At fast exercise, a horse takes one stride for each breath. Striding and breathing are coordinated so that they occur in synchrony. Anything that interferes with breathing (such as a bit) must, therefore, interfere with striding. The bit, to a degree that varies with the individual, results in a loss of that grace and rhythm of movement that is so characteristic of a horse at liberty. The constraint of movement is expressed in a more stilted gait and a shorter (therefore slower) stride.