The best approach is to use a hybrid system. Use PushPress to manage payments and use a dedicated scheduling software to handle booking and rescheduling of appointments. With our google calendar integration you can keep all your appointments and schedules sync'd up in one place and on a single calendar.
Set up a Punchcard plan for each member who books personal training sessions. Sell an initial card of 5 or 10 sessions (just an example) then when they need to buy more sessions use the plan modifier to add/sell additional sessions.
It depends on your needs as a gym to which software will work out best for this part of the equation. Generally you want to use a dedicated scheduling software for this. They all vary in features and cost. I would start with looking at these 2:
They are both excellent, we have personally used both.
You can either use the PushPress Check-in app or the Control Panel to mark off sessions when members use them. Its best to do this at the time of their session.
This hybrid approach falls in line with one of our key philosophies. We stick to what we do best and integrate with best in class software to do what they do best. In this case scheduling, and we use our google calendar integration to tie it all together.