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Title:	Estimation of arm muscle forces of primary school students during load carriage
Authors:	Abdalla Faisal Saleh (P47402)
Supervisor:	Azmin Sham Rambely, Dr.
Keywords:	Arm muscle forces Load carriage Primary school students Muscles.
Issue Date:	27-Jan-2015
Description:	A scenario of primary school children carrying heavy backpack at their back, which amounted to more than 10% of their body weight (BW), happens in most developing countries in the world. Several medical problems associated with heavy backpack have been reported. Yet there is no study that focuses on the transferred load to the distal segment. In this study, an investigation to reduce heavy backpack load was done by maintaining the maximum 10% BW load in the backpack and transferring the excessive load to the distal segment of subjects' arms. This study aims to examine the mechanical properties of biological tissues as indicator of human muscle tissue physical integrity, study muscle behaviours of an arm segment, the biceps, triceps, brachialis, flexor carpi radialis (FCR), and extensor digitorum (ED) which acted as actuators during heavy load carriage, investigate the arm muscle loading, determine the arm muscle forces via optimization models, and validate the estimated muscle forces using electromyogram (EMG) measurements during load carriage. A technique to reduce the backpack weight, by transferring the excess load to the subject's arm, has been suggested. Optimization models were developed to estimate the arm muscle forces and a load limit which can be carried by the subjects. The muscle loading of human arm was estimated during walking with three different load conditions. The first condition was identified as no load applied on the distal segment, amount of load carried by the arms from the difference of 10% BW and the maximum load, 4.8 kg, as second condition and double of the second load condition as third condition. The uniaxial mechanical testing on bovine muscles to estimate Young's Modulus (YM) values for estimation of human muscle forces has not been done elsewhere. The obtained values were used to calculate joint moments to be included in the optimization models. The experiment involved 10 school children (with mean age 8.09±0.85 years, height 127.2±9.15 cm, and weight 25.54±4.52 kg) who carried load of 10% BW at the back and the extra load carried by the arms. Movements of the subjects were captured using Vicon motion capture system comprised of four infrared cameras. EMG measurements were recorded during the same experiment designs. The arm muscle forces estimated by the optimization models were compared to their maximum forces (Fmax) to determine a percentage of BW safe load that can be carried by the arm of primary school students. Paired t-test was used to statistically investigate the significance difference between the load conditions and validate the estimated muscle forces by the optimization model with the EMG measurements. Uniaxial mechanical testing revealed that FCR has the largest YM value indicating that it is more elastic than other muscles while triceps has the smallest YM value reflecting that it is stiffer than the other tested muscles. The findings showed that the obtained muscles forces were highly influenced by the change in load applied on the arm. All the muscle forces, estimated by the optimization models, where found to be less than their calculated Fmax in 0-L and 1-L conditions. For 2-L condition, it was found that Fbiceps > Fmax in static model and Ftriceps > Fmax in dynamic model. The paired t-test showed that the comparisons between 0-L, 1-L and 2-L conditions and the two methods of optimization and EMG were significantly different (p-value < 0.005). Therefore, it is concluded that the excess load carried produce an effect to the arm segment and it can be transferred to the arm segment to prevent the back injury of heavy load carriage. However, carrying a load of 4.5 kg (2-L condition) using the arm segment is not suggested.,Ph.D
Pages:	138
Call Number:	QM577 .A235 2015
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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