It's a question of ankle mobility, a lot of people have very tight Achilles tendons and can't do it without a lot of stretching, flexibility exercises and pract

It's a question of ankle mobility, a lot of people have very tight Achilles tendons and can't do it without a lot of stretching, flexibility exercises and practice. Depending on how close you are to being able to squat with flat feet, you can put books or something under your heels.