Male ballet dancers are male dancers that perform ballet. Male ballet dancers may begin training between 5 and 7 in order to be prepared to dance professionally. Being able to dance ballet professionally requires years of strict training to learn proper technique. Ballet has strict hierarchies and gender roles for performances. Male ballet dancers may dance solo or with a female partner. Male ballet dancers are prone to injury due to the constant stress on their bodies when turning out, leaping, and bending. Rudolf Nureyev is regarded as one of the most famous male ballet dancers hailing from the Soviet Union before defecting to the West during the Cold War.