The present research aims to examine the relationship between the four dimensions of sedentary behaviours and academic performance, as well as to test the association between sedentary behaviours and academic performance in boys and girls in a sample of Spanish adolescents. A total of 2,216 adolescents aged 11 to 16 years old, both males (13.30 ± 0.92) and females (13.06 ± 0.86), participated. Sleep duration, physical activity, and sedentary behaviours were measured through questionnaires. Academic performance was assessed with students´ marks. Potential confounders such as sex, age, socioeconomic status, and cardiorespiratory fitness were also measured. Descriptive analysis, correlation analysis, analysis of differences, and multiple mediation analysis were conducted. It was observed that girls spend more time on sedentary educational or social behaviours, while boys spend much more time on screen time. Sedentary behaviours such as educational time, screen time, and relaxing time were associated with academic performance. Specifically, educational time appears to be positively related to academic performance. Nevertheless, screen time and relaxing time were negatively associated with academic performance. The multiple mediation analysis revealed that screen time was the most negative behaviour on academic performance. The outcomes are discussed to improve knowledge about sedentary behaviours and academic performance.
Keywords: Academic performance; adolescents; cognitive achievement; sedentary behaviour.