Bicep curls refer to a type of exercise that targets the biceps, which are the muscles located in the front part of your upper arm. The goal is to lift a weight (dumbbell or barbell) from a lowered position by flexing your elbow and bringing your forearm towards your upper arm until it's fully extended. This movement primarily works the biceps, but also engages other muscles in the upper body such as the triceps, shoulders, and chest. Bicep curls are a popular exercise among weightlifters and bodybuilders looking to build size and strength in their arms.