Begin at the top of a pull-up with your chin over the bar. The arms will obviously be fully bent with the body hanging and legs tightly extended.
From this position, strive to push your shoulders far back behind your hands as you lift the hips to horizontal. As the body lifts up in the front, the head should be neutral and the back flat with no pike in the hips. The elbows must completely lock each time at the horizontal position.
From the front lever position, return the chin over the bar by dropping the hips and pulling back up with the arms.
Make sure to fully complete each rep by bringing the feet back directly under you at the end of each rep; do not allow the feet to remain forward when the chin is over the bar.