1
Stand upright with feet shoulder-width apart, arms at sides with a slight bend in the elbows, holding a barbell with an underhand (supinated) grip slightly wider than shoulder-width
2
Ensure neutral spine alignment with shoulders back and down, core lightly engaged, and weight distributed evenly through both feet
3
Lower the barbell in a controlled manner by extending the elbows, maintaining constant tension on the biceps, until arms are nearly fully extended at approximately 90 degrees or slight bend remains
4
Flex the elbows and curl the barbell upward in an arc motion, keeping elbows stationary at sides, until the barbell reaches chest level or upper torso with a full biceps contraction, then return to starting position