Biceps curl form: full range and elbow position

Curls are easy to cheat. Swing your elbows forward and your shoulders join in, which feels stronger but works the biceps less. The camera watches where your elbow sits for the whole set.

How to do it

1. Stand tall with the weights at your sides, palms facing forward.
2. Pin your elbows to your sides.
3. Curl the weight up until your forearm is nearly upright.
4. Lower it all the way until your arm is straight again.

What counts as a full rep

It reads the arm nearer the phone. Your elbow has to go from about 150° (arm hanging straight) to 60° or less (weight up near your shoulder), then back down.

What the camera calls out

You hear a short cue mid-set when something's off. After the set, the report card gives you one line on whichever fault came up most.

Setting up your phone

Stand side-on to the phone, about 2 m away. It counts the arm nearer the phone.

Start with your arms straight down. Only full reps count.

Muscles worked

Mostly your biceps, with your forearms helping.

Exercises this check works on

• Dumbbell curl
• Alternating dumbbell curl
• Barbell curl
• EZ-bar curl
• Hammer curl
• Cross-body hammer curl
• Cable curl
• Seated dumbbell curl
• Zottman curl

A tip from the coach

If you have to lean back to finish the last few reps, drop the weight. Slow, full reps do more for your arms than heavier swinging ones.

Other exercises

• Squat
• Push-up
• Lunge
• Romanian deadlift
• Overhead press
• Plank
• Glute bridge
• Sit-up
• Lying leg raise
• Lateral raise
• Bent-over row
• Jumping jacks
• Pull-up
• Wall sit
• Side plank

Updated 11 October 2026. General fitness and nutrition guidance, not medical advice.