A hollow back and elevated head under saddle is one of the most common performance problems in western horses — and one of the most frequently misdiagnosed.
A horse that hollows its back under saddle is either responding to pain by contracting back muscles away from discomfort, or avoiding engagement due to weakness, lack of training, or learned evasion. Pain-driven hollowing almost always has a saddle fit component. Rule it out completely before treating as a training problem.
When a saddle creates pressure on the horse's back, the longissimus muscle contracts away from the painful stimulus. This contraction drops the back and raises the head. Training through it — demanding more collection from a horse whose back is contracting in pain — teaches the horse that engagement means pain. The problem worsens over time.
Ride the horse bareback or in a well-fitted bareback pad for several sessions. A horse that moves freely bareback but hollows immediately when the saddle is applied is pointing directly at the saddle as the cause. A horse that hollows regardless of riding surface is more likely dealing with a training or suppleness issue.
In NRHA reining, a hollow-backed horse cannot produce the sliding stop, spin depth, or lead change smoothness that scores require. These maneuvers all require the horse to engage the hindquarters under a round, swinging back. A horse performing hollow is physically incapable of the movement quality judges reward, regardless of training level. If a reining horse's scores are plateauing, evaluate saddle fit before assuming the training ceiling has been reached.
David Solum has been evaluating saddle fit problems for 40+ years. Call, text, or email him directly — he can advise on whether it's a fit issue, a tree problem, or a saddle you should replace.
See also: Free Saddle Tools · How to Fit a Western Saddle · Parts of a Western Saddle · How to Buy a Certified Used Saddle