Biomechanics and Intrinsic Foot Muscle Roles in Subjects With Chronic Ankle Instability

The current study involves a prospective interventional study that primarily intends to compare foot joint loadings of participants with chronic ankle instability (CAI) with those of subjects who recovered after an ankle sprain (LAS copers) and healthy controls during running and more challenging tasks. This study further aims to explore the impact of foot muscle properties and fatigue on the same biomechanical outcomes. Therefore, the investigators will recruit 72 participants (24 per group) aged from 18 to 44 years. Each of them will come only once to the CMAL laboratory (UZ Leuven, Pellenberg).


Eligibility Criteria:
Three groups of participants : Chronic ankle instability, lateral ankle sprain copers and healthy controls.

INCLUSION CRITERIA:

1. For all three groups :

   * Physically active male subjects between 18 and 44 years of age
   * Able to run at low speed.
   * For homogeneity purposes, the investigators will only recruit subjects who perform a regular physical activity on a weekly basis, including competition participation.
2. Chronic ankle instability :

   * A history of at least one significant ankle sprain that occurred at least 12 months before study enrolment, associated with inflammatory symptoms, creating at least 1 interrupted day of desired physical activity;
   * The most recent injury occurred more than 3 months prior to study enrolment;
   * At least two episodes of giving way in the 6 months prior to study enrolment, recurrent sprain, and/or "feelings of instability"; and
   * Poor disability status according to the Cumberland Ankle Instability Tool (CAIT) (score ≤ 24/30).
3. Lateral ankle sprain copers :

   * A history of one significant ankle sprain that occurred at least 12 months before study enrolment, associated with inflammatory symptoms, creating at least 1 interrupted day of desired physical activity;
   * A return to at least moderate levels of weight-bearing physical activity less than 12 months after initial sprain without recurrent injury, episodes of giving way, and/or feelings of instability;
   * Minimal, if any, level of self-reported disability (CAIT score ≥ 28/30); and
   * Minimal, if any, alteration in self-reported function (ADL- and Sport-subscales ≥95%).
4. Healthy controls :

   * The same inclusion criteria as the LAS coper group, with the exception reported in the exclusion criteria.

EXCLUSION CRITERIA:

1. For all three groups :

   * Being younger than 18 years
   * Any medical contraindication to physical exertion,
   * Any systemic or neurological disease,
   * A recent surgery,
   * A difference in leg length of more than 3 cm,
   * Pregnancy,
   * A body mass index higher than 30kg/m² (due to less accurate motion analysis by absence of anatomical landmarks).
   * LAS copers and controls will also be excluded if: constant or intermittent ankle pain, ankle fractures, or surgeries, and recent participation in a physical revalidation programme.
   * Healthy participants must never have suffered an inversion trauma resulting in disability.
2. For healthy controls : the healthy control subjects may not have suffered from an ankle sprain.