I have been incorperating bear crawling into my routine for about 18 months and find it a great exercise. I regularly do anywhere between 5 minuts and half an hour of continuous bear crawling and at times put on a 20 kg weight vest whilst doing the exercise. I have also done the exercise with a 130kg training partner on my back for 1 min to 2 min periods. So I thought that I had a good level of exercise specific strength and conditioning. So when I was thinking of a way to fininsh my cardio session today I looked at the stairs in my gym and thought I'll bear crawl up the stairs feet first then come back down the stairs head first. There are about 20 steps and the stair case is on a steep incline I only did the drill twice as I was afraid that if I slippied, the first thing that would break my fall would be my face. Focusing on the positive though, I found the exercise to be very strenuous and there was constant tension on my muscles especially on my delts and core. I don't think I could handle much more than 5 minutes at the moment. So if you have a stairway that you could try this on give it a go. And yes I got some funny looks from the gym owner but he's used to me doing weird things in the gym and didn't say anything.