I have a black lab who is almost 6 months old. He's doing pretty well with his training, he's friendly and relaxed but we have one problem. His recall is really good but he gets quite excited when I recall him and will jump up when he reaches me. My dog trainer says my correction isn't strong enough but I don't really know what she means. Am I supposed to shout at him when he does it? I don't really see how that will help if he's already done the behaviour? Does anyone have any advice how to correct this behaviour?