Skull crushers on a stability ball
Performing skull crushers while balanced on a stability ball will tone your triceps while also challenging your core. Simply lie on a stability ball as though it was a bench with your arms extended straight over your chest and a dumbbell in each hand. Carefully lower the dumbbells toward your forehead while keeping your upper arms fixed in place. When your elbows form a 90-degree angle, reverse the movement and return to start. Aim to perform 10 to 12 repetitions.
Photo Credit: Girls Gone Sporty