Threshold intervals: progressive or steady?

Really? I would have thoght that lactate levels would increase along the workout if one ran the same pace. When I run the same pace for a 20 min tempo it definitely feels harder in the end so I figured it would make sense to actually run regressively? Am I running too fast?

Or does it make sense to run 20 min steady but intervals progressively?

That makes intuitive sense. At the very start of the tempo, lactate level is resting. It rises from there. Also ATP's answer on this (related) thread was interesting...

this is not true. that's not to say that a fartlek or progressive workout may not have some separate benefit (though i'm uncertain of the benefit of a progressive workout so close to T pace). but T pace is T pace. your "feel" may (and very often does) adjust as you continue a workout, but your T pace and lactic threshold do not alter during a workout. in fact, progressing to too fast a pace entirely destroys the point of a T workout. you're not stressing the same system and you're putting in pointless work that will hamper your ability to recover before the next workout.

Thus sayeth the Daniels' "system" zealot. There's only one system: your whole body. Calling progression "pointless" is stupid. I'm going to guess that you're a guy who buys into there are only 4 paces (hmm, let's call them E, I, T, and R just for fun) and any pace in between is wasted. It doesn't work that way. And, oh, Daniels never coached anyone good nor do any elites that I'm aware of follow Daniels in the slightest. (Even Daniels has backed off some of his more rigid pacing pseudo-science when it comes to tempo sessions.)

^^ the best coaching comes from observation of what works best for the athletes as far as performance, not from theory. The whole 'Norwegian threshold' method is from Bakken's observations of successful athletes, and his own personal trials of different ways to organize that training to fit his own circumstances of training at home at low altitude. Ingebrigtsens' success is fruit of that. Pretty high success rate. It comes down to what allows athletes to consistently get in lots of good work and recover from it quickly. Although in defense of Daniels, doesn't he write many times in his book that if a workout feels too hard, the athlete should slow down some? I feel like his charts get misused.

I would meet in the middle hear, and say progressive but less drastic. If the threshold pace is supposed to be 3:50, start at 3:55 and go down to 3:45. 4:00 down to 3:40 is a pretty big jump, it's a range of like 30 seconds per mile which I think is too wide for a threshold workout. I think it's good to be progressive because sometimes you may not know exactly what your threshold is that day so if you're in a window most of them will probably be very close to threshold instead of 100% of them being slightly fast or slightly slow.

OP you are just starting base phase. You could try a few weeks of one workout, then try a few weeks of another workout. See which you prefer, which one leaves you feeling stronger and fresher.

Okay, I just did the workout yesterday. Did the progressive option.

4:05, 4:00, 3:57, 3:53, 3:48, 3:49, 3:46, 3:44

Felt pretty good, slightly harder than expected. I definitely recommend the workout. Maybe I'll try them steady next time.

That is ridiculous. Heart rate and blood lactate do NOT remain the same. If they do you are no where near your LT2 threshold.

Please post your data then DukeofDenmark

Here's your problem though, if you wanted to stay under threshold, unlikely you accomplished your goal there.

Let's say your threshold is in the ballpark of 3:50. You are not really going to know how you respond on that given day without a meter, but 3:50 is probably best case that you are at 2.5-3.0 mmol with 1:00R. So you are probably looking here at something like under 2.0 on the first 3, probably on threshold for the next 2-3, and then clearly above threshold for the last 3.

Not saying you cant handle that or recover from that adequately, but in the confines of that workout, 6 seconds under threshold for a 1k will push you very likely over threshold.

A threshold workout is any workout you stay under threshold. That doesnt correlate to a specific pace but what your physiological response within that workout is going to be. If you are working threshold it is also better to be UNDER rather than OVER.

But if you are simply picking an arbitrary pace that you are going to hit for every interval, then you have no idea if you are performing a proper threshold workout. Your body doesnt know you are running 3:50 vs 4:00 on the day. The lactate level is the lagging data point that tells you on that day what you body feels like a certain effort feels like. Maybe 3:50 you are right on threshold on the avg day, so youd probably want to be safe and be at 3:55 as a 'target'. Some days, 3:50 pace you may stay under for the whole workout, depending on rest/hydration/etc factors.

Bottom line, threshold efforts shouldnt feel 'harder than you expected'

You can go a lot over threshold at the end unless You run ridiculous mileage and can't recover from workouts.

I am doing 8x1000m between 5 and 10k pace. Though, I am 800m runner and my 10K PB is weak compared to 800

Both have value. Training yourself to lock into a certain pace and just hold it lap after lap is very useful. It can also help prevent you from getting too excited and running too hard if the goal is simply to maintain pace as closely as possible. I do admit I prefer progression runs though, but I do keep them mild, like mile 1 is a little slow, middle miles are mostly about even, then I pick it up some the last mile (or more depending on how long I'm running).

One of my favorite workouts that I would do when I was in stellar shape was a 4 mile LT run fairly evenly paced followed by a 2 mile LT run at a moderately faster pace with only about 3 minutes active rest between. When I was at my best I did the 4 miles at about 5:08 pace and the 2 miles at 5:00 pace feeling relaxed. Worked well for me.

Some good training ideas here however be careful not to peak too early. You've got plenty of time before your cross country season begins.

It's very simple. The very best pace to "clear" lactate more effectively is to run close to half marathon race pace. It's a pace that's not too fast nor too slow. If one does this there is absolutely no need for double threshold a' la Ingebrigtsens 🧙‍♂️.