The Effects of Stroboscopic Visual Conditions on Gait and Lower Limb Muscle Activity in Individuals With Chronic Ankle Instability
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In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: Stroboscopic Visual Conditions.
- Who it may be relevant to
- Registry conditions: Chronic Ankle Instability. Basic parameters: 18 years — 45 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- South Korea
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
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Overview
This interventional study will investigate the effects of stroboscopic visual conditions on gait patterns and lower limb muscle activation in adults with chronic ankle instability (CAI). CAI often results in impaired sensorimotor control, leading to altered gait strategies such as slower walking speed, shorter step length, and increased visual reliance. Stroboscopic glasses intermittently restrict visual input, potentially reducing visual dependence and enhancing proprioceptive feedback. Participants will complete walking trials under three randomized visual conditions: high-frequency stroboscopic, low-frequency stroboscopic, and no-glasses control. Gait parameters will be measured using the GAITRite system, and surface electromyography (sEMG) will record activation of the tibialis anterior, peroneus longus, and gastrocnemius muscles. Findings may provide insight into sensorimotor adaptation mechanisms and inform rehabilitation strategies to improve functional stability in individuals with CAI.
Detailed description
Chronic ankle instability (CAI) is a frequent outcome after ankle sprains, characterized by recurrent giving-way episodes, pain, and functional limitations. Approximately 40% of individuals with ankle sprains develop CAI, which is associated with deficits in proprioception, neuromuscular coordination, and postural stability. Increased visual reliance is a common compensatory strategy, but this can impair balance and gait when visual input is limited, raising the risk of re-injury.
Stroboscopic glasses alternate between transparent and opaque states, intermittently restricting visual information. This challenges the sensorimotor system, potentially reducing visual dependence and enhancing proprioceptive engagement. Prior research has shown benefits for static and dynamic balance, but little is known about effects on walking in CAI populations.
This randomized crossover study will assess the impact of high-frequency and low-frequency stroboscopic visual conditions compared with normal vision on gait and lower limb muscle activation in CAI. Adults aged 18-45 years with CAIT scores \< 24 and a history of ankle instability within 6 months will be recruited. Exclusion criteria include recent lower limb surgery/fracture, systemic conditions affecting balance, or inability to follow instructions.
Participants will perform walking trials on a 5-meter GAITRite walkway under three randomized visual conditions:
1. High-frequency stroboscopic (rapid alternation) 2. Low-frequency stroboscopic (slower alternation) 3. No-glasses control (normal vision)
Gait parameters (step length, step time, gait velocity, swing/stance phases) will be measured, and sEMG (Noraxon) will assess activation of the tibialis anterior, peroneus longus, and gastrocnemius, normalized to MVIC. Subjective measures include CAIT, FAAM, IdFAI, and VAS pain scores.
It is hypothesized that stroboscopic conditions will produce measurable changes in gait and muscle activity compared with control, reflecting adaptive sensorimotor strategies that can inform rehabilitation programs to improve stability, mobility, and reduce re-injury risk.
Interventions
- Behavioral Stroboscopic Visual Conditions
Participants will perform walking trials under three visual conditions: high-frequency stroboscopic glasses, low-frequency stroboscopic glasses, and no-glasses control. Each participant will complete three 5-meter walking trials per condition, with the order of conditions randomized. Gait parameters will be recorded using the GAITRite walkway system, and muscle activity will be measured using surface electromyography.
Primary outcome measures
- Change in Gait Velocity (cm/s) Under Different Stroboscopic Visual Conditions [Time frame: Day 1 (single experimental session; immediately after each walking condition)]
Secondary outcome measures (12)
- Change in Step Length (cm) Under Different Stroboscopic Visual Conditions [Time frame: Day 1 (single experimental session; immediately after each walking condition)]
- Change in Step Width (cm) Under Different Stroboscopic Visual Conditions [Time frame: Day 1 (single experimental session; immediately after each walking condition)]
- Change in Swing Phase (%) Under Different Stroboscopic Visual Conditions [Time frame: Day 1 (single experimental session; immediately after each walking condition)]
- Change in Single Limb Support (%) Under Different Stroboscopic Visual Conditions [Time frame: Day 1 (single experimental session; immediately after each walking condition)]
- Change in Double Limb Support (%) Under Different Stroboscopic Visual Conditions [Time frame: Day 1 (single experimental session; immediately after each walking condition)]
- Change in Tibialis Anterior Muscle Activation (%MVIC) Under Different Stroboscopic Visual Conditions [Time frame: Day 1 (single experimental session; immediately after each walking condition)]
- Change in Peroneus Longus Muscle Activation (%MVIC) Under Different Stroboscopic Visual Conditions [Time frame: Day 1 (single experimental session; immediately after each walking condition)]
- Change in Gastrocnemius Muscle Activation (%MVIC) Under Different Stroboscopic Visual Conditions [Time frame: Day 1 (single experimental session; immediately after each walking condition)]
- Correlation Between Foot and Ankle Ability Measure - ADL Subscale (FAAM-ADL) Score and Gait Velocity (cm/s) [Time frame: Day 1 (questionnaire administered before walking tasks)]
- Correlation Between Foot and Ankle Ability Measure - Sports Subscale (FAAM-Sports) Score and Gait Velocity (cm/s) [Time frame: Day 1 (questionnaire administered before walking tasks)]
- Correlation Between Identification of Functional Ankle Instability (IdFAI) Score and Gait Velocity (cm/s) [Time frame: Day 1 (questionnaire administered before walking tasks)]
- Correlation Between Visual Analogue Scale (VAS) Pain Score and Gait Velocity (cm/s) [Time frame: Day 1 (questionnaire administered before walking tasks)]
Eligibility criteria
Inclusion criteria
- Individuals with a Cumberland Ankle Instability Tool (CAIT) score of less than 24
- Individuals diagnosed with ankle sprain or instability within the past 6 months
Exclusion criteria
- Individuals who have undergone lower limb surgery or experienced a fracture due to ankle trauma within the past 6 months
- Individuals with systemic diseases, such as cardiovascular disorders, that may affect balance
- Individuals who have difficulty understanding or following instructions during assessment or training
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: No
Study design
- Allocation
- N/A
- Model
- Single group
- Masking
- Open label
- Primary purpose
- Basic science
Study locations
South Korea · 1 center
- Sahmyook University — Seoul
Identifiers
NCT: NCT07134829 · SYU 2025-06-026-002