It is a meta-analysis, so the limitations are those of the studies used for the meta-analysis. Although methodologically sound, the studies on which it is based are small. Moreover, it is very difficult to conduct these studies in a blinded fashion, so they have a significant bias. Even so, the results are in line with common practice and previous studies that can be extended to adults. 

Moderate physical exercise is a protective factor for the development of mental disorders such as anxiety and depression, and once these disorders are present, it accelerates improvement when combined with different treatments indicated with scientific evidence. One factor to take into account that introduces a bias is that people with depression who do sport have a higher degree of motivation, so it is not possible to infer direct causality between sport and improvement in depression.  

Even so, and bearing in mind that depression is a whole-body illness, physical exercise is an important aid that clinicians use in our routine practice with patients.