A flat-bench press with a dumbbell in one hand, so your core and hips must resist being twisted off the bench. It exposes and fixes left-right strength gaps.
Primary muscles
Secondary muscles
This information is general fitness guidance, not medical advice. Stop if you feel pain and consult a qualified professional.
Main muscles working (thicker lines)
Lie on a flat bench with feet planted wide, holding one dumbbell over your shoulder with a straight arm, palm facing your feet, and your free hand resting on your hip or gripping the bench.
Lower the dumbbell under control until it is level with your chest, elbow about 45 degrees from your torso.
Keep your hips and shoulders square on the bench as the weight pulls you to one side.
Press the dumbbell back up over your shoulder.
Finish all reps on one side, then switch.
Breathing: Inhale on the descent, exhale as you press.
Stay square
Brace as if both hands were loaded
Forearm vertical
Rolling toward the working side
Letting the hips lift off the bench
Using the free hand to help the press
Start lighter than your usual dumbbell weight; resisting the twist is the real challenge.