OrangeOne, I accept more or less your point about technique. Regarding massive injury I think you used that expression to emphasise the point or maybe not. For a grown adult male 1kg is not heavy and will not build massive muscles. I was thinking more along the lines of the additional weight acting as resistance training.
I'll come clean and say I tried it once but stopped not because of any pain but because the weight couldn't be strapped on tightly enough so it moved about as I was serving so was irritating me.
Yeah - I was partially doing it to emphasise a point
, but also because I think the injury risk really is there.
My concern isn't about 'building massive muscles', it's about the force that 1kg can generate. Sure - lifting 1kg for a grown adult (male or female) is nothing, most of us can lift 20, 30, 40+ kilos with one arm, some maybe more.
But it's the force that 1kg exerts at the end of a serving arm. A serving arm is a massive lever, and putting the 1kg at the end of that lever results in *much* greater force. As I added, if someone insisted on doing this, I'd want them to start very low - 50 or 100grams, and approach it progressively - the same way people should add lead to a frame.
I would add that I think the real injury risk isn't related to the lifting or accelerating component of the swing, it's in the slowing-down, where the shoulder and arm have to stop the arm from swinging at a *much* faster speed, while carrying much more momentum.
Another way to think about it? The serve is, at the core, very similar to a throwing motion. Most of us can throw a tennis ball, or a baseball, or many things. Asking us to throw a 1 kilo weight - which is effectively the same as tying one to your wrist while serving - is difficult enough. But serving with it attached - you don't get to release it, you have to slow it.
I've been a fitness trainer, and I've coached juniors too. I'd never recommend the wrist weight to anyone, and especially not jumping straight into the one kilo end of the pool.
[AAAA - thanks for the polite and intelligent reply, by the way. Some would not have seen my post for what it was, I appreciate that you took it the way I'd hoped people would].