PHYSIOLOGICAL RESPONSES ON LIFTING POSTURES DURING MANUAL LIFTING TASK

Despite the growth of automated technologies in many industries, manual lifting task activities still play an important part in their daily services. Lifting task contributed as one of the back injuries problems, which comprises the loss of productivity and increased the compensation cost for the employers. This study presented the result of physiological responses aimed at the lifting postures of stoop and squat on manual lifting task. The physiological aspects of lifting posture on heart rate and energy expenditure for the Malaysian population were studied. Different weight loads, lifting weights, frequencies and twist angle have been studied to identify and recommend the appropriate lifting tasks to be used by the workers. Experimental work was conducted involving 36 subjects between 20 and 40 years old with no history of back pain. The subjects performed lifting tasks with loads of 10 kg, 15 kg, 20 kg and 23 kg to a lifting height of 70 cm and 130 cm, with the frequency of 1 lift, 3 lifts and 6 lifts per minute and twist angle of 0 degrees and 90 degrees. The results of the study showed that heart rate is linearly related to the height of lifting, weights, frequency and angle of twisting. These findings can be used as a guide to design lifting tasks for the Malaysian population.