1
Stand upright with feet shoulder-width apart, arms at sides with palms facing forward, shoulders relaxed and back, core engaged
2
Maintain neutral spine with slight knee bend, keep elbows close to torso throughout movement, establish neutral wrist position with palms facing forward
3
Lower arms in controlled manner by extending elbows, allowing dumbbells or resistance to lengthen biceps while maintaining elbow position close to body
4
Curl forearms upward by flexing elbows, bringing hands toward shoulders in smooth arc, squeeze biceps at top of movement, return to starting position with control