Compensation and Working Conditions Spring 1999 29

Workers' Health

Putting a Strain

on Workers' Health

Safety and Health

BLS data indicate that sprains, strains, and tears

accounted for approximately 44 percent of all

occupational injuries that resulted in days away

from work in the United States in 1996.

TIMOTHY WEBSTER

Timothy Webster is an economist in the Office of Safety, Health and Working

Conditions, Bureau of Labor Statistics.

Telephone: (202) 606-6179

E-mail: Webster_T@bls.gov

When you think of occupational injuries and illnesses, what

comes to mind? Fractures and lacerations? Bruises and

burns? Respiratory disease? These occupational injuries

and illnesses do occur, but not in the majority of cases. The

most prevalent nature, or principal physical characteristic

identifying nonfatal occupational injuries and illnesses involving days away from work in the United States, is sprains,

strains, and tears. BLS data indicate that this type of injury

accounted for approximately 44 percent of all days away

from work cases in 1996. Sprains, strains, and tears also

accounted for a high percentage of the total number of cases

within each industry division in 1996, ranging from a low

of 34 percent in agriculture, forestry, and fishing to a high

of 53 percent in transportation and public utilities. Although the number of sprains, strains, and tears has fallen

between 1992 and 1996, such injuries have remained a relatively constant proportion of the total number of cases.1

(See table 1.)

What are sprains, strains, and tears? They are traumatic

injuries to muscles, tendons, ligaments, and joints resulting from sudden wrenching, twisting, stretching, and ripping. This classification does not include tendonitis or bursitis, illnesses that generally occur over time as a result of

repetitive activity. How do sprains, strains, and tears occur? What part of the body is most affected? Which occupations have the highest number of cases? These and related questions can be answered using data on case

characteristics from the BLS Survey of Occupational Injuries and Illnesses. The remainder of this article refers to

data from the 1996 survey.

Selected characteristics

Event or exposure. Event or exposure is the manner in

which an injury was inflicted. Examples of events include

falls, slips and trips, assaults, and contact with objects. As

can be seen in table 2, overexertion was the major event or

exposure for sprains, strains, and tears. This occurs when

the physical effort of a worker who lifts, pulls, pushes, holds,

carries, wields, or throws an object results in an injury. The

object being handled often exceeds the weight that a worker

should be handling or is handled improperly, for example,

lifting from a shelf that is too high, or in a space that is

cramped. Within the broad category of sprains, strains,

and tears caused by overexertion, most incidents resulted

specifically from overexertion in lifting.

The second most common event or exposure was bodily

reaction. This occurs when a single incident of free bodily

motion imposes stress or strain on a part of the body. This

classification includes bending, crawling, reaching, twisting, sudden reaction when surprised, and walking or running—without other incident. This classification also includes standing, and slips, trips, or loss of balance—without

fall. Falls on the same level were the third most common

event, followed by contact with objects or equipment.

Part of body. Among cases involving sprains, strains, and

tears, the part of the body most affected was the back. This

is not surprising, especially given that 31 percent of all

sprains, strains, and tears cases are the result of overexer-
30 Compensation and Working Conditions Spring 1999

tion in lifting. Shoulders and knees tied for the second

most often sprained, strained, and torn parts of the body.

Source of injury. The source of the injury is the object,

substance, or bodily motion that directly produced the injury or illness. For example, the event causing an injury

may be “struck by object,” while the source is the object

itself, say a beam or a pipe. Containers and worker motion

were the two leading sources of sprains, strains, and tears

cases, each accounting for approximately one-fifth of the

cases. Containers include boxes, crates, cartons, tanks,

buckets, packages, bundles, and bales. The most frequent

event associated with containers as the source was overexertion. Injuries recorded as having worker motion or position as the source almost always have bodily reaction as the

event, and were inflicted because of bodily stress resulting

from reaching, twisting, bending, turning, or walking. This

is one instance for which event and source are essentially

the same. Floor and ground surfaces were the third most

common source, followed by parts and materials, and health

care patients. Floor and ground surfaces are frequently associated with falls, while parts and materials and health

care patients are most often associated with overexertion.

Occupation. Operators, fabricators, and laborers incurred

the highest number of sprains, strains, and tears cases.

Within this category, handlers, cleaners, helpers, and laborers had the most cases, followed by transportation and

material moving occupations, specifically truck drivers.

Handlers, cleaners, helpers, and laborers includes construction laborers, non-construction laborers, stock handlers and

baggers, and freight and material handlers. Next in frequency were service occupations, specifically nurses’ aides

and orderlies. Not surprisingly, all of these occupations

require a significant amount of lifting, moving of objects,

and bodily motion. Handlers, cleaners, helpers, and laborers, and truckdrivers most frequently move containers and

parts and materials, while nurses’ aides and orderlies primarily move health care patients.

Workdays lost. The median number of days away from

work designates the point at which half the total cases involved more days away and half involved fewer. The median number of days away from work for sprains, strains,

and tears cases is 6, 1 day more than the median for all

cases. In 1996, a large number of sprains, strains, and tears

involved a significant number of days away from work. In

18 percent of the cases, workers were away from work 31

or more days.

Summary

The category sprains, strains, and tears is the leading nature of injury among nonfatal occupational injuries and

illnesses. Workers receive these injuries when lifting objects that are too heavy, when working in awkward positions for an extended period of time, or when twisting,

bending, falling, and slipping. These injuries tend to be

serious, with a median 6 days away from work.

1

 The Census of Fatal Occupational Injuries (CFOI), a companion to the

Survey of Occupational Injuries and Illnesses (SOII), counts the annual number of fatal injuries in the workplace. As in SOII, CFOI records case and

demographic information (for example, industry, occupation, nature, event,

source) for each incident. According to the census, between 1992 and 1997,

33 cases with sprain, strain, and tear as the nature of injury resulted in death

due to medical complications associated with the injury. Medical complications included those related to surgery following the injury, embolism, or other

causes.
 Compensation and Working Conditions Spring 1999 31

Workers' Health

TABLE 1. Number of sprain, strain, and tear nonfatal occupational injury cases resulting in days away from work, by major industry

division, private industry, 1992-96

Number Percent Number Percent Number Percent Number Percent Number Percent

All injury and

 illness cases ............ 2,331,100 2,252,500 2,236,600 2,040,900 1,880,525

Sprains, strains, tears .......... 1,022,746 100 959,163 100 963,496 100 876,792 100 819,658 100

Agriculture, forestry and

 fishing ........................... 18,273 2 15,948 2 14,845 2 15,711 2 13,080 2

Mining ............................. 9,508 1 8,928 1 8,238 1 8,367 1 5,849 1

Construction ................... 79,022 8 76,971 8 80,967 8 72,404 8 68,649 8

Manufacturing ................. 247,895 24 222,548 23 223,269 23 198,682 23 176,699 22

Transportation and

 public utilities ................ 113,560 11 116,142 12 123,304 13 112,809 13 117,749 14

Wholesale trade .............. 80,700 8 73,470 8 74,611 8 72,146 8 64,299 8

Retail trade ..................... 172,502 17 163,225 17 165,888 17 143,412 16 135,008 16

Finance, insurance, and

 real estate ..................... 24,248 2 22,128 2 20,252 2 17,259 2 17,154 2

Services ......................... 277,038 27 259,803 27 252,121 26 236,003 27 221,171 27

 NOTE: Because of rounding, components may not add to totals.

Major industry division

1992 1995 1993 1994 1996

TABLE 2. Percent distribution of sprain, strain, and tear nonfatal occupational injury cases involving days away from work, by selected

characteristics, 1996

 Total cases (819,658) ............................. 100

Event or exposure

Total ............................................................. 100

Overexertion, all types ...................................... 52

Lifting ........................................................... 31

Bodily Reaction ................................................. 19

Fall on the same level ........................................ 10

Contact with object, equipment ......................... 6

Fall to lower level ............................................... 4

All other events, exposures ............................... 9

Part of body

Total ............................................................. 100

Trunk ................................................................. 62

Back ............................................................ 49

Shoulder ...................................................... 8

Lower extremities .............................................. 20

Knee ............................................................ 8

Upper extremities .............................................. 9

Wrist ............................................................ 3

All other parts of body ....................................... 9

Source of injury

Total ............................................................. 100

Containers ........................................................ 22

Worker motion or position ................................. 21

Floor, ground surfaces ...................................... 15

Characteristics Percent Percent Characteristics

Parts and materials ........................................... 10

Health care patient ............................................ 8

All other sources ............................................... 24

Occupation

Total ............................................................. 100

Operators, fabricators, and laborers .................. 42

Handlers, cleaners, helpers, and laborers ... 16

Transportation and material moving ............. 13

 Truckdrivers ............................................ 10

Service ............................................................. 20

Nursing aides, orderlies ............................... 8

Janitors and cleaners .................................. 3

Technical, sales, and administrative support ..... 15

Precision production, craft, and repair ............... 14

Managerial and professional ............................. 6

Registered nurses ....................................... 2

Farming, forestry, and fishing ............................ 3

Workdays lost (median workdays lost = 6) .............

Total ............................................................. 100

1 .................................................................... 14

2 .................................................................... 13

3 to 5 ................................................................. 23

6 to 10 ............................................................... 14

11 to 20 ............................................................. 12

21 to 30 ............................................................. 6

31 or more ........................................................ 18

NOTE: Overall categories may include data for classifications not shown.