I used to do a lot of triceps pushdowns next to a friend who was also doing a lot of triceps pushdowns. (Isn’t this how all great stories start?!) We joked that I had Herculean-like* triceps because I could do a lot more volume. This went on for some time until she noticed that I was doing palms-down pushdowns and she was performing them with palms up. My jig was up.
*Fiiiiiiiine. I called it Herculean.
Wait, why? It could very well be that I have Roman god-like strength in my triceps. But, sadly that’s not the end of the story.
Let’s back up a minute though. We should really discuss the triceps first.
Since we talked about biceps last time, it’s really only fitting to discuss the triceps today (not because I wanted to tell you about my strong triceps, not one bit.). One thing I love about muscles is that they are often named for where they live. The triceps brachii consist of three bellies (triceps) livin’ it up on the arm (brachii). This muscle does a lot, but its primary function is elbow extension and that’s precisely the opposite action of the biceps. These muscles are called antagonists because of their opposite actions of one another.
Here’s all the info:
This is when things start to get cool. Biceps flex, triceps extend (…since we’re stickin’ only with actions on the elbow). We know an elbow flexing exercise (biceps curls) works the biceps, so the opposite, an elbow extending exercise (triceps extensions) works the opposing muscle group the triceps.
Great segue back to pushdowns. The difference is in the hand placement. Palms-up on the left (also known as a reverse-grip triceps pushdown, or triceps pulldown) and palms down on the right (known as a triceps pushdown or triceps pulldown). Can you see why we were doing different things? So. many. names.
You’re right, though, both versions work the triceps. However, with the palms up version you’re also working wrist extensors (the muscles that hold your wrist straight here) which means you’re not going to be able to lift as much weight. Think of the wrist extensors as “the weakest link”—the muscles that prevent you from loading the prime mover, in this case, the triceps. In a very simplistic way, you can think of the palms-up version as a compound movement because you act on both the elbow and wrist. Your body not only has to extend your elbow, but it also has to keep your wrist straight whereas on the palms-down version you’re acting solely on the elbow. That means, the more isolated movement for your triceps is the palms-down version and you’ll likely be able to lift more weight and complete more reps because you’ve taken the weakest link out of the equation.