Sit with your forearm resting on your thigh or a table, palm facing down. Grasping the dumbbell, raise your hand at the wrist ...

In his video, Cavaliere highlights the biggest lifting mistakes for nine muscle groups: biceps, triceps, legs, calves, chest, back, shoulders, abs, and forearms.

If you’re considering running your first ultramarathon, here's a complete guide to training, racing, nutrition, and gear.