Every horse has a different back. Additionally it changes shape constantly due to age, training and / or season. Even during the ride, the back moves and takes on different shapes, depending on the collection, sideways bend and position of head.
(The picture shows the same horse, simply with a different head position)
When the horse moves with his head up high, the back automatically curves downwards. Is it ridden long and low or correctly on the bit, this curve changes and will actually arch upward. This is a result of biomechanics, so it is true for every horse and pony: the nuchal ligament is the main connection between the cranium and the entire back, all the way to the onset of the tail. In combination with the muscles of the rump a difference of 5 cm in height is often noticeable – depending on the individual horse. Most saddles are too rigid to adjust to these changes. The flexible Barefoot however can follow the anatomic changes and the line of the back at all times.