The walk is slow, steady and even which makes it easy on the horse and easy to ride.

Walking your horse is good because it:

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The correct posture for riding a walking horse is to sit up straight, keeping your center of gravity over the horse's center of gravity which is directly under the saddle. You should relax. letting your seat and lower back move with the movement of the walk. You should also let your arms and hands relax so that the horse can stretch its neck.