Girth (tack) place, other pieces of equipment are also used in jumping or speed sports such as polo, eventing, show jumping, and fox hunting; or on rough terrain such as trail riding. These include breastplates, overgirths, cruppers, and, on pack saddles, breeching. Studies have shown that, although girths may restrict the movement of the ribcage in the horse, they have no effect on the horse's ability to take in air. Several types of girth are shaped to allow ample room for the elbows. The Balding style is a flat piece of leather cut into three strips which are crossed and folded in
Girth (geometry) width, with the same width "w". All curves of constant width have the same perimeter, the same value "w" as the circumference of a circle with that width (this is Barbier's theorem). Therefore, every surface of constant width is also a surface of constant girth: its girth in all directions is the same number "w". Hermann Minkowski proved, conversely, that every convex surface of constant girth is also a surface of constant width. For a prism or cylinder, its projection in the direction parallel to its axis is the same as its cross section, so in these cases the girth