I have a four month Lab and a couple of weeks ago in the park she went up to a lady and started barking and had her hackles up.  She then went on her back to have her tummy tickled.
At the same time she saw this lady a Lurcher was pounding up to the Lab.

I go out every day with her and the first person she sees she would repeat this.  After that she was fine.
She is good at the recall and comes back on the first whistle.
However it does concern me and before I start to do anything about this behaviour-ie I do not want to reinforce it-I was wondering if anyone could advise me of what to do.

Are you really brave enough to let her off lead when she barks and has her hackles up - I dont think I would be.  But then I wouldnt be confident enough in my own ability to recall and know mine would come to me.  I will be interested to read the advice you get - I'm learning on all these things.  Hope you get the advice you need.  Max

At only four months she's still very unsure of herself so doesn't yet know that strangers aren't a threat - hence the hackles, bless her! :D The rolling on her back is normal puppy submission, so there's no need to worry - she's just showing anxiety at the situation - so you're doing exactly the right thing by letting her off; when they're older and have gained confidence in the outside world they're much less likely to be interested in coming back to boring safe old mum! When she's offlead keep her attention on you by frequently changing direction (calling "This way!" when you do so) and walking away from her. Then she'll learn to watch where you are and you'll have fewer recall problems as she grows.

Thanks JeanGenie-you have put my mind at rest.  I will follow your advice.

My own Lab was much the same in her behaviour till about a year old.  She was off-leash as well and I am happy to see JeanGenie's support in this area.  Perhaps JeanGenie could also comment on my solution to the problem?  As it might help you too, but I am not a trainer. 

I found that Jet only did this with people I did not know.  Neighbours that I greeted with a big, "HELLO, great day, isn't it?" did not illicit the same behaviour from Jet.  So I took to saying that to everyone, whether I knew them or not.

And I asked Jet to come to me and to heel.  I did not put her on leash but sometimes I did just touch her collar.  It seemed to me that she needed this display from me that showed I was the boss, not her.  Until I did this and the above it seemed she thought it was her job to accost strangers.

Like you I was quite concerned that my Lab, a breed that supposedly loves everyone, apparently did not.  I consulted with her breeder too, who said I must control the situations in which she met strangers till she felt more sure of herself.  Jet is a very submissive girl, highly obedient, excellent recall as I believe is typical of a submissive dog.  I must say, it wasn't till she was 6 years old that she willingly approached a stranger and allowed them to have a little pet.  But at least she stopped bounding up and scaring people sooner than that.

>And I asked Jet to come to me and to heel.<

I wholeheartedly agree with this.  I used this approach when one of my puppies went through an anxious phase and it really seemed to teach her that if she wasn't sure about something, the best place to be was next to me.    I would release her to go and say hello, once I figured out what/who it was or when her behaviour became more relaxed.  She grew out of the anxiety but if we ever encounter anything with a strange outline or that she doesn't "recognise", the first thing she will do is turn and look at me.  If I need to, I can call her to heel.  Borilar, you say your dog comes back on the first whistle, so you shouldn't have a problem using this method. 

I also agree that dogs pick up on our tension, so to greet people in a friendly way will be reassuring and I bet Jetstone Jewel made some new friends ;-)

Thank you Lillith for your sound advice.  Wilma the Lab is getting better and better. I take her where she knows the dogs and the people-and she has a super time mixing with three Labs and a Springer.  I think it gives her confidence and also helps me.  I will venture to new places in the next couple of weeks.  I do walk her round the block in the evening and she is really good-mind you she is on the lead at all times.

Glad to hear she's getting better and better.  Good luck with your ventures into the unknown - positive experiences in new places and of new people will build up her confidence no end.

Have fun with your puppy and keep us posted on her progress! :-)