Comment: Why drop your hands every time you kick?
Response: Thank you for your comment. What you are watching here is a set of drills. Calasanz’s reality based system includes a lot of focus mitt work emphasizing power strikes. Your observation is correct in that the student leaves himself totally vulnerable. What you are not seeing is the corrections made by the instructor regarding the student dropping his hands between attacks. The YouTube video was instructive for the student in watching his form and later correcting it with his instructor’s guidance.