This exercise develops lat strength for muscle-ups, pullovers and front levers.
Starting in a pullup or chin over bar position, press the bar away, leaning the shoulders back as the toes rise. It is critical to keep a tight hollow position, so that the hips to not pike while performaing the movement. If piking is happening regress the movement to the Gorilla Flatback.
Hanging from a bar (or rings) engage shoulders, and lift legs to at least 90 degrees. Squeezing the ankles together and keeping the legs straight, tighten your core, tuck tailbone under slightly and hold the position. When first working this position try to hold for 15 seconds. Once strength develops lengthen the amount of time.