Chronic Ankle Instability: Can Proprioceptive Neuromuscular Facilitation Improve Recovery? | Find Your Stride | Edinburgh Podiatrist
- Joshua Francois
- 1 day ago
- 4 min read
Chronic ankle instability - a systematic review
Chronic ankle instability (CAI) derails training, alters running mechanics, and drives re‑sprain risk and long‑term joint degeneration. A new systematic review and meta‑analysis in PLOS ONE (2025) aggregates 12 randomised trials (n=405) testing proprioceptive neuromuscular facilitation (PNF) for CAI. For podiatrists, physios, and performance coaches working with runners, the paper is timely. PNF is already in many clinics, but its specific value over “standard care” has been murky.
What the study found (clinically translated)
Balance improves, meaningfully:
Y‑Balance Test improved by about 3.6 normalised reach units versus controls.
Star Excursion Balance Test improved by about 5.5 units overall, with gains across all eight directions after sensitivity analysis.
Why this matters: Dynamic balance and reach control relate to single‑leg stance tasks—stance phase control, cutting, trail running on uneven ground. Expect better reach, steadier landings, and potentially fewer near‑rolls.
Strength improves, but direction‑specific:
Small overall effect (SMD ≈ 0.19), driven by plantarflexion and dorsiflexion; no superiority for inversion/eversion strength.
Why it matters: Push‑off mechanics (PF/DF) may get a bump; the frontal‑plane stabilisers (invertors/evertors) didn’t clearly outperform controls—important for runners who keep spraining into inversion.
Pain decreases:
VAS dropped by ~1.4 points versus controls—clinically noticeable for many runners, particularly returning to hills and speedwork.
Self‑reported function improves:
Common CAI scales (e.g., CAIT, AJFAT) improved by roughly 3 points.
Why it matters: Symptom and confidence shifts often track return‑to‑run readiness better than isolated impairments.
Joint position sense and dorsiflexion ROM:
Within‑group improvements occurred, but did not beat controls convincingly.
Why it matters: If your goal is pure dorsiflexion gain (think stiff ankles, limited tibial progression) or fine proprioceptive acuity, PNF alone isn’t a lock—pair it with targeted mobility and sensorimotor retraining.
Persistence:
Some benefits held after treatment ended (limited follow‑up data).
Why it matters: Useful carryover, but true durability under running load remains under‑studied.
Strengths of the meta‑analysis
Broad database sweep (Western and Chinese literature) and RCT only inclusion raise confidence.
Methodological quality generally medium–high (PEDro ~7 average).
Sensitivity and subgroup analyses clarify that balance improvements are robust even when heterogeneous studies are trimmed.
Where to be cautious
Heterogeneity and mixed comparators:
“PNF” wasn’t one thing. Protocols varied (D2 flexion/extension patterns, rhythmic stabilisation, hold‑relax, combo with core/balance/conventional rehab), and controls ranged from no treatment to bike or standard rehab. The positive signal is real, but the “best” PNF recipe is unresolved.
Small effects on strength overall:
The strength win is modest and not seen in inversion/eversion, precisely the plane many runners sprain. If re‑sprain prevention is the target, you likely need more frontal‑plane loading than typical PNF provides.
ROM and JPS not superior to controls:
Gains did not clearly exceed standard care, suggesting PNF is not a standalone solution for mobility or proprioceptive acuity.
Athletic outcomes are indirect:
Balance tests and questionnaires improved, but return‑to‑running metrics, re‑sprain rates during sport, and performance outcomes (pace, ground contact time, variability) were largely not captured.
What this means for runners and clinicians
Use PNF as an accelerator, not a replacement:
Expect reliable improvements in dynamic balance, modest pain relief, and small plantar/dorsiflexion strength gains.
Don’t rely on PNF alone for inversion/eversion capacity, dorsiflexion ROM, or proprioceptive precision.
Build a CAI‑smart program around PNF
Foundation (2–3 weeks)
PNF lower‑limb patterns (e.g., D2 flexion/extension) 2–3x/week; rhythmic stabilization at end‑range.
Foot intrinsic activation (short‑foot, toe yoga); isometrics for invertors/evertors in sprain‑relevant positions.
Pain‑graded calf raises (straight and bent knee) for PF/DF strength; gait drills in stable footwear.
Progression (3–6 weeks)
Combine PNF with single‑leg balance progressions: SEBT/YBT practice, unstable but controllable surfaces, eyes‑closed trials.
Add frontal‑plane strength: inversion/eversion with bands, lateral step‑downs, Copenhagen side‑planks (ankle bias), lateral sled drags.
Mobility: dorsiflexion self‑mobilizations (knee‑to‑wall with banded talar glide), calf soft tissue work, loaded ankle dorsiflexion in split squat.
Return‑to‑run integration
Criteria: pain ≤2/10 during hops, symmetrical YBT composite within ~4% of the uninjured side, ≥25 single‑leg hops with stable landing.
Introduce run‑walk intervals, then cadence‑optimized easy runs; layer in hills last.
Sport‑specific perturbations: trail drills, lateral shuffles, cut‑and‑stick patterns, reactive cone work.
Programming tips
Dose: Most included PNF protocols used 2–3 sessions/week for 6–8 weeks; 15–20 minutes of targeted PNF within a 45–60 minute session plays well.
Pairing: PNF first (neuromotor priming), then balance and strength, finishing with plyo/light run prep.
Footwear/orthoses: For runners with repeated inversion, consider a slightly more stable shoe or subtle lateral posting during the return phase—while you build true frontal‑plane strength.
Track what matters: Use CAIT or AJFAT for symptoms, YBT/SEBT for control, and simple hop/stick tests. Re‑test every 2–3 weeks.
Bottom line
PNF is a useful, evidence‑supported component for CAI, with consistent gains in dynamic balance, modest pain reduction, and small strength benefits (chiefly PF/DF).
It likely won’t, by itself, solve the exact deficits that drive many running re‑sprains—limited dorsiflexion, weak/inhibited invertors/everters, and chaotic terrain reactions.
Best practice is PNF layered into a progressive, runner‑specific plan emphasising frontal‑plane strength, dorsiflexion mobility, and reactive single‑leg control.
What we still need from research
Standardised PNF protocols and dosing to identify the most effective elements.
Trials that report re‑sprain rates, time‑to‑return, and field performance metrics (not just lab balance tests).
Subgroup analyses for trail vs road runners, hypermobile vs stiff ankles, and history of high‑grade sprains.
Cost‑effectiveness vs other neuromotor strategies (e.g., balance training alone, perturbation‑based training, sensorimotor biofeedback).
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Citation
Yin Y, Wang J, Lin Q, Luo Y, Liu Y, Sun J. Effect of proprioceptive neuromuscular facilitation on patients with chronic ankle instability: A systematic review and meta-analysis. PLoS ONE. 2025;20(1):e0311355. doi:10.1371/journal.pone.0311355
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