Stand holding a weight plate by your groin using a pronated (overhand) grip, with your hands at the 11 o’clock and 1 o’clock positions.
Keeping your body still and your elbows tucked in to your sides, exhale as you curl the plate up toward your neck.
Hold for a count of two and squeeze your biceps.
Inhale as you lower the plate to the starting position.
Comments and tips
If the weight plate does not have proper handgrips through which you can put your fingers, you will of course have to squeeze the plate to ensure an adequate grip. In this case, if the plate is sufficiently heavy, multiple key gripping muscles in your forearms can also be counted as synergists.
The weight plate reverse curl is a decent exercise for strengthening your forearms and improving your grip. Use it as an auxiliary movement towards the end of your arm workout.