Im coming off of a shoulder surgery, so I havent been able to work out in any capacity, but Im going to start a mixed martial arts class (BJJ, Muay Thai) and I want to get in shape before I take the class, because it is very strenous (2 1/2 hours). Im 28 and I dont think jumping into a class like that without preparing is the best thing to do. Any martial artists here have any suggestions?