Tag: High Intensity Interval Training

Try Sprint Interval Training To Improve Your Running Performance

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.

What Type of HIIT Works Best?

HIIT (High Intensity Interval Training) works.  The jury has come back on that ruling and there isn’t much debate about it anymore.  You can improve aerobic fitness, strength, grow muscle, even turn on inactive genes.  Over the past few years study after study has shown the benefits of HIIT.  What is missing are some more conclusive answers to how different approaches to HIIT vary and which one you want to follow.

Doing repeated intervals on the bike or the treadmill is certainly different than using body weight exercises, which is again different then using external resistance like barbells and dumbbells.  Add in the challenge of how do you even compare the different modalities.  The variables you use to control the intensity on a piece of cardiovascular equipment (heart rate, time) may or may not translate to what you can control doing more traditional strength moves like squats, deadlifts and presses.  It is one thing to compare the length of two different bike intervals but how do you control and compare the intensity of a bike interval to that of a strength exercise?

Let’s not forget the impact different populations and their objectives have.  The average person looking for improved health doesn’t need the same program that someone looking to drop the maximum amount of body fat which is again different from what a runner/cyclist needs or what a strength athlete is looking for.  Everyone needs a combination of both strength and cardiovascular benefits but the mix changes depending on the person’s activities and objectives.

Androulakis-Korakakis et at. (2018) started to answers the question of which type of interval is best by comparing aerobically based intervals to resistance based intervals in well trained strength athletes.  The aerobic group performed 8 weeks of cycling intervals twice a week.  Each interval was for 30 seconds at 85% of maximum heart rate followed by 90 seconds of recovery at 50-60% max heart rate.  They performed 8 rounds.  The strength group used squats one day a week and deadlifts for their second training day.  They performed 8 rounds of the prescribed exercise with a weight equal to 60% of their 1 repetition maximum weight.  Each set was conducted until the subject reported a level of exertion equaling 80-90%.  This came to 8-15 repetitions over 16-30 seconds.  This group rested for 90 seconds between sets.  Both groups were allowed to continue doing their normal training the rest of the week.

If you guessed that after 8 weeks both groups saw improvements in their aerobic fitness then pat yourself on the back, you’re correct.  If you guessed that the group that did their intervals on the bike saw a significantly greater increase in cardiovascular fitness then you’ve earned a cookie.

When it came to strength improvements if you said both groups saw an improvement in strength then you area 3 for 3.  Now for a perfect score did was there a difference in strength improvements between the two groups?  No there was not.  Sorry to ruin your perfect record.  Both groups saw similar improvements in strength.  I know you had your money on the lifting group.

So what does all of this really mean?  Well, if you are a well trained strength athlete and you want to improve your cardiovascular fitness you can use strength based exercises to build your intervals.  The results won’t be as great as if you used aerobic exercises but they will be positive and meaningful.  Now what if you aren’t a well trained strength athlete?  I think you would be safe assuming the same general conclusion applies to you though the exact magnitude of the changes and the difference between the two different training approaches may be different, however they will probably both still improve your aerobic fitness and your strength.

I appreciate this study because it is one of the first to look at the practical question of what type of exercises we can use for our HIIT and how they differ.  The reality is in the gym all sorts of different movements are used to create HIIT circuits and trainers have been assuming they can create similar effects using body weight or strength exercises as they can with traditionally aerobic movements.  This study starts to provide some evidence to that question and clearly shows that the strength exercises will create improvement in cardiovascular measures, though not as great as if you use aerobic based intervals.  As always, you have to ask what your objectives are.

There are still some serious shortcomings to this study that keep us from implying any overly broad conclusions.  First, the study was done with trained strength athletes.  Their experience in the gym and the training state of their bodies means that they will have different responses then untrained individuals.  The subjects were also primarily in their early 20s and the reactions of middle aged and older exercisers could be different.  The subjects were also allowed to continue doing their normal training in addition to the prescribed HIIT.  Both groups showed similar improvements in strength and that could be the result of their other training and have nothing to do with the HIIT.  The squat/deadlift group also had a rather long rest period, far longer than is usually used in the gym for HIIT and this could be impacting the results this group saw.  I am also concerned about the testing choices used by the authors.  While valid, they are not as rigorous as other common techniques.

So what do these concerns mean to how I interpret this study?  I still like that they are examining the difference between different types of HIIT circuits.  I think the difference they found in cardiovascular improvements between the groups is suggestive of a more meaningful difference.  While only limited conclusions can be drawn this a good first step in helping us really figure out what works best for HIIT and what the differences are between different HIIT approaches.

If you are more concerned with aerobic improvements but still want some strength gains then you should be utilizing more traditional aerobic movements.  Not necessarily to the exclusion of traditional strength moves but certainly they need to form the foundation.  If you are more focused on strength and similar benefits this study would suggest it doesn’t matter what you use for your interval tough I think the subjects continuing their regular training hid potential strength advantages to the lifting centric approach.

Androulakis-Korakakis, P., Langdown, L., Lewis, A., Fisher, J., Gentil, P., Paoli, A. and Steele, J. (2018) Effects of Exercise Modality During Additional “High-Intensity Interval Training” on Aerobic Fitness and Strength in Powerlifting and Strongman Athletes.  Journal of Strength & Conditioning Research. Feb:32(2):450-457.