Doing a shorter set of intervals on trainer and then riding outside

This Saturday I was prescribed Mono, which has 4x6 minutes of over-unders between endurance riding (90 minutes total). Since I’d like to ride outside some on Saturday, but don’t have a great place to do intervals, I was thinking of doing a shorter threshold workout (30 or 45 minutes) on the trainer that has a similar progression level (Maybe Sill -5) followed by an hour or so of mountain biking outdoors. Has anyone tried a strategy like this to get some high-quality intervals on the trainer and some time outdoors on the bike?

I’ve done the opposite. I’ve commuted home (1-1.5 hours endurance) and then hopped on the trainer at home to do threshold or vo2 work. Works great. (Full disclosure: I did completely fail a threshold set after a commute recently, but I think that had nothing to do with the endurance ride and everything to do with it being my first threshold workout after ~2 weeks of extremely reduced volume.)

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My wife used to do her 2 x 20 min L4 efforts on the erg, then pad out the workout with laps of Stone Mountain Park ((which is hilly).

A friend of mine who was competitive in the old Coors Light duathlon series used to combine trainer efforts with outdoor running (to simulate the demands of the transition).

TL, DR: Do what it takes.


I’ve done the exact same before and it’s worked well. I don’t have a place near my home where I can do 6 mins over-unders. I find that type of workout very challenging to execute outside and generally prefer to do inside.

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I’ve often read that this is the preferred prescription for elite riders during winter and spring when the weather is bad.

Get the intervals done in the safety of indoors, then get the slower miles/hours in outside after.


Sounds like a plan, I’d use alternates to shorten the indoor HIIT session to one that lets you comfortably ride outdoors after. I haven’t done it, taking the whole workout outdoors in the past or keeping it entirely indoors if it felt unsafe; so I may do the same in future.

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This time of year, I like to do the intervals inside in the morning, then go for a spin outside to 'cool off" and extend the workout.

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I like the idea. A few years ago, I was living in the city and had the idea to do this too. However, I was doing it at the end of a bike commute, not that it’s any different.

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Thanks everyone! Sounds like the consensus is yes, this can be a good strategy. I’m going to try it out this weekend.

just to pile on. I’ve done this pretty often, with intervals early in the AM and then riding to a moderate, no drop, social group ride. Sometimes I’ve noticed I feel GREAT during the friendly, spicy/sprinty portions of the ride when doing an indoor interval workout first. My theory is that it acts as a bit of an opener.

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Nothing wrong with that, but when you get to a higher progression level these endurance parts will be replaced with more intervals.

Even if you will be able to find a shorter version of the workout with the same progression level doesn’t mean it will have the same training effect. It is only an indication of how hard it is (how likely you are to be able to complete).


Ive done this before with good success. Especially in the winter when im trying not to get too sweaty on my longer rides. And its a good warmup before heading out in the cold

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That’s a great point–I will plan accordingly!

I’ve done this for about two years now when the weather is bad and doing hard intervals outside would be at least difficult if not dangerous. Works great during winter and early spring but I’d make sure to get at least a couple of hard workouts outside before A-races. Riding your bike hard indoors is one thing and riding fast outdoors is a skill that takes some practise.

Also, organizing your gear beforehand is key. If I don’t have all my gear set up it takes way too much time faffing around between the indoor and outdoor portion.

But overall this works great for me and makes riding both effective and enjoyable during winter. I’d recommend to give it a go and see if you like it. No harm done from fitness perspective.


I am pretty organised for my morning workouts, but even now, it’d be near enough a complete change to head outside - last weeks spin was full winter gear with the “feels like” temp!

But, food for thought to combine with the commute.

Something I’ve done in winter if icy or frosty / foggy first thing

  1. Do the intervals on the trainer, first thing in the morning.
  2. Wait till middle of day when the frost / ice has gone and then go out on the bike and return before temps drop again.
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