Start in a kneeling position facing the barbell with one hand holding the end of the barbell at your shoulder with your elbow tucked beneath your wrist.
Keeping your elbow pointing forward, drive the barbell up overhead until your arm is fully extended and switch the bar to your other hand at the top of the movement.
Control the descent of the bar to your other shoulder and repeat movement for desired reps, switching hands at the top of each rep.