Instructions:

1. Stand with your feet shoulder-width apart and hold a barbell with an underhand grip, palms facing up.
2. Let the barbell hang at arm's length in front of your thighs.
3. Keeping your upper arms stationary, curl the barbell up towards your chest by contracting your biceps.
4. Pause for a moment at the top, then slowly lower the barbell back down to the starting position.
5. Repeat for the desired number of repetitions.