Balance skull crushers
Tighten up your triceps with the skull crushers exercise. Lie on a stability ball as if it was a bench. Hold a dumbbell in each hand, and extend your arms directly over your chest. Bend your elbows, and lower the dumbbells toward your forehead. When your elbows form a 90-degree angle, reverse the movement and return to start. Do two sets of 12 repetitions.
Photo Credit: Girls Gone Sporty