Let’s say you are riding a horse in rising trot and the horse’s body is in right bend. You must post or rise out of the saddle when the left foreleg is moving forward and sit when the left foreleg is stepping on the ground. This is posting with the horse’s correct diagonal movement to keep in balance. Now let’s say your horse is still in right bend, but you are travelling left around the arena or ring. In other words, your horse is in counter bend. Most instructors I know will tell you to sit a bounce and post on the left diagonal which matches the direction of the arena. But this will not make your horse a happy camper. It will create discomfort and imbalance in the horse. Please ride with awareness of bend. Ride the horse, not the arena.
When riding, are you consistently aware of which bend your horse is in? How do you determine which way the horse is bending in his body? Do not be fooled by the direction his head is turning. Some horses can have their body in right bend, but have their head or nose tilting to the left. True bend is established through the horse’s barrel and continues forward through the spine up the neck. Glance at the horse’s neck just in front of the withers where it extends out from the back. This will give you a true reading of which bend your horse’s body is projecting.