What is the best way to isolate the bicep head during workouts?
One of the things you can do is try seated bicep curls. The bicep is activated primarily at the half way point upward. the start of a normal bicep curl uses primarily the brachialis and the brachio-radialis as the prime movers when the biceps become more emphasized after the arm passes the 45 gedree mark upward. Seated bicep curls with a barbell placed on the lap allows for more weight to be uses and places more of an emphasis directly on the bicep head.