Join Date: Feb 2012
Location: South Wales, UK
• Horses: 0
Most saddle fitting has to be educated guesswork.
There are 'fixed guidelines', that is generally acknowledged recommendations which should be followed regarding tree and panel width and shape, but even these can be subjective depending on the individual fitter's views.
An eminent vet (ex British team) once said at a lecture I attended, years ago, 'the best one can hope for (when fitting a saddle) is to minimise interference to the horse.' Meaning you can't improve its performance or way of going, only maximise its potential to achieve them.
As an add-on to BSMS's great post on back movement, the makers of WOW saddles designed a tree specifically to deal with the difference between a lot of shoulder movement and little across the loins. This flexes behind the (rigid) head, allowing the front of the saddle to move with the horse while the seat stays still. Combined with air flocking, this system is probably the closest match to a human backside/animal's back interface we'll see in my lifetime.
Dynamic balance is almost impossible to judge, even when the saddle is ridden on, simply because each horse is an individual and can feel different each day, same as us. So a saddle which appeared spot-on when fitted may, a couple of days later, not fit as well. There are pressure test systems ('Pliance' is the most commonly used) which can give an idea of how evenly the saddle panel is distributing weight but these, like any scientifically based test, need many repetitions to achieve a mean reading, which means they're not very practical for most saddle fitters' purposes.
So in most cases, despite following the guidelines, we have to fall back on experience (and sometimes a gut feeling) when considering if a saddle fits well. All saddles, even specialist competition saddles, are based on an average horse type for whatever breed or discipline. They have to be, from a manufacturer's viewpoint, because long gone are the days when the local saddler made each one individually to fit a particular horse. There'll always be horses where you think the saddle's a good fit but it's not, or the flock adjustment you did last week was too little, or too much, or the saddle which fitted fine a fortnight ago is now awful because the horse was so comfy in it he grew half a tree-width almost overnight. That's a saddle fitter's lot, and I'm sure such return-visit hassle (and unrecoverable cost) is what puts a lot of fitters off.
Fitting is usually more common sense than rocket science. And there's the rub - 'usually'. Sometimes you need second sight because I'm sure horses, being what they are, conspire against us!! :(