Stand facing a low cable with a straight bar attachment, gripping it with your palms facing down. Curl the bar up toward your shoulders while keeping that overhand grip throughout — don't let your wrists rotate toward a normal curl as the weight gets tough. Your elbows stay at your sides as the pivot point. The overhand grip shifts the work toward your forearms and the outer part of your upper arm rather than the main biceps muscle you'd feel in a standard curl. Lower back down slowly, since the cable's constant tension makes the lowering phase harder here than it would be with a barbell.