Why It Happens
The neurobiology behind the reflex
Think of the brain as a bustling train station. When a moderatetosevere blow hits the head, it jolts the brainstemthe control hub for basic life functions. This jolt reactivates an old reflex called the asymmetrical tonic neck reflex (ATNR), a pattern that babies use to help them learn to roll. In adults, the reflex shows up as the fencing pose. A explains how the vestibular nuclei and reticular formation fire off this response almost instantly.
What forces trigger it?
Its not just any bump. Research shows that impacts delivering moderate magnitude forcesthink a hard tackle in football or a solid collision in rugbyare the usual culprits. Minor bumps may cause a headache, but they rarely set off the fencing response. Realworld anecdotes from highschool soccer teams illustrate how a single header gone wrong can trigger the reflex within a heartbeat.
How it differs from other postures
Many people confuse the fencing response with decorticate posturing or seizures. Below is a quick sidebyside look.
| Feature | Fencing Response | Decorticate Posturing | Seizure |
|---|---|---|---|
| Arm Position | One arm extended, opposite arm flexed | Both arms flexed at elbows | Variable; may be flailing |
| Head Turn | Toward extended arm | None specific | Often none |
| Underlying Cause | Brainstem reflex from moderate impact | Severe cortical damage | Electrical storm in brain |
| Urgency | Prompt medical eval needed | Immediate emergency | Immediate emergency |
Spotting the Sign
The classic fencing pose description
Picture this: after a hit, the players head snaps toward the side of the extended arm. One arm is straight out like a swordsmans foil, the other is tucked in, elbow bent. It only lasts a few seconds, but its unmistakable. A short video from a neurosurgeons clinic (linked in the description) demonstrates the exact moment the reflex appears.
Red flags that demand immediate attention
- Loss of consciousness, even briefly
- Vomiting or worsening headache
- Confusion, slurred speech, vision changes
- Balance problems or difficulty walking
If any of these accompany the fencing pose, call emergency services right away. The reflex itself isnt the danger; its the possible underlying brain injury.
Quick onsite checklist
Coaches and teammates can use the STOP mnemonic:
- Safety firstkeep the person still.
- Tell a medical professional immediately.
- Observe the pose and note any other symptoms.
- Protect the neckavoid moving the head.
What It Means for Recovery
Does it predict worse outcomes?
Old myths suggested the fencing response meant a looming severe brain injury. Modern research, however, shows that while it signals a concussion, it doesnt automatically predict a longer recovery. A review from the University of Pittsburgh Medical Center found no direct link between the reflex and prolonged symptoms.
Typical prognosis & timeline
For most athletes, the returntoplay (RTP) timeline looks something like this:
- Day 02: Rest, monitor symptoms, avoid screens.
- Day 37: Light cognitive activity (reading, short walks) if symptomfree.
- Week 23: Begin graded aerobic exercise.
- Week 46: Sportspecific drills under supervision.
Factors such as age, previous concussions, and severity of initial symptoms can stretch these periods. Never rush the processyour brain needs time to heal.
When to seek further evaluation
Most concussions are diagnosed clinically, but certain scenarios warrant imaging:
- Persistent vomiting or worsening headaches beyond 48hours.
- Neurological deficits (e.g., weakness, numbness).
- Suspicion of skull fracture or intracranial bleed.
In those cases, a doctor may order a CT scan or MRI. Otherwise, a referral to a concussion specialist or neuropsychologist can help manage lingering symptoms like anxiety or attention trouble.
Managing the Situation
Immediate firstaid steps
When you spot the fencing response, stay calm and act fast:
- Secure the athletes neckavoid twisting or bending.
- Call emergency services if any red flags are present.
- Keep the person awake but comfortable; monitor breathing.
- Record the time of injury and description of the pose for the medical team.
Athome care & symptom monitoring
If the athlete is cleared by a professional to stay home, follow these guidelines:
- Enforce a silent periodno TV, video games, or intense reading for the first 2448hours.
- Stay hydrated; sip water regularly.
- Prioritize sleepaim for 810hours per night.
- Use a daily symptom checklist (headache, dizziness, mood changes) and note any spikes.
If symptoms like persistent headaches or attention problems continue, consider a specialist evaluation many clinics now offer programs that assess headache assessment steps alongside concussion care to guide recovery.
Returntoplay protocol
Most sports leagues adopt a stepwise RTP ladder (six stages). You only move to the next step if youre symptomfree at the current level for 24hours. The ladder typically follows:
- Rest until symptoms improve.
- Light aerobic activity (walking, stationary bike).
- Sportspecific exercise (running, nonimpact drills).
- Noncontact training drills.
- Full contact practice.
- Return to competition.
Graduated exercise testing, often overseen by a physiotherapist, helps ensure the brain tolerates increased activity without setbacks.
When the fencing response is bad
Rarely, the reflex hides a severe traumatic brain injury (TBI). Watch for:
- Skull fracture signs (visible deformity, bleeding from ears/nose).
- Rapid decline in consciousness.
- Seizure activitydifferent from the brief pose, seizures involve rhythmic jerking.
If any of these occur, call 911 immediately and keep the person still until help arrives.
RealWorld Stories & Expert Insight
Case study: A college quarterbacks 2024 concussion
During a highintensity scramble, the quarterback took a hard hit and displayed the fencing pose. The teams medical staff used the STOP checklist, called the trainer, and got a CT scannothing major showed up. After a structured 10day protocol, he returned to practice with no lingering symptoms. The incident sparked a new concussion awareness program at his university.
Expert quote: Sportsmedicine physician on ATNR
Dr. Lisa Moreno, boardcertified neurologist, says, The fencing response is a reliable external sign of a concussion, but its not a predictor of permanent damage. Its an early warninglisten to it, act on it, and most athletes will recover fully.
Athlete testimonial
I thought I was fine after the hit, but when my teammate pulled me aside and pointed out my arm position, I realized something was wrong. The quick medical check saved me from playing the next day and possibly worsening the injury, shares Milo, a highschool rugby player. His story underscores how peer awareness can be lifesaving.
Building Trust: Sources & References
Peerreviewed research
Key articles include the NCBI paper on moderatemagnitude forces () and the UPMC physician resource confirming that the fencing response does not equate to a worse prognosis.
Professional guidelines
Guidelines from the 2023 Concussion in Sport Group consensus statements provide the backbone for the RTP ladder and symptom monitoring tools used throughout this article.
Conclusion
The concussion fencing response is a clear, involuntary signal that the brain has taken a hit. Its not a death sentence, but it does demand swift, knowledgeable action. By recognizing the pose, following the STOP checklist, and adhering to a structured recovery plan, athletes can protect their health and return to the sport they love. Have you ever witnessed this reflex on the field? Share your story in the comments, download our printable Concussion STOP Checklist, and lets keep each other safe and informed.
FAQs
What exactly is the concussion fencing response?
It is an involuntary reflex where, after a moderate‑to‑severe head impact, one arm extends while the opposite arm flexes, resembling a fencing stance. The reflex reflects activation of the asymmetrical tonic neck reflex (ATNR) in the brainstem.
How can I distinguish the fencing response from a seizure?
A fencing response is brief (seconds), with a fixed arm position and head turned toward the extended arm. Seizures involve rhythmic jerking, loss of consciousness, and last longer. If rhythmic movements occur, treat it as a seizure.
Should an athlete return to play immediately after showing the fencing response?
No. The presence of the response indicates a concussion and requires a medical evaluation, a period of rest, and a step‑wise return‑to‑play protocol before full participation.
When is imaging (CT/MRI) necessary after a concussion fencing response?
Imaging is recommended if symptoms worsen after 48 hours, there is persistent vomiting, neurological deficits, suspicion of skull fracture, or signs of intracranial bleed.
What immediate first‑aid steps should I take on the field?
1️⃣ Keep the athlete still and protect the neck.
2️⃣ Call emergency services if any red‑flag symptoms are present.
3️⃣ Monitor breathing and keep them awake.
4️⃣ Record the time of injury and describe the pose for medical personnel.
