Position yourself with your back on a flat bench and feet firmly on the floor. Place your hands up on the bar using an underhand grip slightly less than shoulder width apart. Take a deep breathe in, extend the elbows and lift the bar up off the rack until elbows are extended but not locked. Keeping your elbows tucked in close to your body and pointed directly forwards, slowly lower the weight directly down to your lower chest. Inhaling as you do so. Pause when the weight is just above the lower chest, then press the bar directly up again, exhaling as you do so and squeezing your triceps. Repeat for the number of reps or time required before re-racking the barbell.