Despite all the noble reasons to strength train — increasing your bone density, metabolic rate, and mood — it’s OK if you’re motivated by more superficial goals, like growing some big ol’ arms. There exists an exercise that can help you do just that, which not only has Arnold Schwarzenegger’s stamp of approval, but was also created by the legend himself: the Arnold press.

In addition to helping you chisel a pair of enviable arms, this variation of the standard shoulder press targets all three heads of the deltoids and can improve shoulder stability. Here’s how to perform the Arnold press with perfect form.

Arnold Press: Step-by-Step Instructions

• Hold two dumbbells in front of your chest with your palms facing toward your body, keeping your elbows close to your body. This is your starting position.
• As you press the dumbbells up above your head, rotate your palms out so that when you reach the overhead position, they face away from your body.
• Reverse the motion to lower the dumbbells back down, corkscrewing your hands so your palms end facing your body, and repeat.

How to Make the Arnold Press Easier

You can make this exercise more stable by performing it seated. This will reduce the demand placed on your core to stabilize your body and can also allow you to press more weight.

How to Make the Arnold Press Harder

Intensify the Arnold press by increasing your weight or by letting the weights come down to the sides of your body and curling them up before performing each rep.

Arnold Press: Muscles Worked

The Arnold press primarily works two muscles in the arms: the shoulders and triceps.

Deltoid

The deltoid is the muscle on the outside of your shoulder joint. Due to the rotational element of the Arnold press, it trains all three heads of your deltoid: 

• Your front (anterior) delt flexes your arm, or raises it in front of your torso. It’s worked in moves like overhead presses, bench presses, and dips.
• Your side (lateral) delt abducts your arm, or lifts it directly out to the side. It’s worked in lateral raises and also assists your front and rear delts.
• Your rear (posterior) delt extends your arm, or moves it backwards behind your body. It’s worked in moves like the reverse fly and rows. 

Triceps

Like the deltoid, your triceps are a three-headed muscle composed of the long head, lateral head, and medial head. The triceps extend your arm at the elbow joint and are worked in exercises like overhead presses, bench presses, and push-ups. You can also isolate them with exercises like triceps push-downs, kickbacks, and extensions.