Training hard 2 days in a row

You'll be fine. I've done it before. Tempo day on the first day is a good setup. And I don't see any reason you would get injured. Just make sure you keep to a true tempo pace (not too fast) and get a good warmup for the second day.

A lot of injuries caused by b2b workouts isnt from a one off stent but the build up of fatigue caused by multiple weeks of overtraining. should be fine but sometimes its worth it to just take the extra rest day.

Why do you "have" to do this?

I'd pick one workout in this case and try to even out the rest days before/after.

Just run baby

Scheduling conflicts mean I can't run more than 45 mins on Saturday and Sunday (busy 7am-10pm both days), so I'll do 5-milers those days

That leaves Thursday and Friday to do a tempo and an interval session

I don't have to do 2 hard runs back-to-back, but that would mean just skipping one of the harder sessions.

As long as you're feeling healthy and not already overloaded on Thursday, this sounds like a reasonable plan to me.

Also keep things in perspective. Workouts are not races. You can run a workout on tired legs, and it's OK if your splits are not perfect. The goal is to produce a desired training effect, not logging ideal splits.

You'll be fine. Jack Daniels actually recommends this, with his "Q" days on M, T, and F

Or you can just combine them into one harder workout, like 15 minute tempo and then 4x800m

You mentioned Thursday, Friday, Saturday, Sunday. What about the other 3 days that comprise a week/7 day period?

Also, you mentioned your tempo run being 20 minutes at 60 minute race pace. Why can't you squeeze that into a 45 minute period?

I would never do these back to back workouts, but I know the Daniels followers do.

It's not so much an injury thing for me, but whether or not I'll be able to hit my target paces on day 2 and get the intended benefit.

Reasonable modifications:

-Do the 6 x 800 day 1 then do the tempo the next day by feel, ie, "comfortably hard" not looking at watch and forcing a pace that could be too much, without adequate recovery.

- Doing the tempo day 1, then day two doing 10 x 100m strides (fast but not all out) instead of 6 x 800, to touch on speed some, without overdoing it.

-Do the 6 x 800 day one, run easy the next day, then incorporate a 20 min tempo segment into the end of a long run a few days later.

It's this week only, so I only have Thursday, Friday, Saturday (busy), Sunday (busy) left.

"Also, you mentioned your tempo run being 20 minutes at 60 minute race pace. Why can't you squeeze that into a 45 minute period?"

Fair question. The course (1.25 mile loop that I use to time everything) takes longer than 25 mins to get there and back. However, I could just do it somewhere else if I had to. However, the biggest reason is that I'm not even sure if I'll get 45 minutes to run on those days (I'm depending on trains/buses etc).

Thanks GettingFasterDude - that 10*100m idea is a good one. I might look into that - could see how my legs feel, then decide on 800s or 100s at that point.

What about combining the sessions into something like a Mona Fartlek- 20:00 tempo + 2x90s, 4x60s, 4x30s, 6x15s?

I think you can do both the way you outlined as a one off kind of thing. 20:00 for a tempo & 4800m of work @ 5k isn't a ton of volume. Stick to prescribed paces. Run closer to marathon pace for the tempo.

Yes this is totally fine ! I have recently trainined like that and I found it quiet produktive. Ingebritsen stack 2 workouts twice a week next to each other. Pfizinger, Daniel's and Bruce Tulloh all have shedules with this

I would do

Day 1 Tempo Intervall 4x6T 1min Jog

Day 2 6x800m 90 sec rest

Tempo intervalls probably better to make sure you don't get too lactic on day 1 and really stay in controll.If you are concecerned you are not polarized enought just do day 1 workout in the evening followed by day 2 in the morning.

True, ingebrigsten stack 2 workouts twice a week, but it's on the same day, ie tuesday has two sessions of threshold and thursday has two sessions of threshold, and wednesday and friday are easy days. the OP proposes doing workouts on back to back days, which is a larger time frame.

Workouts on consecutive days can make sense early in a training cycle when they aren't that hard. But I would just do a hard workout Thursday or Friday and another on Monday if I were in your scenario.

Do 2 moderate workouts in one day. Not worth cramming back to back days just “to get it done”

As one poster has mentioned, you could easily cram your 20 minute tempo into one of the days in which you only have 45 minutes set aside for running.

If not, just do the interval session.

It's a case of risk vs. reward.

It's unlikely that squeezing in both sessions is going to give you some huge fitness boost (in fact, it'll likely make very little difference to your fitness).

However, the risk of injury is not zero - and I'd dare say that it's raised quite significantly.

Yes, interestingly i think JD s logic was that your body peaks for inflammation and DOMS --2 days after a hard workout not one! Not sure if any high achieving college runners or pros can comment on this theory in practice? But I think he felt that 2 days in a row is all sort of one quality workout? Then you recover. But I see many holes in this practice.