JMIR Publications

ABSTRACT

Background:

The numbers of overweight and obesity in adolescents continue to increase, and intervention programs are needed to promote physical activity in this population. However, this population is considered hard to reach in physical activity programs due to lack of adherence and poor results. Following the increase in the use of new technologies in the adolescent population after the pandemic, and the effectiveness of mobile phone interventions in the normal-weight adolescent population, this line of research may provide benefits in overweight or obese adolescents, although it is still unexplored in the scientific literature.

Objective:

For this reason, the objective of the present research was to evaluate the effects of a 10-week intervention using step tracker mobile apps in after-school physical education classes, on the physical activity, body composition, physical fitness, and psychological state of overweight or obese adolescents.

Methods:

The study is based on a randomized controlled trial (RCT) with an initial sample of 50 adolescents aged between 12 and 16 years old (from 1st to 4th Compulsory Secondary Education), whose body composition, physical activity level, physical condition, and psychological state were measured. Participants were divided into an experimental group (EG) and control group (CG), where the EG performed a series of walking steps in their free time outside physical education classes. A mobile application was selected for the intervention because it included numerous behavior change techniques. Adolescents in the control group continued to perform their physical activities as normal but did not use any mobile application. Inclusion in the intervention and control groups was randomized, and the researchers were blinded during the measurements as to which adolescents belonged to which group.

Results:

the results showed significant differences in the EG, with an increase in corrected arm girth (p=0.047), curl-up (p=0.015) and push-up (p=0.035) after the intervention. In the CG, the results showed a significant increase in hip girth (p=0.047), corrected thigh girth (p=0.043), and muscle mass (p=0.035), as well as a significant decrease in competence (p=0.028). And the covariate gender showed an effect on corrected arm girth (p=0.042), curl-up (0.039) and push-up (p=0.044) of the EG; while in the CG it affected corrected thigh girth (p=0.038), competence (p=0.039) and relatedness (p=0.047).

Conclusions:

A ten-week program of mobile application use by overweight and obese adolescents for practicing physical activity outside school hours could be effective in improving physical fitness and maintaining an adequate psychological state if it is promoted by the physical education school subject. Clinical Trial: the present research was pre-registered on ClinicalTrials.gov (code: NCT06089876).