The Science Behind Intervals
I have a hearty bunch of runners who come along to our interval training sessions, and when I say hearty what I really mean is they are as “hard as nails”. Each week they turn up, come rain or shine, and literally do whatever it is that I tell them to do. And the last few weeks have not been pretty- they have run around a freezing cold, windy car park as fast as they can until I shout no doubt their favourite word, “RECOVER!”
Why do they do it?
Because, according to research, when interval training is slotted neatly into the “performance enhancing” puzzle of a training programme, it helps you improve your performance. Hard training sessions help you run faster; and who doesn’t want to run faster?
What do I mean by performance?
You might be saying to yourself, I don’t want to run any faster, I’m ok doing what I’m doing, and that’s ok, performance probably means something different to everyone. It could also mean that you’re striving to achieve the perfect run, you know the ones, the runs where everything feels right, and you believe that you could run forever. Wouldn’t it be nice to have more runs like that?
Whatever it means to you, improving performance is typically about being able to accomplish a goal or race that will inevitably challenge you, and you need to be ready to take on this challenge, a bit like preparing yourself mentally and physically for “war on the battlefield!”
Being ready to “do battle” is about being prepared and doing what you must do to keep fatigue at bay on race day, and interval training is an important part of the recipe; races require energy and an arsenal of fatigue resistance strategies.
What is Interval Training?
Interval training consists of alternating high-intensity effort, effort that is unsustainable, followed with low intensity effort, either full or partial rest. Both intensities are critical ingredients to elicit improvement in your physiology and performance.
How long you rest for depends on what you’re training for; sadly there isn’t a one size fits all with the interval training sequence, it all depends on what you’re training for that enhances the best physiological adaptation, plus, of course, we’re all human and we’re all different. Sessions can be used to either improve your pure speed (the maximum you can run over a short distance) or speed endurance, which is the ability to sustain a faster pace over a longer distance.
When training to get faster, you need complete rest after a sprint because speed relies on maximum effort, explosive power, and full recovery of your muscles and nervous system. If you're still tired, you can't sprint at 100% intensity, which is necessary to get faster.
For speed endurance, you don't need full rest because the goal is to maintain a faster pace even while fatigued (remember the battlefield), there needs to be an element of being able to keep going, to resist and not give in to that fatigue. Shorter rest times or rolling rest (continued running at a lower intensity), helps your body adapt to running fast when tired which improves your stamina.
How to improve your speed
Try short sprints between 10 – 30 metres with maximum effort and long rest usually between 2 to 5 mins.
These types of session use the ATP-PC energy system providing immediate energy, are best for increasing/recruiting fast-twitch muscle fibres, and enable you to react quicker and be more explosive in your movements, think strong and powerful!
Speed endurance sessions tap into your anaerobic glycolytic energy system, which basically means increasing your lactate tolerance. Lactate tolerance is your body's ability to keep you running fast even when your legs are screaming at you to stop because they’re on FIRE!
When you run hard, your muscles produce lactate and it’s this that can make them feel heavy, tired and as though they are burning! However, the better your lactate tolerance is then the longer you can push through the discomfort before you slow down; hence longer sprint efforts run above your lactate threshold, coupled with shorter amount of rest, trains your body to handle and clear lactate more efficiently.
These sessions also help improve your VO2 max (more on this in last week’s post, incase you missed it) and cardiovascular efficiency plus they strengthen your slow-twitch and fast-twitch fibres; they really are the gold standard of how to get faster over longer distances.
So, why isn’t everyone signing up to do Interval Sessions?
Because running hard is hard! Keeping to your normal routine is what your brain and body know, your current routine is safe and you know how you do these, there is no risk. But when you put yourself out of your comfort zone, physically and mentally, then there is the chance that there might be social, physical and cognitive consequences.
Socially, you might fear that people might laugh at you, running hard and at effort is ugly, there’s no doubt about that. You might also be worried about being last, that you’re holding the rest of the group up, and you’ve already spent so much time getting to the comfortable place that you are right now, why would you change that?
Your brain is designed to keep you safe, wonderfully designed to keep you in a state of homeostasis, which is your body's way of keeping everything balanced and stable, controlling your body’s temperature, heart rate, hydration thus ensuring everything is in perfect working order, so you don’t die! When you understand this, then there is an understanding of how persuasive your brain can be, convincing you NOT to be crazy and purposefully run above your lactate threshold with an increased heart rate, sweating profusely to the point of dehydration, your brain will go into overdrive, I promise you, in fact, I’m sure.
But there is something so wonderful about pushing yourself out of your comfort zone, turning up in all weathers to run hard. Not only do intervals and hard runs bring you closer to your running goals, they also give you a huge sense of accomplishment that you can carry through in to the rest of your day and life. And if you do it with others, there is a camaraderie that comes with the shared sense of being as tough as old boots!