The most common training mistake recreational runners make is running their easy days too hard. Research on elite endurance athletes, and studies on everyday runners, point to the same pattern: keep about 80% of your training genuinely easy, and put real effort into the other 20%. Here is what the 80/20 approach is, what the evidence says, and how to use it with your running group in Bedfordview.
In short:
- About 80% of your running should be at an easy, conversational effort.
- About 20% should be genuinely hard: hills, intervals or tempo running.
- Avoid running every session at a medium "grey zone" effort that is too hard to recover from and too easy to make you faster.
- In a study of recreational runners, a polarised 80/20 style plan improved 10 km times more than a plan built around medium-hard running.
Where the 80/20 rule comes from
Sports scientist Stephen Seiler studied how the world's best endurance athletes actually train: runners, rowers, cross-country skiers and cyclists. Across sports, a clear pattern emerged. Roughly 80% of their training sessions were done at low intensity, below the point where breathing becomes laboured, and only about 20% were done at high intensity. They did surprisingly little at the in-between, "comfortably hard" effort that many recreational runners default to every day.
This pattern is often called polarised training, because most training sits at the two ends of the intensity scale: easy, or hard.
Does it work for ordinary runners?
A study published in the International Journal of Sports Physiology and Performance compared two ten-week plans in recreational runners preparing for a 10 km race. One group followed a polarised plan, with most running easy and a small amount hard. The other did more of their running at a moderate, between-thresholds effort.
Both groups got faster. The polarised group improved their 10 km time by 5.0% on average, compared with 3.6% for the moderate group, a difference of about 41 seconds. Among the runners who stuck most closely to their plans, the gap was larger: a 7.0% improvement with polarised training compared with 1.6%.
A separate study in well-trained endurance athletes, published in Frontiers in Physiology, compared polarised training with threshold training, high-intensity interval training and high-volume training. The polarised group showed the largest improvements in key endurance measures.
Why easy running makes you faster
- You can do more of it. Easy running builds your aerobic engine, the heart, blood vessels and muscle fitness that power every distance from 5 km to Comrades, without wearing you out.
- You recover between hard days. When easy days are truly easy, you arrive at your hard sessions fresh enough to run them properly.
- It lowers the strain on your body. Running everything medium-hard adds fatigue without adding much fitness.
How easy is easy?
Use the talk test. On an easy run you should be able to speak in full sentences. If you can only manage a few words at a time, slow down. For many runners, easy pace is one to two minutes per kilometre slower than their 10 km race pace.
In Bedfordview there is an extra reason to go by feel rather than pace: at about 1,640 m above sea level, your heart and lungs work harder at any given speed. Read more in our article on running at altitude.
What the hard 20% looks like
One or two quality sessions a week are enough for most club runners. For example:
- Hill repeats: 6 to 10 climbs of 60 to 90 seconds at a strong effort, jogging down to recover. Bedfordview is full of good hills for this.
- Intervals: 5 to 6 repeats of 3 to 4 minutes at about 5 km race effort, with 2 to 3 minutes of easy jogging between.
- Tempo: 15 to 25 minutes at a "comfortably hard" effort, where you could speak in short phrases.
- Strides: 4 to 6 relaxed 15 to 20 second accelerations at the end of an easy run. A simple way to stay quick.
Common mistakes to avoid
- Racing your training partners. Group runs can quietly turn into races. Pick a group whose easy pace really is easy for you.
- Turning the long run into a time trial. Long runs should mostly be easy. If you want some quality, add a few kilometres at goal race effort near the end.
- Doing too many hard days. Two hard sessions a week is plenty for most people. More is not better if it leaves you tired.
Using 80/20 with Bedfordview Athletics
Running in a group makes the 80/20 approach easier, as long as you choose the right group. The club's running schools are organised by pace and goals:
- Walking School: the official walking group.
- Steel Bullets: ideal for newer runners and anyone returning from a break.
- Sky Hawks: regular runners who want to get fitter and faster.
- Navy Seals: runners building towards half marathons, marathons and Comrades.
- Azzurri: experienced runners chasing personal bests with structured quality sessions.
On easy days, run with a group a notch slower than your race pace. Save the faster groups and the hills for your quality days. See the training runs for times, or follow our 12-week half marathon plan, which is built on the same principle.
Questions runners ask
How slow should my easy runs be?
Slow enough to speak in full sentences. For many runners that is one to two minutes per kilometre slower than 10 km race pace.
Does 80/20 training work for beginners?
Yes. Beginners benefit most from mostly easy running. Add a little faster running, such as strides or short hills, once you are running comfortably three times a week.
Do I need a heart-rate monitor?
No. The talk test works well. If you do use heart rate, set your zones from your own tests rather than age formulas, especially at altitude.
Sources
- Seiler S. What is best practice for training intensity and duration distribution in endurance athletes? International Journal of Sports Physiology and Performance, 2010.
- Muñoz I, et al. Does polarized training improve performance in recreational runners? International Journal of Sports Physiology and Performance, 2014.
- Stöggl T, Sperlich B. Polarized training has greater impact on key endurance variables than threshold, high intensity, or high volume training. Frontiers in Physiology, 2014.
