Stand upright, feet together, with 10 pound dumbbells at your side. Take a controlled step forward with your left leg, lowering your hips toward the floor by bending both knees to 90-degree angles. The back knee should point toward but not touch the ground, and your front knee should be directly over the ankle.
Press your left heel into the ground, and push off with your right foot to bring your right leg forward, stepping with control into a lunge on the other side. This completes one rep.