Dumbbell curls are a popular strength training exercise that primarily targets the biceps, the muscles located at the front of the upper arm. To perform a dumbbell curl, stand with a dumbbell in each hand, arms fully extended at your sides. Keeping your elbows close to your body, curl the weights upward by bending your elbows, then slowly lower them back to the starting position. This exercise can be done with various weights to suit different fitness levels and can be performed seated or standing. Incorporating dumbbell curls into your workout routine can help improve arm strength and enhance overall upper body muscle tone.