Hanging from a bar (or any kind of support), using both hands and starting with arms fulling extended, raise yourself until your chest makes contact with said bar. Varying hand grips can be used, including overhand, underhand, or switch grip (one hand overhand, one hand underhand). In addition, numerous styles exist. Strict, kipping, and butterfly kipping utilise different body parts and muscles to achieve the same goal: to raise yourself until your chest makes contact with the bar.