Most people think primitive reflexes only matter for babies. But what if one of these early movement patterns never fully integrate — it can still shape how you sit, move, and even how well your brain and focus functions today?
One such reflex is the Symmetrical Tonic Neck Reflex (STNR). This reflex plays a critical role in the transition from lying on the belly to crawling on all fours — a major milestone in brain and body development.
What Is the STNR Reflex?
Unlike some other primitive reflexes, the STNR isn’t present at birth. It emerges around 6–9 months of age, after the Tonic Labyrinthine Reflex (TLR) has integrated. Its job is to help babies get up on their hands and knees, rock back and forth, and eventually begin crawling.
The STNR links head movement with limb responses:
- When the head looks up ➝ arms extend, hips flex.
- When the head looks down ➝ arms bend, hips extend.
This reflex helps a baby position their body in preparation for crawling and develop postural control. Once the baby master cross-crawl movement, the STNR should integrate by around 11 months.
Why It Still Matters as an Adult
If the STNR doesn’t integrate properly, it can hang around and create subtle but significant issues in adulthood — often without you realising it.
Signs of a retained STNR reflex in adults:
- Slouching or poor posture (especially when sitting at a desk)
- Poor coordination
- Difficulty with sustained focus or learning
- A history of awkward or skipped crawling in early childhood
Test Yourself: Is the STNR Reflex Still Active?
Here’s a simple way to test whether the STNR is still influencing your movement.
STNR Test Instructions:
- Get into an all-fours position (hands under shoulders, knees under hips).
- Slowly look up toward the ceiling and hold for 10 seconds.
- Positive sign: your hips shift back or knees bend involuntarily.
- Slowly tuck your chin toward your chest and look at your belly button for 10 seconds.
- Positive sign: your arms bend or elbows drop involuntarily.
If either of these happens, it could suggest your STNR is still active.
STNR Reflex Integration: 3-Phase Exercise Progression
Here’s a structured approach to help you mimic, refine, and override the STNR reflex using functional movements. These exercises aren’t just about reflex integration — they also build core strength, shoulder stability, and overall motor control.
Phase 1: Mimic the Reflex
Exercise: Elevated bare-crawl Hold (STNR Mimic with Knees Off Ground)
This variation brings in strength and endurance while mimicking the classic STNR pattern.
Instructions:
- Start in a modified bear crawl position (hands under shoulders, knees bent, lifted 4-610cm off the ground).
- Lift your head— arms straighten, hips flex.
- Tuck your chin — arms bend, hips extend.
- Move slowly between the two positions, holding each for 2-4 seconds.
Why it works: You’re reinforcing the head–limb relationship encoded in the STNR movement into the higher brain centres like the motor cortex.
Phase 2: Refine the Movement
Exercise: Japanese Push-Up Flow (Push-Through to Squat)
This dynamic flow blends mobility and strength while improving body control in and out of STNR-patterned movements.
Instructions:
- Start in Downward Dog.
- Bend your elbows and scoop your chest forward into Cobra, keeping knees and thighs lifted off the ground.
- From the Cobra position, shift your weight back into a deep squat (knees bent, hands remain on the floor).
- Repeat the flow rhythmically.
Why it works: This smooth, strength-based flow builds voluntary control over the STNR-driven movement patterns. You’re creating refined movement patterns around the reflex that is controlled rather than reflexive. This voluntary control stems from the motor cortex rather the brainstem where the STNR reflex stems from.
Phase 3: Override the Reflex
Choose one or alternate between both exercises below.
Option A: Mountain Climbers to a Metronome
- Get into a plank with your head flexed down so that you are looking at your feet.
- Drive opposite knee to elbow in a cross-crawl rhythm.
- Use a metronome app (start at 60 bpm).
- Stay steady through the shoulders, core tight, keep your head in neutral.
Option B: Swiss Ball Flutter Kicks to a Metronome
- Lie on your stomach with your legs hanging off a Swiss ball and neck extended back.
- Brace your core, keep your arms grounded.
- Flutter kick rhythmically.
Why it works: These movements challenge coordination, rhythm, and core control — drawing on higher brain centres to override reflexive patterning while the neck is positioned in flexion or extension.
Final Thoughts
Primitive reflexes aren’t just for babies. They shape how your brain and body connect — and if one is hanging around past its use-by date, it can impact posture, coordination, and performance.
If you found this helpful, watch the full video above for a demonstration of each exercise and the STNR test in real time.