ERGONOMIC EVALUATION OF PHYSIOLOGICAL COST OF SOME CERTAIN HOUSEHOLD CHORES PERFORMED BY HOME MAKERS IN KADUNA METROPOLIS, NIGERIA  

ABSTRACT

This study examined the ergonomic assessment of physiological cost of household work among women in Kaduna metropolis, Nigeria. It assessed the energy cost, heart rate, rate of perceived exertion and postural stress of cooking activities of kneading dough, stirring hard porridge (tuwon-shinkafa) and pounding yam among women in Kaduna metropolis, Nigeria. The study had five specific objectives, five research questions and four null hypotheses. A 3 x 1 x 3 factorial experimental research design was employed for the study. The population of this study comprised of women residents in three (3) bedroom apartments of Government Secondary Schools within Kaduna Metropolis, Kaduna State, Nigeria. The simple random sampling was used to select sixteen (16) homemakers residing in three (3) bedroom apartments purposively selected among Government Secondary Schools within Kaduna metropolis, Nigeria. The

Standiometre, Omron body Composition Monitor, Heart rate monitor, Flexi-curve, and Borg Scale were the instruments used to obtain relevant data. Three cooking activities were selected kneading dough, stirring hard porridge (tuwon-shinkafa) and pounding yam. Descriptive statistics of mean, standard deviation, standard error, frequency and percentage were used to analyze the demographic characteristics, postural assessments and research questions. Repeated measures analysis of variance was used to test hypotheses 1 and 2 while one way analysis of variance was used to test hypotheses 3 and 4. The result revealed that Kneading dough, stirring hard porridge (tuwon-shinkafa) and pounding yam led to high energy cost (expenditure) especially during and at the end of the cooking activities among women in Kaduna Metropolis, Nigeria (p = 0.001). The cooking  activities increased the resting heart rate of  women during and  immediately after kneading dough, stirring hard porridge (tuwon-shinkafa) and pounding yam in

Kaduna Metropolis, Nigeria  (p = 0.012). The rate of perceived exertion was maximum during pounding yam but were moderate during stirring hard porridge (tuwon-shinkafa) and kneading dough among women in Kaduna Metropolis, Nigeria. (p = 0.001). Postural stress was significant at both upper curve and lower curve during pounding yam, stirring hard porridge (tuwonshinkafa) and kneading dough among women in Kaduna metropolis, Nigeria (P = 0.001). The study concluded that the cooking activities and time spent during the performance of the activities had effect on the physiological and postural conditions of homemakers residing at the four (4) selected Government Secondary Schools within Kaduna metropolis, Nigeria. The researcher recommends among others that homemakers should make cooking activities of kneading dough, stirring hard porridge (tuwon-shinkafa) and pounding yam a regular activity so that the body‟s physique becomes used to the activity.

CHAPTER ONE

 INTRODUCTION

     1.1       Background to the Study

Ergonomics has to do with designing systems, work methods, tools and equipment which enhance human capabilities. International Ergonomics Association (2010) opined that, ergonomics is the natural human tendencies to seek ways to make life easier, it is about paying attention to the dynamic interaction between person and environment, and the study of people in their work situations. Also, it is the knowledge about the interaction between people, the equipment they use, their enrolment and their tasking is applied to provide the optimum of condition in term of health, comfort and efficiency of work (International Ergonomics Association, 2010).

As a unique scientific discipline, ergonomics systematically applies the knowledge of human abilities and limitations to the design of a system with the goals of optimizing the interaction between people and other system elements to enhance safety, performance and satisfaction (Carayon, 2006). Human factors are relevant anywhere because people work with systems, whether they are social or technical in nature. The breath of the socio-technical systems include situations and circumstances where people interact with other systems, elements including artifacts; (for example, tools, machines, product, software); tasks; environments; teams;  organizations; legal (for example, regulations and enforcement) and political (Carayon, 2006). Therefore ergonomics is concerned with the „fit‟ between people, their technological tools and the environment. It takes account of the user‟s capabilities and limitations in seeking to ensure that tasks, equipment, information and environment suit each user (Brookhuis, 2005).

Accordingly, Barkeley (2008) stressed that in the assessment of the „fit‟ between a person and the use of technology; the ergonomists consider the job (activity) being done and the demands on the user, the equipment used (its size, shape, and how appropriate it is for the task), and the information used (how it is presented, assessed, and changed). Ergonomics draws on many disciplines in its study of human and their environments which include anthropometry, biomechanics, mechanical engineering, industrial engineering, industrial design, kinesiology, Psychology and physiology (Berkeley, 2008).

According to the International Ergonomics Association (2010), physical ergonomics is concerned with human anatomical, and some of the anthropometric, physiological and biomechanical characteristics as they relate to physical activity. Cognitive ergonomics is concerned with mental processes such as perception, memory, reasoning and motor response, as they affect interactions among humans and other elements of a system. Such areas include mental work load, decision making, skilled performance, human computer interaction, human reliability and work stress. (IEA, 2010)

Ergonomics is employed to fulfill two goals of health and productivity. It is relevant in the design of such things as safe furniture and easy to-use interfaces to machines. Ergonomics in the workplace has to do largely with the safety of employees during long and short terms and that it can help reduce energy costs by improving safety (IEA, 2010).

 

Waugh & Grant (2001) define physiological cost of work as energy expended during an activity. Energy expenditure is the amount of fuel the body needs during specific work. The human body expends energy, which is the amount of energy needed to maintain basic physiological functions of the body organs in breathing, blood circulation, synthesis of compounds; the thermogeric effect of food-energy needed to process the food we eat to produce energy; and physical activities: energy is required to do work.

 

Energy expenditure depends on the type, duration and intensity of the activity as well as the body size and the fitness level of an individual (Bridger, 2008). The energy requirement for various activities is often referred to as energy “cost” of such activities. The information on the energy cost or physiological cost is obtained by a series of tests based on measurement of oxygen consumption with respect to the resting energy expenditure and read in term of kilocalories per kilogram body weight per minute (i.e. kcal/kg body weight/min) (Waugh & Grant, 2001). Jobs or working conditions presenting multiple risk factors will have a higher level of causing    musculoskeletal problems. The levels of risks depend on the intensity, frequency and duration of the exposure to these conditions. Environmental work condition that affects risk includes intensity, frequency and duration of activities (Bridger, 2008)

 

Heart rate is the number of heart beats per unit of time, expressed as beats per minute (bpm). Tom (2010) and Pheasant (2010) reported that heart rate is used for measuring the physiological condition and oxygen consumption of women while performing various house-hold tasks. It is a better index of measurement, which has a linear relationship with energy expenditure. Postural condition refers to the state in which a person holds the body upright against gravity while standing, sitting, or lying down. Posture is the way the muscles and skeleton hold the body erect (Sandhu, 2003). Right Posture is essential in the maintenance of the natural curve of the body while wrong posture causes stress and fatigue. According to Roberts (2013) and Jeremy (2013) good posture is considered to be the natural and comfortable bearing of the body in normal healthy persons. This refers to the natural standing position of a person, a comfortable sitting position. Poor posture results from certain muscles tightening up or shortening while others lengthen and become weak which often occur as a result of one‟s daily activities.

Women are critical to the well being of any household. Aside from raising children, women routinely partake in most household activities, as preparing meals, dish washing, table setting, laundry, heavy lifting of objects, sweeping, vacuuming, defrosting refrigerator, ironing, scrubbing, lifting young children or heavy basket of wet clothes among others. The daily work schedule of women is very demanding, arduous, and are not only strenuous but repetitive also. The women are exposed to continuous non neutral postures, the non-neutral posture of the trunk frequently adopted by workers is risk for lower back pain (Suthar & Kaushit, 2011). This study therefore, sought to examine the physiological conditions of women while performing selected cooking activities in their kitchens in Kaduna metropolis, Nigeria.

 

     1.2       Statement of the Problem

The home is a workplace for a woman; it is where she performs most of her domestic duties of washing, cooking, pounding food, lifting, sweeping and many others. A woman spends a major part of her time in the Kitchen (Verghese 1996). According to Lagomarsino (2004) a kitchen can make anybody‟s health and at the same time it can destroy anybody‟s health. By interpretation, while the kitchen activities can be seen as a means of physical activities that contribute to good health, it may also hinder the health of an individual if there is excessive weight gain and if the wrong posture or equipment is used. The researcher as a female has had personal interactions with some of whom are either overweight or obessed and therefore, suffer fatigue after the performance of household activities. Some of these women often complain of tiredness, fatigue, body aches and several other musculo-skeletal problems. This situation, the researcher of the present study feels,s may be the resultant effect of poor work habits, wrong postures and physical inactivity due to increasing sedentary nature of many forms of work, changing modes of transportation and increasing urbanization.

This may not be unconnected to the fact that women‟s work demands high degree of physical efforts due to the different types of activities, tools and equipment used and the manner in which the body segments are manipulated within the available space, and thus results in change in posture leading to increase in physiological cost of work. It may also result in permanent change in spine, in position of the joints, ligaments and muscles and in location of the organs of the body, thus enhancing the physiological cost of work and fatigue (Blum, 2009). The researcher of the present study wonders to what extent poor work habits and wrong postures relate to health, physical inactivity and physical stress of the women.

 

     1.3       Objectives of the Study

The major objective of this study was to determine the physiological cost of work of women (body composition, energy cost, heart rate, rate of perceived exertion and postural stress) while performing cooking activities of kneading dough, stirring hard porridge and pounding yam among women in Kaduna metropolis, Nigeria.

The Specific Objectives of this study are to: 

1. estimate the body composition of women (body fat (%), visceral fat, body mass index

(BMI), and resting metabolic rate) used in of kneading dough, stirring hard porridge (tuwon-shinkafa) and pounding yam among women in Kaduna metropolis, Nigeria 2. access the energy cost of cooking activities of kneading dough, stirring hard porridge

(tuwon-shinkafa) and pounding yam among women in Kaduna metropolis, Nigeria.

3. determine the heart rate of women as they perform cooking activities of kneading dough, stirring hard porridge (tuwon-shinkafa) and pounding yam in Kaduna metropolis, Nigeria.
4. assess the rate of perceived exertion among women as they perform cooking activities of kneading dough, stirring hard porridge (tuwon-shinkafa) and pounding yam in Kaduna metropolis, Nigeria.
5. evaluatethe postural stress of women as they perform cooking activities of kneading dough, stirring hard porridge (tuwon-shinkafa) and pounding yam in Kaduna metropolis, Nigeria.

 

     1.4       Research Questions

The following research questions were raised and used in this study.

1. what is the body composition of women (body fat, visceral fat, body mass index, and resting metabolic rate) used in kneading dough, stirring hard porridge (tuwonshinkafa)and pounding yam among women in Kaduna Metropolis, Nigeria?
2. what is the energy cost of cooking activities of kneading dough, stirring hard porridge

(tuwon-shinkafa) and pounding yam among women in Kaduna Metropolis, Nigeria?

3. What is the heart rate of women in Kaduna metropolis with regards to cooking activities of kneading dough, stirring hard porridge (tuwon-shinkafa) and pounding yam?
4. what is the rate of perceived exertion of cooking activities of kneading dough, stirring hard porridge (tuwon-shinkafa) and pounding yam among women in Kaduna metropolis, Nigeria?
5. what is the postural stress of cooking activities of kneading dough, stirring hard porridge

(tuwon-shinkafa) and pounding yam among women in Kaduna metropolis, Nigeria?

 

1.5       Research Hypotheses:

The following null hypotheses were formulated and tested:

1. There is no significant difference in the effect of kneading dough, stirring hard porridge (tuwon-shinkafa) and pounding yam on energy cost at three assessment levels among women in Kaduna metropolis, Nigeria.
2. There is no significant difference in the effect of kneading dough, stirring hard porridge (tuwon-shinkafa) and pounding yam on heart rate at three assessment levels among women in Kaduna metropolis, Nigeria.
3. There is no significant difference in the effect of kneading dough, stirring hard porridge

(tuwon-shinkafa) and pounding yam on rate of perceived exertion among women in Kaduna metropolis, Nigeria.

4. There is no significant difference in the effect of kneading dough, stirring hard porridge (tuwon-shinkafa) and pounding yam on postural stress among women in Kaduna

metropolis, Nigeria.

 

     1.6       Significance of the Study

The research specifically focuses on the physiological cost of household work among women with a view to improving the existing practices and enhancing the household activities. It will benefit women, building engineers, home economics curriculum developers, health professionals and many others.  The result of this study will clarify understanding and create awareness among women and the general populace on proper ergonomics. It will clearly emphasize the need for the woman to reduce frequently encountered fatigue due to boredom which lead to stress and frustration, particularly at a time when the woman combines other jobs with household chores.  The result will also draw the attention of Building Engineers who design buildings specifically kitchens. The right surface for work in the home should be according to the anatomical measurement of age, sex and postural consideration of the user. Also the proper designing of space for storage and the effective performance of routine activities should be of utmost consideration. The study benefit the health professionals by enabling all the stakeholders to reflect on the present health delivery and make a range of decisions necessary in the context of improving the quality of health among women.

The study will also provide inputs that will assist the Home Economics curriculum developers and guide the to make emphasis in the area of Ergonomics in Home Management courses. It will serve as a guiding document for self assessment on physiological cost of work in the home, food industries and other work places. Non-Governmental Organizations, Teachers, Students and other future researchers can make very good use of this document for future researches, and it will add to the body of existing knowledge.

 

     1.7       Assumptions

The study was based on the assumptions that:

1. physical characteristics of women would influence their energy cost, heart rate, rate of perceived exertion and postures during cooking activities.
2. cooking activities of kneading dough, stirring hard porridge(tuwon-shinkafa) and pounding yam would lead to energy expenditure among women.
3. cooking activities of kneading dough, stirring hard porridge(tuwon-shinkafa) and pounding yam would affect the heart rate of women.
4. cooking activities of kneading dough, stirring hard porridge(tuwon-shinkafa) and pounding yam would affect the rate of perceived exertion of women.
5. cooking activities of kneading dough, stirring hard porridge(tuwon-shinkafa) and pounding yam would cause postural stress among women.

 

     1.8       Scope and Delimitation of the study

The study was delimited to the ergonomic assessment of physiological cost of household work among women in Kaduna metropolis, Kaduna State, Nigeria. The study was delimited to women residing in four (4) Government Secondary Schools in Kaduna Metropolis each of the schools provides three (3) bedroom residential quarters for their staff. The schools are:

1. Queen Amina College Kaduna
2. Rimi College, Kaduna
3. Government College, Kaduna
4. Sardauna Memorial College Kaduna

The choice of Kaduna metropolis is based on the fact that the study is an experimental one and therefore needed to capture a large area. The study was also delimited to sixteen (16) women who were overweight and obesed and whose BMI was between 25.0 -30.0kg/m² and above. The study was further delimited to three (3) selected cooking activities of kneading dough, stirring hard porridge (tuwon-shinkafa) and pounding yam. The choice of these three (3) cooking activities was made because there are numerous cooking activities and household tasks for which this study did not cover all.

The following instruments were used for this study; Standiometre for height and weight measurement; Omron Body Composition Monitor for the measurement of physical parameters; Heart Rate Monitor for the measurement of heart rate and energy  expenditure; and Flexi-curve for the measurement of postural curves.  All these instruments are delimited to this study to adequately measure the found.

ERGONOMIC EVALUATION OF PHYSIOLOGICAL COST OF SOME CERTAIN HOUSEHOLD CHORES PERFORMED BY HOME MAKERS IN KADUNA METROPOLIS, NIGERIA