The Fencing Response: When Primitive Reflexes Reveal Brain Trauma
When Miami Dolphins quarterback Tua Tagovailoa hit the ground after a devastating tackle, something chilling happened. His arms locked into an unnatural positionâone extended forward, the other bent at his side, like a fencer holding an Ă©pĂ©e. The image burned into viewers' minds, and for good reason. This "fencing response" signals something far more serious than a typical concussion.
As traffic pours into neurofeedback clinics after these high-profile incidents, parents and athletes want answers. What exactly is happening in the brain when we see this alarming posture? And why should it change how we think about brain injuries in sports?
The Brain That Moves Like Jelly in a Hard Shell
First, let's dispel a common misconception. When you see a brain on televisionâheld confidently in a medical examiner's handâyou're looking at a fixed, chemically-treated organ. A living brain bears little resemblance to this firm prop.
"A dead brain is pretty sloppy," I often tell people. The living human brain pulses and moves constantly. Delta waves at 2 Hz create washing machine-like agitation throughout brain tissue at night. We're discovering massive physical movement in the lymphatic system that we never knew existed.
This jelly-like organ sits encased in your hard skull. During impact, it doesn't move as one solid unit. Instead, it sloshesâfirst in the direction of impact, then rebounding in the opposite direction. This is the "coup-contrecoup" mechanism (French for "blow-counterblow") that creates the mechanical tissue damage we call concussion.
Imagine putting an egg in a jar and shaking it violently. The egg doesn't just crack where it first hits the wallâit gets damaged throughout as it ricochets back and forth. Your brain experiences similar mechanical forces during head trauma.
When Ancient Reflexes Resurface
The fencing response represents something profound: the reassertion of primitive reflexes that disappeared in your first year of life.
The asymmetric tonic neck reflex (ATNR)âthe technical name for the fencing postureânormally vanishes between 9 months and 1 year of age. In healthy babies, when you turn their head to one side, their arm on that side extends while the opposite arm flexes. This reflex helps infants learn to roll over and eventually crawl.
As your nervous system matures, higher brain centers develop inhibitory control over these primitive patterns. The reflexes don't disappearâthey become masked by more sophisticated motor systems.
When severe brain trauma occurs, particularly to the brainstem, these inhibitory systems fail. Ancient reflexes break through like buried code suddenly executing in a computer crash. In a 300-pound athlete hurtling through the air, this creates the disturbing spectacle of primitive infant reflexes playing out on a massive adult frame.
Not Just "Getting Your Bell Rung"
Here's what parents and coaches need to understand: if you see a fencing response, you're not witnessing a mild concussion. This represents major brain injury.
The appearance of primitive reflexes indicates brainstem compression and significant mechanical damage. There's likely bleeding, secondary inflammation, and extensive tissue disruption beyond simple "getting your bell rung."
This isn't posturing that develops over timeâyou see it instantly as the trauma occurs. Compare this to "decorticate posturing," where swelling gradually disconnects the cortex from deeper brain structures over minutes to hours. The fencing response happens in real-time as tissues get mechanically disrupted.
The Broader Picture: Different Types of Brain Posturing
The fencing response belongs to a family of abnormal postures that reveal different types of brain dysfunction:
Asymmetric Tonic Neck Reflex (Fencing Response): One arm extends, the other flexes. Triggered by neck movement or brainstem trauma.
Symmetric Tonic Neck Reflex: Both arms lift and extend, neck stretches, legs pull up. Helps babies prepare to crawl. You'll see this in premature infants as a sign they're still developing.
Moro Reflex: The "startle" response where babies throw their arms out and then pull them back in, often triggered by sudden movement or loud sounds.
Babinski Reflex: When you scratch the bottom of a baby's foot, their toes fan out instead of curling down. In adults, a positive Babinski sign indicates serious central nervous system problems.
All these reflexes serve important developmental functions in infants. Their reappearance in older children or adults signals that something has gone seriously wrong with higher brain function.
The Gender Factor in Brain Injury
One critical factor often overlooked in brain injury discussions is the role of neck anatomy. Female athletes face disproportionately higher concussion rates, and neck girth plays a major role.
Women typically have more elegant, slender neck structure compared to the thick, muscular necks common in male football players. This anatomical difference means less mechanical stability during rotational forcesâthe kind that cause the most severe brain injuries.
This explains why young women playing soccer show some of the highest brain injury rates in youth sports. It's not just about headers (though those contribute). It's about fundamental biomechanical differences in how impact forces transfer through the neck to the brain.
The Uncomfortable Question: Child Athletes and Calculated Risk
When adults choose high-risk professionsâFormula One racing, professional football, combat sportsâthey make calculated decisions with mature brains capable of weighing long-term consequences.
The uncomfortable reality is that youth sports place developing brains at risk before children can make truly informed decisions. We know the statistics: 98% of retired NFL players show signs of chronic traumatic encephalopathy (CTE). Yet we continue enrolling children in activities that carry similar mechanical risks.
This raises difficult questions. At what point does youth participation in high-impact sports cross the line from acceptable risk to potential child neglect? The brain doesn't finish developing until around age 25, yet we make participation decisions for children based on athletic potential and cultural expectations.
Beyond Football: Hidden Concussion Sources
Football grabs headlines, but brain injuries occur across youth sports in surprising patterns. Cheerleading, gymnastics, and soccer all produce significant head trauma. Young women's soccer may actually represent the highest brain injury risk in youth athletics when you account for both impact frequency and neck biomechanics.
The mechanisms varyâheaders in soccer, falls in cheerleading, collisions in basketballâbut the outcome can be equally devastating. The fencing response doesn't discriminate by sport.
What This Means for Parents and Coaches
If you see any abnormal posturing after head impactâfencing response, arm stiffening, unusual positioningâthis is a medical emergency, not a "tough it out" moment. The child or athlete needs immediate medical evaluation and should not return to play.
Modern protective equipment helps but doesn't eliminate risk. Guardian helmets may reduce impact forces by 10%, but they can't overcome the fundamental physics of a soft brain moving inside a hard skull.
The most important protection is education. Understanding these warning signsâprimitive reflex reassertion, abnormal posturing, altered consciousnessâcan prevent secondary injuries that often cause more damage than the initial trauma.
Moving Forward
The fencing response serves as a visible reminder of brain injury's serious nature. When primitive reflexes surface, they're showing us that sophisticated neural networks have been disrupted enough to let ancient patterns break through.
This isn't about ending sports or wrapping children in bubble wrap. It's about making informed decisions based on real understanding of risk. Every time we see a fencing response on television, it should reinforce our commitment to better protection, better recognition, and more honest conversations about the true costs of impact sports.
The brain's primitive reflexes evolved to help infants develop motor skills. When they appear in athletes after trauma, they're delivering a different message entirely: this injury demands serious attention, regardless of the game's outcome or the season's stakes.
Dr. Andrew Hill is a neuroscientist and brain optimization expert with 25+ years of experience in neuroplasticity and brain training. He has analyzed over 25,000 brain scans and specializes in neurofeedback therapy for cognitive enhancement and brain injury recovery.