Hip and wrist accelerometers showed consistent associations with fitness and fatness in children aged 8-12 years

AIM

Physical activity (PA) has traditionally been measured wearing accelerometers on the hip, but they are increasingly being worn on the wrist. We compared hip and wrist accelerometers with regard to their acceptability and any associations between PA and fatness and fitness.

METHODS

This cross-sectional study comprised 103 children aged 8-12 years (62% boys) who participated in the ActiveBrains trial by the University of Granada, Spain, in 2014-2016. The children wore both ActiGraph GT3X+ hip and wrist accelerometers round the clock for 7 days. The acceptability of both placements was evaluated by a questionnaire, while the children's fat mass index, waist circumference and cardiorespiratory fitness (CRF) were assessed.

RESULTS

Wearing wrist accelerometers caused less disturbance, mainly because hip accelerometers caused more issues during the night. The measurements from both placements showed that lower PA levels were associated with fatness and that higher PA levels were associated with better CRF.

CONCLUSION

Both placements showed consistent results with regard to measuring associations between PA levels and fatness and fitness. However, wearing them on the wrist caused less discomfort at night. Future studies are needed to confirm the best placement for accelerometers during PA studies.

Active commuting to school was inversely associated with academic achievement in primary but not secondary school students

AIM

Physical activity has numerous benefits for children when it comes to academic achievements. This study determined whether active commuting - walking or cycling - to school, as a way of increasing total physical activity levels, was associated with academic achievements in students aged seven to 18 years.

METHODS

A total of 2138 students participated in the study, which took place in the 2012/2013 academic year in three Spanish cities. We used a self-reported questionnaire to assess how the students travelled to and from school and their final school grades.

RESULTS

We enrolled 489 primary schoolchildren and 1649 secondary schoolchildren, with similar numbers of boys and girls. The primary schoolchildren who travelled to school by motorbike, car or bus had better grades for all the selected school subjects (p ≤ 0.009) than those who walked or cycled. No significant associations were found for secondary schoolchildren, except for mathematics and their grade point averages. All models were adjusted for sex, age and school.

CONCLUSION

Active commuting to school was inversely associated with academic achievement in primary school students but not those at secondary school. Longitudinal and intervention studies are needed to further understand our findings.