Intermediate

Partial prone pull-ups with closed grip

Biceps

This exercise focuses on isolating the biceps as much as possible, trying not to perform the shoulder extension that would involve more of the back.
To do this, perform close-grip pull-ups, bringing the elbows outwards and with a partial range of motion.
From completely stretched to the crown reaching the bar.
Try not to separate your body backwards during the execution of the exercise, always keeping your head under the bar.