Impact of chronic ankle instability on gait loading strategy: a comparative study

Key points

1. 01Most walking loading measures (stance time, weight acceptance time, medial and lateral foot load, forefoot load) showed no significant difference between groups.
2. 02The only significant difference was higher load over the lateral rearfoot in the chronic ankle instability group (p = 0.017).
3. 03The overall multivariate test found no significant difference in gait loading strategy between groups (p = 0.404).
4. 04The extra outer-heel loading may reflect a laterally deviated center of pressure and greater inversion in early stance, a vulnerable moment beyond conscious control.
5. 05Authors suggest clinicians target rearfoot inversion and consider gait reeducation and foot orthoses, while noting the finding could be a cause or a consequence of instability.

How it was conducted

Design

Prospective observational comparative study (NCT05703828), barefoot walking at self-selected speed

Participants

56 male subjects: 28 with unilateral chronic ankle instability (age 24.79 +/- 2.64) and 28 healthy controls without ankle sprain history (age 24.57 +/- 1.17)

Measurement

FREEMED baropodographic platform with FREESTEP software (400 Hz); mean of three successful footprints per participant

Outcomes

Stance time, weight acceptance time, and load distribution across medial foot, lateral foot, medial forefoot, lateral forefoot, medial rearfoot, and lateral rearfoot

Analysis

MANOVA comparing the affected foot of the instability group with the right foot of controls; significance set at p <= 0.05

What they found

• Overall MANOVA showed no significant difference in gait loading strategy between groups (Wilks' Lambda = 0.847, F = 1.064, p = 0.404).
• Load over the lateral rearfoot was significantly higher in the instability group: 17.67% +/- 3.14 versus 15.56% +/- 3.27 in controls (p = 0.017).
• Stance time did not differ: 725.11 +/- 79.63 msec versus 719.32 +/- 67.59 msec (p = 0.771).
• Weight acceptance time did not differ: 172.18 +/- 66.01 msec versus 181.64 +/- 83.94 msec (p = 0.641).
• Load over medial foot (47.31% vs 46.24%, p = 0.441), lateral foot (52.58% vs 53.70%, p = 0.423), medial rearfoot (16.38% vs 16.52%, p = 0.858), medial forefoot (26.49% vs 26.95%, p = 0.589), and lateral forefoot (23.04% vs 23.54%, p = 0.609) all showed no significant difference.
• Groups were well matched on age, height, weight, and BMI (Wilks' Lambda = 0.979, F = 0.270, p = 0.896).

Limitations

• Only one of eight outcomes reached significance and the overall multivariate test was non-significant, so the single positive finding may be a chance result.
• Small single-center sample of only young adult males, so results may not generalize to women or other age groups.
• Observational design cannot establish whether altered loading is a cause or a consequence of chronic ankle instability.
• The study did not measure lower limb muscle activity or joint angles, limiting biomechanical interpretation.

Why it matters

For patients

If you have chronic ankle instability, your overall walking pattern is likely close to normal, though you may put slightly more weight on the outer heel as your ankle compensates.

For clinicians

Consider addressing rearfoot inversion through gait reeducation and possibly foot orthoses, while recognizing the evidence for altered loading is a single isolated finding.

For readers

This small observational study found mostly similar gait loading in people with chronic ankle instability, with one isolated difference in lateral rearfoot loading that warrants cautious interpretation.