Aim: The aim of this study is to conduct a Turkish cultural adaptation, validity, and reliability study of the Youth Activity Profile (YAP), developed to assess physical activity and sedentary behavior in a sample of individuals aged 12-17 years of Turkish descent.

Method: Online surveys will be distributed to participants through social media platforms, messages, and emails. Participants' demographic information will be obtained using an online assessment form prepared by the researchers. Subsequently, the Physical Activity Questionnaire for Adolescents (PAQ-A) will be used to determine the levels of physical activity. This survey will be completed by participants at a time convenient for them during the academic term. Following this, questions from the Youth Activity Profile (YAP) will be administered. Once the targeted number of participants is reached, the data collection process will be concluded, and the survey link will be deactivated.

Potential Outcomes: It is expected that this study will contribute to a better understanding of the health behaviors and physical activity trends of adolescents aged 12-17 years, thereby informing health policies.

Adolescence represents a critical developmental period during which individual lifestyle preferences and behavioral patterns are formed. According to the World Health Organization (WHO), the age range of 10-19 years is defined as the adolescent period. Regular physical activity (PA) is crucial for maintaining health during this period. WHO recommends that children and adolescents aged 5-17 years engage in moderate to high-intensity physical activity for at least 60 minutes a day. However, it is reported that globally, 80.3% of adolescents do not reach the recommended PA level. Studies have indicated an increase in the prevalence of diseases such as obesity, mental health problems, and hypertension during adolescence, highlighting the critical importance of physical activity during this phase. Therefore, accurate assessment of PA and sedentary behavior (SB) is essential. Self-report questionnaires, as subjective methods, provide an accurate and reliable means to define the PA/SB ratio and also offer a more cost-effective evaluation opportunity. It is believed that evaluating personal factors such as gender, age, and weight, along with contextual factors both in and out of school, is important in assessing the physical activity level and quality of adolescents.

Currently, there is no specific questionnaire validated and reliable in Turkish that covers the age range of 12-17 years for assessing PA and SB levels. Studies have shown that the methodological quality and validity of commonly used questionnaires to measure PA and SB in adolescents have some limitations. Therefore, further research is necessary to enhance and standardize surveys in this field in Turkey. These studies are crucial for better understanding the health behaviors and trends among young people and for guiding health policies.

The aim of this study was to conduct a Turkish cultural adaptation, validity, and reliability study of the Youth Activity Profile (YAP), developed to assess physical activity and sedentary behavior in adolescents within a sample of Turkish individuals aged 12-17 years.

Inclusion Criteria:

• Aged between 12 and 17
• Enrolled in primary or middle school
• Volunteering to participate in the study

Exclusion Criteria:

• Having any serious visual impairment or mental health problem
• Not having the ability to read and write in Turkish
• Having any orthopedic, neurological, or rheumatological disease that may affect physical activity levels

Healthy children aged between 12 and 17, both male and female, attending primary or middle school.

In order to determine the validity and reliability of the scale, the number of items of the tested scale was taken into consideration in determining the sample number to be included in the study (15 items in total). The number of volunteers was determined as ten times the number of items (150 participants) and 15 substitutes were added to the number of volunteers considering the drops and the number of the sample was determined as 165.