Rings For Swings
There is no better way to train for the swing than to use gymnastics rings. I agree with Mickey Mantle, who said, "In baseball, the real secret of power is the strength you have in your wrists, forearms, and shoulders." If that's true, the next question becomes, "How can we train them in such a way that not only avoids injury, but actually makes your joints more resilient?"
The answer to that question is unequivocally gymnastics rings. They promote more hanging, and humans need to hang. It's healing. Dr. John M. Kirsch was a surgeon for thirty years and stopped his practice when he noticed that most patients would get better simply by hanging. Kirsch recommends you hang from a bar, but I think gymnastics rings, because of they offer more freedom of the wrist, are much healthier for the joints.
You see, the key to training for the baseball swing is to be as easy on your joints as possible. The swing has already done a lot of damage. You don't want to exacerbate that damage in training. Also, the cartilage around the joints aren't like muscle. They don't rebuild very well after damage. So, with joints, they're pretty much wearing down from day one.
Trainers out there don't seem to realize this. Maybe they're too young, and too eager to grow their following online. If they can post a video of some strong young kids doing a one-rep maxi with an impressive load, what's it matter if the kid suffers a knee injury three years in the future.
It's really sad when I see the training kids are being put through. I'm gonna say it since nobody else is: If you can't do basic movements with ease - like a bridge, a dip on rings, pull ups on rings, a pistol squat, a twisted half moon, or any other exercises that prove you have a modicum of command over your mobility and body control - you have no business picking up weights at all.
This shouldn't be a bummer. It's going to feel much better to put the things that are most important at the forefront of your training. Not including weights may seem like your are making training less fun at first, but I think you'll learn to have much better mind muscle connection and you'll be living in a body that is much healthier.
I am not affiliated with this company in any way but these are the rings I recommend. Please let us know how your progress is coming on the rings!