|Year : 2022 | Volume
| Issue : 2 | Page : 129-132
Carrying load and related health disorders and disability
Seyedeh Negar Assadi
Social Determinants of Health Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
|Date of Submission||18-Dec-2021|
|Date of Decision||11-Feb-2022|
|Date of Acceptance||29-Apr-2022|
|Date of Web Publication||4-Jul-2022|
Dr. Seyedeh Negar Assadi
Social Determinants of Health Research Center, Mashhad University of Medical Sciences, Mashhad - 91889.86773
Source of Support: None, Conflict of Interest: None
Introduction: If carrying loads is not done correctly, it may cause many disorders and diseases, such as musculoskeletal disorders, which are considered the first cause of disability. The aim of the study is a comparison between two methods of calculating load limits and determining the health effects and disorders of carrying loads. Methods: Two methods were used to examine and calculate the maximum permissible load weight. The first method was introduced by the National Institute for Occupational Safety and Health (NIOSH), and the second was introduced by the Washington Industrial Safety and Health Act (WISHA). The researcher used both methods to determine the maximum load weight and to compare the responses. Health effects were listed in the checklist. The study was descriptive, evaluated, and analyzed by Statistical Package for the Social Sciences (SPSS) software. Findings: In the first method, recommended weight lifted (RWL) and lifting index were calculated, and in the second method, the maximum allowable load was calculated. The weight obtained by the first method was smaller than the weight obtained by the second method. Carrying heavy loads resulted in low back pain, discopathy, herniation, high ocular pressure, and osteoarthritis. Conclusion: The first method is suitable for determining the permissible load limits. In this way, the pressure on the spine is less likely to occur. In general, health disorders and related disabilities were less likely to happen in this situation.
Keywords: Health, lifting load, musculoskeletal disorders
|How to cite this article:|
Assadi SN. Carrying load and related health disorders and disability. Indian J Occup Environ Med 2022;26:129-32
| Introduction|| |
The personnel's health is a very important factor, especially the ones who handle and move the load. If carrying load is not done properly, it may cause many disorders and diseases such as musculoskeletal disorders, which are considered the first cause of disability. In different situations, industries, and schools, carrying load is done when it is required. Some methods have been designed to determine the maximum allowable weight of the load. One of these methods has been introduced by the National Institute of Occupational Health and Safety (NIOSH) 1,, and the other has been proposed in the Washington Industrial Safety and Health Act (WISHA) 2. Based on the results, necessary recommendations were presented regarding the correct transportation of the load.
- National Institute of Occupational Safety and Health
- Washington Industrial Safety and Health Act
In the first method, the recommended load weight should be obtained first based on six variables or coefficients. The six coefficients or multipliers are horizontal multiplier (HM), vertical multiplier (VM), displacement multiplier (DM), asymmetric multiplier (AM), frequency multiplier (FM), and coupling multiplier (CM). The actual weight lifted (AWL) was then divided by the recommended weight limit (RWL) and the load lifting index (LI), which were obtained.
In the second method, the maximum permissible weight of the load was obtained in another way. The maximum permissible load and the correct way of transporting the load were examined, and the results were reported according to the Washington Industrial Safety and Health Act (WISHA) method. In the second method, the effect of age was considered with the coefficient. Also, for women, special coefficients were applied.
The use of Snook tables is another way to determine the permissible limits of the load.
Musculoskeletal disorders always have been considered due to their debilitating effects.,, Low back pain and disorders of the upper limbs are among the most debilitating diseases and disorders.
Proper control, management, and prevention of risk factors for these disorders have been considered, and ergonomics is a science considering these disorders. Numerous studies have examined the risk factors for these diseases., All of these studies discussed that the prevention of these kinds of diseases is a priority. For instance, load transportation is one of the most important risk factors that can be controlled.,
Research has been done considering different methods., Since no similar study has been done on this subject and this index should be evaluated in homecare services and warehouses' staff, the researcher intended to examine the lifting index as well as the maximum allowable load. The purpose of the study was a comparison between two methods of calculating load limits and determining the health effects and disorders of carrying loads.
| Methods|| |
Investigating homecare services and warehouses' staff that usually have to lift and move the load, the maximum permissible load weight was calculated in two ways. One of these methods has been introduced by the National Institute of Occupational Health and Safety (NIOSH), and the other has been proposed in the Washington Industrial Safety and Health Act (WISHA). The researcher used both methods to determine the maximum weight of the load and, based on the results, presented necessary recommendations regarding the correct transport of the load.
In the first method, the recommended weight limit was obtained based on six multipliers or coefficients:
H: horizontal distance in centimeters
V: vertical distance in centimeters
D: vertical displacement distance in centimeters
A: angle of back rotation in degrees
C: coupling of load with hand in three levels
F: Frequency of load carrying according to a related table.
The formulas of coeffitients are:
Horizontal Multiplier (HM) = 25/H
Vertical Multiplier (VM) = 1-0.003lV - 75l
Displacement Multiplier (DM) = 0.82 + 4.5/D
Asymmetric Multiplier (AM) = 1-0.0032A
Coupling Multiplier (CM) = 1-0.95-0.90
The formula for recommended weight limits is:
RWL = 23 x HM x VM x DM x AM x FM x CM
The formula for lifting index is:
Lifting Index (LI) = AWL/RWL
In the second method, the maximum permissible load weight was obtained as follows:
The maximum allowable load with the WISHA method was investigated as follows.
The method of the Washington Industrial Safety and Health Act has six steps:
- At first, the actual load weight (load weight in kilograms) was entered.
- The corresponding number was written according to the position of the person's hand at the beginning of lifting or lowering the load.
- According to the number of times the load is lifted per minute and also the time used to lift the load during the day, the coefficient was read from the relevant table.
- According to the angle of the spine during the lifting of the load, if it is more than 45 degrees, the coefficient will be 0.85, and if it is less than 45 degrees, the number will be 1.
- The researcher multiplied the numbers selected in steps 2 to 4:
- If the number obtained at this stage is greater than the actual weight of the load, there will be no risk to health.
Load-carrying complications were also assessed using a checklist.
The statistical method was used to describe and compare measurable outcomes. This is a descriptive study, and it was evaluated and analyzed by SPSS software using the mean and standard deviation. To compare the results of the two methods, first, the normality of quantitative data was tested, and if the result was normal, a T-test was used; otherwise, the Mann Whitney-U test was used.
| Findings|| |
Fifty-one people were evaluated. In the first method, RWL: Recommended weight limit Lifting Index (0-1) = AWL/RWL, and the maximum allowable load was obtained by the second method. The number obtained by the first method was always smaller than the one obtained by the second one (e.g., 15 vs. 17). Therefore, statistically, the maximum allowable load calculated in the first method was less than the second. [Table 1] shows a comparison of variables related to lifting and permissible weight limit determination with two methods.
|Table 1: Comparison of variables related to lifting and permissible weight limit determination with two methods|
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Based on research objectives
The participants were 51 people chosen from homecare services and warehouse staff. The mean age was 42.5. ± 1.12 years, and all were men. They had 15.24 ± 0.43 years of work experience. They participated in carrying a load with permissible limits of methods 1 and 2. Related disorders were examined, and their frequency was obtained. Disorders such as low back pain and intervertebral disc herniation, abdominal and groin hernias, increased intraocular pressure, and other musculoskeletal disorders such as knee osteoarthritis, tendonitis, and shoulder osteoarthritis (glenohumeral joint) are related to disability.
[Table 2] shows the results of the frequency of disorders related to lifting according to the permissible limits in methods 1 and 2.
|Table 2: Frequency of disorders related to lifting according to the permissible limits in methods 1 and 2|
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| Discussion|| |
The maximum allowable load weight calculated in the first method was less than the second. [Table 1] shows a comparison between the variables of the two methods. This is due to the involvement of several variables such as asymmetric multiplier, repetition multiplier, coupling multiplier, which are mentioned in the methods and are evaluated, Horizontal multiplier, vertical multiplier, vertical displacement multiplier. In addition to the maximum permissible weight limits, the coefficient or variable related to the angle of the spine or asymmetric was also significant because the angle of the spine is not allowed to carry the load and in the first method had a greater impact on determining the allowable weight of the load. It was calculated separately, while in the second method, it was only one number in the table.
The coefficient of repetition, which exists in both methods, was obtained using the relevant tables. The first method dealt with this issue in more detail. The second method had a more general view on this issue., Horizontal, vertical, and vertical displacement coefficients were also effective. In the first method, there was a separate formula for calculating each one. The second method used a graded form, and they acted and had almost the same effect.
Musculoskeletal disorders are important because of their debilitating effects.,, Low back pain and disorders of the upper limbs are among the most debilitating diseases and disorders and disabilities.
Proper control, management, and prevention of risk factors causing these disorders have been considered, and ergonomics is a science that is working on this issue. Methods of carrying loads and determining the allowable weight of the load are discussed in ergonomics.
Numerous studies have examined the risk factors for these diseases., All of these studies have prioritized the prevention of diseases. Low back pain and intervertebral disc herniation are more common than unauthorized loads, and other diseases are caused by increased intra-abdominal or cranial pressure, such as hernias or hernias of the abdomen and groin. Some of these disorders require surgery, and some of them may lead to disability.
Also, increased intraocular pressure, which occurs as a result of high pressure on the body and skull, increases the risk of glaucoma and requires medical treatment. Load transportation is also one of the most important risk factors that can be controlled.,
Knee osteoarthritis is also common as a result of the pressure on lower limbs while carrying a load. Osteoarthritis of the shoulder also occurs during prolonged heavy handling.
In addition, shoulder tendonitis and stretching of the rotating cuff tendons of the shoulder have been found as a result of infrequent use of this limb. Now, the heavier load and the longer time used in transporting caused the most complications. As shown in [Table 2], the present study provided similar conclusions. These disorders can cause impairment, sickness absence, and disability in the workers of organizations, and prevention is necessary.
Conclusion: In sum, it is best to use the first method as far as possible in determining the permissible limits of the load. In this way, the pressure on the spine is less likely to occur. In general, health disorders and related disabilities were less likely to happen in this situation.
The author would like to thank the Vice Chancellor for Research of Mashhad University of Medical Sciences for supporting the research project 971443.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]