Strengthen Your Lower Back in 15 Minutes
Start with feet in a staggered position with the right foot forward and place a dumbbell on the ground to the left of the right foot. With your abs contracted, bend both knees into a lunge and, keeping your back flat, pick up the dumbbell with your left hand (top).
Return to a standing position (center). Switch the dumbbell to your right hand as you turn on your toes to face the opposite direction.
With a flat back, lunge with the left leg forward and bend down to place the dumbbell on the right side of the left foot (bottom). Stand up and repeat the action in the other direction for one rep.
Targets: Deep-back muscles and obliques, plus hip and leg muscles.