We explored peer acceptance and friendships during adolescence, and their relationship with subsequent changes in the level of adolescents' academic achievement. Participants were 447 students (51% girls) aged from 11 to 16 years. The students completed sociometric assessments of their peer acceptance and friendships during the autumn semester (Time 1). Academic achievement data were also obtained from students' report-card grades at Time 1 as well as during the spring semester (Time 2) of the same academic year. Regression analysis indicated that peer acceptance positively predicted subsequent academic achievement. This relationship was also moderated by age, with the effect of peer acceptance on subsequent academic achievement being greater during early adolescence than in midadolescence. This research deepens understanding of the mechanisms by which positive peer relationships influence adolescents' academic achievement.

The recent pandemic has influenced teachers’ mental health and well-being. The present work follows the Job-Demands-Control model, analyzing changes in the demands, control, and social support during COVID-19, and how they influence job satisfaction, emotional exhaustion, depersonalization, and personal accomplishment among school teachers. The sample comprised 172 school teachers. The instruments applied were The Maslach Burnout Inventory (MBI), The Job Satisfaction Teacher Index (Organization for Economic Cooperation and Development (OECD), 2014), and The Demand Control Support Questionnaire (DCSQ). Job satisfaction was predicted exclusively by social support, revealing the importance of social interactions at work. Emotional exhaustion and depersonalization were predicted by job demands, showing that an increase in job demands (i.e., COVID) affects individuals’ feelings of burnout. The results show that it would be interesting to design strategies that guarantee job control in the teaching context. This would open multiple pathways to implement healthier methodological processes for teachers and the consequent research to support these processes.

The current scientific literature has shown significant disparity in results when physical activity is linked to academic achievement among adolescents. Thus, the main objectives of this study were (1) to analyze the relationship among students’ academic achievement, intention to be physically active, and physical activity levels depending on the country (Spain or Chile), as well as to analyze these relationships based on students’ socio-economic status, type of school, school year, gender, and body mass index; and (2) to analyze the differences between all these variables depending on the students’ country and gender. In total, 3052 adolescents participated in the research (14.58 ± 1.39 years): 734 Chilean students (336 males and 398 females) and 2318 Spanish students (1180 males and 1138 females). Various questionnaires were used to measure the study variables. The results revealed significant relationships between academic achievement and the rest of the variables in Spanish adolescents, but in the Chilean population, academic achievement was significantly related only to socio-economic status and the type of school. Moreover, Spanish students obtained higher scores, especially the males, except for academic achievement, which was higher in females. There were also significant differences in academic achievement, intention to be physically active, physical activity levels, and socio-economic status depending on the country, with all scores being higher in Spain. Given the results, the country seems to be an important factor when comparing academic achievement and physical activity levels, besides other demographic variables.