A bicep curl uses a supinated grip (also known as an underhand grip), while the hammer curl uses a neutral grip (where your palms are facing each other). It’s a subtle change, but it makes a big ...
You need to switch to dumbbells and press with a neutral—that's palms facing in—grip. To ingrain that crucial elbow tuck, train the neutral-grip dumbbell bench press for eight to 12 weeks.