This is a question I get asked oh so often. I like to keep it simple in my answer. I could go into the whole science, biomechanical talk but it is more understandable to keep it simple as to be honest it’s not rocket science.
My answer is we fit to the moving shape of the potential healthy back. This is because when a horse is moving “correctly” their backs are lifted and therefore wider. So, why should we fit narrow saddles????We do not fit the static shape of the horse nor do we ride standing still.
It also takes a certain eye to be able to visualise where we want a horse’s back to be in the future in terms of development. We see a lot of horses with asymmetry and atrophy, where the muscle is wasted under the saddle area. Let me point out that this can obviously be caused by ill fitted saddles but can also be cause by injury and postural tension.
Our principles are to fit wider than the static shape and then to use shimming systems to allow for balance. This can be the balance of the horse, where there is development needed. Balance for the rider, to improve the position in the saddle and allow for their own potential asymmetries. I like to see a shimming system as a buffer or Polly filler where the needs to be support for the time it is needed to make the improvements.
But again, it is about the bigger picture. I believe it is important to share knowledge so horse owners can take responsibility and ownership in their relationships and journeys.