Hands in pullup grip (pronated), pull the chin over the bar, while also pulling the knees to the chest. This exercise can be done repetitively, or used as an isometric exercise where we hold the chin over the bar, and knees to the chest for a period of time.
Hanging in either a pullup grip (pronated) or chinup grip (supinated), pull until your arms are bent at less than 90 degrees. This movement is isometric, so we will be holding the static position for a length of time. It is important the elbows stay close to the body and not flared out to the sides.
Variations: Pulling until your chin is over the bar, and your elbow angle is compeletely closed, and hold. Or pulling until your elbow angle is 90 degrees and holding in this position.