Have you ever seen a dog sitting at the start line, looking around or sniffing the ground as the handler leads out? One of the reasons this might happen is that over the dog’s career, rewards have been given mostly in one of 2 situations: a release to an obstacle (after a lead out) or a reward at the startline (after the handler walks away and walks back to the dog). With this kind of reinforcement history, the dog learns that if they don’t receive an immediate reward for sitting, no reward or release is coming until the handler stops leading out. At that point, the dog will suddenly pay close attention, because the handler will either release them to an obstacle, or come back to reward them with a treat or toy.
You can prevent this “checking out” behavior by convincing your dogs that a reward or release can come at any point during the lead out.
To create an intense, focused start line stay, make sure you reward your start line stays often, and from many different points along the lead out, both while moving and while still. A clear verbal release independent of body language is usually best for most teams.