I haven't found that to be the case. If anything its good just for getting used to the weight of the gloves. Other then that it just gets your arms cut up
it will work high workrate, punching endurance, do it with 2-3 kgs on each hand that for long periods of time a long time = 30 mins +
Ive tried it and so has my brothers, we all agreed that it definitely improved speed... I originally got the idea from a Don Familton instructional video way back, he mentioned that the russian team used the method to increase handspeed and they produced great results. The idea is you do it with light weight, then shadow box without the weight fast.
It works if your consistant with it and do it at least every second day for 4+ rounds. People that say it doesnt work just havent done it long enough.
It definetly build speed. Know it from experience from multiple fighters that i´ve trained that way. But not to heavy weight´s, best are those that you strap on to your hands or gloves with small weights inside. Keep it up. The Predator
Basically builds up better overall athleticism in the muscles used in punch movements due to resistance training. Strength, endurance, speed and muscle memory. You would probably find your arms sit cocked and ready a lot more when a proper routine is adherred to. I dont personally do it as I'm not in a serious routine right but I would have to say, don't worry so much on perfect combos as you would in normal shadow boxing but rather treat the weights as a stamina exercise. Like skipping or speed ball. Try and tire yourself as opposed to trying to be like roy jones when u shadow box..