I have had absolutely NO issues with a treadmill motor and a MC-30 Motor Control board controlling it. Mine is rated at 1-1/2 HP, and set for a crawl (well under 100 RPM) I can try to stop it with my hand and cannot.
Moreover as soon as the controller senses the load, it automatically adjusts for it and the speed will come right back to what was set. I've done this by hand, with an without a leather glove on, and in use drilling and hole cutting. NEVER had an issue.
All this with the 1.5 HP motor and MC-30 controller, Most TM motors are 2-1/2 HP and above, and use MC-60 controllers so it can only get better from a lost torque perspective.
I've been using this setup for almost 7 years and could not be happier. The motor has a 3" pulley driving a 4" pulley, and I've NEVER had to use anything else.
A treadmill motor is an AC/DC motor, and does not have the "torque issues" a straight AC motor might have at lower RPMS.
A link to my Treadmill build:
https://www.garagejournal.com/forum/showthread.php?t=159224