SELF-REPORTED MUSCULOSKELETAL SYMPTOMS AMONG OPERATORS OF HEAVY 

CONSTRUCTION EQUIPMENT 

N. Kumar Kittusamy

National Institute for Occupational Safety and Health 

Spokane Research Laboratory 

Spokane, WA. USA 

Email: NKITTUSAMY@CDC.GOV 

The purpose of this study was to assess the adequacy of the cab design and to determine the percentage of 

musculoskeletal symptoms among workers. A questionnaire was designed to assess demographics, work 

information, job history, and musculoskeletal symptoms in operators of heavy construction equipment. 

Information concerning equipment included design of the seat/chair, levers, pedals, bothersome vibration, 

quality of egress from the equipment, proper preventative maintenance and repairs, and age of the 

equipment. The body regions that were evaluated included the neck, middle/upper back, low-back, 

shoulder/upper-arm, elbow/forearm, wrist/hand, hip, knee, and ankle/foot. One hundred and eighty nine 

operators completed the questionnaire. The results indicate that these workers are at risk for developing 

musculoskeletal disorders, the need to perform a larger survey to further substantiate the outcome, and the 

need to quantify risk factors (i.e., whole-body vibration and static sitting postures). 

INTRODUCTION 

Wikstrom et al. (1994) reviewed 45 health studies 

in which index groups exposed to WBV were 

compared to a reference group not exposed to 

WBV. In all, the review covered about 18,000 

workers exposed to WBV and around 29,000 

control subjects. The following conclusions were 

advanced from their review: 1) accumulative 

exposure (in years) to WBV may contribute to 

injuries and disorders of the lower back; 2) WBV 

in combination with awkward posture (including 

static sitting) may result in excessive risk of injury 

and disorder to the lower back; 3) an exposureresponse relationship cannot be established at this 

time; and 4) disorders of the gastrointestinal 

system and urogenital system, especially in 

women, have been observed in those exposed to 

WBV. As such these health effects warrant 

further study. 

Hulshof and Veldhuijzen van Zanten (1987) 

performed an evaluation of 19 epidemiological 

studies on the effect of WBV. In all, this review 

covered about 17,000 exposed and 11,000 

reference workers. This review was restricted to 

the relationship between WBV and symptoms 

and/or signs of thoracic and lumbar disorders. A 

scoring procedure was used to assess the relative 

contribution of each epidemiological study. The 

evaluative criteria were: the quality of exposure 

data, effect (health) data, study design and 

methodology. The most frequently reported 

adverse health effects were low back pain, early 

degeneration of the spinal system and herniated 

lumbar discs. Studies, particularly those with 

better methodology, demonstrated a strong 

tendency in a similar direction, thus the authors 

concluded that long-term exposure to WBV could 

be harmful to the spinal system. An exposureresponse relationship cannot be established at this 

time. The main shortcomings of the 

epidemiological studies to date were that their 

description of vibration exposure, the exposuretime history and the contributing occupational 

environment was not sufficient, and that the 

challenge of finding groups that were not exposed 

to vibration was not met. The authors suggested 

that more epidemiological research, especially 

with better study design and methodology, are 

needed to understand the relationship between 
long-term WBV exposure and adverse health 

effects. 

A simple descriptive study by Zimmermann et al. 

(1997) provided insight into the specific 

population of interest (operating engineers). They 

investigated work-related musculoskeletal 

symptoms among operating engineers (N=410). 

There were no control groups used for 

comparison. There was a response rate of 38% 

among the operating engineers. Work-related 

musculoskeletal symptoms were greatest in the 

low back, neck, shoulders, and knees. Operators 

with longer work histories consistently reported 

greater percentages of symptoms, missed work, 

and physician visits than the less experienced 

group. For all body regions the percentage of 

work-related symptoms, missed work, and 

physician visits varied greatly among the five 

different types of equipment (backhoe, crane, 

pushcat/dozer, pull scraper, and end loader). 

These results are suggestive of equipment specific 

demands and stress experienced by the operating 

engineers. Operators using older equipment 

reported a higher percentage of missed work and 

physician visits due to musculoskeletal symptoms 

than those using newer equipment, and those 

using a combination of both newer and older 

equipment. 

METHODOLOGY

A work and health questionnaire was designed to 

assess demographics, work information, job 

history and musculoskeletal symptoms in 

operators of heavy construction equipment. 

Information concerning equipment included 

design of the seat/chair, levers, and pedals, 

bothersome vibration, quality of egress from the 

equipment, proper preventative maintenance and 

repairs, and age of equipment. The body regions 

that were evaluated included the neck, 

middle/upper back, low-back, shoulder/upperarm, elbow/forearm, wrist/hand, hip, knee, and 

ankle/foot. 

Self-administered work and health questionnaires 

were distributed to operating engineers at the 

Western States Operating Engineers Institute of 

Training (located in Spangle, WA and Pocatello, 

ID USA). The operators who attended their 

regularly scheduled training classes, from 

December 2001 to June 2002, at the Training 

Institute were requested to complete the 

questionnaire during their training session. The 

participation was voluntary, but participation was 

highly encouraged by the training officers. All of 

the participants were briefed about the purpose of 

the study and they signed an informed consent 

form. 

RESULTS

One hundred and eighty nine operators out 192 

(98%) completed the questionnaire. A majority of 

the participants were male (88%). The operators 

averaged 45 years of age and 18 years of 

experience. The majority of the operators (>65%) 

indicated that the cab (i.e., seat/chair, levers and 

pedals) was adequately designed for their job. 

Some of the operators reported that they were not 

bothered by vibration and that the quality of 

egress from the equipment was good. Most of the 

operators (>80%) indicated that proper 

maintenance and repairs were performed on their 

equipment. The classification of equipment as 

being old or new was almost identical. Five body 

regions that received the highest total percent of 

symptoms categorized as somewhat severe or 

higher, in descending order, included the 

low-back, hip, knee, shoulder/upper-arm, 

elbow/forearm, and wrist/hand. 

SUMMARY

The current study is in agreement with the 

prevalence of musculoskeletal symptoms in 

various body regions as reported by Zimmerman 

et al. (1997). Also, similar results were observed 

in a pilot study of operators of heavy construction 

equipment (Kittusamy, 2003) that further reiterate 

the findings in the current study. 

Construction workers are often afflicted with 

musculoskeletal symptoms that compromise their 

health and well-being. However, there have been 

few formal studies of the nature and potentially 

preventable causes of these symptoms. This study 
assessed the adequacy of the cab design and 

determined the percentage of musculoskeletal 

symptoms among workers. The results from this 

study indicate that the operators are at risk for 

developing musculoskeletal disorders, the need to 

perform a larger survey to further substantiate the 

outcome, and the need to quantify risk factors 

(i.e., whole-body vibration and static sitting 

postures). 

REFERENCES

Hulshof, C. and Veldhuijzen van Zanten, B.V. 

1987. Whole-body vibration and low-back pain: 

A review of epidemiologic studies. International 

Archives of Occupational and Environmental 

Health, 59: 205-220. 

Kittusamy, N.K., Reports of Musculoskeletal 

Symptoms among Operators of Heavy 

Construction Equipment: A Pilot Study, American 

Industrial Hygiene Conference and Exposition,

Dallas, TX, May 2003. 

Wickstrom, B-O., Kjellberg, A. and Landstrom, 

U. 1994. Health effects of long-term 

occupational exposure to whole-body vibration: A 

review. International Journal of Industrial 

Ergonomics, 14: 273-292. 

Zimmerman, C.L., Cook, T.M. and Rosecrance, 

J.C. 1997. Operating engineers: Work-related 

musculoskeletal disorders and the trade, Applied 

Occupational and Environmental Hygiene, 12: 

670-680.