According to your equipment, it's possible to change the global difficulty of the video from the app.
If you have interactive equipment, you'll see a difficulty option with a '+' and '-' button :
100% difficulty means the original difficulty is applied. You can change the difficulty from 0% to +200%.
For users having non-interactive equipment, here is what you'll see:
As we can't control the difficulty of your equipment, you have to apply the resistance percentage manually.