ORIGINAL ARTICLES  EPIDEMIOLOGY 

The Journal of Sports Medicine and Physical Fitness 2014 October;54(5):631-5

Copyright © 2014 EDIZIONI MINERVA MEDICA

language: English

Knee alignment can help predict sedentary behaviour in children: a pilot study

Shultz S. P. ^{1, 2}, Kagawa M. ^{1, 3}, Fink P. W. ², Hills A. P. ⁴ ✉

¹ School of Human Movement Science, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia; ² School of Sport and Exercise, Massey University, Wellington, New Zealand; ³ Institute of Nutrition Sciences, Kagawa Nutrition University, Saitama, Japan; ⁴ Mater Mothers’ Hospital, Mater Research, Centre for Musculoskeletal Research, Griffith University; Brisbane, Australia

AIM: The purpose of this pilot study was to introduce knee alignment as a potential predictor of sedentary activity levels in boys and girls.
METHODS: Dual energy x-ray absorptiometry (DXA) and anthropometric assessment were conducted on 47 children (21 boys and 26 girls; 5-14 y) and their gender-matched parent. Body Mass Index (BMI) and abdominal-to-height ratio were calculated. Lower extremity alignment was determined by anatomic tibiofemoral angle (TFA) measurements from DXA images. Time spent in moderate-to-vigorous physical activity and sedentary activities were obtained from a parent-reported questionnaire. Stepwise multiple regression analyses identified anthropometric, musculoskeletal, and activity factors of parents and children for predicting total time spent in sedentary behaviour.
RESULTS: Weight, total sedentary time of parents and TFA are moderate predictors of sedentary behaviour in children (R2=0.469). When stratifying for gender, TFA and total sedentary time of the parent, as well as waist circumference, are the most useful predictors of sedentary behaviour in boys (R2=0.648). However, weight is the only predictor of sedentary behaviour in girls (R2=0.479).
CONCLUSION: Negative associations between TFA and sedentary behaviour indicate that even slight variations in musculoskeletal alignment may influence a child’s motivation to be physically active. Although growth and development is complicated by many potentialities, this pilot study suggests that orthopaedic factors should also be considered when evaluating physical activity in children.