Bronc riding toward the rigging handle, spurring at each jump in rhythm with the motion of the horse. Bareback bronc riding began to develop as a professional rodeo sporting event around 1900. The riding equipment used during that era varied. In some cases, the rider simply held onto the horse's mane, called a mane-hold. Others held a loose or twisted rope tied around the horse's girth, and other methods involved using multiple handhold leather riggings based on a surcingle. In the early 1920s, when the old rodeo rules allowing two handed riding were being phased out and replaced with the newer rule
Tree girth measurement is measured at a height of , , or . The base of the tree is measured for both height and girth as being the elevation at which the pith of the tree intersects the ground surface beneath, or where the acorn sprouted. On a slope this is considered as halfway between the ground level at the upper and lower sides of the tree. This "breast height" value is a measurement grandfathered from decades of forestry applications. It was developed because of the simplicity and ease of measurement. There is no one ideal height at which to measure girth. Tree