Glad you like my suggestion. But trust me on this, it's not an aging issue. I've seen perfectly healthy young people with shoulder pain from leaning too hard on their bridge hand. It's one of those repetition-type injuries that creep up on them over time. And by the way, if they're leaning hard on that side of their body, their stances are probably off as well, and will likely need a stance adjustment.
Some players prefer to put their entire arm down on the table, up to their elbow. If you're playing on a snooker table with lots of room to do that, I guess it's okay. But in pool, we don't have the luxury of space to do that. It's not something I would teach a pool player to do because it also requires a stance change, and it also puts the player's head closer to the cue ball. I don't like it.
See how something as basic as hand pressure can turn into something much bigger? LOL
I find everything after the first couple of sentences to be very compelling, and a great argument for moderating the weight you're putting forward in terms of stance, head distance from the cue. I will gladly incorporate that advice! But the physiology related stuff I gotta quibble with...
While I won't deny that it can happen to young people, I will absolutely disagree and I think a firm consensus of physiologists out there will agree with me that in terms of both structural weakness
and behavioral weakness - shoulder injury prevalence clearly increases with age. A young person can have bad behaviors that lead to exposure of the shoulder joint when they shoot pool, as was almost certainly the result in the examples you've encountered of 'perfectly healthy young people' with shoulder injuries from leaning too heavily on their bridge hand.
Generally speaking, most soft tissue injuries are caused by shearing forces within the tissue structure. Early in childhood we develop physically while performing actions that involve different muscle activation patterns associated with supporting the joints not only using the immediate muscles, but by engaging the nearby muscle groups. This prevents the exposure of the joints to those forces over time. As we settle into what are largely sedentary lifestyles, most of us stop supporting the joints, like the shoulder and cuff, by properly engaging the muscles around them.
You provided compelling pool related points, and I bow to your expertise on the pool related points and will incorporate them into my learning.
Weight on the hand puts stress on the shoulder over time. More weight, more stress. That pressure coming from the lean of the body makes no difference and there is no way to avoid stressing the shoulder if you are going to include it for stability and carry weight on the bridge hand.
Met a young lady in her mid 20s last week complaining to my friend about her shoulder pain from all the extra hours of play she'd been putting in recently. Sure enough, her weight was quite forward and her shoulder was eating all that. It's a small thing, but after 1000s of shots, it adds up and gets sore even with what feels like you could do all day when you first try it.
More weight, more stress is an oversimplification, though. It is a specific type of stress, as I noted above to FranCrimi.
Proper use of the shoulder to support the body from, effectively, prone involves an entire shoulder-girdle of tissues, and includes the tissues of four separate joints - not just the glenohumeral. People who experience injuries supporting themselves while prone or getting up from prone do so because they are only engaging the glenohumeral, which is necessarily weak against forces acting on it from this direction in order to be as moveable as it is. However, you eliminate those shear forces when you engage the other three joints, taking the load on in the rest of the shoulder girdle, distributing the stress through three other much larger and more capable load bearing structures.
A good example of someone who understands this would be a yoga practitioner who engages frequently in arm-extended prone work, such as extended-planks. A person in an extended plank is, by virtue of position, exposing the glenohumeral joint to an extreme. However the extended plank does not provide much undue stress on the glenohumeral joint itself because the load is taken up by the protective sternoclavicular, acromioclavicular, and scapulothoracic joints. You can put quite a lot of weight on the shoulder for long periods of time, or thousands of times for short periods of time, without injury if you're engaging the shoulder girdle appropriately.
