Aggression during daily walks

[PghRottie]

I adopted a female rottie last year "Bordell". Currently she is 3 years old. When I adopted Bordell, she had very little if any training, and was not spayed. Needless to say I had some serious behavioral problems to deal with during the first few months. But, over the past year, Bordell was spayed, attended obedience classes, and she received much needed attention and patience that she did not have before. As a result, there's been a drastic change in her behavior for the better. However, there are still some things we have to work on. One of the biggest problems I am having with her right now is walking on leash. Bordell generally does well during our walks. She walks in the heel position and sits when I stop just as she was trained to do. I have received numerous compliments on how well trained she looks during our walks. The problems come when another person or animal walks, runs, or rides (bike or skateboard) near us. She flips out. She stiffens up, her neck muscles tense, and her ears perk up, and the closer the person or animal gets, the more excited she gets. She will growl, sometimes bark, and even lunge at times. When she does this I give her a hard correction, and let her know in no uncertain terms her behavior is not acceptable. When I see someone coming, I put her in a sit stay until the person passes, and I praise her if she does not move. But even in the sit stay position she still gets aggressive at times. For example, we were walking a couple nights ago when 2 women and a child were coming down the sidewalk, I put Bordell in a sit stay, she did fine, but one of the ladies said hello, and Bordell gave the woman a sharp bark and jerked toward her. I gave her a quick hard correction and put her back in the sit stay position.
She did not exhibit this behavior in obedience classes, and she does not do it when we go to the pet store or anywhere else away from home which leads me to believe it's a territorial behavior. Although I've seen some improvement in this problem the last few days, it's a major concern, and I'd love some help in solving it. I look forward to hearing from other members about this.
Thanks.

[Judi W]

Instead of giving her a sit, which gives her an opportunity to do a stare down and get her interest totally focused, keep her moving and with turns and changes of direction which will require that she pay attention to you. You can put in a quick halt or two, but to just sit and allow her to stare is not working so change it.