With Coach Kelvin, offering Online Running Coaching for We Run and the We Run Virtual Running Club, and 1:1 Running Coach for Leeds and surrounding areas.
Why Interval Sessions Matter
Hi folks, it’s Kelvin here. We Run Coach for Leeds and surrounding areas, as well as offering online coaching.
In this little video, I’d like to share some thoughts on why it’s beneficial for those doing longer distance races to do interval sessions – bouts of faster pace running.
Interval Sessions and the Cardiorespiratory System
We often think of interval sessions in terms of the cardiorespiratory system – how the heart and lungs deliver oxygen to working muscles.
But in this video, I’d like to share some thoughts on muscle fibre types and how you can improve your endurance by doing faster pace running.
Understanding Muscle Fibre Types
Muscles have slow twitch and fast twitch fibres.
The slow twitch fibres are the ones that we use most of the time for walking and easy and moderate running. They’re not very good at producing lots of force, but they are very good at producing a mid-level of force for long periods of time.
Then we have fast twitch muscles that are predominantly used for faster paced running, sprinting and maybe jumping. They’re good at producing lots of force really quickly, but they fatigue quite quickly too.
What Happens During a Long Run
When we do a longer run, we start to fatigue our slow twitch muscle fibres, so they drop out of the pool of available fibres when they get tired.
The fast twitch muscle fibres have to come in and help with the job. But if you’ve never done any faster paced running, these fast twitch fibres aren’t ready for the job.
That’s when, at the end of a long run, your legs can feel really heavy, and sometimes we slow down. This can have a more negative effect on the stimulus we get on the cardiorespiratory system.
One of the reasons for legs feeling a little bit dead is that fast twitch muscles don’t really like doing the job of slow twitch muscles.
The Role of Interval Training
What fast twitch muscles do like doing is running fast. That’s when adding interval type training – shorter bursts such as 200, 400, or 800 metre repeats of faster paced running with recoveries – becomes helpful.
The recoveries and paces should be appropriate to where you are in your training and what you are training for.
These sessions bring the fast twitch muscles into the equation and train them to run.
Then, when we do longer distance events like 5K, 10K, half marathons, marathons or even ultras, and the slow twitch muscle fibres start to drop out, the fast twitch fibres are ready to help.
They’re already prepared and used to dealing with the kind of running contractions of the muscles. This helps with our resistance to fatigue later on in races.
Final Thoughts
Even if you are doing longer races at slower paces, it’s worth adding interval-style training into your week.
I hope that makes some sort of sense, and if you’ve got any questions, please post them in the comments below.
For now, happy running!
