What distance and rest for reps at 10k pace if I want to run at LT?

Isn't Ingebrigtsen's 25x400 w/30s base workout a bit slower than 10k pace (64s) and right at LT? I might be wrong on that one.

5-10k pace and there is a 3 min break halfway through from the coros article. other people are doing roughly the same work with 45s rest.

A couple things to think about. He is running for 64s. If you are running 80s, you will be doing a lot more work. Your recovery might also not be the same since you probably haven’t don’t 150km/ week of training for half a decade. You would have to see what your recovery looks like.

Now exactly how precise you want to be is up to you. Just want to wing it? 300-400s is close enough. Want to worry about if you are 4s too fast/slow? Time for lactate testing

Try 16-20 x 400m, 100m jog, with 400s at 10k pace. 16 is probably the better repeatable workout; 20 is closer to a race simulation thing. 5k pace seems a little too hard to me if you want threshold effort, but your mileage may vary. Start with 16 at 10k pace; if that seems too easy, then you've got plenty left for next time.

I think 400-600m is about the sweet spot there, around half of the reps length in time for rest, or a 100-200m jog

According to my heart rate data and feel (I don’t test lactate VERY often and haven’t done it on this workout so take it with a grain of salt) 800m @10k with a 400m jog rest puts me at perceived LT2 effort

20x400 at 5k pace with 60 seconds recovery would be brutal. Definitely not a LT session. Personally, I'd look to dot hair reps a couple of seconds slower than 10k pace

For 10k pace, I would be targeting something like 30-45s recovery for 400m and 60s-90s for 800m repeats. You have to stay disciplined though. If you start cheating it a little faster or are too optimistic with your 5k pace, you're going past threshold quickly.

Good post. For most people 1min fast/1 min easy (fast means 5k-10k pace) is better than sticking to the distance of 400m and a given number of repeats, for the reason you have described above. No reason to feel ashamed, if someone has to begin with, for example, 10 x 1/1. Work up to 25 x 1/1 over time and then the rest can be lowered (45sec). The next step would be 400s (perhaps 16 or 18 are enough at first) and so on.

800s @10k with 2-3mins of rest is a bit different than most of these threshold workouts. You are going to push a bit harder and then recover a bit more. You are going to be at the upper edge of what could be considered threshold. That doesn’t mean it is bad but it might not be what you are aiming for.

Personally I think doing like 10+x800@10k pace is hard enough that doing it every week isn’t doable while 20x400@8-10k pace is. But we are right at the edge…

You're throwing together a lot of different concepts/paces. Loosely, LT1 correlates with something around marathon pace & LT2 correlates with what most would call true threshold (something a little quicker than half marathon pace). For shorter reps, you might be running them a little faster or right @ T because that's what you can hold on short rest. 20 x 400m @ 5k w./ 45-60s rest is not a threshold workout. By definition, it's a 5k workout. &, imo, not a great 5k workout. If you want to do work @ 10k pace then do work at 10k pace. It's probably not an LT1 or LT2 session if you want to do longer reps. 10 x 800 @ 10k is a good 10k specific workout. I would do it on 45-60s rest. 90s is too long.

For the LT1/LT2 work you're generally doing a good amount of volume without a ton of rest. Those workouts can help you get strong for the 10k.

4 x 2K at 10K pace as an alternative to the 400m reps. 60-90 seconds rest depending on current fitness.

I save 400m distance reps for speedier stuff.