Tempo, threshold, what does it all mean? Endurance coach Bernard sheds some light.

A difference of opinion

Some years ago now a highly-respected national-level coach said that if you put 10 experienced coaches or endurance athletes in a room and asked them what they understood by the term "tempo run" you'd get 10 different answers. He was absolutely right, and so back in 2010 I wrote a note on what I understood by terms such as "threshold run" and "tempo run". It's probably still buried somewhere on the old club website. I decided to revisit the subject for several reasons, starting from the following three points.

  1. The term "threshold" used to be applied to the running speed at which the concentrations of lactate in the blood started to increase very rapidly. These days with more experimental data these changes in concentrations as we increase running speed tend instead to be expressed in terms of "turnpoints". In fact "threshold" can refer to a different point on the curve altogether, but here I'll stick with the original.
  2. There have been various articles out recently where the terms "tempo" and "threshold" are being used interchangeably (see for example references 1 and 2).
  3. What's more, we now have terms such as "sub-threshold" being used (reference 3).

A short history of 'the Tuesday 10'

From the 1960s through to the 1980s or so, a staple part of the training diet of any senior distance runner during autumn, winter and spring was a good hard mid-week group run (summer was a bit different with mid-week races often going on). Group sessions tended to be on Tuesdays and these runs lasted about an hour, maybe a minute or two over but no more. I was reminded of this when watching the recent programme on Brendan Foster.

This included a clip from a mainstream TV programme from the early 1970s that showed a horde of Gateshead Harriers hitting the road. The voiceover was the inimitable tones of Chris Brasher, and went along the lines of "all over Britain men are heading out into the darkness ….". It was nearly all men at the time and mostly in the 20 - 35 age bracket, veterans and womens distance running had yet to take off big-time.

In addition the relatively few people who ran were regarded as eccentrics, often attracting ribald comments. Wherever we were in the session, we usually responded by indicating that we had two miles to go. We certainly weren't hanging around though, and as track-suited reasonable club runners an hour for just about everyone meant a good 10 miles.

Not surprisingly therefore, the session was commonly known as "the Tuesday 10". None of us had heard about lactate curves at the time, they appeared in Harry Wilson's excellent book, Running my Way, published in 1988 (reference 4), but if we'd seen it I doubt if many would have taken a huge amount of notice (I didn't get to read it until some time in the noughties). Wilson in any case took a more subjective view, prescribing "steady state runs" of varying distances as "fast", "medium" or "easy". There were no heart rate monitors, just empirical evidence that good hard runs of this sort of duration made a huge difference.

This type of session fell out of fashion 20 or more years ago, and it is really pleasing to see a resurgence at Tilsley Park and elsewhere over the last couple of years. The "Tuesday 10" may have a nice alliterative ring to it but things have changed and it is in need of an update. This is the primary aim of this article. The bottom line is however that our athletes that are doing the session consistently are noticing the sorts of improvements that I and many others did all those years ago.

Before going any further I should add that these are purely my personal views.

What are we trying to achieve?

Looking back now with lactate-speed curves to hand (see for example reference 5 pages 36-37) , it's easy to see that what we were trying to do was increase the speed and distance that we could run while staying in the top end of that steady, stable aerobic state.

In reference 3, Livingstone talks about pushing up our abilities from below via "sub-threshold" runs and thinking about it that's pretty much what we were doing. We got back feeling pretty stuffed, any conversation had been monosyllabic (certainly in the latter stages) but we had that satisfied feeling that comes with a tough job well done - "comfortably hard" is not a bad description.

There was much less emphasis on shorter, faster runs in the 20 - 25 min range (which I would have regarded as a "tempo" run), but that was because there were fiercely-competitive cross country, track and road races going on frequently, and the general view was that a race served the same purpose. Again, looking back this sort of session probably was at this threshold point.

Talking of racing, most of us know somebody who wants to race in training - the sort that does better on Tuesday night than they do in the real race at the weekend, who has taken it easy or even rested up the day before. Ignore such folk and choose your training partners carefully. Yes these runs are hard but they are very definitely not a race, they are part of a balanced training week.

How do we achieve it?

If we want to get our systems to adapt to running faster and further at close to this "threshold" pace, we need to start from a session that we can manage at our current level. If that's only 20 min, so be it. We add a few minutes when we are ready for it, keeping to that level of perceived effort (the pace should pick up as you get more used to it). Moving on from 20 to 30 min may take some time. This approach is completely different from that which we use for the weekly long run, where we can increase the distance every few weeks and/or watch how doing that distance becomes easier. So don't start off with a slow 10 miles and aim to bring it up to this "threshold" level - different thing altogether.

Now for some more jargon. The world-famous American coach and exercise physiologist Jack Daniels takes the view that the more we can do at close to this threshold pace, the faster our adaptation will be. So if we can manage a single continuous run of 20 min, maybe we can do 30 min at that pace if we break it up into 3, 4 or even 6 segments with a brief (1 - 2 min) recovery between - "cruise intervals" in Daniels' parlance (reference 6), which others might call long reps.

This makes good sense and it's an approach I would certainly go along with for younger athletes (up to say 17 years of age) and older athletes with limited training background. However, there are no breaks in races and events such as the senior national cross country championships (which is 12 km for men, 8 for women) require mental strength as well as physical fortitude and therefore the single sustained run has a vital additional part to play. I would still include long reps in cross country training for all athletes, but for younger runners they also act as a means of getting ready for the single sustained runs later in their career.

A brief aside here on long reps for younger athletes, since many people feel that their training should be limited to pretty short distances. My view is that it's not the distance that kills (within reason) but the speed. Done at a pace that's right for them, athletes from around 13 can benefit from reps lasting 5 minutes or more (off-track for preference). Bear in mind their "national" is 3 or 4 km, and there is nothing worse than seeing youngsters running round in floods of tears having never done anything like it in training. Or indeed being too afraid to line up at all.

Do I have to do 10 miles?

The answer is emphatically no, it's the principle that matters. If your best 10 km is heading towards the hour, then 10 miles is going to take you up to 2 hours to complete, which is far too long to be holding this level of effort. In my view the important factor is the time over which you can effectively sustain the required effort, and an hour is about the limit for most ordinary mortals. OK a minute or two over isn't critical but 70 min is getting to be too much.

Equally as we've said already if say 35 min is your current limit then stick with that and build on it. Once at a suitable level of fitness (no it should not be part of couch25k) and done to suit individual circumstances this sort of training can benefit anyone, it's not just for the faster end of the spectrum.

And no, it doesn't have to be done on a Tuesday, but I wouldn't recommend doing it a couple of days before a race.

Is it a session?

For some people, there is a tendency these days to regard only rep-based stuff as "sessions" and anything else comes under that dreadful heading "fill-in miles". Trust me, if you do this sort of run properly there will be no question in your mind at the end - "that was some session".


  1. https://www.runnerstribe.com/features/mastering-the-threshold-run-by-sub-214-marathoner-mark-tucker/
    Mark Tucker, Mastering the threshold run (Runners Tribe, January 2018).
  2. https://beaconhillstriders.co.uk/
    Alan Maddocks, The tempo run deconstructed (Beacon Hill Striders newsletter, January 2018).
  3. Keith Livingstone, Healthy intelligent training. Meyer and Meyer Sport (2009).
  4. Harry Wilson, Running my way. Sackville Books (1988),
  5. David Sunderland, High performance long distance running. Crowood Press (2011).
  6. Jack Daniels, Daniels' running formula. Human Kinetics, 2014.