Rollers is originally for learning pedaling skills rather than building muscles. But if you want to use rollers for this purpose too, you can add extra power by adding this unit
Installed between the mid and rear rollers. Driven by rear roller
7 levels resistance power
Quick installation and removal
Part Number: 400-3560-00
Barcode: 4944924407544
Product Code: MIN TRO A MOZ MU