I completely cringed when I read the "trainer's" assessment of Ellie. She is a classic fearful dog, and you really really need to speak to a behaviorist (positive based) about dealing with her anxieties. From all you have posted, she's going to need quite a bit of confidence building. She is NOT being obstinate. She is being a puppy. A Lab puppy. Most have shark tendencies, they are a VERY mouthy breed. Dealing with it in a positive way helps get you through it. Zoomies are good. No, they're great! There is nothing I"ve enjoyed more than watching a Lab get their zoomies out, especially when it's an older dog. It shows enthusiasm and zest for life, NOT being bad, they're not out to get you.
I also cringe when I hear this talk about a "teenage" phase. I have never experienced it, not with multiple dogs over my lifetime, including one that could be classified as a dog from hell. If you expect that kind of behavior,you will get that kind of behavior. Your expectations when looking at Ellie need to not be so regretful, nor frustrated (which I can sense from your posts), and need to be positive.
Here is a good article about a study (with references) about fear in dogs.
The fearful Dog: Causes and Treatment | NJ.com
Please please read this in its entirety.
Some parts of the article (for those that don't want to click through):
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How To Help A Dog Suffering From Fear
Contacting a vet or vet behaviorist and reporting the behavior to your vet should be the first step. The vet will run blood tests and evaluate the dog for underlying medical issues that may be causing the behavior. Many illnesses can cause fear or aggressive responses, so it’s important to rule those out.
Myths Surrounding Fear
There are many misconceptions and myths these days concerning how one should handle a fearful dog. Some suggest the owner should refrain from coddling it. One popular television show often labels these dogs “dominant,” because the fear is expressed through aggressive displays and are misinterpreted. Others assume the animal was abused or mistreated in some way.
The Influence of Human Emotions
Owner emotions often play a role in affecting a dog’s fear levels. Often, owners become frustrated or embarrassed when the dog acts out in public. Some get angry and yell at the dog or resort to punishments such as yanking on collars or fitting the dog with a shock collar to control the behavior. Some alpha roll their dogs thinking that holding the dog on the ground will somehow affect calm behavior. Once the event is over these individuals become loving and doting pet parents again. This is especially true of dogs that fear people and aggress toward them outside of the home. The owner may yell at the dog or even punish it outdoors, but once inside becomes the loving, doting parent once again.
This emotional roller-coaster the dog takes with its owner often exacerbates the behavior and makes it more complex and difficult to treat. Additionally, the animal begins to mistrust its owner because it can never predict their human’s behavior.
Effective Treatment Strategies
The most effective way to handle a dog’s fear is to remain relaxed and in control in all situations and avoid any circumstances that elicits a fear response. This easily can be accomplished by turning around and walking away from something scary, taking the dog outdoors when the presence of fearful stimuli is at its lowest, taking a position in front of your dog to protect it from a perceived threat (especially if it's a child), or soothing the dog with kind words.
Breathing plays an important role. The way one breathes speaks volumes about their emotional state to the dog. The dog relies on these states for valuable clues to decide what constitutes an actual treat. When owners leave the house frustrated or fearful their dogs will react accordingly or remain on high alert the entire time they’re outdoors.
Repeated Exposure to Frightful Stimuli
When an animal is exposed to repeated traumatic events high levels of glucocorticoids (fear hormone) are released. The result is damage to the neurons in areas of the hippocampus, which can result in deficits in new learning.
This phenomena has been reported in post war veterans, police officers and others suffering from Post Traumatic Stress Disorder (PTSD) and those who experienced sustained levels of extreme stress or loud sounds. The most extreme effects of damage to neurons in this area of the brain is reported by those individuals who had to kill another human in order to preserve their own life.
Deficits in learning also have been observed in dogs exposed to shock collars and harsh methods of training. Such animals display what can only be described as the canine equivalent of attention deficit disorder (ADD), learned helplessness (dog shuts down), and general difficulties learning new tasks, problem-solving, or unwillingness to experiment with new behaviors.
Looking To The Future
Owners should be reasonable about their goals. They should have short-, mid- and long-range goals. Training a dog with fear issues can be a lengthy process and it's among the most challenging behaviors to treat. It doesn't necessarily have to be difficult for the owner, though. Training should be fun and filled with games and enjoyable activities so the dog and owner have fun while learning.
Once a dog has been diagnosed by a veterinary behaviorist, a trainer can and should design a customized training program to help the dog overcome its issues, make recommendations for changes in exercise, diet, and more.
Training may include counter conditioning, operant conditioning and desensitization to fearful stimuli. All training should be positively based. Training may also include classical conditioning designed to help the dog change its emotional state in relation to those things it fears. This is called a conditioned- emotional response, or CER. Under no circumstances should the dog be physically punished, coerced, corrected or flooded (bombarded with stimuli until it no longer reacts) during the training process.
Another helpful training tactic is applying the “nothing in life is free” program (NILIF). This means the dog will have to work for everything: food, toys, treats, praise and walks. NILIF helps to instill, in the dog’s mind, that the owner is a competent leader because the owner controls the good stuff and gives the dog much-needed direction. It also provides a very predictable life for the dog and can offer them a great deal of stability. Moreover, it gives the dog something else to do other than worry.
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I highly recommend reading the entire article, and contacting someone other than an apparent dominance based trainer.