Trainerroad

I wouldn't say people train harder on turbos, rather that turbos make training feel harder. Not many people do intense interval sessions on the road.

Also, turbo trainers have much less inertia than riding outside which is what makes them feel different. That, combined with factors like overheating/less cooling and lower motivation means it's pretty common for power output to be at least 10% down on a trainer compared to outside.

What ^ this lot said.

You ride for a shorter time (usually) because;

• There's no junk miles
  
• It's not fun
  

As a rule I ride harder on the Turbo.

A) I want to be on the turbo for a minimal time to, so I need more intensity.
B) I want to enjoy riding outdoors With less training pressure.
C) Its more controlled. So a better Place for structured suffering.

Yes. I like to do all my suffering in private, so that when I ride irl, I appear to glide along so effortlessly as to make Fausto Coppi look like a massive nodder.