When Willow adopted us and before we put our fence up, I got a 25 ft. retractable so at least I could let her run a little and have some space. I searched for an enclosed area nearby, but couldn't find one, so I would take her to a local park, and let her reel it out and get a little crazy. Well, one day, my then 4 year old son was with me. We got out of the car and started toward the grass and I let her pull out the leash. Before I knew it, I realized she had all 25 feet pulled out and was circling back toward me and my SON was in the middle of the loop! I yelled at him to watch out, and tried to run back around him, but it was too late...she ran by and burned the *l^%&^$%* out of the back of both of his legs right above the knees. He was screaming and crying, the dog was freaking out...it was awful!! I can tell you, since then, IF I use that leash (which I don't think I have since we've put up the fence...unless we go to the beach) I am VERY aware of where everyone is at all times. It can happen so fast! They are very dangerous!