Alan, no offense taken..hope I can explain.
Back in the day, when a cowboy worked a cow, he needed a horse that moved quick and when stopping on a cow, he was ready to rollback or do whatever he needed to to get that cow where he needed him to be.
For a horse to work correctly, he should be balanced and working off his hind end. a horse on the forehand isnt balanced and isnt as snappy and quick in a turn then one who is on his hind.
So naturally, a horse working off his hind will start to stop on his hind..think cutting horse here.
Reining morphed off in a different direction then modern day cutting did..although they both descended from "Ranch work". And with most, Im sure there was abit of boosting and chest pounding..every competition in horses I think descended from the "well my horse is better then yours".
The sliding stop went from the rider running the horse hard and pulling him into the ground, to the rider using his body and voice to get the stop..which ment the horse slid further as he wasnt being forced into the stop, he was doing it on his own. Add into that special shoes called slide plates are used..which are wide, flat and smooth and many are long(depending on the horses stopping style) which allow the horse TO slide such lengths and no jar the hell out of their hocks.
The slide stop certainly wont help you when working a cow..in fact, we have to change plates on one horse, if we dont and he works a cow, he will slide right by the cow during his fence work...
As with any horse type competition, the competition is vastly different from the roots which it decsended. It just evolves into what you see today..some would consider it good, some consider it bad..its your personal preference.
As for what it does to a horse, yes, some horses are pushed beyond their physical and mental capabilities and you end up with a lamed up, sour pile of mush..unfortunantly, there are trainers out there who only see glory and dont think of the living being beneath them..or they are swayed by owners who have dillusions of granduer and want to see their name in lights...
It does happen, but when a horse is properly ridden, trained, and managed, they can be quite happy, successful and sound. I own an 18 year old mare who is quite sound..she was started at two, shown heavily..still quite sound and happy.
When a horse works hard, there is bound to be wear and tear on joints..its understanding that wear and tear will happen and helping the horse to perform in peak condition that are key..if that makes sense?
