but the riding down the side of that mountain is very real as all the riding
Just because the cavalry did it that way does not mean it's the right way.
Yes, what they did in the movie worked okay. That shows it is POSSIBLE. It does NOT show it is the best way. To find the best way, they would have needed to try different ways going down the mountain hundreds of times. Maybe thousands. And kept track of which method resulted in the fewest accidents and fewest injuries.
Oh wait. The US Cavalry DID that! With thousands of horses and riders! So yes,
@Acadianartist , that very strongly suggests their way IS the right way
because no one else has ever tried to find the answer! They did it because travelling across extremely rough ground was part of what the cavalry needed to do.
From a scientific or engineering viewpoint, what people do a few times successfully does not show anything other than it is possible. Most people will keep their backs perpendicular to the horizon because that
feels best to us. And how many of us have ever stood beside a steep drop and watched a hundred horses and riders go over the edge, and paid attention to how both horse and rider moved?
Of course, people can and will do as they wish. But anyone who says maintaining a Forward Seat in steep descents is impossible or harmful ought to accept the evidence it is not. And if one wants to know the best technique, it is prudent to consider the conclusions of people who did it all the time and with thousands of horses and new riders.
Slim Pickens jumping a wagon for a movie:
He did it and it is absolutely possible to do it that way. But there is a reason you won't find many professional jumpers using the same technique...
PS: I think "lean forward" is being misinterpreted. I don't think the OP was saying to lean out over the horse's neck. I think the OP means your TORSO leans forward as needed to maintain a regular balance, rather than leaning back to stay perpendicular to the horizon. I think it is obvious
BOTH work relatively well, although at the "professional" level, you'll be less likely to be injured if you follow the cavalry's advice. I also think
it is best to ride the way you prefer so as to be predictable and stable for your horse. There really is more than one way to do most riding.
PS: The US and Italian cavalries rode with an English approach to the reins. I also suspect a tight rein was needed to encourage the horse approaching a steep slide to to turn away. I normally ride with one hand and a little slack. But I also don't ride off of cliffs and Bandit has a say in where we go....