Biceps Curl Form

Check your bicep curl with your phone

RepSensei has a detailed bicep curl check. Prop up your phone and it counts your reps and flags these issues as you move:

• Stopped short of the top
• Elbow drifted forward
• Swinging your body

Stand side-on to your phone with the arm you are curling closest to it. Keep your upper body in view. The bicep curl check is newer and has had less testing on real movement, so expect more misses. It sees one angle, so it won't catch everything.

How to do it

1. Stand tall with a dumbbell in each hand, arms straight, palms facing forward, feet hip width apart.
2. Pin your elbows lightly to your sides, with shoulders down and back.
3. Curl the weights up by bending only at the elbow until your forearms are near vertical.
4. Squeeze briefly at the top without letting the elbows drift forward.
5. Lower slowly, over two to three seconds, all the way to straight arms.

Coaching cues

Elbows are hinges

They stay by your sides; if they move forward, the shoulders are taking over.

Stand still

If your hips or back move, the weight is too heavy to curl strictly.

Slow on the way down

Controlling the lowering keeps tension on the biceps for the whole rep.

Common mistakes and how to fix them

Swinging the body

A hip thrust or back lean throws the weight up so the biceps miss the hard part. Fix: Pick a lighter dumbbell, or curl with your back against a wall.

Elbows drifting forward

The front shoulders lift the weight and the tension leaves the biceps at the top. Fix: Keep your elbows by your sides and stop when the forearm is near vertical.

Half reps at the bottom

Not straightening the arms skips the stretched part of the movement. Fix: Lower all the way to a straight arm each rep, without bouncing.

Dropping the weight

Letting it fall wastes half of each rep and strains the elbow. Fix: Take two to three seconds to lower.

Wrists curling in

Bending the wrists brings the forearms in and makes it harder to load the biceps. Fix: Keep the wrist straight and in line with the forearm.

Muscles worked

Main: Biceps. Also: Forearms, Shoulders.

Who should take care

If your elbows ache, try hammer curls or a lighter weight with slower reps. Pain that persists is a reason to see a doctor or physiotherapist.

Variations

• Hammer Curls: Alternative: palms facing in, often kinder on the elbows and wrists.
• Concentration Curls: Stricter: the elbow is braced on the thigh, so cheating is hard.
• Incline Dumbbell Curl: Harder: the arms start behind you for a bigger stretch.
• Barbell Curl: Alternative: both arms together with a heavier load.

Filming your biceps curl

Prop the phone side-on at chest height, about two metres away, so it can see your elbow and torso. RepSensei has a detailed camera check for curls that counts reps and flags some visible issues from that one angle; it cannot see everything. See how to film your form.

Questions

Should I alternate arms or curl both together?

Both work. Alternating lets you focus on each arm; curling together saves time.

Should I rotate my wrists as I curl?

Turning the palm up as you curl (supination) adds biceps work. You can start palms in and twist up, or keep palms up throughout.

How heavy should my curls be?

Light enough to do eight to fifteen strict reps with no body swing.

See the Dumbbell Bicep Curl exercise guide with a 3D figure.

More form guides

• Pull-Up form

General guidance, not medical advice. Stop if anything hurts. The camera can miss things, so no issue seen doesn't mean perfect form.