As a tall person (200cm) . I wasn't able to do wallsits (or walk stairs) when I was in puberty. It hurts the knees.

Speaking of knee injury. Practice squat techniques very well. IT might look easy, but doing them well takes a lot of practice. Your knees shouldn't go further than your toes, otherwise it's really bad for your knees!

That assertion on wikipedia is also disputed.

>According to wkiipedia, it's safety is disputed

To be more accurate: according to an unsupported claim made by a single random individual.