Anyone ever try it? I understand the dangers of swinging your body (it'll cause the moment about the support to be higher than it would be compared to your body staying still) by possibly damaging the door frame and falling and also being stuck upside down.
Go to amazon and order some gravity boots I use these just about every day. I have yet to find a better ab workout than the gravity boots and they also relieve your back by hanging upside down stretching out your spine. Check them out they were about $100 but well worth every dollar