This study investigates the difference in dynamic Q-angle of patients with chronic ankle instability and those without.

Inclusion criteria:

• Subjects aged between 18 and 30 years.
• Subjects with a history of LAS for at least one year before the study onset, that required at least 1-day weight-bearing restriction.
• Subjects with a self-reported tendency of ≥2 giving way episodes during 6 months before enrollment in the study.
• Subjects with a perception that the injured ankle was chronically weaker, more painful, and/or less functional than the contralateral ankle before the first LAS.
• Subjects who scored less than 24 in the Cumberland Ankle Instability Tool (CAIT), a validated ankle instability specific questionnaire of 9 items, to determine if functional ankle instability is present.

Exclusion criteria

• Subjects who had bilateral LAS
• Subjects with a history of lower extremity injury, fracture, or surgery
• Subjects who participated in supervised or unsupervised ankle rehabilitation within a year before enrollment in the study
• Subjects with LAS within 3 months before participation
• Subjects with a history of knee pain during the last 6 months.
• Subjects diagnosed with knee osteoarthritis.

The participants from both genders aged between 18 and 30 years will be divided into 2 groups: a study group and a control group. The study group consists of 52 participants with chronic ankle instability, and the control group consists of 52 participants without chronic ankle instability, normal participants with no musculoskeletal disorders or history of knee disease and no obvious limb length discrepancy.