"The biceps tendon is one of your most important shoulder stabilizers," Mack told POPSUGAR, and this classic move is a great way to target it.
Stand with your feet hip-distance apart, holding a dumbbell in each hand at the sides of your body with your palms facing out. Pull your abs toward your spine to engage your core.
Keeping your elbows close to your ribs, bend your elbows and slowly raise the dumbbells to your shoulders. Continue to pull in your abs and make sure your elbows stay in line with your sides, not poking back behind you.
Moving with control, lower the dumbbells back to the starting position. Keep your torso stable and don't lean forward as you move.