Cannot imagine running on treadmill or lifting with masks on so hard to breathe.

For GX classes there's likely a limit to the number of people per class.

I'd say... the most costly way to do this is standby a cleaner at every set of equipment ie. someone standby at treadmill area. whenever someone leaves the treadmill, he/she sanitizes the surface of the board then next user uses it. Then again, a lot of cleaners will be needed to standby around and yet machines need to be reduced (to ensure at least 1m apart). Cannot imagine queuing for workout frustrating