2.3. Measurements
SECONDARY, CHILDHOOD OBESITY
Parents answered a questionnaire adapted from a validated Activity and Inactivity of Mexican Students (CAINM) questionnaire [The parents stated the type of exercise or sports activities performed by their children outside of school activities, the frequency (days per week), and the average duration of each session. This information was analyzed based on the categories of PA and type of moderate or intense exertion according to the Youth Compendium of Physical Activities developed by the Youth Energy Expenditure Workgroup of the National Collaborative on Childhood Obesity Research (NCCOR) in the United States [If the activity reported by the parents corresponded to a METy value ≥3.0 (for example, soccer, swimming, or basketball), it was considered to be within the category of moderate and vigorous PA (MVPA). The minutes involved in these activities were added to obtain the total weekly value of AFMV minutes. Additionally, a dichotomous variable was generated to identify whether or not participants performed some MVPA weekly. Likewise, the total PA time (TPA) was calculated by adding the MVPA time and time spent involved in light-intensity PA (e.g., walking). PA performed during physical education class (50 min weekly), which was part of the school curriculum, was not included, because the children in the control and intervention group had the same time dedicated to physical activity in a week within school hours.The time-in-front-of-a-screen variable was constructed to assess the sedentary behavior of the children. The daily amount of time that participants spent watching or looking at TVs, computers, video games, and cell phones were added. A dichotomous variable was also generated that identified whether schoolchildren spent ≤120 min/d or >120 min/d of screen time [Additionally, sociodemographic characteristics were recorded in a questionnaire at the beginning of the study. The educational level of mothers was categorized as primary or secondary education, preparatory or technical school, and university or postgraduate degree. The socioeconomic level was constructed based on information on the assets that the family owned in their home (e.g., telephone, internet, washing machine, car, etc.). It was analyzed using principal components analysis, and a score was obtained according to the number of assets [Anthropometric measurements were made at the beginning of the study in accordance with international procedures [