Switching intervals from controlled indoor trainer to outside hills

I’ve always done my tues/thurs interval sessions on the trainer. Much of that was schedule and convenience, but also for repeatability based on conditions. I recently retired, so now have a bit more time and flexibility to train outside.

In my run-in to Unbound and Leadville this year, I’ve switched to doing my v02max and shorter threshold intervals outside on some fairly steep hills (anywhere from ~7% to over 15% grade).

After years on leaning on high cadence spinning indoors to generate power, these intervals are kicking my ass grinding as low as ~80rpm, but I’m managing them. It’s also gotten hot here in TX, but I’m doing them early (but it was still 80f and 95% humidity at 5:30am yesterday).

I’m hoping just switching things up will drive some benefits, but wondering if there is any science here or if anyone has personal experience? I can definitely push more watts on the trainer inside at high cadence and cool temps, but hoping the climbing/cadence specificity will help even if I can’t quite hit the same numbers. I won’t be spinning 95-100rpm when climbing at leadville. Anyone have experience/opinion on doing a similar switch and what the outcome was? I am a little apprehensive switching things up before my A event, but enjoying the change so far.

In general I’m a fan of training both torque and cadence to generate more power. At 2.9W/kg when I hit steep pitches the cadence drops and torque drives the effort. On the flats I mostly use cadence to push power, unless caught undergeared. All year long I do overgeared and undergeared efforts, from sub-max outputs to way over threshold.

But you’ve got an upcoming event.

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… I’d just focus on specificity at this point (I didn’t pay attention to how soon your event is).


Ya it’s bloody hot here. Not so fun uphill with the wind at your back today.
I think if you can handle it and your event is going to require you grind it out, there will be some benefit doing hill intervals outside.

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Yeah, I’m already rolling a 10/50 cassette, training on my MTB on the road. Running a 38 chainring for training, which actually translates pretty well to the 32 I’ll be running at altitude at leadville (lose about 20% of my ftp). I can climb some stuff at around 90, but climbing at ~80 actually feels more manageable and smooth. There is just a different strain/dynamic to steep climbing watts vs. spinning on the flats (or trainer).

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Doing intervals outside is far better, IMHO, than “repeatability based on conditions” unless you are training for Zwift races. I stole that from Colby Pearce interview in this podcast:

Just another plug for it, as I think Colby offers some interesting insights and perspectives.

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I don’t think you can go wrong by shifting to outside because that is where your event will be. I mentioned it in another thread but the ability to transfer your fitness from the trainer to the road takes time and practice and I think this is especially true if it’s any type of an off road course. Your watts won’t be steady, you’ll have undulations, headwinds, tailwinds, dirt, rocks, etc…What I’ve noticed is that when I attempt my workouts outdoors, I’m training myself for these conditions and I’m calibrating my RPE and learning how hard I can push an interval outside with all of these other things happening. It becomes less about hitting the target and more about maintaining the effort while dealing with the environment and to me that translates to getting that experience while still going after the workout.
With that said, I still do workouts on the trainer because sometimes I don’t have the energy to deal with the real world out there and I just want to nail a workout as efficiently as possible.

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It maybe goes without saying, but I use the same hills frequently and it helps me to map them out in terms of where I expect to be at various time points in the interval to help me gauge the effort and notice improvements.

e.g. one climb is ~5 minutes at my all out RPE. I have a mental note of where I expect / need to be at each minute point when pushing a particular RPE.

Some here: