The assessment of physical fitness in children is crucial for promoting health and preventing obesity-related issues. One of the popular methods for evaluating cardiovascular endurance is the 2min step test, which measures how effectively a child can perform a stepping exercise over a defined duration. The 2 Minute Step Test (2MST) is a simple, cost-effective measure of cardiovascular endurance, often utilized in pediatric populations. Understanding the Reliability and validity of this test is particularly important when considering variations in body composition among children, as differences in fat mass and lean body mass can influence performance outcomes and health implication. To assess the Validity and Reliability of the 2MST in children with varying body compositions, including those classified as normal weight, overweight, and obese. A sample of 360 children aged 6 to 12 years will be recruited and characterized based on their Body Mass Index (BMI). Each participant will undergo the 2MST twice, with performance measured in the number of steps completed in two minutes. Subjects will be recruited based on inclusion criteria. The 2 Min Step test will be conducted, we will count the maximum number of knee elevations that the individual can perform in 2 minutes, in which the minimum height occurs at a midpoint of the distance between the patella and the anterior superior iliac spine (during a stationary gait, without displacing the body). The data will be analyzed by using SPSS software (Statistical Package for Social Sciences version 20.0). To check the normality, Kolmogorov test will be applied as sample size estimated is 360.