SETUP: Take an overhand-grip or a neutral-grip on a PULL UP station. Keep your feet together, with a slight bend in your knees.
REP: Breathe out and squeeze your abs as you pull your knees up high, aiming for your chest. Control the lowering phase, don’t just let your legs drop (this would cause you to swing, making it harder to control).
TIP: Notice how I come wayyyy beyond the 90* angle shown in many muscle building magazines? This is because we MUST break a 90* angle to transfer to workload from our hip flexors to our abs. Tilt your pelvis at the top of the rep and squeeze the life out of those abs.