Introduction to intervals.

This may shock some of you regular readers, but in the past I have tended to stick to the softer, more sentimental side of  running. I've had more feedback saying  that I've brought people to tears than I have saying I've inspired them to run more or train harder. I'm ok with that because people clearly like what they read, or they wouldn't come back. There is no end of really good blogs out there on detailed training and race reports.

Not for me the 5000 word analytical breakdown of a 5k race, every breath and footstrike described to the nth degree. I prefer to pull at heartstrings as much as hamstrings, open my heart to others rather than discuss my heart rate.

This blog came about because I love running and training, but love my family and time with them even more and can't dedicate the sheer amount of time required to do countless long runs in preparation for ultramarathons. If I want to do them and do well, I need to train smarter, rather than just harder.

CV training by itself isn't enough, but it's a great tool to have when you know what areas you want to work on.

So today I'm going to get a little more detailed with you, following on from last week when I mentioned training differently to train better, I am going to delve into the mysterious world of interval training.

This often used and frequently misunderstood training method is more than just an opportunity to hurt yourself and make yourself sick (done that before). Used correctly you can get more benefits than longer training session and more importantly, specifically target the areas that need the most work.

I know I have a mixed audience, so I'm going to start with the basics and go through the various steps over the next few posts. If you want more info contact me directly and if it's too basic, then check back in a week or two when I get into the nuts and bolts of it.

In this instance I am training for a long run, a 50 mile ultramarathon on the trails of the South Downs. I have the ability to run, but in the past my energy levels have not been as reliable as my running. May aim is to improve my CV fitness, increase my lactic acid threshold and improve the efficiency of my muscles.

These are all direct outcomes of interval training.



Another benefit of intervals is the reduction in overuse or overtraining injuries, common in those preparing for longer runs.

There are lots of different types of interval training:

• Sprint intervals
• Cruise intervals
• Tabata
• Fartlek, the list goes on and a lot of them are the same under different names.

When we exercise, or take part in any activity, we use energy. The body has three different energy cycles, which have different characteristics, periods of energy delivery and recovery rates. These three cycles are:

• Aerobic,
• Lactic Acid (LA) and
• Phospho Creatine (PC)

During any activity the body will use all three of these. For example in a 5k race, your fast start will come from the PC system, LA will get you through the first few minutes and then switch to the aerobic system for the majority of the race. Those hills halfway round will require the LA system to kick in again and your sprint finish may dip into the PC again. This all happens subconsciously without bothering you too much.

That bit where your muscles start burning means you've been in LA too long. The bit where you're out of breath and throwing up, that's too much time in PC. Aerobic is where you are aiming to spend the majority of your time, but to do that you need to be well conditioned and this is where interval training comes in.

By adjusting the intensity of your intervals and the rest periods in between, you can trigger these different energy cycles and improve their efficiency. By doing intervals you can train at a much higher intensity for much longer periods than by constant training.

An example would be doing ten intervals which have you running at a high intensity for 30 seconds each time, you would spend a total of 5 minutes at that higher rate. You could never run 5 minutes at that higher rate constantly because it would use you PC and LA systems which just don't deliver for long enough.

The adaptation of the body is accelerated and amplified, causing better recruitment of fasttwitch muscle fibres, improved capillarisation, meaning improved blood flow to the muscles and an increase in the number of mitochondria, the energy factories inside the muscles.

It may sound daunting to the uninitiated, but in practise it's a simple, effective and efficient way to train. Next time I'll go though different interval training systems and how you can reap the benefits I've mentioned above.