The negative muscle up focuses on the eccentric phase of the movement to build the necessary strength and coordination for the full muscle up. Start at the top of the bar or rings in a support position with locked arms. Lower yourself slowly into a deep dip. As you reach the bottom of the dip, lean back slightly to navigate the transition, letting your elbows move from above to below the hands with maximum control. Continue to lower yourself through the eccentric pull-up phase until your arms are fully extended. Maintain a tight core and avoid dropping quickly through the transition.