Ankle sprain is a commonly encountered condition in clinical practice, constituting approximately 15-30% of all musculoskeletal injuries. Long-term studies have demonstrated that up to 73% of patients experience at least one more ankle sprain following an acute ankle sprain. Inadequate treatment of acute ankle instability can lead to chronic ankle instability (CAI) in 30-70% of cases.

Treatment approaches for CAI are classified into conservative and surgical methods. Typically, conservative treatment is initially employed to address proprioceptive deficits and static impairments. Passive, unidirectional treatments such as injections, electrotherapy, and ice, which do not target muscle strength, kinetic chain, tendon capacity, and cortical control, are reported to be insufficient or ineffective in treating CAI, relying solely on symptomatic relief. Therefore, therapeutic exercises are fundamental in CAI treatment, leading to positive developments in parameters such as strength, dynamic balance, functional status, quality of life, and injury risk. Among the most commonly used exercise approaches are proprioceptive and resistive exercises.

Upon reviewing the literature, it is observed that bipedal exercises have been employed from the early stages of CAI. However, due to clinical symptoms such as pain, insecurity, and fear associated with loading the affected limb, patients tend to avoid putting weight on the affected limb, resulting in the frequent use of bipedal exercises in the early phases of rehabilitation.

The aim of this study is to comparatively examine the effectiveness of unipedal exercise interventions used in the early stages of rehabilitation for individuals with CAI in terms of pain, functional stability, fear avoidance, disease severity, functional performance, balance, and patient satisfaction, in comparison to bipedal exercise interventions.

Voluntary participants who have been diagnosed with chronic ankle instability will be included in the study. Signed voluntary consent will be obtained from participants. Participants will be divided into two groups. The study groups will be as follows: a) early bipedal exercise group, b) late bipedal exercise group.

Inclusion Criteria:

• The documented unilateral ankle instability confirmed through clinical examinations (drawer test, talar tilt test) and MRI in cases requiring differential diagnosis.
• A history of an initial ankle sprain occurring at least 6 months ago.
• The presence of a recurrent sense of giving way that started at least 6 months ago and has been intermittently persistent.

Exclusion Criteria:

• Presence of a history of previous surgery in the lower extremity.
• Identification of organic and non-organic lesions such as cartilage injuries, periarticular tendon tears, and impingement syndromes.
• The existence of a fracture accompanying instability in the foot-ankle.
• Presence of congenital deformities in the foot-ankle.
• Diagnosis of talus osteochondral lesion.
• Diagnosis of ankle arthritis.
• Presence of medial ligament lesion.
• Existence of peripheral neuropathy.
• Presence of additional rheumatological diseases.
• Regular moderate-level exercise for at least 3 days a week in the last 6 months.

The assessor will not know which participant received which intervention.