for biceps and core
Kneel down in front of a stability ball holding a 5- to 8-pound dumbbell in each hand. Keeping your arms extended downward and palms forward, slowly roll forward onto your stomach so your hands nearly reach the floor, then lift up onto your toes to create a straight line from head to toe.
Keeping your core still, bend arms and curl hands to shoulders. Extend your arms toward the floor to complete the rep. Do 1 set of 12 reps.