The aim of this observational study was to evaluate the reliability and validity of the 6-minute pegboard and ring test (6PBRT) in patients with systemic sclerosis. The main question it aims to answer is:

- Is 6PBRT a valid and reliable method to assess upper extremity functional capacity in patients with systemic sclerosis? Participants will repeat the 6PBRT 2 times 1 hour apart. In addition, respiratory muscle strength (MIP-MEP), upper extremity muscle strength (hand dynanometer and hand-held dynanometer), muscle oxygen saturation (Moxy Monitor Device) will be evaluated.

Upper extremity functions are of great importance, especially activities of daily living. There are opinions that the impairment of the upper extremity in scleroderma is greater than that of the lower extremity and affects the functional status of individuals more. This activity limitation is related to many activities of daily living, including unsupported upper limb movements that lead to dyspnea and fatigue in patients with cardiopulmonary disease. Therefore, determining the strength, endurance and exercise capacity of the upper extremities is an important issue in scleroderma management. One of the tests that serves this purpose is the 6PBRT, which has been found to be valid and reliable in patients with chronic obstructive pulmonary disease and asthma.

It was planned as a non-interventional reliability study. The study will investigate the validity and reliability of 6PBRT in patients with scleroderma. In this context, a 1-hour rest break will be given after the first test. Dyspnea and fatigue will be assessed using the Borg scale and muscle oxygenation, heart rate and blood pressure will be recorded before and after 6PBRT. After the 1-hour rest period, the second trial of 6PBRT will be performed. The level of dyspnea and fatigue and initial values of heart rate will be checked before the second trial to ensure that patients are stable. All assessments will be performed by the same physiotherapist. In addition, participants will be assessed for respiratory muscle strength, upper limb muscle strength and muscle oxidation during the performance test.

The smallest sample size of the study was 40 subjects with a correlation coefficient of 0.95 between the two tests and 90% power at 95% confidence interval. 50 subjects are aimed to be recruited against a 20% drop-out risk. Shapiro-Wilk test and histogram plots will be used to check the normality of the data. Demographic and clinical characteristics of the participants will be reported using descriptive statistics. Two-way random effects and absolute agreement methods and intraclass correlation coefficient (ICC) will be used to assess test-retest reliability. Reliability strength will be interpreted as excellent for an ICC value >0.90. The 95% Confidence Interval (95% CI) will be calculated to investigate measurement variability.

Inclusion Criteria:

• Being between the ages of 18-75
• 2013 To be diagnosed with systemic sclerosis according to ACR/EULAR classification criteria
• Being clinically stable
• Ability to adapt to tests (visual, cognitive, cooperative)

Exclusion Criteria:

• Those with neurological and/or musculoskeletal problems that may affect the work
• Presence of severe joint contracture or painful ulcers that may affect muscle strength measurement and walking
• Presence of severe infection or sepsis
• Being diagnosed with a known additional rheumatologic disease
• Any stage of cancer
• Pregnant or breastfeeding

The study will be conducted at Selçuk University, Faculty of Health Sciences. The study will include volunteer individuals with systemic sclerosis who are eligible to participate in the study and who are being followed up and treated with a diagnosis of scleroderma in the Department of Rheumatology.

-- Purposive sampling