The head is well-defined, with small, well-placed ears. The breed averages high and . The shoulders and hip are long and sloping, with a short back and strong coupling. The hindquarters are of "moderate thickness and depth", well-muscled, and it is acceptable for the hind legs to be slightly over-angulated, cow-hocked or sickle-hocked. They are found in all solid colors, and several pinto patterns. Common colors such as bay, black and chestnut are found, as are colors caused by dilution genes such as the dun, champagne, cream and silver dapple genes. Pinto patterns include overo, sabino and tobiano. The Tennessee Walking Horse has a reputation for having a calm disposition and a naturally smooth riding gait. While the horses are famous for flashy movement, they are popular for trail and pleasure riding as well as show. The Tennessee Walking Horse is best known for its running-walk. This is a four-beat gait with the same footfall pattern as a regular, or flat, walk, but significantly faster. While a horse performing a flat walk moves at , the running walk allows the same horse to travel at . In the running walk, the horse's rear feet overstep the prints of its front feet by , with a longer overstep being more prized in the Tennessee Walking Horse breed. While performing the running walk, the horse nods its head in rhythm with its gait. Besides the flat and running walks, the third main gait performed by Tennessee Walking Horses is the canter. Some members of the breed perform other variations of lateral ambling gaits, including the rack, stepping pace, fox trot and single-foot, which are allowable for pleasure riding but penalized in the show ring. A few Tennessee Walking Horses can trot, and have a long, reaching stride. Health Some Tennessee Walking Horses may be affected by the following genetic conditions: Congenital Stationary Night Blindness (CSNB2) is a heritable genetic condition that has been found in some Tennessee Walking Horses. It is a recessive missense mutation in the GRM6 gene and is believed to inhibit the ability of the ON-bipolar cell to uptake glutamate. CSNB is characterized by an inability to see in low light conditions. Horses may also be reluctant to move at night and may struggle to find food and water. It is a non-progressive condition that is present from birth. No treatment is available, however management strategies, such as leaving