The bench press is the best exercise to build a strong and massive upper body. But take heed because bad technique can lead to aches, missed gym time, and even serious injuries.

Great lifters spend a lot of time perfecting their bench-press technique because they know they need to use the right muscles, get into the correct positions, and make the barbell move on the most efficient path possible. The further you stray, however, the more strength you’ll lose and the higher your risk of a torn pec or strained shoulder.

Avoid these 10 surprisingly common bench press mistakes, and learn exactly how you can fix them to build a barrel chest without the pain.