You have been hitting the trails, logging miles and doing everything that you are supposed to in order to improve your endurance and power. Maybe you have a race coming up in a few weeks or you just want the personal accomplishment of getting through your regular run a little bit faster. If you are finding that despite all your worthwhile efforts your performance has not changed in a meaningful way perhaps it is time to consider integrating sprint interval training into your program.
This week we take a look at an interesting study that shows a way for well trained individuals to really move the needle on their running performance with a minimal amount of time spent training. As we go through the study keep in mind three things. First, this study was conducted with subjects who were already well trained athletes. We would expect to see positive changes in studies that take subjects who aren’t active and put them on aerobic/endurance/power based training plans. If you are starting from a low level of fitness and get on a regular, supervised program most people will see a change for the better. Taking a group of well trained athletes and coaxing a meaningful change in their performance is much more difficult and demonstrates the power of the training intervention.
Second, this study was done in a real world setting, not in a laboratory. Often the changes that can be achieved in a very controlled setting working on a treadmill or cycle ergometer cannot be replicated in quite the same way in a real world setting. If you cannot go out to the track, trail, road or gym and achieve the benefit of the specific plan studied then it might not matter all that much that it can produce an effect in the laboratory.
Third, this study achieved meaningful results with just a two week intervention. Often we need data over much longer periods of time, weeks, months, even years to determine the impact of a particular intervention. In the case of this study part of what was so interesting is that the trained athletes used as subjects achieved the beneficial effects of the sprint interval training program in just two weeks. Who doesn’t want to do something that will improve their performance in such a short period of time?
The Study
In this study running performance was measured with a 3,000 meter time trial and a run timed to exhaustion at 90% of maximal aerobic speed (MAS). The training program consisted of three workouts per week for two weeks. In each workout the sprint intervals were 30 second all-out shuttle runs followed by 4 minutes of rest. The subjects performed 4 rounds in their first workout, 5 rounds in their second, 6 rounds in their third and fourth workout, 7 rounds in their fifth workout and dropped down to 4 rounds in their sixth workout.
The total sprinting time over the two weeks totaled 16 minutes. The entire 6 sessions only took 110 minutes including the rest time. The shortest workout was 14 minutes and the longest was only 27.5 minutes.
To conduct the actual sprints, cones were placed every 5 meters for a 30 meter distance. During the sprints the subjects would run to the 5m cone and back, then the 10m cone and back and so on until they reached the 30m distance. They would continue running at full speed until the 30 seconds were up.
Three additional variables were also measured for each session. 1) The subjects peak power, which was considered the longest distance they ran in a 30-second period. 2) Mean power which was the total distance they ran for the session divided by the number of sets they ran that workout. 3) Fatigue index was considered the difference between the longest sprint they ran in any given workout and the shortest sprint they ran in the same workout.
Results
Maximal aerobic speed saw a 2.8% increase. This was significant though the effect size was small. For the timed run at 90% of maximal aerobic speed there was a 42% improvement (158.9 seconds) which was considered a large effect size. The timed 3,000 meter run saw a decrease of 50.4 seconds which is a 5.7% improvement in time. The effect size is considered small-to-medium.
Peak power had a 2.4% improvement (3.06 m), significant but a small-to-medium effect size. Mean power had a significant 2.9% improvement (13.9 m) for a medium effect size. The fatigue index showed a positive trend with a medium effect size thought it did not reach a level of statistical significance.
Putting It All Together
So what does this all mean for most runners out there? First and most importantly it shows that a very short 2-week low volume program can produce significant improvements in performance. Most competitive runners already have fairly lengthy training programs and a schedule of competitions to plan around. Even if you are not a competitive runner odds are that you still have a limited amount of time to train and are still interested in improving your performance. A simple low volume, high-intensity program like this can quickly make positive improvements in both endurance and anaerobic performance. Additionally this study demonstrates that the improvements are not limited to untrained subjects that will respond to just about any regular training protocol, already highly trained subjects can make significant improvements with this type of training.
Secondly a program like this does not require any special equipment. A few cones make it look pretty but some water bottles, t-shirts, a big rock all work equally as well. It is always nice to have a new training technique that doesn’t require you to open your wallet. This study clearly showed that the results can be achieved in a real world setting without highly calibrated expensive laboratory equipment.
Third, all you need is a clear 30 meter space to run your sprints. This means it can be done almost anywhere. Even if you don’t have a full 30 meters you could still follow the program and simply limit the longest available distance to 20 or 25 meters. Even if you have to train indoors because of weather it is still simple to perform a program like this.
Fourth, it is easy for multiple athletes to perform this program at the same time. Individuals can set up right next to each other. This makes it ideal for those working with teams to put everyone through the program together. There is the added benefit that running against others often motivates people to push even harder.
A program similar to this can also be used as a tapering plan allowing for high intensities and low volumes to be programmed as you get closer to competition.
So why does such a short duration, low volume program produce such good results? The leading theory is that this high intensity training technique leads to increases in enzymatic activity in both the aerobic and anaerobic energy systems. It is also possible that this approach improved neuromuscular capacity which can result in improved running economy.
The use of shuttle runs was an interesting choice of the authors. It allowed for high intensity training while ensuring that the improvements seen in the actual tests were not the result of skill acquisition but due to physiological adaptations. As previously mentioned it also allowed for a small space to be utilized and a competitive atmosphere to be established between subjects. This leads to the question of if another form of sprint interval training could produce similar results? There is probably nothing magical about the use of shuttle runs in and of themselves. The high intensity that they stimulate is most likely the key factor so it would not be reaching too far to assume that if the same intensity can be maintained for a full 30 seconds on a longer sprint, similar results would probably be achievable. This eliminates the advantage of only needing a small space along with some of the mental variety that shuttle runs introduce but coaches shouldn’t feel limited to only using that one approach to including high intensity sprint intervals.
It would be interesting to compare the results of this study to slightly different training protocols. What would happen if you used a time different then 30 seconds for the sprints? Do you need to go all the way up to 7 sets or can similar results be achieved if the volume is kept lower and only 4 or 5 intervals are used? Would more intervals produce greater results or what happens if the program if followed for more than 2 weeks? Like all studies, this one could had to choose a particular set of variables to use but the positive outcomes they produced makes you want to explore how those variables can be tweaked to produce even greater outcomes or optimize the time actually committed to the program.
There you go. If you are looking for a way to improve running performance but do not have hours to commit over a prolonged period of time now you have a technique that will allow you to turbo-charge your training with a simple to perform, short duration low volume sprint interval plan. Who doesn’t want to see a 42% improvement in their paced running and a 5.7% improvement in their race time for such a small amount of training?
Koral, J., Oranchuk, D., Herrera, R. and Millet, G. (2018) Six Sessions Of Sprint Interval Training Improves Running Performance In Trained Athletes. Journal of Strength and Conditioning Research. 32(3): 617-623.