Both PNF training and strength-plus-balance training improved ankle function in habitually active adults with FAI, but PNF training demonstrated superior improvements in overall balance while strength-plus-balance training was more effective in enhancing ankle inversion strength.
Key Findings
Results
PNF training produced significantly greater improvements in Cumberland Ankle Instability Tool (CAIT) scores compared to strength-plus-balance training after 8 weeks.
A significant group × time interaction was observed for CAIT scores (p < 0.001)
PNF training group improved from 13.00 ± 2.48 to 24.07 ± 3.53
Strength-plus-balance training group improved from 13.47 ± 2.45 to 20.13 ± 2.72
Both groups started with similar baseline CAIT scores, indicating comparable severity of FAI at enrollment
68 habitually active adults with FAI were randomized across the two groups
Results
PNF training produced greater gains in overall balance ability as measured by the Star Excursion Balance Test (SEBT) compared to strength-plus-balance training.
The SEBT was used as an outcome measure to assess overall balance ability
PNF training group demonstrated superior improvements in overall balance ability after the 8-week program
Both groups underwent the same 8-week rehabilitation program duration
Lower limb stability tests were also included among the outcome measures
Results
Strength-plus-balance training was more effective than PNF training for enhancing ankle inversion strength.
The group × time interaction for ankle inversion strength favored the strength-plus-balance training group (p = 0.039)
Ankle muscle strength assessments were conducted before and after the intervention
This finding suggests differential effects of the two training modalities on specific strength components
The result indicates strength-plus-balance training may be preferable when the therapeutic goal is improving ankle inversion strength
Results
Both rehabilitation programs improved ankle function in habitually active adults with functional ankle instability over 8 weeks.
68 habitually active adults with FAI were randomly assigned to either PNF training or strength-plus-balance training
Outcome measures included CAIT scores, lower limb stability tests, SEBT, and ankle muscle strength assessments
Assessments were conducted at baseline and after the 8-week intervention
Both groups showed improvements across multiple outcome measures, indicating general efficacy of both approaches
The study was registered at ClinicalTrials.gov (NCT06308809)
Conclusions
The study identified differential therapeutic profiles for PNF versus strength-plus-balance training, suggesting clinicians should select rehabilitation strategies according to specific therapeutic goals.
PNF training was superior for overall balance improvement
Strength-plus-balance training was superior for ankle inversion strength enhancement (p = 0.039)
The authors suggest these findings 'may assist clinicians in selecting rehabilitation strategies according to specific therapeutic goals'
FAI is described as common among habitually active adults and associated with recurrent sprains, reduced athletic performance, and long-term joint dysfunction
What This Means
This research suggests that two different types of exercise programs can help people with functional ankle instability (FAI) — a condition where the ankle repeatedly gives way or feels unstable, common in physically active people. The study randomly assigned 68 habitually active adults with FAI to either proprioceptive neuromuscular facilitation (PNF) training (which uses patterns of movement and muscle contractions to improve coordination and neuromuscular control) or a combined strength-and-balance training program. Both groups trained for 8 weeks and were tested on measures of ankle stability, balance, and muscle strength before and after the program.
Both programs led to meaningful improvements in ankle function as measured by a standard questionnaire called the Cumberland Ankle Instability Tool (CAIT). However, the PNF training group showed larger overall gains in CAIT scores and performed better on a balance test called the Star Excursion Balance Test. On the other hand, the strength-plus-balance group showed greater improvement specifically in ankle inversion strength (the ability to resist the ankle rolling inward), which is a common mechanism of ankle sprains.
This research suggests that both training approaches are valid options for rehabilitating functional ankle instability, but they have different strengths. If the primary goal is improving overall balance and ankle stability, PNF training may be the better choice. If building specific inversion muscle strength is the priority — for example, to protect against ankle rolling — a strength-focused program may be more effective. These findings could help physical therapists and rehabilitation specialists tailor their treatment plans to individual patient needs and goals.
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Liao W, Xu S, Wang R, Zhang J. (2026). The interventional effects of PNF training on functional ankle instability in habitually active adults.. Frontiers in public health. https://doi.org/10.3389/fpubh.2026.1923487