Bitting rig rig." It is the use of additional reins such as the overcheck, or the use of leverage to place the horse's head in a set position that turns a classic surcingle into a bitting rig. Both a bitting rig and a classic surcingle with side reins are intended only to be used while longeing a horse. They are not to be used on a horse that is standing in a stall (though this is a very common type of misuse), nor are they used while riding. However, the surcingle and side reins are used as safety tools in the sport
Tree girth measurement tree and by extension the girth should be measured with respect to the same base point. This point is fixed at the same location over time as the tree grows. In addition this is a reference point that is present and consistent in all trees no matter the height of the girth measurement. Even if the girth is measured at a non- standard height because of low branching, a large burl, or even on the upslope side of a large girth tree on sloping ground, all heights can still be consistently referenced to this single point present on all trees.