Rock refers to the curve of a horse's back along its length, from the wither to the last rib. It is important to consider rock when looking at saddle fit. If your horse’s back has lots of rock (a distinctive curve/drop) and your saddle tree doesn’t, it may bridge, meaning the tree bars only make contact in the front and back and not in the middle. If your horse’s back has very little rock (flatter), then a saddle with lots of rock might only make contact in the centre and tip forward and back like a rocking horse. Either scenario will result in high-pressure points and soreness on your horse’s back. The rocking horse scenario would also be very unstable. EFS Remedy The EFS Saddle fitting template system includes rock cards that are used to determine the curvature (rock) of the horse’s back along its length from the wither to the last rib. The cards also help us to determine the length of the horse's back and wither. This is how it works: The card is placed 4 inches off the spine. The B mark in the centre of the card is placed on the mark at the base of the withers and held perpendicular to the horse's back. The card should rest on the last rib offset mark and base of the withers offset mark and extend over the withers. Try the various card profiles to determine the appropriate card. Record the card number. Record the distance forward to the back of the scapula and backward to the last rib. Recorded as (example) Rock card 2, front 7.5 & back 8.5. The card should run over the scapula; if necessary, make a note of the gap in the pocket behind the scapula. Make a note of the asymmetry and rotation of the scapula from side to side. If you can take a few pictures, so I can see what you see, that helps.