JMIR Publications

ABSTRACT

Background:

It is not known whether interventions that promote physical activity in adolescents from physical education classes can create a healthy walking habit, which would allow further improvements to be achieved after the mandatory and promoted intervention has been completed.

Objective:

The aims of the research were to analyze if, after a period of mandatory and promoted use of a step tracker mobile app in physical education classes, adolescents continue to use it when its use is no longer mandatory and promoted; and to determine whether there are changes in the level of physical activity, body composition, and fitness of adolescents when the use of the app is mandatory and promoted from the physical education subject, and when it is neither mandatory nor promoted, and whether maturity status, gender, or the apps used can have an influence.

Methods:

A total of 376 students in mandatory secondary education (mean age: 13.92±1.91 years old) participated in the study. A randomized controlled trial was conducted consisting of two consecutive 10-week interventions. The physical activity level, body composition, and fitness were measured at baseline (T1), after ten weeks of mandatory and promoted use of the apps (T2), and at the end of the ten weeks of non-mandatory and non-promoted intervention (T3). The experimental group (EG) used one of the mobile step-tracking apps after school hours.

Results:

The results showed that when the use of mobile applications was neither mandatory nor promoted in physical education, very few adolescents continued to walk (n=18; 8.5%). After the mandatory and promoted intervention (T1 vs T2), a decrease in the sum of 3 skinfolds (Mean diff.: 1.679; P=.02), as well as an improvement in the level of physical activity (Mean diff.: -0.170; P<.001), VO2 max. (Mean diff.: -1.006; P<.001), countermovement jump (Mean diff.: -1.337; P=.04), curl-up (Mean diff.: -3.791; P<.001), and push-up (Mean diff.: -1.920; P<.001) in the EG was recorded. However, the changes between T1 and T2 were significantly greater in the EG as compared to the control (CG) only in the level of physical activity and curl-up performance. Thus, when comparing the measurements taken between T1 and T3, there were no significant changes in the variables analyzed between the EG and CG (P=.07-0.84). The covariates maturity status, gender, and app used showed a significant effect in most of the analyses performed.

Conclusions:

A period of mandatory and promoted use of mobile apps benefited the variables of body composition and fitness of adolescents, but did not create a healthy walking habit in this population, so that when the use of these apps ceased to be mandatory and promoted, the effects obtained disappeared. Clinical Trial: the present research was pre-registered on ClinicalTrials.gov (registration code: NCT06164041).