The 6-Minute Walk Test (6MWT) is a widely used field test for assessing functional exercise capacity, walking endurance, and submaximal performance related to activities of daily living. However, in conventional applications, environmental conditions, observer-related differences, and standardization issues may lead to variability in measurement outcomes. In addition, evaluating only the total walking distance may not adequately reflect clinically important changes such as performance decline and walking-related motor fatigue occurring during the test.

For this reason, recent studies have recommended analyzing 6MWT data by dividing the test into minute-by-minute segments and using performance change metrics such as the Distance Walked Index (DWI). These approaches allow a more detailed evaluation of changes in walking performance throughout the test duration.

With advances in measurement technologies, mixed reality (MR)-based applications have attracted attention as a means of enabling more objective, standardized, and reproducible implementation of conventional clinical tests. MR technology allows users to maintain interaction with the real environment while receiving digital guidance and feedback, thereby providing a safe and standardized assessment setting. Nevertheless, evidence regarding the validity and reliability of mixed reality-based adaptations of the 6MWT, particularly in asymptomatic adults, remains limited.

The aim of this study is to evaluate the criterion validity and test-retest reliability of a mixed reality-based 6-Minute Walk Test (MR-6MWT) developed using the Meta Quest 3 and Unity platform. In addition, convergent validity will be examined by analyzing the relationships between total walking distance, minute-by-minute performance changes, fatigue effect (%), and outcomes of the 4-Meter Walk Test, Timed Up and Go Test, and knee extensor muscle strength.

The findings of this study are expected to contribute to the development of a more objective, standardized, and digitally based mixed reality adaptation of the 6MWT. Furthermore, the results may provide a scientific foundation for future remote assessment and digital monitoring applications.

Inclusion Criteria:

• Aged between 18 and 65 years,
• Asymptomatic, with no known or active cardiopulmonary, neurological, or musculoskeletal disease-related symptoms,
• Ability to ambulate independently without the use of an assistive device,
• Visual, auditory, and vestibular functions sufficient to tolerate mixed reality applications,
• Cognitive ability sufficient to understand and follow test instructions,
• Ability to read, understand, and follow instructions in Turkish,
• Willingness to participate voluntarily in the study and provision of written informed consent.

Exclusion Criteria:

• Inability to safely complete walking tests due to serious musculoskeletal conditions (e.g., recent fracture, severe arthritis, advanced osteoarthritis, significant muscle or tendon injury),
• Presence of severe cardiopulmonary disease or any medical condition that may pose a risk during exercise testing (e.g., uncontrolled hypertension, heart failure, severe arrhythmia history, chronic obstructive pulmonary disease),
• High risk of balance loss or spatial disorientation in the mixed reality environment due to vestibular, visual, or auditory impairments,
• History of epilepsy or neurological conditions contraindicating mixed reality or head-mounted device use,
• Severe migraine, significant motion sickness history, or high risk of dizziness/nausea during mixed reality applications,
• Cognitive impairment or severe psychiatric conditions preventing understanding or completion of test procedures,
• Insufficient motivation or cooperation that may interfere with safe participation in the study.

Asymptomatic adults aged 18-65 years who are able to ambulate independently and tolerate mixed reality applications, with no known cardiopulmonary, neurological, or musculoskeletal conditions affecting walking performance or functional exercise capacity.