Re: Shadowboxing with dumbells
Punching with light dumbells (no more than 3 pounds, but 1 or 2 pounds is better for a smaller guy) actually improves hand speed and power. I recall hearing about a Russian boxing coach who did studies/ experiments that proved this to be true. I can't find any info on the guy right now because I forget his name, but I know I've read in more than one place about this.
It's not a new concept, and as far as I know it's a pretty well accepted technique amongst trainers and fighters. Floyd Mayweather does it all the time and it works pretty well for him. I'd be inclined to take the P4P #1 fighter in the world's advice on boxing over some random dopes on a forum.
The same effect can be achieved by using heavy gloves in sparring and training.
The Russian coach I mentioned earlier advised his fighters to start by doing short intervals using the heaviest weight (usually 3 pounds, but I've heard of heavyweights using 5 pounds or more) and then tapering down in the next intervals by doing a lower weight (maybe 2), and then move onto 16oz gloves, and then shadowboxing for a round or two.
After proper recovery, the end result will be a gain in hand speed and power.
A couple of you mentioned you've done this and it "felt" like you were faster afterwards, but you assumed it was a mental trick of some sort. It probably was, because you don't get stronger immediately. Your muscles have to rest in order to rebuild themselves and get stronger.
It does work, but it's fine if you're skeptical. You don't have to take my word for it. Do some research and you can find out for yourself.