I took a series of boxing classes over the course of a summer several years ago, just to try it out. I'm sure all classes are different, but I'll give you a synopsis of my experience.
It's extremely demanding. I was first taught foot positioning, then footwork and rhythm. In boxing, you are CONSTANTLY moving. If you stopped moving, the instructor would bap you on the head with his training mitt. The lesson is that if you stand still, you're an easy target.
After footwork and movement, they started teaching how to use your hands. You need to keep your hands UP in a defensive posture in front of your face at all times. Drop your hands, and the instructor bops you. Then, they taught punching. Jabs from either hand. Then different angles of punches from either hand. Then.. combinations... and you had to synchronize the rhythm of your footwork to serve as a trigger for your upper body combinations. The thing that was really hard to remember was to keep the hands up AFTER throwing a combination. After you punch, it's so easy to drop your hands and contemplate your result, but if you did so, you opened yourself up to counterattack.
Believe it or not, it is a LOT to think about when you're sparring... keep moving... keep your hands up... remember combinations... KEEP MOVING... DON'T DROP YOUR HANDS... all the while the instructor is using the mitt whenever you screw up. And, you aren't just doing your rhythmic movements... side to side, up and down, etc... the instructor is also forcing you to side step laterally, in a circular pattern around the ring.
Towards the end of my sessions, we did mitt sparring of 3 rounds of 3 minutes each. And, I'm not too shabby of an athlete, but it pretty much kicked my ***. The last three minute rounds of each session seemed like an eternity. I was sweating like a hog.
