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Influence of load carriage on gait kinetics, kinematics and muscle activity in primary school boys
Author
Tarkeshwar Singh
Supervisor
Tan, Swee Kheng
Koh, Michael (Michael Teik Hin)
Abstract
Backpack loads have been steadily increasing over the last two decades raising concerns among medical practitioners and parents about the possible detrimental effects prolonged heavy load carriage can have on the musculoskeletal system. Previous studies have indicated that loads higher than 15% of bodyweight affect the gait and trunk posture of children and can cause long term musculoskeletal problems. It has been reported in many countries that due to the structure of the curriculum, the children usually carry loads as high as 22-25% of their bodyweight. In light of this information, it is important that ergonomic backpacks be designed in order to alleviate the strain sustained by the musculoskeletal system.
The present study investigated whether it was better to place the loads high up or low down on the back in order to make concrete recommendations on where should the loads be placed on the back. Ethics approval was obtained from the University’s Ethics Review Committee. An upper and a lower load configuration were defined. The upper load configuration was when the centre of mass of the load was superior to the T8-T9 vertebrae and vice-versa. Three different load amounts 10%, 15% and 20% bodyweight loads were carried. Kinematic, kinetic, temporal, spatial and muscle activity at the lower and upper back muscles were examined for dependence on the load amount and position. 17 participants with mean age 9.65 (±1.58) years, mean height 134.41 (±11.01) cm and mean mass 31.09 (±7.01) kg participated in the study. The participants walked on the treadmill for six minutes at the end of which data was collected.
Results indicated that 20% BW load induced significant changes in the temporal and spatial parameters compared to the unloaded walking condition. The lower load configuration changed the temporal- spatial parameters more than the upper load configuration with respect to the unloaded walking condition. All the load amounts and configurations brought significant changes in the sagittal plane movement of the hip, pelvis and trunk. Reductions were also observed for the pelvic and trunk transverse plane range of movement but these reductions were not statistically significant compared to the unloaded condition. The lower load configuration induced higher trunk and pelvis forward lean compared to the upper load configuration for the 20% bodyweight load. No significant differences were observed for the ground reaction forces, even though the difference between the lower 20% load condition and the unloaded condition approached significance for the first peak force. No significant changes were observed for the muscle activity at the lower erector spinae and upper trapezius muscles.
To conclude, the centre of mass of the backpack load should not be too low on the back when loads approach 15-20% of bodyweight. The study also showed that the body adopts some counter measures to minimize the musculoskeletal strain on the system. It was found that certain gait patterns changed for loaded conditions in order to minimize shock absorption to the superior segments of the body and also to regulate the peak joint moments.
The present study investigated whether it was better to place the loads high up or low down on the back in order to make concrete recommendations on where should the loads be placed on the back. Ethics approval was obtained from the University’s Ethics Review Committee. An upper and a lower load configuration were defined. The upper load configuration was when the centre of mass of the load was superior to the T8-T9 vertebrae and vice-versa. Three different load amounts 10%, 15% and 20% bodyweight loads were carried. Kinematic, kinetic, temporal, spatial and muscle activity at the lower and upper back muscles were examined for dependence on the load amount and position. 17 participants with mean age 9.65 (±1.58) years, mean height 134.41 (±11.01) cm and mean mass 31.09 (±7.01) kg participated in the study. The participants walked on the treadmill for six minutes at the end of which data was collected.
Results indicated that 20% BW load induced significant changes in the temporal and spatial parameters compared to the unloaded walking condition. The lower load configuration changed the temporal- spatial parameters more than the upper load configuration with respect to the unloaded walking condition. All the load amounts and configurations brought significant changes in the sagittal plane movement of the hip, pelvis and trunk. Reductions were also observed for the pelvic and trunk transverse plane range of movement but these reductions were not statistically significant compared to the unloaded condition. The lower load configuration induced higher trunk and pelvis forward lean compared to the upper load configuration for the 20% bodyweight load. No significant differences were observed for the ground reaction forces, even though the difference between the lower 20% load condition and the unloaded condition approached significance for the first peak force. No significant changes were observed for the muscle activity at the lower erector spinae and upper trapezius muscles.
To conclude, the centre of mass of the backpack load should not be too low on the back when loads approach 15-20% of bodyweight. The study also showed that the body adopts some counter measures to minimize the musculoskeletal strain on the system. It was found that certain gait patterns changed for loaded conditions in order to minimize shock absorption to the superior segments of the body and also to regulate the peak joint moments.
Date Issued
2007
Call Number
QP303 Tar
Date Submitted
2007