Full range of motion, keep upper arms still. Mistakes: Using momentum, incomplete curls.
Stand straight holding the dumbbells in front of your thighs, with palms facing them.
Bend your elbows until the weight is up to shoulder height.
Slowly lower back to just before full extension and repeat.
Using momentum from the body.
Fully locking out elbows.
Elbows moving around too much.
Alternate arms, keep wrists neutral. Mistakes: Swinging weights, using body momentum.