Do not go on the mat with active ringworm. If you catch suspect spots early, it really does not take long to clear up. I believe 72 hours of proper treatment with Lamisil is enough to render the smaller stuff inactive and non-contagious. That really isn't a long period of time to sit out. Just take a little bit of time off to clear up the ringworm before you go back. You don't want to be spreading it all around to everyone.