesize. Research  by Dawson et al (1997) and Borgdanis et al (1996) shows that brief recovery times, as players experience in game situations,  lead to partial restoration in PCr and as PCr is needed for high intensity work it is vital that this area is improved through training. A study by Bishop et al (2008) concluded that completing a high intensity interval training programme of 6-12 sets of 2 minutes at ~100% VO2 max with 1 minute rest can significantly improve phosphocreatine resynthesis.

Recommended alterations to the programmes

In order to make the programmes more specific to playing positions the work to rest ratio stated in the anaerobic training programme can be changed. Based upon reports my King, Jenkins and Gabbett (2011) who found the following specific work to rest ratios according to playing position:

·         Outside backs 1:6

·         Hit-up forwards 1:6

·         Adjustables 1:5

The time spent sprinting could also change as the authors likewise found the longest time spent in high intensity work specific to playing position that is as follows:

·         Outside backs 27 seconds

·         Hit-up forwards 22 seconds

·         Adjustables 35 seconds

The anaerobic training programme tailored specifically to playing position can be used and is as follows:

·         Outside backs 6x(27 seconds sprint, 162 seconds rest)

·         Hit-up forwards 6x(22 seconds sprint, 132 seconds rest)

·         Adjustables 6x(35 seconds sprint, 175 seconds rest)

But, as stated by King, Jenkins and Gabbett (2011) “It is essential that training should prepare the players to cope with the most taxing elements of rugby league match-play, to ensure that the players are not under-prepared”. It is important that all players on the field are therefore able to complete the hardest training programme 1:5 work rest ratio including a 35 second sprint as well as the work bout associated with their specific playing position.

To make the aerobic training programme easier or harder the rest times can be changed. Decreasing the rest period to 45 seconds will allow a shorter recovery period therefore increasing the intensity and effort. To make it easier the rest period can be lengthened to 90 seconds but not any more as to benefit from this training the rest period needs to be shorter than that of the time spent working (2 minutes).

There are few health and safety issues as no equipment is specifically needed except from a whistle, stop watch and a rugby pitch. The coach however needs to keep an eye on players to monitor if any are finding the programme particularly difficult especially those with asthma or any other medical issues.

Reference list

Bangsbo, J., Graham, T., Johansen, L., Strange, S., Christensen, C. and Saltin, B. (1992)‘Elevated muscle acidity and energy production during exhaustive exercise in humans‘, American Journal of Physiology, 263 (4), pp. 891-899.

Bangsbo, J., Krustrup, P., Gonzalez-Alonso, J. and Saltin, B. (2001) ‘ATP production and efficiency of human skeletal muscle during intense exercise effect of previous exercise’, American Journal of Physiology, 280 (6), pp. 956-964.

Bishop, D. and Edge, J. (2006) ‘Determinants of repeated-sprint ability in females matched for single-sprint performance’, Journal of Applied Physiology, 97, pp. 373-379.

Bishop, D., Girard, O. and Mendez-Villanueva, A. (2011) ‘Repeated-Sprint Ability – Part II Recommendations for Training’, Sports Medicine, 41 (9), pp. 741-756.

Bishop, D., Lawrence, S. and Spencer, M. (2003) ‘Predictors of repeated sprint ability in elite female hockey players’, Journal of Science and Medicine in Sport, 6, pp. 199-209.

Bishop, D. and Schneiker, K.T. (2008) ‘Different interpretation of the effect of two different intense training regimens on repeated sprint ability’, American Journal of Physiology, 293 (3), pp.1459.

Bogdanis, G.C., Nevill, M.E., Boobis, L.H., Boobis, L.H. and Lakomy, H.K. (1996) ‘Contribution of phosphocreatine and aerobic metabolism to energy supply during repeated sprint exercise’, Journal of Applied Physiology, 80 (3), pp. 876-884.

Bogdanis, G.C., Nevil, M.E., Lakomy, H.K.A. and Boobis, L.H. (1998) ‘Power output and muscle metabolism during and following recovery from 10 and 20 s of maximal sprint exercise in humans’, Acta Physiologica Scandinavica, 163 (3), pp. 261-272.

Crowther, G.J., Carey, M.F., Kemper, W.F. and Conley, K.E. (2001) ‘Control of glycolysis in contracting skeletal muscle. I. Turning it on’, American Journal of Physiology, 282 (1), pp. 67-73.

Dawson, B., Goodman, C., Lawrence, S., Preen, D., Polglaze, T., Fitzsimons, M. and Fournier, P. (2007) ‘Muscle phosphocreatine repletion following single and repeated short efforts’, Scandinavian Journal of Medicine & Science in Sports, 7 (4), pp. 206-213.

Gabbett, T.J. (2004) ‘Incidence of injury in junior and senior rugby league players’, Sports Medicine, 34 (12), pp. 849-859.

Gastin, P.B (2001) ‘Energy System Interaction and Relative Contribution During Maximal Exercise’, Sports Medicine, 31 (10), pp. 725-741.

Girard, O., Mendez-Villanueva, A. and Bishop, D. (2011) ‘Repeated-Sprint Ability – Part I’, Sports Medicine, 41 (8), pp. 673-694.

Gabbett, T.J. and Domrow, N. (2005) ‘Risk factors for Injury in Satelite Rugby League Players’, American Journal of Sports Medicine, 33 (3), pp. 428-434.

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Gaitanos, G.C., Williams, C. Boobis, L.H. and Brooks, S. (1993) ‘Human muscle metabolism during intermittent maximal exercise’, Journal of Applied Physiology, 75 (2), pp. 712-719

Hultman, E. and Sjoholm, H. (1983) ‘energy metabolism and contraction force of human skeletal muscle in situ during electrical stimulation’, Journal of Physiology, 345, pp. 525-532.

King, T., Jenkins, D. and Gabbett, T. (2009) ‘A time-motion analysis of professional rugby league match-play’, Journal of sports sciences, 27 (3), pp. 213-219.

. Parolin, M.L., Chesley, A., Matsos, M.P., Spriet, L.L., Jones, N.L. and Heigenhauser, J.F. (1998) ‘Regulation of skeletal muscle glycogen phosphorlase and PDH during maximal intermittent exercise’, American Journal of Physiology, 277 (5), pp. 890-990.

Pyne, D.B., Saunders, P.U., Montgomery, P.G. Hewitt, A.J. and Sheehan, K. (2008) ‘Realtionship Between Repeated Sprint Testing, Speed and Endurance’, Journal of Strength & Conditioning Research, 22 (5), pp. 1633-1637.

The Sunday Telegraph (2010) Usain Bolt to race NRL Superstars [ONLINE]. Available at: http://www.dailytelegraph.com.au/sport/nrl/usain-bolt-to-race-nrl-superstars/story-e6frexnr-1225881732222 (Accessed: 5 May 2012).