[header] How to work out your upper chest [title] Perform a guillotine press to work your pectoral muscles. [step] Load weights onto both sides of a barbell. Lie on your back on a flat bench with your feet flat on the floor or feet flat at the end of the bench. 
Use your core strength to hold your lower spine in a neutral position. Hold the bar with an overhand grip with your arms slightly more than shoulder-width apart.