1 Place a pair of dumbbells in front of the ball and kneel directly behind the ball. As you kneel, drape your arms over the ball to grab the dumbbells on the other side using an underhand grip.

2 Brace your triceps on the ball and keep your forearms down and straight.

3 Keep your back straight and curl the weights up gradually until your forearms are just short of being perpendicular to the floor. Slowly lower them and repeat.