Elevating your heels when squatting accomplishes 2 main objectives. One, it allows people with limited ankle mobility to squat deeper & more upright. Two, it targets the quads & stresses the knees more. Start with self-assistance or your bodyweight-only using a slow 3-5 second eccentric or lowering phase with a 1-2 second pause at the bottom. Only use a pain-free range of motion to avoid knee-swelling or flare-ups.

Slant Board Sliding Wall Squats are a great way to safely build the lower quads (or VMO) & strengthen the knees. I also think it’s the best place to start for heels-elevated squatting. Sliding against the wall promotes a perfectly upright trunk position for zero spinal stress & maximal quads work. It’s kind of like using the hack squat machine at home. Slide down to a pain-free range of motion for 5 seconds and hold for 5 seconds before returning to the starting position. Do 10 perfect reps.