Often when you buy a saddle, the only indication of size rider which we have, is the size of the tree, more precisely its length.This measure takes bias between the saddle nail and central cantle.
Of the importance of the tree ...
The comfort of a saddle depends on the tree itself, strapped or molded, flat or hollow, and with what background above. In addition, it depends on what you want to do and how you will use it: if you like to be kept in your saddle, or if you have room to move in.
... In that of the seat
The size of seat is indicative but not an absolute. We choose it according to where we feel good. If your body takes out of the standard, then your saddle too.
Seat hollow, semi-hollow, flat ...It is primarily a matter of personal preference, then an anatomical question. A large person will still be more comfortable on a flat seat. A too spicy cantle, a corollary of the hollow seat, will push the pelvis anteversion, causing an exaggerated lordosis (digging of the vertebrae) and a nice little crush private parts on the pommel. A flatter seat or longer allow less arch your back and engage the pelvis in a neutral position.
Attention on the notion of comfort
The softness of a seat does not determine the comfort ! It is the adaptation of the shape of the tree and the work of the seat then your anatomy which dominate. If the seat is fundamentally unsuitable but covered with a thick layer of foam, you might feel comfortable in the short term, but in the horse running, you will enter in a compensation scheme and ultimately you may make you very ill.
We should find a form of tree that corresponds to both the shape of the horse's back and the posterior rider. If one is to be preferred over the other, there will be fast enough problems ... Hence the necessary compatibility of morphologies of the horse and rider !
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