Barbell Bench Press

Trains the Pecs.

How to do it

Set the safety pins or spotter arms just below your chest height when lying on the bench, so a repetition you cannot finish rests on them instead of on your ribs. If the bench has no pins, use a spotter — a barbell bench press is the one common lift where a failed repetition traps you under the weight.
Lie on a flat bench with your eyes directly under the bar. Plant both feet flat on the floor and keep them there for the whole set.
Grip the bar a little wider than shoulder-width, so that at the bottom of the movement your forearms will be roughly vertical. Wrap your thumbs around the bar rather than leaving them alongside your fingers.
Squeeze your shoulder blades together and down into the bench and hold them there. This gives you a stable base and stops the shoulders rolling forward under the weight.
Unrack the bar and bring it out until it is above your shoulders, arms straight.
Take a breath and lower the bar under control to the lower half of your breastbone — not to your collarbone. The bar travels in a slight arc, ending lower on your chest than where it started.
Let your elbows sit at roughly forty-five degrees from your body rather than flared straight out to the sides.
Touch the chest without bouncing, then press the bar back up and slightly back toward your face, finishing over your shoulders. Breathe out on the way up.

Flaring the elbows to ninety degrees and lowering the bar high on the chest. That turns a chest press into a shoulder press performed on your back — the line of pull runs through the front deltoid rather than the pectoralis major. Lowering to the lower half of the sternum with the elbows nearer forty-five degrees puts the work back into the chest.
Letting the shoulder blades come unstuck and roll forward. The base disappears, the range gets longer in a way that does not help, and the shoulder ends up carrying the weight. Set the shoulder blades before you unrack and keep them set until you rack.
Bouncing the bar off the chest. The rebound does part of the lift for you, and it does it in the range where the pectoralis major is at its longest and most stretched. A brief touch under control is the version that trains the muscle.
Using a thumbless grip with no pins and no spotter. The bar rolling out of the hands is the specific failure that makes this lift different from every other one, and pins or a spotter make it a non-event. Wrap the thumbs and set the pins.