Associations between physical fitness and different aspects of screen time in children and adolescents.

The main purpose of the study was to examine the associations between health-related physical fitness (PF) and screen time in school-going youth. A convenient sample of 3224 children and adolescents aged 10-14 years from 10 schools was recruited to participate in the study. The Health-Behaviours in School-aged Children questionnaire was used to assess the level of screen time during schooldays and weekend days in television (TV) viewing, playing video games (VG) and using electronic devices (ED). Muscular fitness (sit-ups in 30 s and standing broad jump), cardiorespiratory fitness (the 20 m shuttle run test) and motor competence (the 10 × 5 m shuttle run test) were tested to determine the level of PF. Raw data for each test were transformed to quartiles (independent variable), while the outcome variable was not meeting the screen guidelines (> 2 h/day) for each of the screen time behavior. The average total screen time was 9.1 (2.9) h/day. Youth who did not meet the screen guidelines performed significantly poorly than those who met with the guidelines, respectively. A graded inverse association between each PF test and not meeting the screen time guidelines was found. Individuals in upper quartiles of cardiorespiratory and muscular fitness, and motor competence were less likely not to meet the screen time guidelines, compared to their peers in lower quartiles. Similar associations were observed, irrespective of sex. This study suggests that higher PF levels are strongly associated with less time spent in front of screens in a large sample of children and adolescents. From a public health perspective, enhancing muscular and cardiorespiratory fitness may be an adequate method to reduce screen time and re-allocate it to a more active lifestyle.