If fitted incorrectly, the points of the curb hooks of an English curb can dig into the skin every time the rider uses the reins. Prevent such pain by keeping the chain flat, or even sliding it through a rubber curb chain guard. Make sure the points of a bit's curb hooks face away from the horse's lips and chin. Ideally, flexible material bends with the horse's structure or motion, without pressing into the skin. Pressure sores result when the pressure exerted by a pad or strap exceeds the normal amount.
Frictional forces can cause an article to rub the skin as it moves.
Tack that's adjusted too tightly can compress the skin. Transmitted through the skin, pressure impacts underlying tissues and structures, and the compression can result in a lesion. For example, a girth must be snug enough to keep the saddle in place, but not squeeze the skin too tightly. If it rubs the skin excessively, the pressure can produce a friction sore. A girth can be too loose, so it rotates.