By West Bromwich Albion FC, in collaboration with Liverpool John Moores University and supported by Catapult Sports.
The second speaker of the evening was the internationally renowned researcher Prof. David Bishop (@BlueSpotScience). David is the inaugural research leader in sport science at the Institute of Sport, Exercise and Active Living at Victoria University, Melbourne, Australia. He oversees world-class research focussing on understanding skeletal muscle adaptations to training to improve the sporting performance of individual athletes and teams. David has 20 years of experience as both a researcher and applied sport scientist working with elite athletes. He also published more than 200 peer-reviewed articles and 6 book chapters in the area of human movement and sport science.
Latest Strategies to Improve Repeated Sprint Ability
An Introduction to Repeated Sprint Ability
David began his presentation by describing the true definition of Repeated Sprint Ability (RSA) in team sports. He noted in the past that researchers would simply count the number of sprints over a match and divide that by its length, concluding that a sprint would occur only every couple of minutes during a game of football. He claims this early research was misleading and unrepresentative of what actually occurs; a bell does not ring periodically to signal the start of another sprint. A better method is to look at when these sprints occur. During team sports, athletes are required to perform repeated bouts of sprinting within acute periods of a match. Typically, a team sport, characterised as requiring RSA, will involve repeated bouts of sprinting with brief recovery for over 60 minutes.
To support this, David presented data from an English Premier League team that showed that those players that were able to achieve the fastest Mean Time on a test of RSA were most likely to cover greater sprint distance during a match. Also, in Australia during the AFL draft, the athletes that had the best RSA ability were more likely to be selected. And finally, David presented research from Jens Bangsbo that showed that performance on a RSA test was unaffected by a first half of football, but showed significant decreases from half time to the end of the match. He claims these key findings suggest that RSA influences on the field performance for team sport athletes.
Determinants of Repeated Sprint Ability (RSA) and How to Improve Them
When seeking a performance enhancement, David claims it is crucial to look at the sport and what the underlying physiology is; then seek to improve the physiology, to improve performance within the sport. This might not sound complicated, but sometimes we can make the mistake of merely replicating the sporting event. He stresses that he does not claim there isn’t a place for activities such as Small Sided Games, but for many sports the necessary overload cannot be achieved by solely mimicking a match. He uses an example of rowing to illustrate this, stating that during training they do not just ‘go flat out’ for 6/7 minutes, as would occur in competition. In fact, they almost never do this, they implement the training that will prepare them physiologically, so that when it comes to competition they are able to perform at their maximum.
During a single sprint effort, David showed that 54% of the required ATP is supplied by the Phosphocreatine (PCr) system, 31% by Anaerobic Glycolysis, 6% from the Aerobic system and 9% from available ATP. Consequently, for repeated bouts it is important to be able to replenish PCr as quickly as possible to be better prepared for the next occurrence. The glycolytic pathway will quickly reduce the Ph of a muscle by an increase in H+, these therefore need to be quickly removed.
The Anaerobic System
David cited research from a Danish second division football team where mean muscle Ph showed no difference at the end of a match compared to the start. However, immediately following intense periods decreases in Ph were observed. An increased Blood Buffer Capacity has been shown to correlate with a lower decrement of power on a RSA test. Alongside this, a greater buffering capacity within the muscles has been seen to relate to an ability to maintain Wattage output during repeated bouts of effort.
David then presented literature on how best to train this buffering ability. Continuous Training, below Lactate Threshold, has been shown to have little effect on buffering ability. The best results, a 25% improvement, were seen with 2-minute bouts of running at a pace equivalent to around 80% of VO2max, with 1-minute rest between. However, when the pace of the runs was increased to 100% VO2max, less of a training effect was seen. Repeated sprint training, that mimicked the demands of a game, only saw minor improvements.
David suggested that optimal training for improving muscle and blood buffer capacity would consist of training at a pace of around 80% VO2max with inter-bout rest periods that were less than that of the work intervals. He stressed that training harder, as a % of VO2max, is not always optimal. This type of training could be used 2-3/week and has been shown to be effective for up to 4 weeks; at which point these results could be maintained by performing a single session per week.
Depending on the length of the sprint, David claims that an athlete will be very close to depleting the PCr system. He noted that resynthesising PCr could therefore be even more important than buffering ability. Power output recovery has been shown to very closely follow PCr resynthesis. Consequently, athletes that are better able to resynthesise PCr will maintain power output more successfully on a RSA test.
PCr resynthesis occurs solely through Aerobic pathways and David claims that this ability is closely linked to Aerobic fitness. Those with a higher Lactate Threshold are able to resynthesise PCr faster. Interval training similar to the one described previously is likely the best method for training to resynthesise PCr more quickly. Repeated sprint training to date has not been shown to have any positive effect. David personally believes that due to the lack of stress to the aerobic system it is unlikely to be a viable method.
The Aerobic System
Next David discussed the importance of Aerobic Power (VO2max) to RSA. He noted that an athlete could perform a single sprint whilst holding their breath, as the energy is supplied predominantly Anaerobically. Also, there is not a strong correlation between Aerobic Power and performance on tests of RSA. However, following 4 or 5 acute bouts there is an increase in Aerobic demands. He claims that VO2max does play a role in determining RSA but only up to certain standard, therefore it is important for developing athletes to focus on improving their VO2max, however when they reach a certain level its affects are marginal and the abilities mentioned previously become the principal determinants.
So what does all this mean for team sport athletes? David presented his own research comparing team sport athletes to triathletes. They saw that those in team sports had very good Aerobic Power (VO2max), on a par with the triathletes, however they had extremely poor Lactate Thresholds. He claimed that maybe this was due to team sports commonly completing high intensity aerobic work and not enough at a lower intensity, akin to those he had outlined in his presentation. Therefore, when designing periodised programs it is crucial to spend time focusing on all the areas outlined.
David noted also, that as previously mentioned, small sided games may not be the ideal way to train to improve athletic performance. He claimed the duration of the stimulus would be too short to induce physical adaptation, but can be used as part of a whole program. When they are employed, it is crucial to strictly control the variables to achieve the required physiological stimulus.
In planning for football, David spoke of the difficulty in improving fitness when games are every weekend and pre-seasons are so short. However, he did give an example from an AFL team where improvements in Lactate Threshold achieved during pre-season were able to be maintained through the season. He also mentioned the need to be aware of the eccentric component of changing direction in team sports. When the methods outlined are solely employed, athletes could become sore during games due to being trained mainly through linear running. It is important to use some modes that are multi-directional in nature.
In conclusion, David noted that when training RSA, team sport athletes should look to improve single effort sprinting ability through typical sprint training with long rest periods alongside standard strength and power programs. Interval training should be employed to improve recovery between bouts (80-90% Vo2max with rest periods shorter than work periods) through the enhancement of the Lactate Threshold and VO2max, improving buffer capacity and PCr resynthesis. And finally, attention should be paid to eccentric and change of direction work during the pre-season to offset potential muscle soreness.
Tickets to the next event hosted by West Bromwich Albion FC, entitled Strength and Power Development for Team Sports, are now available and details can be found through @StrengthWBA. The evening masterclass will again consist of two speakers. Lead Strength and Conditioning Coach at the Irish Institute of Sport Eamonn Flanagan will be presenting alongside Michael Johnston, Senior Strength Scientist with British Athletics. The event will be held on April 12th 2017.