Grab a pair of 8 to 10-pound dumbbells and get in plank position with your hands on the weights and your feet hip-width apart. Your body should form a straight line from your head to heels. Contract your abs, bend your right elbow and raise the dumbbell until your elbow passes your torso. Press the left dumbbell into the floor for balance. Lower your arm and repeat on the other side. Continue alternating for 40 seconds. Do as many reps as you can with good form.
Image Credits: Dumbbell Renegade Row