The Messy Middle
Have you ever noticed your dog tremble for what seems like no apparent reason?
Most people see their dog shivering and immediately think something is wrong. They assume the dog is scared. They assume the training is failing. And their first instinct is to back off, remove the pressure, and protect the dog from the discomfort.
That instinct is understandable. It is also one of the most common reasons dogs never actually recover from fear or trauma.
What Is the Messy Middle?
The messy middle is the phase of behavior change where things look worse before they get better. Progress stalls. Old problems resurface. The dog trembles, hesitates, or shuts down in moments that seemed like they were already handled.
This is not regression. This is not failure. This is the dog's body doing exactly what it needs to do to heal.
Here is why that matters. When a dog experiences something frightening, the body launches a survival response. Adrenaline floods the system. The dog prepares to fight, run, or freeze. But in most real-world situations, the dog cannot complete that response. The leash prevents flight. The environment blocks escape. The moment passes, but the body never got to finish what it started.
That unfinished response does not just disappear. It gets stuck. The dog carries it forward as tension, reactivity, avoidance, or hypervigilance. The fear is not a memory the dog is choosing to hold onto. It is a physical pattern the body never had the chance to release.
The messy middle is where that release finally happens.
What trembling looks like during the messy middle.
Note: These clips were sourced from publicly available video. They are not Heel & Heal K9 clients or active training sessions. They are included here for educational purposes to illustrate a common and widely misunderstood behavior.
A Quick Note
Dogs tremble when they are overwhelmed by excitement just as readily as when they are working through stress or fear. A dog meeting their favorite person after a long absence may tremble. A dog anticipating a meal or a walk may tremble. The trembling itself is not the diagnosis. It is a signal that the nervous system is highly activated.
Context matters. A dog shivering at the front door when guests arrive is not in the same state as a dog shivering during a controlled exposure to a trigger that previously shut them down. The behavior looks similar. The underlying process is different.
Trembling Is a Good Sign?
Dr. Peter Levine, a trauma researcher with doctorates in medical biophysics and psychology, spent decades studying how the body processes overwhelming experiences. His central observation was that wild animals face life-threatening events constantly yet rarely develop lasting trauma the way humans and domesticated animals do.¹
What he found was that after a survival event, prey animals do not simply return to calm. Their bodies tremble. They shiver. They go through involuntary rhythmic movement. And then they return to baseline, unburdened.¹
That trembling is not leftover fear. It is the body completing what it started. The survival energy that was mobilized during the threat has to go somewhere. Trembling is the discharge. It is the body finishing the job.
Stanford neurobiologist Robert Sapolsky's research supports the broader principle at work here. For wild animals, stress is episodic. A zebra outruns a lion, the stress response fires and resolves, and the animal moves on. The problem arises when stress becomes chronic, when the body never gets the signal that the threat has passed.² For dogs living with unresolved fear or trauma, this is exactly what happens. The threat response activates but never completes. The body stays locked in a state of ongoing alarm.
Dr. Stephen Porges' research on the autonomic nervous system adds another layer. His work describes how mammals, when unable to fight or flee, default to a freeze state. It is not a choice. It is an automatic neurological response to perceived inescapable threat. And critically, the exit from that freeze state involves the same involuntary trembling and physiological activation that Levine observed.³
Dogs do the same thing. A dog working through fear of car rides, fireworks, or veterinary handling may exhibit involuntary trembling during or immediately after a controlled exposure. That trembling is not evidence that you pushed too hard. It is evidence that the dog's body is finally processing what it could not process before.
This is why the messy middle is not just a phase to endure. It is a measurement tool. When you see trembling, shivering, momentary hesitation followed by recovery, you are watching the dog's nervous system do real work. You are watching progress happen in real time, even when it does not look like progress on the surface.
Why Backing Off Too Soon Makes It Worse
This is the part most people get wrong.
Research on how dog owners perceive stress confirms it. Owners most frequently identify trembling and whining as signs of stress in their dogs. But subtler, earlier signals like lip licking, head turning, yawning, and averting gaze are rarely recognized.⁴ This means most owners are not reading the early stages of stress at all. By the time they notice the trembling, the dog is already deep in the processing window, and the owner's instinct is to pull them out of it.
When a dog trembles or hesitates, the natural human response is to remove the pressure. Stop the session. Pull the dog away from the trigger. Comfort them. And on the surface, that feels like the compassionate choice.
But here is what actually happens when you do that. The dog was in the middle of processing. The body had activated. The survival response was finally surfacing so it could complete. And then you interrupted it. Again.
Every time you pull a dog out of that window before the discharge can finish, you reinforce the same pattern that created the problem. The dog learns, once again, that the response cannot be completed. The stuck energy stays stuck. The fear stays intact. And the next exposure becomes harder, not easier, because the dog has rehearsed the interruption one more time.
This does not mean you ignore the dog's state. It does not mean you flood them or push past what they can handle. There is a window where the dog is activated enough to access the stuck pattern but regulated enough to stay in the process without shutting down completely. Staying inside that window is the skill. That is where the work happens.
Two Things That Show Up in the Messy Middle
As you move through this phase, two patterns are common.
The first is the last push before a behavior fades. When something that used to work for the dog stops working, the dog does not quietly accept it. The dog tries harder. A dog that used to jump for attention will jump harder and more frantically when the jumping stops getting a response. This is the behavior's last surge before it dies out. It feels like things are getting worse. They are not. The dog is testing whether the old strategy still pays off. If you hold the line, the behavior drops.
The second is the return of old behavior under new stress. A dog that stopped jumping weeks ago may jump again when a guest arrives or during a thunderstorm. This is not the same as the first pattern. This is the dog reaching back into an old playbook because the current situation feels threatening or unfamiliar. It does not mean the training failed. It means the dog encountered a new challenge and defaulted to a familiar response. It requires a recalibration, not a restart.
Both of these show up in the messy middle. Both feel like setbacks. Neither of them are.
The Messy Middle Is the Work
The temptation is to see the messy middle as an obstacle between where the dog is and where you want the dog to be. But the messy middle is not in the way. It is the way.
Trembling, setbacks, cycles of improvement and withdrawal. These are not signs that something is going wrong. They are signs that the dog's body is doing exactly what it was always trying to do. Complete the response. Discharge the energy. Let go of what was stuck.
Your job is not to prevent the discomfort. Your job is to hold the space steady enough that the dog can finally finish what it started.
Footnotes:
Levine, P.A. (1997). Waking the Tiger: Healing Trauma. North Atlantic Books. Levine's observations on involuntary trembling and discharge in prey animals following survival events form the foundation of the Somatic Experiencing framework. His model is widely applied in clinical trauma work, though the specific animal discharge claims have not been independently replicated in controlled studies.
Sapolsky, R.M. (2004). Why Zebras Don't Get Ulcers. 3rd ed. Henry Holt and Company. Sapolsky's research focuses on the physiological damage caused when the stress response, designed for short-term survival events, becomes chronic. His work supports the principle that animals in the wild resolve acute stress efficiently, while domesticated animals and humans often do not.
Porges, S.W. (2011). The Polyvagal Theory: Neurophysiological Foundations of Emotions, Attachment, Communication, and Self-Regulation. W.W. Norton. Porges' model describes how the mammalian nervous system defaults to immobilization (freeze) when fight or flight is not possible, and how the exit from that state involves involuntary physiological activation including trembling. Note: Polyvagal theory is influential in clinical practice but aspects of its evolutionary claims remain debated within neuroscience.
Mariti, C., Gazzano, A., Moore, J.L., Baragli, P., Chelli, L., & Sighieri, C. (2012). Perception of dogs' stress by their owners. Journal of Veterinary Behavior, 7(4), 213–219. This study found that owners most frequently identified trembling and whining as indicators of canine stress, while subtler early signals such as lip licking, head turning, and yawning were rarely recognized, suggesting most owners intervene too late or misread the stage of stress their dog is in.
