Adjust bar height based on arm length when lying on back. Lay down on ab mat underneath bar and grab with an outside shoulder-width supinated-grip. Your body should be straight, off the ground, heels only touching, and arms fully extended. Begin flexing the elbow, pulling your chest towards the bar. Retract shoulder blades as you perform the movement. Pause at the top of the movement, then lower to start. Repeat this movement for all reps.
Helpful tips and Tricks
Keep your head, back, & chest in proper alignment. Pause at the top of the movement to prevent swinging or using momentum.