UNIVERSITI TEKNIKAL MALAYSIA MELAKA

Transcription

1 UNIVERSITI TEKNIKAL MALAYSIA MELAKA EVALUATION OF PSYCHOPHYSICAL EXPERIENCE AND HEART RATE OF MALAYSIAN FEMALE WHILE MANUAL LIFTING ACTIVITIES This report submitted in accordance with requirement of the Universiti Teknikal Malaysia Melaka (UTeM) for the Bachelor of Manufacturing Engineering (Manufacturing Management) (Hons.) by NURFARAHANA BINTI SIMUN B FACULTY OF MANUFACTURING ENGINEERING 2013

2 UNIVERSITI TEKNIKAL MALAYSIA MELAKA BORANG PENGESAHAN STATUS LAPORAN PROJEK SARJANA MUDA TAJUK: Evaluation of Psychophysical Experience and Heart Rate of Malaysian Female While Manual Lifting Activities SESI PENGAJIAN: 2012/13 Semester 2 Saya NURFARAHANA BINTI SIMUN mengaku membenarkan Laporan PSM ini disimpan di Perpustakaan Universiti Teknikal Malaysia Melaka (UTeM) dengan syarat-syarat kegunaan seperti berikut: 1. Laporan PSM adalah hak milik Universiti Teknikal Malaysia Melaka dan penulis. 2. Perpustakaan Universiti Teknikal Malaysia Melaka dibenarkan membuat salinan untuk tujuan pengajian sahaja dengan izin penulis. 3. Perpustakaan dibenarkan membuat salinan laporan PSM ini sebagai bahan pertukaran antara institusi pengajian tinggi. 4. **Sila tandakan ( ) SULIT TERHAD TIDAK TERHAD (Mengandungi maklumat yang berdarjah keselamatan atau kepentingan Malaysia sebagaimana yang termaktub dalam AKTA RAHSIA RASMI 1972) (Mengandungi maklumat TERHAD yang telah ditentukan oleh organisasi/badan di mana penyelidikan dijalankan) Disahkan oleh: Alamat Tetap: NO. 83, Jalan Pantai, Kampung Tanjung Genting, Mersing, Johor. Cop Rasmi: Tarikh: Tarikh: ** Jika Laporan PSM ini SULIT atau TERHAD, sila lampirkan surat daripada pihak berkuasa/organisasi berkenaan dengan menyatakan sekali sebab dan tempoh laporan PSM ini perlu dikelaskan sebagai SULIT atau TERHAD.

3 DECLARATION I hereby, declared this report entitled Evaluation of Psychophysical Experience and Heart Rate of Malaysian Female While Manual Lifting Activities is the results of my own research except as cited in references. Signature :. Author s Name : Date :

4 APPROVAL This report is submitted to the Faculty of Manufacturing Engineering of UTeM as a partial fulfilment of the requirements for the Bachelor of Manufacturing Engineering (Manufacturing Management) (Hons.). The member of the supervisory is as follow: (Project Supervisor)

5 ABSTRAK Di dalam industri pembuatan, mengangkat beban secara manual dilakukan dengan meluas oleh para pekerja. Bagaimanapun, teknik mengangkat beban secara manual yang tidak betul boleh menyumbang kepada kecederaan-kecederaan berkaitan kerja seperti sakit belakang dan sakit bahu kepada pekerja. Tujuan kajian ini ialah untuk merangka model matematik untuk meramal kesan paras ketinggian angkatan, berat beban dan sudut pusingan terhadap pengalaman psikofizikal dan kadar denyutan jantung wanita Malaysia semasa mereka mengangkat beban secara manual. Kajian ini melaksanakan pemerhatian tempat kerja dan kajian soal selidik bagi menentukan teknik angkatan dan masalah kesihatan yang dialami oleh pekerja wanita. Kemudiannya, satu eksperimen makmal telah dijalankan untuk menyiasat kesan paras ketinggian angkatan, berat beban dan sudut pusingan terhadap pengalaman psikofizikal dan kadar denyutan jantung subjek wanita semasa mengangkat beban secara manual. Berdasarkan analisis statistik, kajian ini mendapati berat beban telah dikenalpasti sebagai penyumbang utama kepada pengalaman psikofizikal, tahap kesakitan dan kadar denyutan jantung subjek wanita. Sembilan model matematik telah dirangka untuk meramal kesan ketinggian angkatan, berat beban dan sudut pusingan terhadap pengalaman psikofizikal dan kadar denyutan jantung wanita Malaysia. Semua model tersebut telah disahkan melalui data sejarah dan data eksperimen. Berdasarkan analisis statistik, satu kesepadanan yang baik di antara keputusan model matematik, data sejarah dan data eksperimen. Oleh itu, kajian ini menyimpulkan bahawa model yang telah dibangunkan di dalam kajian ini boleh dipercayai untuk meramal kesan ketinggian angkatan, berat beban dan sudut pusingan terhadap pengalaman psikofizikal, tahap kesakitan dan kadar denyutan jantung semasa mengangkat beban secara manual. Kajian ini mencadangkan kesan saiz beban dan cara angkatan seharusnya dipertimbangkan untuk kajian masa depan. i

6 ABSTRACT In manufacturing industry, manual lifting is widely practiced by the workers. However improper manual lifting technique can contribute to occupational injuries such as lower back pain and shoulder pain to the workers. The aim of this study is to develop mathematical models which are specifically used to predict the effects of lifting height, load mass, and twist angle on psychophysical experience and heart rate of Malaysian female while they are manual lifting. This study has performed workplace observation and questionnaire survey to determine lifting techniques and health problems experienced by the female workers. Subsequently a laboratory based experiment was conducted to investigate the effects of lifting height, load mass, and twist angle on psychophysical experience and heart rate of female subjects in manual lifting. Based on statistical analysis, this study found that the load mass has identified as main contributor to the psychophysical experience, pain level and heart rate of female subjects. Additionally nine mathematical models have been developed to predict the effects of lifting height, load mass, and twist angle on psychophysical experience and heart rate of Malaysian female. All models have been validated through historical data and experimental work. Based on statistical analysis, there is a good agreement between the results of the mathematical model, the historical data and the experimental work. Therefore, this study concluded that the models developed by this study are reliable for predicting the effect to the psychophysical experience, pain level and heart rate with respect to lifting height, load mass and twist angle in manual lifting. This study suggests that the effects of load sizes and lifting style should be considered in future study. ii

7 DEDICATION I would like to convey my appreciation to my beloved parents, siblings, and friends who have giving me their moral supports continuously throughout my entire life. Thank you for undivided loves and supports. May God bless them for their positive supports which give me motivation to excellence in my future. iii

8 ACKNOWLEDGEMENT First and foremost, great deals appreciated go to the contribution of my faculty and university, Faculty of Manufacturing Engineering of Universiti Teknikal Malaysia Melaka. I am also would like to thank to my supervisor, Dr. Isa bin Halim, whose invaluable guidance, advice, assistance from initial to the final level enabled me to develop understanding of this project. He inspired me greatly to work in this project. His willingness to motivate me contributed tremendously to my project. I appreciate the knowledge and advices that has gained from my supervisor. He has given me valuable cooperation, assistance, support and suggestion during this completion of project. Special thank goes to Jati Beringin Sdn. Bhd. and Infineon Technologies (M) Sdn. Bhd. for providing fruitful case study during data collection. Moreover, I would like to thank to my family who have giving me the supports and motivation to carry on from beginning until the completion of this project submission. Finally, I would like to thank to my course mate for their cooperation, comprehensive and explanation as well as is providing some useful information in my final year project. iv

9 TABLE OF CONTENTS Abstrak Abstract Dedication Acknowledgement Table of Content List of Tables List of Figures List Abbreviations, Symbols and Nomenclatures i ii iii iv v viii xi xii CHAPTER 1: INTRODUCTION Background of Study Problem Statement Objectives Scope and Limitation of Study Significance of Study Report Outlines 4 CHAPTER 2: LITERATURE REVIEW Lifting Techniques and Health Problems in Manual Lifting Lifting Techniques in Manual Lifting Health Problems Associated with Manual Lifting Manual Lifting Assessment Methods Control Measures for Health Problems Associated with Manual Lifting Review on Psychophysical Experience and Heart Rate Assessment Method for Psychophysical Experience Assessment Method for Heart Rate 13 v

10 2.3 Review on Mathematical Model of Psychophysical Experience and Heart Rate in Manual Lifting Summary of Literature 15 CHAPTER 3: METHODOLOGY Investigation of Lifting Techniques and Health Problems in Manual Lifting Investigation of Lifting Techniques in Manual Lifting Investigation of Health Problems in Manual Lifting Assessment of Psychophysical Experience and Heart Rate while Performing Manual Lifting Subjects Replications Randomization Standard Operation Procedures (SOP) Pilot Study and Actual Experiment Formulation of Mathematical Model of Psychophysical Experience and Heart Rate in Manual Lifting Descriptive Statistics Comparative Statistics Regression Statistics 31 CHAPTER 4: RESULTS AND DISCUSSION Lifting Techniques and Health Problems in Manual Lifting Lifting Techniques in Manual Lifting Health Problems due to Manual Lifting Psychophysical Experience and Heart Rate while Performing Manual Lifting Psychophysical Experience Psychophysical Experience (Pain Level) Heart Rate 48 vi

11 4.3 Formulation of Mathematical Model Psychophysical Experience Pain Level Heart Rate 67 CHAPTER 5: CONCLUSION AND SUGGESTION FOR FUTURE WORK Lifting Techniques and Health Problems in Manual Lifting Psychophysical Experience and Heart Rate of Female in Manual Lifting Formulation of Mathematical Model for Female Suggestion for Future Work 72 REFERENCES 73 APPENDICES A Questionnaire Form for Direct Survey in Industry B Borg Scale for Psychophysical Experience used in LBE for Test 1 C Likert Scale for Pain Level used in LBE for Test 1 D Heart Rate Table used in LBE for Test 1 Lifting vii

12 LIST OF TABLES 3.1 The Combination of Dependent Variables and Independent Variables Standard Operation Procedure of Psychophysical Experience Standard Operation Procedure of Heart Rate Lifting Techniques in Manual Lifting from Literature and On-site Observation Lifting Techniques and Its Figure in the On-site Observation Details of Subjects Minimum, Maximum, Mean and Standard Deviation of the Subjects Sequences of Tests in LBE ANOVA: Psychophysical Experience (Left) versus Twist Angle, Load Mass, Lifting Height in Lower Back ANOVA: Psychophysical Experience (Right) versus Twist Angle, Load Mass, Lifting Height in Lower Back ANOVA: Psychophysical Experience (Left) versus Twist Angle, Load Mass, Lifting Height in Upper Arm ANOVA: Psychophysical Experience (Left) versus Twist Angle, Load Mass, Lifting Height in Upper Arm The Correlations Results for Psychophysical Experience in Lower Back The Correlations Results for Psychophysical Experience in Upper Arm ANOVA: Pain Level (Left) versus Twist Angle, Load Mass, Lifting Height in Lower Back ANOVA: Pain Level (Right) versus Twist Angle, Load Mass, Lifting Height in Lower Back ANOVA: Pain Level (Left) versus Twist Angle, Load Mass, Lifting Height in Upper Arm 47 viii

13 4.15 ANOVA: Pain Level (Right) versus Twist Angle, Load Mass, Lifting Height in Upper Arm The Correlations Results for Pain Level in Lower Back The Correlations Results for Pain Level in Upper Arm Data of Subjects Heart Rate for 27 Tests ANOVA: Heart Rate versus Twist Angle, Load Mass, Lifting Height The Correlations Result Regression Analysis: Psychophysical Experience (Left) versus Lifting Height, Load Mass, Twist Angle in Lower Back Regression Analysis: Psychophysical Experience (Right) versus Lifting Height, Load Mass, Twist Angle in Lower Back Regression Analysis: Psychophysical Experience (Left) versus Lifting Height, Load Mass, Twist Angle in Upper Arm Regression Analysis: Psychophysical Experience (Right) versus Lifting Height, Load Mass, Twist Angle in Upper Arm Validation Data of Psychophysical Experience in Lower Back Validation Data of Psychophysical Experience in Upper Arm T-test for Validation of Results in Lower Back T-test for Validation of Results in Upper Arm Regression Analysis: Pain Level (Left) versus Twist Angle, Load Mass and Lifting Height in Lower Back Regression Analysis: Pain Level (Right) versus Twist Angle, Load Mass and Lifting Height in Lower Back Regression Analysis: Pain Level (Left) versus Twist Angle, Load Mass and Lifting Height in Upper Arm Regression Analysis: Pain Level (Right) versus Twist Angle, Load Mass and Lifting Height in Upper Arm Validation Data of Pain Level in Lower Back Validation Data of Pain Level in Upper Arm T-test for Validation of Results in Lower Back T-test for Validation of Results in Upper Arm 67 ix

14 4.37 Regression Analysis: Heart Rate versus Load Mass, Lifting Height Validation Data of Pain Level in Upper Arm T-test for Validation of Heart Rate 69 x

15 LIST OF FIGURES 1.1 Report Outline Squat, Stoop and Semi-squat Lifting Techniques Symmetry, Asymmetry, One-handed and Two-handed Lifting Heart Rate Monitor (Polar, Finland) The Literature Survey of the Lifting Techniques in Manual Lifting The Process of Direct Survey The Literature Survey of the Health Problems due to Manual Lifting The Process of Questionnaire Survey Worker fill up the Questionnaire Form Flow Chart of Experiment Activities Number of Respondents with Pain Level from 5 to 10 for Right Side of Body Number of Respondents with Pain Level from 5 to 10 for Left Side of Body Psychophysical Experience in Left and Right of Lower Back Psychophysical Experience in Left and Right of Upper Arm Pain Level of Subjects for Left and Right Side of Lower Back Pain Level of Subjects for Left and Right Side of Upper Arm Average of Heart Rate (after) for 27 Tests Heart Rate of 10 Subjects for Test Heart Rate of 10 Subjects for Test xi

16 LIST OF ABBREVIATIONS, SYMBOLS AND NOMENCLATURE - Degree < - Less than > - More than ANOVA - Analysis of Variance BPDR - Body part discomfort diagram rating bpm - Beat per minute CI - Confidence Interval cm - Centimeter DF - Degree of freedom DOE - Design of experiment Eq. - Equation F - F Test (ANOVA) H 0 - Null hypothesis H 1 - Alternate hypothesis HRM - Heart rate monitor kg - Kilogram LB - Lower Back LBE - Laboratory based experiments LBP - Lower back pain p - p-value (ANOVA) R - R-squared (regression analysis) RPE - Borg Rating of Perceived Exertion Scale SD - Standard deviation SOP - Standard operation procedure SS E - Sum of squares error T - T-ratio (ANOVA) xii

17 UA - Upper Arm UTeM - Universiti Teknikal Malaysia Melaka VAS - Visual analogue scale VS - Versus α - Alpha xiii

18 CHAPTER 1 INTRODUCTION This chapter presents the background of study, problem statements, objectives, and scope and limitation of study. In addition, the significance of study and the report outlines are also provided in this chapter. 1.1 Background of Study Manual lifting requires a person to use force to carry an object by using both of his or her hands. There are few techniques of lifting such as stoop lifting and squat techniques, but those techniques only can use for a load that not so heavy. Many of the industry in Malaysia still use the manual lifting techniques without assistance of equipment. The ergonomics risk factor associated with manual lifting can lead to occupational injuries. According to Lin et al. (2002), the incidence, severity, and potential disability of low back pain are related to the demands on the individual in the workplace. This study is about evaluation of psychophysical experience and heart rate of Malaysian female while manual lifting. The heart rate is interaction of human body when do some lifting, while psychophysical experience is the feeling or experience after the lifting like tired, pain or others feeling. This study aims to develop mathematical models of psychophysical experience and heart rate with respect to twist angle, load mass and lifting height in manual lifting 1

19 activities. The method to collect the data is direct surveys and questionnaire surveys of workers at an industry that applied the manual lifting technique and the laboratory based experiments. 1.2 Problem Statement Based on observation, workers in industry require manual lifting in their daily job activities. However manual lifting practices lead several problems as summarized as follow: a) Ergonomics risk factor associated with manual lifting can lead to occupational injuries such as low back pain and shoulder pain to industrial workers. Manual lifting contributes to occupational injuries associated with low back pain that can affect the life quality of industrial workers (Zurada, 2012). b) Due to occupational injuries, the motivation, productivity and efficiency of the workers may be affected. Poor workers health can reduce productivity and work quality (Shikdar and Sawaqed, 2003). c) The company has to spend money for medical, treatment and rehabilitation to the injured workers. Workers health issues have the potential to both increase costs and decrease revenues for any organization (Miller and Haslam, 2009). d) Lead to absenteeism and high rate of turnover in the company. The absenteeism and turnover of workers can be reduced by increasing workers spirit at work (Kinjerski and Skrypnek, 2008). Poor working practices lead to low motivation of workers to come to workplace. In the worst case, they might be resigning from the position. Hence ergonomic working environment including safe lifting techniques is necessity for the workers. 2

20 1.3 Objectives The aim of this study is to develop mathematical models of psychophysical experience and heart rate with respect to postures, loads mass and lifting height in manual lifting activities. Specifically this study embarks the following objectives: a) To investigate the technique applied by the workers while performing manual lifting and the health problems experienced by female workers due to manual lifting task. b) To assess the psychophysical experience and heart rate of female workers while performing manual lifting tasks. c) To formulate mathematical models of psychophysical experience and heart rate of female subjects with respect to twist angle, load mass and lifting height in manual lifting activities. 1.4 Scope and Limitation of Study This study focuses on the how manual lifting affected the psychophysical experience and heart rate of the subjects. In order to get all the data and information for the study, laboratory based experiments (LBE) have been carried out. The subjects are female and all of them are selected at Universiti Teknikal Malaysia Melaka (UTeM). The subjects must in good health and not having physical disabilities. The following section describes the variables used in the LBE. As the subjects, 10 female (Maiti and Bagchi, 2006) students from UTeM will do the laboratory based experiments (LBE). The loads that used for this experiment is 5 kg (Maiti and Bagchi, 2006), 10 kg (Rabinowitz et al., 1998; Maiti and Bagchi, 2006) and 15 kg (Lee, 2003). The subjects need to lift the loads from floor to the shelf with lifting height 55 cm, 75 cm (Rabinowitz et al., 1998) and 120 cm with three twist 3

21 angles which are 0, 45 and 90 (Plamondon et al., 2006). The limitation of this study is only limited to develop the mathematical model based on experimental works. 1.5 Significance of Study There is a significance that has potential to help the workers in industry. Therefore, the occupational health of the workers can be improved especially in manual lifting task. The workers can practice the proper way to perform manual lifting task to avoid the occupational injuries such as low back pain. Moreover, this study can be as future reference and research for the academicians. The results from the study can be delivered to society to enhance awareness on manual lifting activities. 1.6 Report Outlines Chapter one provides background of study, problem statements, objectives, scope of the study, significance of study, and report outlines. In chapter two, the literature review of lifting technique and health problem in manual lifting are presented. The literature review is provided to support the methodology and discussion. The literature reviews have been found by using the journals and direct survey to the industry. Chapter three is all about methodology. It provides the method to identify the lifting techniques and health problems due to manual lifting, the psychophysical experience and heart rate in manual lifting and the method to formulate mathematical model for the psychophysical experience and heart rate with respect to postures, loads mass and lifting height in manual lifting activities. Chapter four presents the results obtain from the questionnaire survey and laboratory based experiments (LBE). Chapter five provides the conclusion and recommendation about the manual lifting tasks. Figure 1.1 shows the report outline of the study. 4

22 Chapter 1 Background of Study Problem Statement Objectives Scope and Limitation of Study Significance of Study Report Outline Chapter 2 Literature review - Lifting Techniques and Health Problems in Manual Lifting - Review on Psychophysical Experience and Heart Rate in Manual Lifting - Review on Matehematical Models of Psychophysical Experience and Heart Rate in Manual Lifting Chapter 3 Methodology - Investigation of Lifting Techniques and Health Problems in Manual Lifting - Assessment of Psychophysical Experience and Heart Rate while Performing Manual Activity - Formulation of Mathematical Model of Psychophysical Experience and Heart Rate while Performing Manual Activity Chapter 4 Results and Discussion Chapter 5 Conclusion Figure 1.1: Report Outline 5

23 CHAPTER 2 LITERATURE REVIEW This chapter provides literature review on lifting techniques that applied by the industry worker while doing manual lifting. In addition, this chapter also provide the health problems in manual lifting. 2.1 Lifting Techniques and Health Problems in Manual Lifting There are lot of manual lifting activities in the industry, so that there is also a lot of lifting techniques applied by workers while performing the manual lifting. The workers also can expose the health problems due to manual lifting. The details of lifting techniques and health problems in manual lifting are describes in the following sections Lifting Techniques in Manual Lifting Manual lifting is defined as jobs that performed manually by humans including lifting, holding, carrying and moving heavy objects in the workplace (Zurada, 2012). Lifting happen when an object is move from a starting point to an ending point with a consequent increase in its vertical position (Hsiang et al., 1997). While lifting, both trunk muscles and hip muscles provide the extension torques to lift the torso upward. The following section describes the lifting techniques. There are lot of lifting techniques. The common lifting techniques are stooping and squatting lifting techniques. According Straker (2003), squat technique starts with 6

24 position of deep knee flexion with the trunk close to erect. In addition, Straker stated stoop technique starts with position of stretched knees and the inclined trunk. Furthermore, there is semi-squat technique, the posture between the squat and stoop lifts. The above mentioned techniques are shown in Figure 2.1. Squat Lifting Technique Posture Stoop Lifting Technique Posture Semi-squat Lifting Technique Posture Figure 2.1: Squat, Stoop and Semi-squat Lifting Techniques 7