Smith seated wrist curl

Sit on a bench in front of a Smith machine with your feet flat on the ground. Grasp the barbell with an underhand grip, hands shoulder-width apart. Rest your forearms on your thighs, allowing your wrists to hang off. Slowly curl your wrists upward, bringing the barbell towards your forearms. Pause for a moment at the top, then slowly lower the barbell back down to the starting position. Repeat for the desired number of repetitions.