Is it a front lever?
Recently Steve Maxwell wrote of one arm body weight rows and leg raises. I'm on my way to buy the supplies to make a chin up bar suggested in BradJ's newletter.
BTW Steve, the door jam pistol is saving my left knee. Thanks everyone.
I'd assume it's where your feet are touching the ground in front of the bar/ring that you are performing rows on. You'll be leaning back and grabbing the bar/ring with one hand. You feet are on the ground and taking away some of your weight, which makes it easier than a front lever and especially a front lever pullup.
I believe Steve Maxwell has written about this exercise elsewhere. One variation is to loop a towel around a pair of doorknobs, plant your feet on either side of the bottom of the door, then lean back. Pull yourself back to standing with one or both arms. Your starting position is facing the edge of the door, and the direction you lean is away from the edge of the door.
The general idea is that you have some kind of handle you can use to lean against and use to work a rowing movement instead of a pullup. You could do this lying down, or standing and leaning.