This is for advanced training only. If you do not have a healthy and strong body (arms, core, legs) do not try it. This exercise greatly increases intraabdominal, intrathecal and vascular pressure. This means if you have weak tissue or previous injuries like stroke or herniation (disc, stomach, abdominal, inguinal etc.) you are more susceptible to recurrent injury. See a qualified Chiropractic physician before attempting.