This study analyzed the heart rate and muscle activation pattern associated with carrying of school trolley and school backpack with different loads. Methods: Twenty-five school children which 14 were males and 11 were females was included with a mean age 13.4 (SD = 1.1) year, a mean height of 154.1 (SD = 7.7) cm, and a mean weight of 42.8 (SD = 8.0) kg to walk at a self-selected speed under 24 experimental conditions: 1) carrying a school trolley or 2) carrying a school backpack with 1) 0%, 2) 10%, 3) 15% and 4) 20% of the subject’s body weight (BW) during 1) level walking, 2) upstairs walking and 3) downstairs walking respectively. The students performed upstairs and downstairs walking on a thirty-step staircase (stair dimensions of 15.0 cm height and 33.0 cm depth). The subjects completed 30 steps in each condition in a randomize order, and 15 gait cycles were identified in each walking trials. Electromyography data is normalized in terms of the percentage of maximum voluntary contraction (MVC%) from twelve muscles. Averages and standard deviations of heart rate, maximum MVC% and mean MVC% were obtained from both of the left and right sides of tibialis anterior muscle, gastrocnemius muscle, lumbar erector spinae muscle, rectus abdominus muscle, semitendinosus muscle and rectus femoris muscles. The mean heart rate increased significantly with the greater load carriage during the walking trials. No significant difference was found in heart rate response between carrying of school trolley and carrying of school backpack during level walking, upstairs walking, and downstairs walking. Notably, pulling school trolley with load during level walking has less muscle activation in most of the muscles except semitendinosus muscle compared with carrying of school backpack. However, the carry of the school backpack is superior to the school trolley in terms of less muscular activities in twelve muscles during upstairs walking with load carriage. Moreover, carrying the school backpack is superior to the school trolley in terms of less muscular activities in twelve muscles during downstairs walking with load carriage. It is therefore suggested that the school backpack is a more effective carrying method than the school trolley as it minimizes the asymmetrical work in lumbar erector spinae muscle activities during upstairs and downstairs walking. Conclusions: Pulling a school trolley with load not more than 20% BW in time of level walking is recommended for school children to carry school necessities. Carrying the school backpack is superior to the school trolley with 10% to 20% BW load carriage in terms of less muscular activities’ patterns of trunk and lower limb during upstairs and downstairs walking. All rights reserved.
|Qualification||Doctor of Education|
|Publication status||Published - 2021|
- Surface electromyography
- Theses and Dissertations
- Thesis (Ed.D.)--The Education University of Hong Kong, 2021.