Use an assisted pull-up machine or securely attach a heavy-duty band to a pull-up station, securing it around just one knee. The tension should be taut enough to pull that lower leg up. Grasp the bar with an underhand grip, about shoulder-width apart, and hang at full arm extension. This is your start position.
Keeping your body straight, contract your biceps and lats to pull yourself up as high as you can, driving your elbows down.
Slowly release to full arm extension. Repeat for the required number of repetitions and safely dismount from the apparatus.