BY EBENEZER SAMUEL, CSCS
Weight range is the first number you think of when purchasing adjustable dumbbells. But if your goal is big arms, check another stat: Plate circumference.
Here’s the deal: If you’re working to build your biceps and triceps, then your training is about nuance. Sure, you need to lift heavy, but you also need to dominate lighter exercises like curls and skullcrushers. You can do these more often in your routine without wiping out your body, and that frequency can spur growth.
There are technical nuances to these motions, and many adjustable dumbbells fail here. In this curl, done with SMRTFT’s 100-pound adjustable, I’m doing three things that sometimes don’t happen with other options. And that’s because many other dumbbells have larger plate circumferences than SMRTFT’s bells.
STRETCH WORK:
I’m using a full range of motion at the bottom of each rep, because I don’t have oversized, ungainly plates bumping into my hips. That means more time under tension as the muscle is lengthening, a research-backed way to spur gains.
SUPINATION:
I’m rotating my palms toward the ceiling as I curl. Your biceps helps flex your elbow, but it also handles this action. With larger plates, I might not be able to do this as effectively.
PEAK CONTRACTION:
A fatter dumbbell plate may contact my chest or shoulder early in the curling motion, preventing me from getting the aggressive squeeze I get during this rep. That can hold me back from building mind-muscle connection.
I can attack all these functions of the curl in large part because of SMRTFT’s slim plates. The second flaw is even more noticeable: Plate circumference. If your dumbbells have exceptionally fat plates (and some adjustables can get very chunky), you may miss out on these little benefits.
Several leading adjustables have plate circumferences well above 8 inches. And one well-known (but cheap, if I’m honest) adjustable is a whopping 9 inches across. SMRTFT’s 80-pound and 100-pound adjustables are both sub-8 inches. The 80-pounders have a 7.5-inch circumference. And the 100s, which aren’t fully circular, are just 7.1 inches at their narrowest.
This makes both dumbbells ideal for curling, as you’ve seen. And they’re great for skullcrushers, too; the lack of circumference lets you keep the loads close to your head as you lower, preventing you from flaring your elbows (and keeping those elbow healthier).
All of this is worth noting especially if you’re trying to fill out your sleeves.