You're not totally off. Hard rackets tend to be heavier, and that heaviness has a big impact. Back in the day when rackets weighed 400 grams plus and were hard as sticks it was very rare to come across epicondylitis, shoulder pains, wrist pains etc etc. In my opinion for two reasons:
\-Hard and heavy rackets are difficult to move and even more difficult to change directions mid-movement. This substantially reduces jerk (ie the 3rd derivative of position or the rate of change in direction) which is the primary driver of tendon injuries.
\-Because they're so hard to move, you tend to use larger muscle groups to move them. This also contributes to saving smaller joints.
\-Third bonus reason, heavy rackets move less with impact from hard balls and mishits, which also contribute to injuries via jerk (much more than the vibration nonsense everyone worries about).
So if a player were more concerned about arm health than performance, they should play with a hard, heavy racket with a large surface and a thick grip. Which is not necessarily what you should do if you're already injured, but that's a different conversation.
Your argument is about larger mass (weight) as a way of absorbing more vibration while correct, it is not the reason why you get hurt playing padel. This is somewhat true for tennis but that's also related to string tension and frame RA.
Under no reason people that are struggling with arm pain should use a heavier padel racket as a means of recruiting bigger muscles. If someone has bad technique, they should go to a coach and if anyone experiences pain while playing, go to a doctor or physiotherapist. Do not play through pain if your livelihood does not depend on it. More often than not a lower balance, lower weight, soft racket and some technique lessons will do the trick.
Vibration has nothing to do with it. It's jerk, ie sudden changes in direction of acceleration, that causes tendon injuries. A larger mass/swingweight jerks proportionately less for a given force and so spares your joints.
Like I said if you're already injured obviously different precautions are needed, but again switching to a light racket ain't it chief. What someone would need would be to drastically reduce playing volume, drastically increase strength work and return to play with a less jerk-inducing technique for a while. If they actually want to get better and not just manage pain.
All of this is only true for intermediate to advanced players who have good technique. For beginners, it would be a massive injury-inducer to play with a heavier racquet, because they're more likely to try and generate racquet speed with their elbows and wrists, meaning that those joints would take the force of the deceleration. That would be much more injury-inducing than absorbing the shocks from a lighter racquet.
You realize the first people to ever play this game used 500 gram wooden rackets, correct? And so did everyone who started playing before 1995 or so? Their arms didn’t explode.
