Can someone explain how a 20 minute threshold run is enough stimulus to trigger adaptation?

Like a change in environmental stresses such as heat, humidity, altitude etc?

It has a nice ring to it. A nice roundness. Or is it round-aboutness?

It's approximately Lactate Thresholdness kinda sorta thingy like doodah.

But only approximately, not absolutely specifically, you understand?

Done correctly, lactate threshold running is running as fast as you can without accumulating lactic acid. Usually correlates with 85% of max heart rate. Well trained athletes can manage this for longer than 60 minutes. Glycogen should be limiting factor.

The adaptations you make, independent from easy volume, are increased tolerance and ability to buffer acidity. Like with most things, more is better...until it is not. You have to work up. If done correctly, 20 minutes of threshold may be relatively easy, but 40 minutes of threshold with warm up and cool down is a lot of volume and maybe puts you at risk for injury given your current development.

Be patient, tempo runs will likely get longer as you get stronger.

I would also imagine that the 20 minute threshold isn't a peak workout, it's a stepping stone to longer threshold sessions like 4 x 10 minutes or 3 x 15 minutes that you would do when you're really deep in your training, maybe a month or two before your goal race.

The tempo run never helped me in anything except the marathon. For example when I was in 37:30 shape I was doing 7-10 mile tempo runs at 6:30-6:40 and my 5k and 10k would not budge. I've tried 20 minutes at 6:15 average and again, no improvement in the shorter distances. Now I sometimes do 4x1 mile at 6:00-6:10 which does help. Personally, I would never do a continuous 20 or 30 minute tempo at 6:00-6:10 because it is like a race effort every week and at my level I can't recover or can I mentally get myself to do it.

Most people end up racing their tempos. If you’re controlled enough to run at 5k+25 pace, you get more adaptation

Your 10k was ~6:02 pace so your 5k should be about 5:47, so your tempo range should be between 6:07 and 6:17.

4xmile at 6:00 is a good 10k workout - of course you can't do a 30 minute tempo at 6:00 because you're running 5/6ths of your 10k.

Physiology aside, I think that tempo runs are very useful from a mental conditioning perspective. If you run 20-30' at your true HM pace, that's going to feel pretty tough in a workout context (no taper, no hype, possibly without company).

I find that although in theory a session with longer threshold type intervals looks longer and harder, this type of session gives you a mental "out" (the rest) which doesn't exist in a race. There is value to doing intervals of course, but doing harder efforts that are similar in length to your race (time) or longer is important for mental adaption IMHO.

For those doing 5k/10k, the 20-30' tempo is a key session. For HM/marathon longer "steady" type runs achieve a similar goal. Personally I find that although the objective effort that is put into this type of session (pace) is slower than race pace, the feeling of distress during the session is actually quite similar. However, it is much easier to recover from than the true race effort.

Good post.

20 minutes at LT can cause adaptation.

5x1k at lactate threshold can cause adaptation.

12x400 at lactate threshold can cause adaptation.

Honestly, if people would stop debating tempos and just add up 5k-8k of tempo-paced work through literally any workout once per week, the world would be a better place.

You tell it to Ingebrigtsens.. brah 😎

Agreed. There is numerous ways to do it. So we just have to choose the right way for us, from our strengths and weaknesses.

I think it comes down to the individual. I never understood or liked "20 minute tempos". I get tons of value out of mile repeats, 2 mile repeats, and even 3 mile repeats. The volume at "threshold effort" ends up being a lot higher and the fitness gains don't lie.

By "goal pace" do you mean the pre-determined workout pace? You have two options in my mind that aren't mutually exclusive. You either key off recent races or you go by feel. You should never be unable to finish a threshold workout. That's a sign you're running too hard.

Hate to be boring, but just do all of them over the course of a training block. You can get faster turnover with interval-based tempos which is beneficial, and continuous tempos prepare you mentally for sustaining running at pace. I run the same workouts on a three week cycle when training for 5/10k - mile repeats (4-6 with 60 seconds recovery), 3x2 miles with 2 minutes recovery, and 4-5 miles continuous tempo.

When talking about these various workouts what sort of rest are you typically prescribing for 5x1k or 12x400? I always air on the side of too much rest for these type workouts, but I'm curious what others think.

Everything we do act as a stimulus. The question is how much stimulus. There is always a sweet spot between doing too little and too much. And that varies from person to person. For someone who never did threshold runs or is only now starting to do them, 20 mins can be very optimal. Doing 45 mins may certainly be too much, and lord forbid, 60 mins could be injury causing or overtraining.

To help you grasp this concept, look at someone now starting running. That person may only be doing 3 miles and very slow. But that is enough of a stimulus to lead him to eventually be doing 5 miles, then 7 miles and then 9 miles.

The game of training is a game of being patient but consistent and always doing a little more and then a little more. Good Luck!

Well, every workout can be a stimulus for athlete A and no stimulus for Athlete B. The training is never the result of one magic workout but the result of many months if not years of training. So 20 minute tempo at LT pace is a good workout but is only a workout. You need at least 6 or 8 weeks of training at LT to see a certain improvment. And to stress the LT you will start using the shortest distance that give you a benefit . This is the first training rule. So here it is Mile repetitions or 5 minute repetitions at LT. This will be a lot better than 20 minutes all in once . Same benefit and less stressful and your body will learn to run at LT pace little by little. You just cant go out and run for one hour at LT, It's a nonsense. Is like when you train for the marathon you will never do 40 k at marathon pace all in a once. Kipchoge trains for the marathon working on LT repetitions 1k or 2k ,2'50 /km at altitude basically is around Kipchoge LT. no more, He doesn t even do the Long Marathon pace tempo run. Of course a lot of long "fast"run 30 k at 3'20/km at altitude , on hilly but not tempo run the way we use to know it. He doesnt even run HM (LT) since a long time and anyway his training works well for him. Training is one thing race is another thing. The race is after a lot of months of good training and we must see the training like a cumulative effect that will take you from point A to point B after some months with a better shape and ready for the race .

I'd agree with that. It's subjectively quite hard to run 30 min at half marathon pace, solo on a regular session day.

I generally do a lot of aerobic reps, but recently did 5 miles on the track instead, for the mental conditioning aspect mentioned above.

I was just over 36 min (7:12 per mile), but I'm 65, and that would work out at a respectable half-marathon age graded. By HR it wasn't that hard, but it certainly felt like work.

When Daniel’s brought the tempo run over from Astrand’s training group, they were doing four miles at onset of blood lactate accumulation, defined as 4mmol lactate, which was at that point in history approximately their 10k pace.

at some point “tempo” has been convoluted to different lactate concentrations, equivalent race paces, and philosophical goals, and you end up w its initial purpose lost in translation.

this is why things like 20 min at half marathon pace doesn’t make sense. Half marathon is closer to 3mmol for elites, and yes they typically go approximately 40’ in training, depending on race and training goals. We should all be more precise in definitions when communicating.

Sorry, should have clarified that as separate from the threshold talk.

Intervals referring to more of the 10x400 kind. How challenging should that pace be? 50% chance you might not be able to hit it on the last rep? 10%, 5%?