Gymnastics is a sport involving the performance of exercises requiring strength, flexibility, balance, agility, endurance and control. The movements involved in gymnastics contribute to the development of the arms, legs, shoulders, chest and abdomen muscle groups. Alertness, precision, daring, self-confidence and self-discipline are mental traits that can also be developed through gymnastics. Gymnastics evolved from exercises used by the ancient Greeks that included skills for mounting and dismounting a horse, and from circus performance skills.