I just did 30 minutes in the 85% MHR range on the turbo. In some ways I would expect that to be equivalent to more than 30 minutes on the road, as inside I pedal constantly at the same rate, whereas outside there is the inevitable start/stop of traffic and lights and natural ‘breaks’ as you stand on the pedals, etc.

Any idea how the t/t compares to a real ride in terms of calories burnt and other factors?

It’s all just watts. Ride at the same power indoors and out and the calories expended will be the same (assuming this is road and not mtb.)

Can sometimes feel a bit harder to ride at the same NP outdoors over rolling terrain as the effort is a lot more dynamic. Other times it can feel easier. Unless you are riding with a PM there can be a tendency to slack off a bit outdoors too.

Unless you have a good turbo setup it can feel harder on the turbo, less cooling may mean the effort feels harder than it is. Also turbo feel is different which might make it feel easier or harder.

Surly you can adjust the resistance to equal ( sorta) wind resistance you would get if riding outside….then you would burn calories the same rate
If anything the turbo is harder as your no going down any hills

I did a turbo the other day on the lowest resistance and I was riding like a pro……normally I have it on 3 ( 5 is max) and it more or less equals outside riding

Resistance is a red herring. 100w is 100w. whether you do that spinning like a loon or mashing a huge gear doesn’t matter, indoor is the same as out.

I don’t have a power metre but would love to be able to calculate (fairly) accurate calories burned per turbo session.

Would help with updating MFP

WHats the cheapest reliable power meter? would love to have one on the bike in the real world but think its prohibitively expensive from what I’ve seen.

New, probably Stages 105.

See if you can find the power curves for your turbo (or use trainerroad.) Won’t be that accurate but probably as best as you’ll get without a power meter.

love to be able to calculate (fairly) accurate calories

afraid the calculations are very generic. And its more dependent on your body, how fit you are and how its metabolises food. Did yo have a rest day before the training session? Body metabolises food differently post exercise. And so on. My view is divorce training from weight loss or calorie burn. Control weight by diet and train as you need to train. This means scales and BMI.

Yes exercise and diet are a very good way to loose weight. But once your fit things change. You need less food and water for the same energy output because your burning less. Whereas the calculations pretty much assume a steady state.

Resistance is a red herring. 100w is 100w. whether you do that spinning like a loon or mashing a huge gear doesn’t matter, indoor is the same as out.

But the OP asked about 30 mins on the turbo vs the road – not using a PM.

Turbo is more taxing IME, assuming he’s actually trying.

Turbo is more taxing IME, assuming he’s actually trying.

Oh, he’s trying alright.

As I said above, I try to do a solid 30 mins in the 85% range.

At least I think that’s trying. 😐

I only said that to pre-empt a pedantic contradiction.

I’m sure you’re very trying trying very hard.

Turbo probably puts more tax effort on your legs, particularly if your going by heart rate, as you’re not doing 101 other things like using your arms/core (which would burn off more calories on the road) having your HR elevated by adrenaline etc (which would burn off less calories on the road at a given HR).

Turbo is more taxing IME.

Not necessarily because you are putting out more power. There’s a lot of reasons why turbo can be a lot more taxing than road despite you putting out less power.

Good blog post on just that here..
http://alex-cycle.blogspot.co.uk/2009/01/turbocharged-training.html

Not necessarily because you are putting out more power.

But still using more calories, no?

I don’t think significantly so, it just feels more taxing.

As the blog post states, things like inadequate cooling, a lack of adaptation, and monotonous boredom, can make the same level of effort seem a lot more taxing on the turbo than outdoors.

For me, inertial load is a big one. Try putting out the same power on a mag turbo at a high resistance setting and a low resistance setting. Same power, but you’ll likely find one a lot more taxing than the other, as you’re using muscles differently.

Cooling is also a big issue for me. I put out a fairly respectable amount of power and need two big 18″ fans to keep cool. Without those any sort of effort starts to feel very taxing very quickly.

Watts is watts, they maybe +/- either way for stop/start and overcoming inertia and some for the extra muscles to turn and lean. Also don’t we burn more calories in the cold?

TBH it all sounds a bit marginal, so I’ll say same.

Actually one other point, my HR increases through my our at ftp from 150 to 160, I suppose you could argue that I’m missing watts when at 150 but I don’t think I could hold 160bpm for an hour.

So as my road rides are generally longer they may be at a higher bpm and burn more calories.

So i’ll change my mind and say 5% more for IRL.

Same power

How are you measuring that?

Change the resistance and something has to change, power. bpm(effort) or cadence.

How are you measuring that?

Change the resistance and something has to change, power. bpm(effort) or cadence.

Err.. yes, gearing! Measuring with a PM. Set the turbo to high resistance and put in a low gear, or set the turbo to low resistance and put in a high gear. Pick resistance and gear combinations so that power and cadence is the same. Point is that the turbo will be spinning a lot faster for the same power at a low resistance setting. This (typically) results in a lot more inertia and will change the feel of the turbo.

Resistance is a red herring. 100w is 100w

Not sure it’s quite that straightforward.

You have less momentum on a turbo or rollers, so you have to overcome the dead spot in the pedals. I think this uses slightly different muscles, which seem to tire more. I get very tired knees on the rollers.

I have a power meter, and I find it a LOT harder to maintain power on the turbo as I do on road. Never quite worked out why. Heat stress is a possibility too.

EDIT what mr blobby said.

🙂

Why would you increase the resistance and reducie gearing keep the same power and cadence?
Your artificially emphasing the weakness of cheap trainers, if you need to run at higher watts, have money and sufficient commitment to own a power meter you will likely have a fluid trainer with large flywheel and less of a flat spot.

I’m just using it as an example to illustrate the difference the inertia and feel of a turbo can make and how that can impact your ability to make power on the turbo (and how hard making that power can feel.)

(You may actually want to do this if you want to model scenario for high inertia, e.g. a flat time trial, and low inertia, e.g. ploughing through muddy field.)

I’ve actually got a LeMond which has a very road like resistance curve and probably the most kinetic energy of any commonly available turbo. Bloody loud but my efforts indoors and outdoors are very similar in terms of power and cadence.

I’ve had to do a lot of turbo over the past few years and looked into this a fair bit as I use to have trouble adapting between periods of turbo work and outdoor work. With setup, kit choices, etc there’s a lot more carry over now.