I had an email last week asking about how to pace the threshold run.
“George I’m training for a half marathon. Should I be running my thresholds slower or faster than my 10k pace?”
I talk a lot about intensity as a yardstick to measure how fast you should be going but this is wide open to interpretation.
Runners in possession of a GPS watch tend to prefer hard data in the form of minutes per mile to gauge performance.
Subjective measures of ‘8 out of 10’ aren’t as easy to aim for and stick to as ‘8mins/mile pace’.
This post is designed to give you a starting point for figuring out your pace for threshold runs, so you have something concrete to shoot for.
If you’re unsure what threshold running is, have a watch of this video from a few years ago.
I’ll get to the meat of the article in just a second but first an important caveat.
The reason I prefer intensity above pace (and heart rate) is that a constant intensity over a 10 minute period is likely to mean a variable pace.
Get tired towards the end of a threshold block and your pace is going to drop.
Hit a bit of an incline, if you’re maintaining a constant intensity then your pace will drop.
And on the flip side, a constant pace is likely to mean a variable intensity.
8 minute miles might feel ok to begin with but it might soon start to build up to these point you can no longer sustain it.
So the recommendations and observations are designed as a starting point, but my advice is the same: adjust your pace to keep your intensity at the correct level.
A Note on Heart Rate Training
If you use HR training correctly it can be a valuable way to pin point the intensity you should be training at.
But therein lies the problem: it needs to be used correctly for it to have any real value.
If you’re going off the Karvonen Formula of 220-age you could be +/-15bpm out.
That makes a big difference if you’re trying to hold your pace to keep your heart rate at 85% of your theoretical maximum.
If you are going to use your HR as a guide to intensity (rather than pace or subjective intensity) make sure you have undergone a sub-maximal (or maximal if you’re brave and already fit) HR test.
When you know what your real max is you can begin to work out more accurate percentages and then get the most from your training.
Calculating your threshold pace
The question of ‘should my threshold runs be faster or slower than 10k pace’ is a good one.
Whilst there’s no single answer for everybody, there does seem to be a switchover point at around 40 minutes.
If you’re cranking out 10k runs in under 40 minutes, you’re probably running faster than your threshold pace.
During the course of the run you’re building up lactic acid because your body isn’t able to get rid of it quickly enough.
Which is just about sustainable because you’re only in this state for about 40 minutes.
Runners taking longer than 40 minutes to run 10k (which is most of us!) are almost certainly going to be running faster in a threshold session.
Your 10k is run below your threshold pace, unless you go off too fast of course and then you’ll know about it with about 3k to go!
Some Starting Points
Let me stress that these are starting points, and you’ll need to experiment to find the pace that truly fits with your own ability.
If you’re a 40 minute 10k runner that’s a 6:27 per mile pace. This is probably quite close to your threshold pace.
50 minute 10k is just over 8:00 per mile. A good starting point for threshold would be 7:30 per mile
A 60 minute 10k gives you an average of 9:40 per mile. 8:30ish per mile for threshold wouldn’t be unusual.
A 70 minute 10k is around 11:20 per mile. You can probably handle 10 minutes per mile for your threshold runs.
Learning to Tune In
Remember, threshold is meant to feel hard.
‘Comfortably uncomfortable’ is a great way to describe the level of intensity.
When I talk about tuning into your body and finding your level of intensity, this takes time to get good at.
Don’t worry about being perfect right from the start.
With practice it gets easier.
What makes it hard is that at the start of a run you feel ok.
You feel as though you can go harder and when you succumb to this temptation you find a world of unpleasantness waiting for you in the not-too-distant future.
Having a rough idea of the pace you should be aiming for on your threshold runs will give you that starting point.
Keep scanning your body and correlate the overall intensity that you’re experiencing to a number on that 1-10 scale.
The more races you do and the more threshold sessions you put your body through, the easier it becomes to tune into these relative intensities.
And the better you are at hitting the right intensity, the better your results will be.
Want to get faster?
Hundreds of people have taught themselves to run faster with the i10 Project.
10 weeks of progressive and structured thresholds, intervals and hills with one objective: to add more speed into your legs.
Some do this program with a 10k in mind at the end whilst others do it to leapfrog their half or full marathon performance.
If you tell yourself that you ‘only have one speed’, then the i10 Project will change everything.