Associations of objectively assessed levels of physical activity, aerobic fitness and motor coordination with injury risk in 7-9 year old school children
Martin-Diener Eva, Wanner Miriam, Kriemler Susi, Martin Brian
(University of Zurich/Institute of Social and Preventive Medicine, Switzerland)
Introduction: The beneficial effects of physical activity (PA) are well accepted. However, its promotion may lead to more activityrelated injuries. Little is known about injuries in young children when exposure to PA is taken into account, in particular in children of the general population and not only in child athletes. Also the relationship between PA behavior and total injury incidence is unclear: Do inactive children overall have an elevated injury risk compared to their more active counterparts?
The aim of this study was to assess activity-related correlates of injuries in children
of the general population under the age of 10 while accounting for exposure to objectively assessed PA. Methods: Cross-sectional study with 249 7-9 year old children from 20 school classes. All-cause injuries were assessed with a parental questionnaire, asking for injuries that had occurred during the past 12 months, had needed treatment by a medical professional or a guardian and had caused the child to stop the current activity for the rest of the day. PA exposure was measured with accelerometers for seven days, aerobic fitness with the 20m shuttle run test and motor coordination with the ”Körperkoordinationstest für Kinder” (KTK test). To describe injury risk factors the numbers of injuries per 1000h of moderate to vigorous physical activity (MVPA) were calculated and a multivariate logistic regression ccounting for clustering within classes was developed. Results: For 15% of the children an injury was reported, the incidence rate was 0.29 injuries/1000h of MVPA. 64% of all injuries had been treated professionally and more than 90% were related to some kind of physical activity. For all outcome measures, levels of PA were not associated with injury risk. After controlling for socio-demographic variables and accounting for exposure to PA and all other PA-related exposures of interest,
children with medium and high compared to those with low levels of aerobic fitness were at decreased injury risk (OR=0.33 (0.13-0.83); OR=0.29 (0.14-0.64). Children with high motor coordination scores were at increased injury risk compared to those in the normal range (2.65 (1.05-6.73). Discussion: Low aerobic fitness and good motor coordination, but not PA were related to injuries in prepubescent school children. These results suggest that in HEPA promotion in this age group it might be useful to supplement measures aimed to promote motor skills with those aimed to promote fitness.
Keywords: physical activity, children, injuries, aerobic fitness, motor coordination
