when you work out on the punching use 14oz gloves you will get sronger very quickly. i have. i'm almost at a six pack now from doing crunches. i find when i work the bag start out slowly then get faster and faster then slow down at the end.

start of slow on the bag then slowly progress going faster this will increase your atamina much more(starting off slow and progressing faster just like a real fight)....you should first complete all other workouts before you hit the bag.... although it is better to use heavier than regulation gloves..... when u put on regulation gloves they will feel a load lighter....