Forward Backward Lunge Stand with your feet together. Put weight on the left foot, lift your right knee up, and step into a forward lunge. The front knee should be at a 90-degree angle with the left knee just barely hovering above the ground. Push into your right heel, come to stand, and immediately step the right foot behind you into a reverse lunge with the left knee at a 90-degree angle. This counts as one rep. Complete 10 reps. Image Source: POPSUGAR Photography / Kat Borchart