Jago, R, Salway, R E, Collison, L G, Sebire, S J, Thompson, J & Lawlor, D A 2020, ' Association of BMI category with change in children’s physical activity between ages 6 and 11 years : a longitudinal study ', International Journal of Obesity, vol. 44, pp. 104–113 . https://doi.org/10.1038/s41366-019-0459-0 International Journal of Obesity (2005)