VOL. 11, NO. 1, JANUARY 2016 ISSN 1819-6608 ARPN Journal of Engineering and Applied Sciences © 2006-2016 Asian Research Publishing Network (ARPN). All rights reserved. www.arpnjournals.com 433 EXPERIMENTAL ANALYSIS OF HUMAN LUMBAR VERTEBRAE DURING PROLONGED DISTANCE DRIVING M. A. Amir 1 , S. F. Toha 2 , I. B. Aris 3 and H. Md. Yusof 2 2 Department of Mechatronics Engineering, Kulliyyah of Engineering, International Islamic University Malaysia, Malaysia 3 Department of Electrical and Electronics Engineering, Faculty of Engineering, Universiti Putra Malaysia, Malaysia E-Mail: araiamir91@gmail.com ABSTRACT Back pain is commonly associated with a heavy driving or a person driving for a very long period. Inexpensive vehicles have a low system of absorbers such that the person behind the wheel and the passenger will experience pain in their back. This is mainly caused by several factors, such as the condition of the road, the performance of the absorber system of the vehicle and also the condition of the person inside the vehicle itself. This paper will discuss the factor that can be prevented and optimized to reduce whole-body vibration that might lead to fatigue. Keywords: lumbar vertebrae, whole-body vibration, long distance driving. INTRODUCTION Whole-body vibrations occur when the human body is in contact with a vibrating surface. Oscillations in the frequency range from 1 to 80 Hz are called vibrations in existing standards [1]. For higher frequencies, the human body becomes less and less sensitive. Movements with frequencies below 1 Hz are denoted as motions and the excitation with such low frequency movements produce motion sickness [2]. The effects of vibrations on human spinal from hydraulic steering system was investigated to lies a bit higher than the perception level, which causes stress and sickness on the human body [3, 4]. The main function of the lumbar spine is to bear the weight of the body. If an individual’s joints are not functioning properly of even worse, dislocated discs, they are at harm of getting lumbar spine injury. These vertebrae are much larger in size to absorb instant shock and provide comfort while carrying heavy load in various postures, such as standing, squatting and bending [5]. A lumbar sprain or strain happens when someone has an excessive mechanical demands put onto the surrounding muscles, or ligaments or both. A small electric potential across the muscle is produced when a muscle is pulled, or in other words, contracted. Surface electrodes can sense this muscle activity potential when placed over the muscle. The signal produced is then sensed by the electrodes. The device amplified the signal to produce clearer readings and recorded with the device. It is known as the EMG [6]. Whole-body vibration can response activity in the electromyogram (EMG) part of lumbar back muscles of seated persons [7]. Many of the modelling approaches before have come out with mathematical equations which assumptions made that restrict the actual performance of the vehicular vibration impact [8, 9]. The standard in measuring vibration is the ISO 2631-1. It is an international standard titled Mechanical vibration and shock - Evaluation of human exposure to whole-body vibration [10]. This standard states that the measurement of vibration needs to be on the position as shown in Figure-1. The measured vibration is classified in Table-1 (a) to value the level of comfort of the person. Vibration of more than 0.5 m/s 2 is considered harmful to the person as it will make him uncomfortable even though in the earlier state he was not moving. As stated in previous studies, the specified frequency range for whole-body vibration is between 0.5 to 80 Hz. For instance, motion sickness is associated with frequencies below 1 Hz [11] and specifically from 0.1 to 0.5 Hz [12, 13]. Table-1 (b) shows that the relevant frequency ranges for vibration exposure [14]. Table-1. a) Levels of comfort for vibration environments, b) Frequency ranges for vibration exposure. Measured vibration (m/s 2 ) Level of comfort Less than 0.315 Not Uncomfortable 0.315 to 0.63 A Little Comfortable 0.5 to 1 Fairly Uncomfortable 0.8 to 1.6 Uncomfortable 1.25 to 2.5 Very Uncomfortable More than 2 Extremely Uncomfortable (a)