The curl is a core training staple that can build size and strength in your triceps and chest—but are you sure you're even doing the exercise correctly? What about variations on the old standard, like the spider curl?

For this twist on the basic gym necessity, you shouldn't settle for anything other than perfect form—especially because it's such a simple, essential movement that should serve as one of the centerpieces of your training plan. Let Men's Health fitness director Ebenezer Samuel, C.S.C.S. and associate fitness editor Brett Williams guide you through the move's subtleties, saving you from the bad habits that are keeping you from unlocking your fitness potential.

Before you grab your dumbbells and take your position on the bench, take note that it's extremely important to pay attention to the subtleties of the movement here. You'll miss out on the potential gains if you're not focused on your every single biceps squeeze, or if you don't approach the position the right way.

Live Back

Eb says: The bench is a tool to help you find the proper angle for your body, but it's not a bed. So don't lie on there and get comfortable. Find the right angle, and then create rigidity throughout the rest of your frame. Squeeze your glutes, and actively try to breathe your abs into the bench; this will help set your spine in neutral. Then flex your upper and mid-back muscles so that your shoulders don't slump forward; your mid- and upper-back muscles should stay live throughout the curl. That'll protect your shoulders long-term and also make it easier to do the next thing.

Own the Upper Arm Angle

Eb says: The spider curl is essentially a chest-supported concentration curl, so we're working to isolate the biceps as much as possible. To do that, you need to keep your upper arm perpendicular to the ground for the life of every set. That'll set up the biceps to almost solely drive the entire curling motion. It gets tempting to let your elbow shift forward, involving the front shoulders in the lift ever-so-slightly and taking emphasis off your biceps, but you don't want that to happen. If you do that, you miss the opportunity to really stress and grow your biceps, which is why you're here doing the lift in the first place.

Twist The Wrist

Eb says: As you curl upwards, you should work to twist your pinky up high, as if you're trying to get your palm to turn away from you (it won't happen drastically, but that's the idea you want to go for). That'll force your biceps to work that much harder. The muscle isn't simply responsible for flexing your elbow, but it's responsible for that twisting action of the forearm, called supination. Trying to twist your forearm so your pinky winds up high will emphasize that bit of contraction and make this a complete biceps motion.

Squeeze!

Eb says: Once you've curled up as high as you can without letting that elbow shift forward, and twisted, you should feel a strong sensation in your biceps. Use this! Finish each rep by squeezing your biceps hard, building a strong mind-muscle connection with your biceps.

Headshot of Brett Williams, NASM
Brett Williams, NASM

Brett Williams, a fitness editor at Men's Health, is a NASM-CPT certified trainer and former pro football player and tech reporter who splits his workout time between strength and conditioning training, martial arts, and running. You can find his work elsewhere at Mashable, Thrillist, and other outlets.

Headshot of Ebenezer Samuel,  C.S.C.S.

Ebenezer Samuel, C.S.C.S., is the fitness director of Men's Health and a certified trainer with more than 10 years of training experience. He's logged training time with NFL athletes and track athletes and his current training regimen includes weight training, HIIT conditioning, and yoga. Before joining Men's Health in 2017, he served as a sports columnist and tech columnist for the New York Daily News.