Your interval running training questions answered

Runners of every speed and age can use this simple ratio – 80:20 – when they’re thinking about what training they should do and whether they should include interval training. By that we mean spending 80% of your week running slowly. But to get the improvement you’re hoping for, you should spend 20% doing some faster work that includes interval training.

It’s something I used when I ran a sub four-minute mile in the 1980s and still use today most weeks. Most of the time I go out and run nice and easy, no hurry, but every 10 days or so I run a little quicker, with intervals between the efforts.  

The 80:20 theory was first researched by exercise physiologist Stephen Seiler about 20 years ago, as it had become increasingly popular with athletes like mile legends Seb Coe and Steve Ovett. His research also showed that it works as well for runners clocking less than 20 miles a week and those hammering out 100. Coe, for instance ran around 30-50 miles a week, while Ovett ran approximately 80 – yet they achieved the same results almost to a tenth of a second. 

Interval training was invented by Finnish runner Paavo Nurmi, who won five gold medals in one Olympic Games. He created a structured method of running hard and easy as he trained in the forest. His system has been around since the 1920s and is used in all sports, from swimming to your local spin class.  

The good news is that this is very much up to you. I see from my 1987 running diary – when I was at my peak – I ran anything from 15-second efforts with 15 seconds of rest (in other words, an interval), to my personal favourite workout, five lots of three minutes with 60-second intervals. You could run a workout like this very easily on any given run. So, start with five minutes of slow jogging, then pick up the pace slightly for 15 or 20 seconds, then back off to a slow jog or walk for roughly the same amount of time. 

For this, the fartlek training approach is perhaps the best place to start, in that you can run when you feel like it. Fartlek is a great way for runners over 50 to discover pace variation for themselves. It spread from Sweden in the 1940s after being invented in a forest there. It involves running fast between, say, two trees and then stopping when you see a rabbit or, a sparrow, for instance. Of course, you can be a bit more structured, but using fartlek means there’s no harm in running fast when you see, for example, a post box, and then easing off when a bus goes by. Or hit the accelerator when you run by a bus stop and ease back when you see a cat. It’s fun and teaches you pace.  

Think about what distance you’re planning to run. If it’s to complete anything up to 10k (six miles, 376 yards), then creating a workout over half, then three quarters and finally, after 10 weeks, the whole distance, is a great formula to use. So, you’d start with three lots of three minutes, with three minutes of recovery (walking or jogging). Then edge that workout up to six repetitions. From there, increase the distance you run up to about six minutes, and reduce the recovery to one minute. Again, that 1987 training diary reveals I could run six miles with 60 seconds of recovery between each mile, completing each mile in four minutes and 40 seconds. I ran 10k in 28 minutes that year.

Don’t forget to build in recovery. Over the years I’ve run a few miles with Paula Radcliffe, and one thing stands out more than even her ability to train hard and complete astounding running interval sessions. She knows what rest and recovery means. I remember watching her run an interval workout in Font Romeu, a mountain town in the Pyrenees, and before she’d even started her cool-down jog, she’d taken some protein. Then she’d finish the day with an ice bath. For Paula, recovery mattered as much as training. 

You’ll burn more calories. Higher intensity work over short distances is a great way to shed a few pounds.  

You’ll develop a better understanding of pace. If pacing a 5k (three miles, 188 yards) for instance, is on your agenda, you can run race pace for a short distance with a longer interval and slowly switch that around to a longer distance with a shorter interval. Reduce the rest and run further. 

You’ll get fitter, quicker. Interval training really is all about fast-tracking your running improvement. But we must stress, interval training can be intensive, which in turn means it increases the risk of injury.  

With that risk of injury in mind, it’s a good idea to slow down and take away that intensity. You’ll be less out of breath, and done in this way, interval running training will help you improve your form. This is particularly true for runners aged 50 and older. Instead of running an interval as hard as you can, try instead to feel smooth and relaxed. The shorter distance will mean you’ll still run quite fast, while the recovery means your body becomes more efficient at using oxygen as your capillaries grow in strength (and process oxygen more efficiently) as a result of the training.