Squat University's Dr. Aaron Horschig breaks down what you should be doing before you get under the bar.

Physical therapist Dr. Aaron Horschig regularly shares videos on the Squat University channel designed to help people exercise more effectively and safely, getting the most benefit out of their workouts without risk of injury. In a new video with record-breaking bench presser Julius Maddox, Horschig breaks down the "Lock 3," coined by Dr. Andrew Lock: three exercises that he recommends you do before each bench press workout to "prime" your shoulders.

The first movement focuses on internal rotation of the shoulder. Llie horizontally face down, arms down at your sides. With your elbows straight and your palms facing upwards, simply lift your hands up and then slowly set them down again, for 20 repetitions. Maddox demonstrates this with a 1-pound weight in each hand.

"What he's doing is focusing on the rhomboids on, the posterior muscles of the rotator cuff, and this is excellent for people especially who are trying to come back from shoulder pain," explains Horschig.

The second move is all about external rotation. While still in that horizontal position, rotate your hands so they're now facing down. Perform the same movement again for another 20 reps. "Don't over-cue scapular retraction," says Horschig. "You're just going to think about picking up the arms up and gently setting them back down."

Third and finally, extend your arms outwards so you're lying in a T shape, and perform the same careful, controlled movement.

"If you're dealing with any type of shoulder issues with bench press, the Lock 3 shoulder routine... is an excellent way to prime the posterior shoulder muscles before getting under the bar," says Horschig, "addressing the 'why' behind most common shoulder issues, which is that imbalance between front side and back side."

Watch Martins Licis Train With Lifter Rauno Geinla

We Tried This At-Home Cable Machine Solution

4 Shoulder Training Mistakes to Avoid

Shop NordicTrack's Labor Day Sale

We Tested New Balance's New Marathon Training Shoe

3 Bear Plank Variations to Carve a Killer Core

Mark Wahlberg Looks Jacked, Even For Mark Wahlberg

Marcus Filly Uses Stability to Hack His Workouts

This Ultrarunner Outlasted a Fully Charged Tesla

9 Golf Club Sets That Are Perfect for New Golfers

14 Best Compression Shirts for Men

39 Early Labor Day Fitness Deals You Can Score Now

A Part of Hearst Digital Media

Our product picks are editor-tested, expert-approved. We may earn a commission through links on our site.

©Hearst Magazine Media, Inc. All Rights Reserved.