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Year : 2017  |  Volume : 6  |  Issue : 2  |  Page : 99-104

Generic work capacity assessment tool for working conditions in India: Preliminary results of development and standardization

1 Department of Community Based Rehabilitation, JSS College of Physiotherapy, Mysore, Karnataka, India
2 Department of Physical Therapy, Sikkim Manipal Institute of Medical Sciences, Sikkim Manipal University, Gangtok, Sikkim, India

Date of Web Publication18-May-2017

Correspondence Address:
Kavitha Raja
JSS College of Physiotherapy, Mysore, Karnataka
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijhas.IJHAS_172_16

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BACKGROUND: The work capacity assessment (WCA) tool is a new tool developed specifically to assess worker suitability for working conditions in India. This study presents the preliminary results of reliability (interrater) and internal consistency of the WCA tool.
AIMS: The aim of this study is to develop a work capacity tool for working conditions in India.
MATERIALS AND METHODS: The steps for instrument development were followed stringently. The newly developed tool addressed three categories of work: heavy manual labor, sustained labor, and sedentary work. Four participants in heavy manual labor, five in sustained labor, and five in sedentary work performed activities specified by the new scale; videography was done simultaneously.
STATISTICAL ANALYSIS: Internal consistency between the items in the scale was ascertained by Cronbach's alpha. Spearman's rank correlation coefficient was calculated for intertester reliability.
RESULTS AND CONCLUSIONS: Some items in each of the three categories were removed from the final tool due to lack of variance between participants. After omitting these items, alpha was 0.65 and 1 in heavy manual labor, 0.95 and −0.14 in sustained labor, and 0.83 in sedentary work. All test items with the exception of isometric strength and posture sustainability in heavy manual labor correlated well with other items (>0.7). The final tool is fairly robust in terms of internal consistency and reliability. This is a preliminary report, and the tool needs to be further validated before clinical use on a larger and heterogeneous population.

Keywords: Internal consistency, manual labor, sedentary work, sustained postures

How to cite this article:
Raja K, Mathew J, Bista B. Generic work capacity assessment tool for working conditions in India: Preliminary results of development and standardization. Int J Health Allied Sci 2017;6:99-104

How to cite this URL:
Raja K, Mathew J, Bista B. Generic work capacity assessment tool for working conditions in India: Preliminary results of development and standardization. Int J Health Allied Sci [serial online] 2017 [cited 2023 Dec 10];6:99-104. Available from: https://www.ijhas.in/text.asp?2017/6/2/99/206420

  Introduction Top

Work-related injuries and dysfunctions are on the rise, especially in the unorganized sector due to lack of adequate controls and policies in developing nations. The Indian Ministry of Labor acknowledges that the informal sector comprises the bulk of the workforce [1] in the country. To thwart the public health burden of work-related injuries, it is essential that workers are screened/evaluated for their ability to perform the tasks required of them at their workplace. In case of injury, this evaluation becomes doubly important, prior to return to work. India has a population of approximately 500 million, who are in the working age group, but <10% of workers are covered by existing health and safety legislation.[2] Due to these factors, there is a dire need to assess job-specific fitness of workers before placement, and after rehabilitation, using functional capacity evaluation (FCE) batteries.

Functional capacity assessments (FCAs) were developed as a joint venture of physiotherapists (PTs) and occupational therapists (OTs) by compiling specific tests meant to assess an individual's capabilities.[3] These were generally related to job-specific tasks of posture and manual handling of loads.

The components of an FCA model are as follows. The first process is to gather information about the patient's medical history. Some examiners also obtain the psychosocial information.[3] In the second stage, the measurements of a person's ability to perform a number of job-related functions are done. The activities are categorized under three headings:[3] weighted activities, posture and tolerance, and upper extremity activities.

There are a variety of FCA tools available, but there is a dearth of research on most, with the exception of Blankenship FCA system and Isernhagen FCA work system.

The Isernhagen work systems (IWS) are one of the commonly used batteries of FCA.

Brouwer et al.[4] reported on the test–retest reliability of the IWS FCE on chronic low back pain patients and found that 15 tests showed an acceptable test–retest reliability based on Kappa values and percentage of absolute agreement (79%) and 11 tests (61%) showed an acceptable test–retest reliability based on intraclass correlation coefficient values.

The Blankenship model is another battery that is frequently used. Brubaker et al.[5] studied its sensitivity and specificity. They reported a sensitivity of 80% and a specificity of 84.2%. The positive likelihood ratio was 5 and the negative likelihood ratio was 0.2. A systematic review done by Gouttebarge et al.[6] revealed a dearth of studies on the reliability and validity of Blankenship system.

Most of the FCAs currently available require specific training and have been developed essentially in the USA. They are long and time-consuming, requiring on an average 24–48 h to complete. The activities which are tested in the existing FCAs may not actually mimic the demand of the repetitive job activities.[7] Moreover, no FCA has been developed for application to unique working conditions in India and similar countries. By conventional definition, FCEs use mathematical calculations. Since we needed a versatile on-site tool, we decided to develop a work capacity assessment (WCA) tool that would be easier to use and would require minimal training.

The objectives of the study were as follows:

  • To develop a new short form WCA battery, suited, to evaluate a variety of working conditions in India
  • To find content and construct validity
  • To assess the reliability of the new WCA.

  Materials and Methods Top

Seven PTs and OTs took part in the study. This included two PTs for item generation, three PTs for item reduction, and two PTs and one OT for content validity. The study employed an observational study design and participants were recruited by purposive sampling.

Seventy-four uninjured participants took part in the pilot testing, which included twenty heavy manual laborers (HMLs) for standardization of prone plank test for the Indian population, fifty students (postgraduates, interns, and undergraduates) for standardization of reaction time (RT) for the Indian population, and four postgraduate physiotherapy students for pilot testing. Fourteen asymptomatic participants fitting the work categories were recruited for reliability testing which included four participants for heavy manual labor and five participants each for sustained labor and sedentary jobs. The study was approved by the University Ethics Review Board, and a written consent from the individual participants was obtained prior to the commencement of the study.

The inclusion criteria were PTs and OTs, with a minimum of 2-year experience were considered for participation in the tool development stage. Workers who were engaged in the specified category of job for a minimum of the preceding 1 year were recruited for reliability testing, and participants with no reported morbidity were recruited for pilot testing.

The operational definitions used in the study as follows:

  • HML:[7] Workers engaged in jobs requiring lifting of objects weighing 25 kg or more at least four times on an average working day or routine lifting of objects weighing 10 kg at least twice in an average working hour were considered as HML
  • Sustained manual laborer (SML):[7] Workers engaged in jobs involving routine static holding of an upright posture of the lower limbs and trunk and dynamic overhead use of one or both upper extremity (ies) were considered as SML
  • Sedentary worker (SW):[7] Workers engaged in jobs involving sustained sitting or lying postures and use of distal upper extremity were considered as SW.

The instruments used were Sony Digicam DSC-W120, 7.2 megapixels for videographic analysis, and articles required for testing. A three-stage Delphi process was undertaken for generation of items and scoring form. Each reviewer noted the limitations of existing tools from an independent list review. Thereafter, a consensus meeting was arranged, and the construct was identified and defined. Applicability to Indian conditions was emphasized upon.

Apart from feedback from the reviewers, visual observation and interview of the target population at work were done to outline important aspects to be included in the FCA as a part of item generation. This was an essential step to ensure applicability.

Following this, items were generated by participants involved in this part of the study. Only those suggestions which were feasible and seemed realistic were taken into consideration. After the items were generated, the assessment form and scoring information were generated. The items and scoring criteria were given to three PTs not included in the previous phase for item reduction.

Following tool construction, face validity was assessed by giving the questionnaires to 3 experts (2 PTs/1 OT) not involved in the item generation phase. Appropriate changes were made as per the experts' suggestions. The content validity was assessed based on theoretical constructs. Standardization of RT was done on fifty normal students. Standardization of prone plank test, to ascertain hold time, was done on twenty laborers.

A pilot study was conducted on four normal participants for applicability, feasibility, and clarity. The participants recruited were normal university students, with no apparent morbidities. The procedure of testing was standardized including rest breaks and order of assessment.

The final scale was applied to five participants in SML and SW categories, and four participants in HML category [Appendice 1] [Additional file 1], [Appendice 2] [Additional file 2], [Appendice 3] [Additional file 3] to identify the reliability and feasibility of the tool. The population tested was all involved in the job for at least a year.

Scoring was done [Appendice 4] [Additional file 4], [Appendice 5] [Additional file 5][15],[16] on videorecordings of participants performing activities specified in the scale. Intertester reliability was estimated by two therapists, one of whom was naïve to the study details. Both testers evaluated the same video independent of each other.

The stages of tool development are as follows:

The data analysis was done using SPSS version 11.5 (USA, IBM corp). Descriptives were used for normative data on RT, prone plank, and Biering–Sorensen test. Internal consistency of the individual category of workers was estimated using Cronbach's alpha. Factor analysis was performed to divide the scale into components measuring different constructs of the scale. Cronbach's alpha was calculated for individual components. An α of ≤0.70 was considered acceptable. Reliability was estimated using Spearman's rank correlation coefficient. P value was kept at ≤0.05.

  Results and Discussion Top

Literature review of all the existing FCE protocols revealed that there was no tool that evaluated all the requirements for blue collar jobs in India and similar countries.

Components of existing FCEs that were relevant to Indian workers were adopted or adapted with modifications, and new items were added to mimic all situations that were foreseen.

Carrying loads on the head and floor to overhead lifting were incorporated in the scale. Consensus was sought at a reconciliation meeting of the scale developers. Those items not having 75% concurrence were omitted from the scale, resulting in four items being removed. These were a goniometric measurement of spinal rotations, dynamometric measurement of trunk muscle strength, and cognitive evaluation. Pain measurement was changed to the rate of perceived discomfort (RPD).

An indigenous tool was constructed for testing RT. Since normal values were not available for the Indian population, standardization was done using fifty students. The standard timing was found to be 385.97 ± 56.42 ms. The scoring criteria were haphazard in the beginning. The scoring criteria was changed universally from 0 to 5, 0 being maximal risk or unable to do a task, and 5 being minimal risk or able to do a task to maximum requirements.

After pilot testing, the following procedural changes were made. A rest period of 5–6 min was incorporated between the testing of muscular strength of extremities, the functional and biomechanical analysis (FBA), the instrumented activity, and the spinal muscular endurance (SME) in the HML category. A rest period of at least 2–3 min was incorporated between the isometric, isotonic, and eccentric control of the SME in all three categories. The grading of the prone plank test of muscular endurance was changed and is presented in [Table 1]. The aerobic fitness test was changed from 1 mile run to submaximal exercise test using Astrand-Rhyming protocol for ease of performance. The results according to the stages of construction of the scale are given in [Table 2].
Table 1: Grading of the prone plank test of muscular endurance

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Table 2: Results of the different stages of the scale construction

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Some items in the overall scale did not have a variance between participants and were omitted. These items, with the categories they belong to, are listed in [Table 3].
Table 3: Items lacking variance in the different categories

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In the HML category, the alpha after removing, the items having no variance (balance, posture, and other job-specific tasks [OJST]) were 0.64. Factor analysis revealed that the components were divided into two constructs. The items in the two constructs and the alpha values are depicted in [Table 4].
Table 4: Items representing different constructs with their alpha values in the heavy manual labor category

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In SML category, the alpha after reducing items having no variance (dynamometric muscular strength) was 0.62. Factor analysis categorized the components into three principal components as given in [Table 5].
Table 5: Items representing different constructs with their alpha values in the sustained labor category

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The alpha for the first component was 0.96. For component 2, α was −0.15. Component 3 comprised only one item and (posture) was not consistent with other items of the scale.

In the SW category, there were three items having no variance (sensation, aerobic fitness, and OJST). The alpha for the other items was found to be 0.84.

Spearman's rank correlation coefficient was calculated for only those components which had variance in grading as a part of. Items having no variance suggested that they had a perfect correlation. The correlation for relevant items in the HML category is shown in [Table 6], for the SML category in [Table 7], and for the SW category in [Table 8].
Table 6: Spearman's correlation values for heavy manual labor

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Table 7: Spearman's correlation values for sustained labor

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Table 8: Spearman's correlation values for Sedentary Job

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The processes for the development of a new scale and its validation have been described in detail by Benson and Clark.[8] The authors have tried to adhere to these processes. A method of lift commonly encountered in the Indian setup – the head to overhead lift was not included in the scale. The authors realized the significance of this type of lift at the end of the study when they encountered a participant who did this regularly. Participants in the HML and SML categories were of poor educational background and they were unable to follow the instructions in the Astrand-Rhyming protocol. Hence, there is a need to incorporate an easier to follow aerobic test.

The face validity of the scale was ascertained to be satisfactory. However, the therapists involved in the process had no experience with FCEs and the knowledge base was purely theoretical.[9] Despite this, most of the items have acceptable internal consistency. This lack of variance in certain items can be attributed to the homogeneity of the participants and the small numbers. To comment conclusively on the relevance of these items, it would be necessary to test larger numbers of workers.

OJST would vary from person to person. Hence, it is meaningful to delineate this item as well as the overall assessment into the latter part of the scale, dealing with the therapists' recommendation.[10] It is our opinion that both of these would be better as narrative assessments.

In the SML category, future research should incorporate workers with heterogeneous job demands (requiring sustenance of varying postures for varying periods of time) as this may better reflect actual job characteristics. Extremity strength fell under different constructs in this category which is logical when the working requirements are considered.

SW category revealed three items with no variance. The constructs were sensation, aerobic fitness, and OJST. This finding is logical and can be considered as a strength of the scale. In this category, the participants were able to follow the instructions for the Astrand-Rhyming test.[11] We attribute this finding to the fact that the participants were postgraduate students. This was the only category, where women were included as participants as they form a major part of the sedentary workforce.

Some of the items could not be tested at all due to lack of applicability. They were aerobic fitness in the heavy manual labor and sustained labor categories; change in direction in the FBA of the heavy manual labor category due to the lack of cooperation of the participants, and pushing and pulling ability in the heavy manual labor category because none of the participants did significant amounts of these activities.

Longer video clips of workers at work with better clarity, cooperation of the workers for a simulated task analysis, and better work and personal history would have lent greater feasibility to the use of the scale. Although one of the objectives was to construct a scale that could be completed in an hour, this objective could not be met. Further testing and item reduction may enable the fruition of this objective. Although other researchers have developed and validated short from FCE tools,[12] none of them have been developed for Indian requirements. Hence, comparisons cannot be made meaningfully.

While the authors have provided some data in support of use of this tool,[13],[14] the evidence needs to be further examined. The fact that a small sample size was tested is a limitation of this study. Lastly, it has been established by various researchers that working conditions in India and similar countries are different to the Western world. Reasons are inadequate mechanization, extreme climatic conditions, and lack of stringent occupational health and labor laws. The authors believe this tool to have wide application in the developing world where much of the work continues to be performed by human effort.

Future directions

This is a preliminary report and further investigation into psychometric properties is required before the tool can be conclusively recommended for use in work settings.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Joseph D. International occupational health. Int J Hyg Environ Health 2003;206:1-11.  Back to cited text no. 1
Brecker N. Occupational health in India. Occup Med (Lond) 2010;60:577.  Back to cited text no. 2
Key GL, editor. Functional capacity evaluation. In: Industrial Therapy. 1st ed. St. Louis: Mosby; 1999. p. 220-53.  Back to cited text no. 3
Brouwer S, Reneman MF, Dijkstra PU, Groothoff JW, Schellekens JM, Göeken LN. Test-retest reliability of the Isernhagen Work Systems Functional Capacity Evaluation in patients with chronic low back pain. J Occup Rehabil 2003;13:207-18.  Back to cited text no. 4
Brubaker PN, Fearon FJ, Smith SM, McKibben RJ, Alday J, Andrews SS, et al. Sensitivity and specificity of the Blankenship FCE system's indicators of submaximal effort. J Orthop Sports Phys Ther 2007;37:161-8.  Back to cited text no. 5
Gouttebarge V, Wind H, Kuijer PP, Frings-Dresen MH. Reliability and validity of Functional Capacity Evaluation methods: A systematic review with reference to Blankenship system, Ergos work simulator, Ergo-Kit and Isernhagen work system. Int Arch Occup Environ Health 2004;77:527-37.  Back to cited text no. 6
Fishbain DA. Functional capacity evaluation. Phys Ther 2000;80:110-2.  Back to cited text no. 7
Benson J, Clark F. A guide for instrument development and validation. Am J Occup Ther 1982;36:789-800.  Back to cited text no. 8
Kuijer W, Brouwer S, Reneman MF, Dijkstra PU, Groothoff JW, Schellekens JM, et al. Matching FCE activities and work demands: An explorative study. J Occup Rehabil 2006;16:469-83.  Back to cited text no. 9
Gross DP, Battié MC. Functional capacity evaluation performance does not predict sustained return to work in claimants with chronic back pain. J Occup Rehabil 2005;15:285-94.  Back to cited text no. 10
Reneman MF, Brouwer S, Meinema A, Dijkstra PU, Geertzen JH, Groothoff JW. Test-retest reliability of the Isernhagen Work Systems Functional Capacity Evaluation in healthy adults. J Occup Rehabil 2004;14:295-305.  Back to cited text no. 11
Gross DP, Battié MC, Asante A. Development and validation of a short-form functional capacity evaluation for use in claimants with low back disorders. J Occup Rehabil 2006;16:53-62.  Back to cited text no. 12
Gross DP, Battié MC. Reliability of safe maximum lifting determinations of a functional capacity evaluation. Phys Ther 2002;82:364-71.  Back to cited text no. 13
King PM, Tuckwell N, Barrett TE. A critical review of functional capacity evaluations. Phys Ther 1998;78:852-66.  Back to cited text no. 14
Butler DS, Jones MA. Tension Testing-The Upper Limbs. In: Butler DS, ed Mobilization of the Nervous System. Melbourne: Churchill L Livingstone; 1991. p. 147-159.  Back to cited text no. 15
Butler DS, Jones MA. Tension Testing-The Lower Limbs and Trunk In: Butler DS, ed Mobilization of the Nervous System. Melbourne: Churchill L Livingstone; 1991. p. 139.  Back to cited text no. 16


  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7], [Table 8]


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