The lack of physical activity and increasing time spent in sedentary behaviours during childhood place importance on developing low cost, easy-toimplement school-based interventions to increase physical activity among children. The PREVIENE Project will evaluate the effectiveness of five innovative, simple, and feasible interventions (active commuting to/from school, active Physical Education lessons, active school recess, sleep health promotion, and an integrated program incorporating all 4 interventions) to improve physical activity, fitness, anthropometry, sleep health, academic achievement, and health-related quality of life in primary school children. A total of 300 children (grade 3; 8-9 years of age) from six schools in Granada (Spain) will be enrolled in one of the 8-week interventions (one intervention per school; 50 children per school) or a control group (no intervention school; 50 children). Outcomes will include physical activity (measured by accelerometry), physical fitness (assessed using the ALPHA fitness battery), and anthropometry (height, weight and waist circumference). Furthermore, they will include sleep health (measured by accelerometers, a sleep diary, and sleep health questionnaires), academic achievement (grades from the official school’s records), and health-related quality of life (child and parental questionnaires). To assess the effectiveness of the different interventions on objectively measured PA and the other outcomes, the generalized linear model will be used. The PREVIENE Project will provide the information about the effectiveness and implementation of different school-based interventions for physical activity promotion in primary school children.

Physical activity (PA) and sleep contribute to better children’s health. Nonetheless, the bidirectional relationship between both of these health-related factors is unclear when using objective measures. The aims of this study were (1) to describe the PA (light PA and moderate-to-vigorous PA (MVPA) and sleep (duration, latency, and efficiency) patterns of children and compare them with recommendations, and (2) to analyze the bidirectional association between PA levels and sleep patterns in 470 Spanish children according to sex (average age of 8.4 (0.4) years, 51.9% boys). A tri-axial accelerometer and sleep logs were used to measure PA (light PA and MVPA) and sleep patterns (duration, latency, and efficiency) in the children for seven consecutive days. Linear mixed models were conducted to analyze the bidirectional association (PA → sleep and sleep → PA) adjusted for the child, the sex, the school, and the day of observation. The results showed that, overall, the children did not meet the sleep duration recommendations per day. Regarding the bidirectional association, increased light PA and MVPA during the day was related to decreased sleep duration but an improvement in sleep efficiency that night. However, sleep duration and sleep efficiency were only related negatively and positively to light PA the following day, respectively. Regarding sex, light PA was associated with decreased sleep duration in both sexes, although the average value was lower in boys. In addition, light PA was also related only to an improvement in sleep efficiency the same night in both sexes, with girls generally having more efficient sleep. More studies in a representative sample of children that use objective measures to corroborate these results are needed.

Higher sedentary time and lower physical activity (PA) are associated with a poor health-related quality of life (HRQoL) in children. The aims of this study were: (1) to analyze the sedentary time, objectively measured PA levels (light, moderate, vigorous, and moderate-to-vigorous physical activity (MVPA)), and HRQoL dimensions (physical well-being, emotional well-being, self-esteem, family, friends, school, and total score) in children; and (2) to examine the association between sedentary time, PA levels, and HRQoL in children separately by sex. A total of 459 children (8.4 ± 0.4 years old, 50.54% males) from 15 schools in Granada (Spain) participated in the study. A tri-axial accelerometer was used to measure PA levels in the children for 7 consecutive days. The Revidierter KINDer Lebensqualitätsfragebogen (KINDL-R) questionnaire was used to determine the children’s HRQoL dimensions. The results showed that males presented more minutes engaged in MVPA than females. Both sedentary time and PA levels were associated with self-esteem and total score (all p < 0.05). In males, moderate and vigorous PA levels were associated with higher HRQoL, whereas light PA was associated with higher HRQoL in females. Future studies should take into account the use of activities with difference intensities in order to increase HRQoL in males and females.

The goals of this study were to (1) describe physical activity levels during school recess in 8-year-old children, (2) analyse the percentage of children who achieved physical activity recommendation at recess, and (3) examine if recess physical activity levels varied by gender, weight status, and parental educational level. In all, 291 children (mean age ± SD = 8.3 ± 0.3 years, 156 boys) from 7 schools of Granada (Spain) were recruited by convenience. To analyse sedentary time and physical activity levels during recess, children wore a tri-axial accelerometer attached to the wrist over five consecutive school days. Sedentary time (29.6% vs 40%) and light physical activity (33.2% vs 35.5%) were lower in boys than in girls (all p < .001). Conversely, moderate physical activity (26.7% vs 20%), vigorous physical activity (10.5% vs 4.4%) and moderate-vigorous physical activity (37.2% vs 24.4%) were higher in boys than in girls (all p < .001). Only 12% of the children accomplished the moderate-vigorous physical activity recommendations during recess (21.2% boys vs 1.5% girls). Lower body mass index values were associated with higher vigorous physical activity intensity. Levels of moderate-vigorous physical activity during school recess are very low in children, being lower in girls than in boys, a very low percentage of children achieve moderate-vigorous physical activity recommendations during school recess, and girls and overweight/obese children show lower values in moderate-vigorous and vigorous physical activity.

The relationship between physical activity (PA), cardiorespiratory fitness (CRF) and academic achievement in young people is unclear. The aim of this study was to analyze the relationship between PA, CRF and academic achievement in 152 children according to sex (average age of 8.6 ± 0.3 years) in southern Spain. A tri-axial accelerometer was used to measure PA; the 20-m Shuttle Run Test was performed to assess the CRF; and to know the academic achievement, the official school records were considered. The results showed a weak correlation between moderate PA and moderate-to-vigorous PA (MVPA) with CRF in boys (all, 0.2 > r < 0.4; p < 0.05), whereas the vigorous PA showed a moderate and weak correlation with CRF (all, p < 0.05), in both boys (r = 0.537) and girls (r = 0.382), respectively. In addition, a weak inverse correlation between moderate PA and MVPA with academic achievement showed in girls (all, 0.2 > r < 0.4; p < 0.05). Finally, the CRF weakly correlated with academic achievement only in boys (all, 0.2 > r < 0.4; p < 0.05). Our study showed a relationship between PA and CRF in both sexes. Nonetheless, the PA was inversely related to academic achievement in girls, whereas the CRF was related to academic achievement in boys.

Physical education (PE) can contribute to total daily physical activity (PA) among children. In consequence, the Spanish Ministry of Education, Culture and Sport has developed 16 teaching units focused on increasing PA levels during PE lessons, called Unidades Didácticas Activas (UDA; Active Teaching Units). The goal of this study was to compare whether children participating in UDA lessons spent more time in moderate-to-vigorous physical activity (MVPA) than children participating in traditional lessons. Quasi-experimental design. A total of 355 children (8–9 years old, 53.9% boys) from 7 schools in Granada participated in the study. Students were divided into two groups: a traditional PE group (n = 204) and a UDA group (n = 151). Time spent in MVPA was assessed using tri-axial accelerometers. Time spent in MVPA was higher in the group engaged in the UDA lessons compared to the group that received traditional lessons (13.6 vs 15.2 minutes, p = .021, Standard Error = 0.27). The percentage of children who met international MVPA recommendations was similar for both groups (UDAs: 12.7% and traditional: 13.2%, p = .504). UDA lessons and their methodology favoured greater participation in MVPA compared to a traditional PE approach. It will be important to change PE methodology (including duration, frequency and focus) to achieve MVPA goals.