Dumbbell bicep curl on exercise ball with leg raised

Sit on an exercise ball with your feet flat on the ground and your back straight. Hold a dumbbell in each hand with your palms facing forward and your arms fully extended. Slowly curl the dumbbells towards your shoulders, keeping your elbows close to your sides. Pause for a moment at the top of the movement, then slowly lower the dumbbells back to the starting position. While performing the bicep curl, raise one leg off the ground and hold it in the air for the duration of the exercise. Repeat for the desired number of repetitions, then switch legs and repeat.