Treadmill pace vs outdoor pace is very difficult to compare. Especially when it comes to grade. If the treadmill has a strong motor the belt might be able to move at the same speed at 6% vs 1% grade (with the runner on it) but if not it could be slowed down by longer foot contact quite a bit. I would probably go by HR and feel and not necessarily treadmill speed.

I have done A LOT of treadmill hill reps.

4% to me was something where I noticed an uptick in respiration rate and intensity but not enough to make me concerned if I was doing a zn2 type run. 5% and 6% elicited a stronger response. but I personally have something like 4min @4% + 1min @5% + 1min @6% for 30-40 minutes straight and never had it feel like a threshold workout, maybe a tempo.

I think some of this is going to come down to how long the workout is, as you know the greater the duration they are running uphill the greater the chance of them having a workout feel like tempo or threshold. The runner themselves: how good they are at pacing ie do they tend to run at the top of zn2 all the time or are they more willing to just go run easy on those bread n butter type runs, how good they are at/on hills (oddly I suck at them in a race), are they manipulating the speed or not and if doing repeats the recovery.

Hope that helps give you a better framework. email me (it's in my profile) if you have more specific questions as I write a ton of treadmill workouts for my athletes, especially this time of year and have had athletes that did 95% of their yearly run training on a treadmill

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Brian Stover USAT LII
Accelerate3 Coaching
Insta

Thanks Brian. This is exactly what I am looking for. Ballpark effort. Thanks again.

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Geoff from Indy
http://www.tlcendurance.com

I often do sets of 30/30 or 90/30 on my TM, typically one set at 6% and a second at flat. Speed diff is usually a little less than 2mph between. I don’t know if it really works that linearly, but perhaps 1% grade is worth ~.3mph. Thinking for myself, if I started at a typical z2 type pace 7mph and gradually ratchet to 6%, if we assumed 7/6% was similar to 8.8/0% then that’d be closer to marathon pace than threshold for me.

There’s also this table, which doesn’t quite match my experience, but was perhaps more thoughtfully put together.

https://www.hillrunner.com/...ll-pace-conversions/

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Dimond Bikes Superfan

I'm still wondering what happened to THIS thread?

https://forum.slowtwitch.com/...BBigToe%5D_P7994954/

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"What's your claim?" - Ben Gravy
"Your best work is the work you're excited about" - Rick Rubin

I'm wondering, too. Did the Dude run faster every time on the treadmill for 4 months, with little recovery or downtime? My guess is that he imploded.