Average acceleration and intensity gradient of 9–11-year-old rural and urban Kenyan school-going children and associations with cardiorespiratory fitness and BMI: The Kenya-LINX project
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Date
2025-08
Journal Title
Journal ISSN
Volume Title
Publisher
plos
Abstract
Abstract
Background
Physical activity (PA) is crucial for children’s health, cardiorespiratory fitness (CRF)
and weight status. However, research on the PA profiles of Kenyan children, especially between rural and urban areas, is limited.
Method
This study examined the PA profiles of 537 school-aged children (51.6% girls,
9–11-year-olds) from Nairobi City County, Kenya (urban setting), and Kitui County,
Kenya (rural setting), using stratified multistage random cluster sampling. Participants wore an accelerometer (Axivity AX3) on their non-dominant wrist for 24 hours
a day over seven days. Raw accelerations were extracted and averaged over a 5-s
epoch (AvgAcc) to estimate PA volume. Intensity gradient (IG) was calculated as a
standardised metric of PA intensity. Participants’ CRF was assessed by the 20-metre
multistage fitness test. Anthropometric measurements (mass and stature) were taken
to compute BMI z-scores.
Results
PA metrics varied by sex, weight, and CRF. Boys had higher AvgAcc (p<.001) and IG
(p<.001) than girls. Healthy weight participants differed significantly in AvgAcc from
overweight (p=.001) and obese (p=.001) groups and in IG from overweight (p=.039)
PLOS One | https://doi.org/10.1371/journal.pone.0329173 August 4, 2025 2 / 14
and obese (p=.003). Participants with sufficient CRF and insufficient CRF differed
significantly in AvgAcc (p<.001) and IG (p<.001). AvgAcc was negatively associated
with BMI z-scores (β=−0.02, p<.001) and positively associated with CRF (β=0.21,
p<.001), independent of IG and other covariates. IG showed a significant negative
association with BMI z-scores (β=−1.27, p=0.003) and a significant positive association with CRF (β=18.93, p<.001), dependent on AvgAcc.
Conclusions
This study introduces AvgAcc and IG metrics among Kenyan children. Urban children
accumulate less PA volume and exhibit an inferior intensity profile, which is reflected
in important health indicators (BMI and CRF). These findings will inform policy as well
as targeted interventions to enhance children’s health in diverse contexts.
Description
research article
Keywords
Citation
Kinuthia SK, Stratton G, Wachira LJ, Okoth VO, Owino GE, Ochola S, et al. (2025) Average acceleration and intensity gradient of 9–11-year-old rural and urban Kenyan school-going children and associations with cardiorespiratory fitness and BMI: The KenyaLINX project. PLoS One 20(8): e0329173.