So, last week I started doing Muay Thai kickboxing and Brazilian Jujitsu. 2-4 hours a session and it is so intense! Sure, you get a few strained joints, and maybe a bloody nose or two, but totally worth it! A lot of cardio, and overall, a total body workout. The classes are a bit pricey, but if you can handle the strain you will start seeing results almost instantly. I train 2 days a week at the mma gym, and 2-3 days at my regular gym.