Studies examining musculoskeletal strength, respiratory function and muscle strength, physical activity level and exercise capacity in children with CKD and evaluating the relationships between these parameters have not been found both in the world and in our country. In this study, it is aimed to evaluate skeletal and respiratory muscle strength, respiratory parameters and exercise capacity in children with CKD primarily and compare them with healthy children. Secondly, it is to examine the relationship between endothelial function, arterial stiffness, sarcopenia and physical activity in children with CKD. It is thought that the results to be obtained with the study will support the literature with the prediction that rehabilitation programs for patients in all stages of CKD will be structured and in this way will contribute positively to the management and prognosis of the disease.

Hypotheses H0: There is no difference between children with chronic kidney disease and healthy children in terms of skeletal and respiratory muscle strength, respiratory parameters and exercise capacity.

H1: There is a difference between children with chronic kidney disease and healthy children in terms of skeletal and respiratory muscle strength, parameters and exercise capacity.

H0: There is no relationship between endothelial function, arterial stiffness, sarcopenia and physical activity in children with chronic kidney disease.

H1: There is a relationship between endothelial function, arterial stiffness, sarcopenia and physical activity in children with chronic kidney disease.

Children who applied to Gazi University, Faculty of Medicine, Department of Pediatrics, Department of Pediatric Nephrology and met the specified inclusion criteria will be included in our study. Patients will be referred to Hacettepe University, Faculty of Physical Therapy and Rehabilitation, Department of Physiotherapy and Rehabilitation, Cardiopulmonary Rehabilitation Unit after the routine evaluations including demographic and clinical characteristics, laboratory tests and anthropometric measurements are completed. Here, patients will be evaluated with physical therapy and rehabilitation measurement and evaluation methods such as muscle strength, exercise capacity and physical activity. The healthy control group will be formed by inviting the healthy relatives of the patients who applied to our faculty to participate in the study. After obtaining informed consent, healthy children will be evaluated.

Details of Working Method For each child with chronic kidney disease, age, gender, body weight, height, systolic and diastolic blood pressure, and results of routine blood tests (complete blood count test parameters: hemoglobin, hematocrit, erythrocyte, leukocyte and platelet count) biochemistry test parameters (blood sugar, blood urea nitrogen, creatinine, uric acid, sodium, potassium, chlorine, calcium, phosphorus, alkaline phosphatase, total protein, albumin, alanine aminotransferase, aspartate aminotransferase, triglyceride, total cholesterol, high-density lipoprotein, low-density lipoprotein levels , venous blood pH and bicarbonate etc. values), ferritin, parathormone, 25 hydroxy vitamin D level) will be recorded. The age at diagnosis, duration and etiology of the disease, current treatment information and drugs used will be recorded. Body composition data will also be recorded for children with CKD. Bone mineral density parameters in the last six months, left ventricular mass index values in the last three months, 24-hour blood pressure monitoring (ABPM) in the last month, and heart rate measured on the same device are used in the follow-up of the patients. wave velocity (pulse wave velocity-PWV) evaluation results will be used, if there is none, ABPM and PWV will be performed again. After these evaluations, parameters such as skeletal muscle strength, respiratory muscle strength, and exercise capacity will be evaluated in both the patient group and healthy children, and the obtained data will be compared. In addition, the relationship between parameters such as complete blood count parameters, biochemistry test parameters, routine bone markers, BMD, heart and vascular function evaluations and parameters such as skeletal and respiratory muscle strength, exercise capacity, and physical activity level will be examined in children with CKD. In case of adequate data, children with CKD will be subgrouped according to disease stage and assessment data will be analyzed by subgroups.

Group: CKD group

Inclusion Criteria for Volunteers (Inclusion Criteria):

• 6-18 age range,
• According to the Chronic Kidney Disease Assessment and Classification Guide prepared by the National Kidney Foundation- Kidney Disease Outcomes Quality Initiative (NKF-KDOQI); Stage 2, glomerular filtration rate 60-89 ml/min/1.73 m2, Stage 3, glomerular filtration rate 30-59 ml/min/1.73 m2, Stage 4, glomerular filtration rate 15-29 ml/min/1.73 m2,
• Presence of kidney transplantation was determined as inclusion criteria.

Exclusion Criteria for Volunteers:

• acute infection,
• Ongoing dialysis,
• Congenital heart disease,
• Hypertension that cannot be controlled with dual antihypertensive medication,
• Neurological and/or genetic musculoskeletal disease,
• The presence of orthopedic and cognitive problems that prevented the tests from being performed were determined as exclusion criteria.

Group: Control Group

Inclusion Criteria for Control Volunteers:

• Not have cardiovascular, neurological and/or genetic musculoskeletal disease
• Not having orthopedic and cognitive problems that prevent testing
• The patient's and/or family's willingness to participate in the study

Children who applied to Gazi University, Faculty of Medicine, Department of Pediatrics, Department of Pediatric Nephrology and met the specified inclusion criteria will be included in our study. Patients will be referred to Hacettepe University, Faculty of Physical Therapy and Rehabilitation, Department of Physiotherapy and Rehabilitation, Cardiopulmonary Rehabilitation Unit after the routine evaluations including demographic and clinical characteristics, laboratory tests and anthropometric measurements are completed. Here, patients will be evaluated with physical therapy and rehabilitation measurement and evaluation methods such as muscle strength, exercise capacity and physical activity. The healthy control group will be formed by inviting the healthy relatives of the patients who applied to our faculty to participate in the study. After obtaining informed consent, healthy children will be evaluated.