Forearms
Shoulders
Lie prone on bench, chest supported.
Hold light dumbbell in one hand, arm hanging off side.
Bend elbow 90 degrees, upper arm parallel to floor.
Start forearm perpendicular to floor, palm up/neutral.
Rotate forearm inward (pronation) until palm faces down/forearm parallel to floor.
Keep elbow fixed.
Slowly return to start.
Repeat reps, switch arms.