The most common, and costly, misake is pressing with your elbows flared out at 90 degrees. This is the way bodybuilders have traditionally benched, and it does activate the pec muscles best, but it’s also the reason so many complain that benching caused their rotator cuff tear, impingement, or other shoulder problems.
Tuck your elbows about 45 degrees when you press. This is a much more shoulder-friendly position and also a stronger one. And start thinking of the bench press as a total-body lift.
Take this tip from Chris Duffin, a record holding powerlifter in the 220-pound weight class: Use your lats as a platform to push from. When you take the bar out of the rack, pull it forward. “Start cranking the lats in hard,” says Duffin, which pulls the shoulders down and back. “Think about inflating and pressurizing your obliques,” the muscles that form the sides of your abs.
“If you just do that, you can put 5% more on your lift immediately.”