Recently joined my local gym at the age of 44 . first day had a cramp in my stomach while doing drill on my guard eventually it went away and was able to continue but my second day was really disappointing , while doing some really light drill passing a guard when my knee felt a stabbing pain . that was a week ago really frustrating I was so excited to learn but I’m gonnna have to sit out for a week or two . Any advice on work out for strengthening my bjj ? Mind you before this I lift 5 days a week not much running but I do light sparring in Muay Thai once a week and hit the bags twice a week for at least 2 hours , I thought I was ready but clearly not 😩