Anyone who has used an indoor trainer and compared power numbers to what they make outdoors, will notice a weird difference. Almost everyone notices that the power levels they can achieve on the road, are better than the indoor trainer. Mysteriously, there never seems to be a very good answer why. Well, that’s because there’s a few different reasons, and they affect people differently. Here’s the top reasons why your power is lower on the indoor trainer:
The hotter the ambient temperature, the more your efficiency is affected. If you watch the 2016 Road Cycling Worlds in Doha, you’ll see riders using ice vests before and after races to mitigate the heat, and that’s something riders are using more and more anywhere it gets hot like the velodrome. Lack of air movement on the trainer causes heat build-up and that makes it harder to produce power. You can help that by using a big fan and if you are doing a hard interval, put it on really hard – it helps a lot.
Trainer Adaptation/ Pedalling Dynamics
Any time you change your position or bike type, there is usually a period of getting used to the position and the variation in muscle activation and recruitment. The same thing applies to indoor trainers, partly because trainers apply resistance in a much more constant way than you are subject to pedalling on the road. The little pauses you get from torque application on the road reduce perceived exertion. It’s the same effect when you ride a fixed gear bike on the track. The more you get used to a position and/ or trainer, the better this gets, as you adapt.
Boredom And Lack Of Sensory Input
Who remembers watching the clock in 5th Form Maths Class? The period of time from 2:59 to 3:00PM lasted about 4 years. It can be like that doing long trainer intervals too. You can listen to music, watch cycling videos, or use Zwift but ultimately it’s never as good as riding outdoors, but it helps.
In summary, there are multiple reasons why the indoor trainer feels harder than riding outdoors, but if you mitigate these top three as much as possible you’ll get the difference down to just a couple of percentage points and your indoor sessions will be (a tiny bit) more enjoyable.