My 10 month old male GSP becomes over exhuberant and lunges at people / dogs in excitement. He will sit nicely by my side when I speak to someone, then suddenly lunge excitedly. He has just dislocated 2 of my fingers which required an op - Help!  He gets loads of exercise, works daily and is very obedient in all other areas except for this lunging.  Can anyone offer advice please as I need to stop this behaviour. 

Hi thanks for your response.  I use a martingale collar and when he lunges give a firm 'NO' and walk away before returning back and getting him to sit again.  He then seems to associate the correction with the person / dog he lunged at, and doesn't lunge on them again, but will repeat the behaviour when he meets someone new.  As he won't lunge on people he has met, he now lunges on strangers in the street who stop to talk to him or hold eye contact with him.  As he is now powerful and injured me in the process I need to put a stop to it but don't know how.  He is very obedient in all other respects and has a wonderful happy go lucky nature.

Thanks for your advice.  A new collar and very short leash are making a big difference.  I have set up potential lunge situations and am really pleased with the progress we have made over the last couple of days.  Hopefully he will soon stop this behaviour for good.