Stand upright with your arms fully extended, gripping the barbell shoulder-width apart with an overhand grip.
Keeping your upper arms by your side, exhale and raise the barbell up towards your shoulders by flexing your arms. Avoid using your legs or back to lift.
Continue until your arms are fully flexed and the barbell cannot be curled any further.
Inhale and lower the barbell back down, returning to the starting position.