How to: Start from a standing position, with your feet hip-width apart. Take a big step forward, bend your knees, and lower down until both knees are bent at 90-degree angles, and your back knee is a few inches from the floor. Jump up explosively and switch legs so your rear leg is in the front, and front leg is in the rear. Repeat in the opposite direction. That’s one rep. Complete 20.
Jump-free option: Try forward-to-backward lunges. Stand with your feet hip-width apart. Take a big step forward, bend your knees, and lower down until both knees form 90-degree angles. Then, immediately lift your front foot and lunge backward on the same leg. Complete all reps on one leg before switching to the other leg.