Begin in a plank position holding a five-pound dumbbell in each hand, keeping your wrists stiff to protect the joints. Open your feet a little wider than hip distance.
Lift your left hand to the ceiling, twisting through your entire torso — keep the motion smooth and controlled. Your pelvis will rotate, but keep it level without letting it raise or drop.
Bring your left hand back to the floor, and repeat this action on the other side to complete one rep.
Do 10 to 15 reps to complete a set.
Twisting in a plank position fires up the core and challenges your arms strength, too.