What kind of weight training is good for boxing. but without gaining any weight, im trying to lose some.

I know low weight and a lot of reps, but what exactly is lil wieght? The bar?? Also how many reps is a lot ? 12 , 20??

if all you can possibly do is 3-7 reps you will build muscle and get bigger and stronger. Doing lighter weight at about 20 reps or more will make you more lean and give you indurance.