Background: Carrying a backpack and pulling a school trolley have been previously related to changes in spatiotemporal gait parameters.
Objective: Analyze gait asymmetry and rating of perceived exertion carrying a backpack and pulling a trolley with different loads.
Methods: Fifteen students from an elementary school (aged 10.1 ± 1.7 years) participated in this study. The participants walked with no bag, and carrying a backpack or pulling a trolley, both with 10%, 15% and 20% of the participant's body weight (BW). A 3D motion capture system was used to analyze the spatiotemporal gait variables. Then, the ratios, symmetry angles and gait asymmetry of the step length, swing time, and stance time were analyzed. Furthermore, the rating of perceived exertion was recorded.
Results: None of the asymmetry parameters were significantly different between those who carried a backpack and those who pulled a trolley. In the backpack condition, the ratings of perceived exertion were higher among participants in the 20% BW (2.07 ± 2.09, p = 0.003) and 10% BW (0.27 ± 0.59, p = 0.004) conditions compared to those in the control condition (0.07 + 0.26). Pulling a trolley did not significantly increase the perceived exertion ratings.
Conclusions: Carrying a backpack and pulling a trolley from 10% - 20% BW did not induce gait asymmetry in children. The use of the school trolley required less subjective effort than carrying a backpack with the same loads.
Keywords: Children; OMNI scale; load; students; wheeled backpack.