Content uploaded by Gregory W Heath
Author content
All content in this area was uploaded by Gregory W Heath on Dec 05, 2017
Content may be subject to copyright.
Medicine& Science in Sports & Exercise
Issue: Volume 30(8), August 1998, pp 1246-1249
Copyright: (C) Williams & Wilkins 1998. All Rights Reserved.
Publication Type: [Epidemiology]
ISSN: 0195-9131
Accession: 00005768-199808000-00010
Keywords: INJURY RATES, PHYSICAL ACTIVITY
[Epidemiology]
Injury rates from walking, gardening, weightlifting, outdoor bicycling, and aerobics
POWELL, KENNETH E.; HEATH, GREGORY W.; KRESNOW, MARCIE-JO; SACKS,
JEFFREY J.; BRANCHE, CHRISTINE M.
Author Information
National Center for Injury Prevention and Control and the National Center for Chronic Disease
Prevention and Health Promotion, Centers for Disease Control and Prevention, Atlanta, GA
Submitted for publication April 1997.
Accepted for publication July 1997.
The authors thank Jeffrey P. Koplan, Caroline Macera, and Russell R. Pate for their suggestions
on the manuscript.
The following are members of the ICARIS project, which designed and conducted the survey
from which these data were obtained: Principal investigator: Jeffrey J. Sacks, M.D., M.P.H.;
Project core group: Barbara Houston; Marcie-jo Kresnow, M.S.; Joann M. O'Neil, B.A.; and
Suzanne M. Smith, M.D., M.P.H., of NCIPC. James Hersey Ph.D.; Rick Williams Ph.D.; and
Aiman Zeid, M.S., of Battelle. Sherry Marcy, M.P.H., and Deborah J. Zivan, BA of DataStat;
Project associates: Julie Bolen, Ph.D.; Christine M. Branche, Ph.D.; Peter Briss, M.D.; Terence
Chorba, M.D., M.P.H.; Alex Crosby, M.D., M.P.H.; Yvette Davis, V.M.D., M.P.H.; Jennifer
Friday, Ph.D.; Arlene Greenspan, Dr.P.H., PT; James Mercy, Ph.D.; Phil McClain, M.S.; Lloyd
Potter, Ph.D., M.P.H.; and Kenneth E. Powell, M.D., M.P.H. of NCIPC.
Thomas Matte, M.D., M.P.H., of the National Center for Environmental Health.
Address for correspondence: Kenneth E. Powell, M.D., M.P.H., Associate director for Science,
Mailstop K-60, Division of Violence Prevention, National Center for Injury Prevention and
Control, 4770 Buford Highway, Chamblee, GA 30341-3724. E-mail: KEP1@CDC.GOV.
----------------------------------------------
Outline
ABSTRACT
METHODS
RESULTS
DISCUSSION
REFERENCES
ABSTRACT
Injury rates from walking, gardening, weightlifting, outdoor bicycling, and aerobics. Med. Sci.
Sports Exerc., Vol. 30, No. 8, pp. 1246-1249, 1998.
Purpose: The objective of this survey was to estimate the frequency of injuries associated with
five commonly performed moderately intense activities: walking for exercise, gardening and
yard work, weightlifting, aerobic dance, and outdoor bicycling.
National estimates were derived from weighted responses of over 5,000 individuals contacted
between April 28 and September 18, 1994, via random-digit dialing of U.S. residential telephone
numbers. Self-reported participation in these five activities in the late spring and summer of 1994
was common, ranging from an estimated 14.5 +/- 1.2% of the population for aerobics (nearly 30
million people) to 73.0 +/- 1.5% for walking (about 138 million people).
Among participants, the activity-specific 30-d prevalence of injury ranged from
0.9 +/- 0.5% for outdoor bicycle riding to 2.4 +/- 1.3% for weightlifting. The estimated number
of people injured in the 30 d before their interview ranged from 330,000 for outdoor bicycle
riding to 2.1 million for gardening or yard work. Incidence rates for injuries causing reduced
participation in activity were 1.1 +/- 0.5[middle dot]100 participants[middle dot]30 d for
walking, 1.1
+/- 0.4 for gardening, and 3.3 +/- 1.9 for weightlifting. During walking
+and
gardening, men and women were equally likely to be injured, but younger people
(18-44 yr) were more likely to be injured than older people (45+ yr). Injury rates were low, yet
large numbers of people were injured because participation rates were high. Most injuries were
minor, but injuries may reduce participation in these otherwise beneficial activities.
Conclusions: Additional studies to confirm the magnitude of the problem, to identify modifiable
risk factors, and to recommend methods to reduce the frequency of such injuries are needed.
----------------------------------------------
Within the past several years the health benefits of regular physical activity have been affirmed
and summarized in reports from the Surgeon General of the United States (14), a National
Institutes of Health Consensus Development Conference on Physical Activity and
Cardiovascular Health (8), the Centers for Disease Control and Prevention and the American
College of Sports Medicine (10), and the American Heart Association (1). These entities
conclude that regular physical activity is associated with important health benefits: namely,
reduced rates of coronary heart disease, hypertension, non-insulin-dependent diabetes mellitus,
osteoporosis, colon cancer, anxiety, and depression, and improved quality of life. Importantly,
they emphasize that these and probably other health benefits do not require highly strenuous
activity but will accrue from participation in activities of moderate intensity. Further, they
recommend that actions be taken to encourage and facilitate participation by all segments of the
population in physical activity of moderate intensity.
Surprisingly little information is available about the frequency of injuries and other adverse
effects of physical activity among the general population (4,6,9,14). Information is particularly
sparse for injuries related to commonly performed moderately intense activities such as walking
or gardening. Such data would be valuable because injuries are a health burden themselves, and
they may lead to permanent reductions in activity, thereby impeding efforts to promote
widespread participation. For example, among a group of recreational runners, injury was the
most common reason for men and second most common reason for women to stop running (7).
As a first step toward understanding the impact of injuries from moderately intense activities, we
included a few questions in a nationwide telephone survey of risk factors related to injuries. We
sought information about the frequency of injuries resulting from participation in five common
physical activities:
walking for exercise, gardening and yard work, weightlifting, aerobic dance, and outdoor
bicycling.
METHODS
Data for this analysis are from the 1994 Injury Control and Risk Survey (ICARIS). Conducted
between April 28 and September 18, 1994, ICARIS was based on random-digit dialing of U.S.
residential telephone numbers. English-or Spanish-speaking adults (aged 18 yr and older) in all
50 states and the District of Columbia were eligible. Households in exchanges with high
minority representation were oversampled to ensure adequate representation.
Respondents were asked, "During the past 30 days have you participated in any of the following:
outdoor bicycle riding, aerobics or aerobic dance, weightlifting, walking for exercise, or
gardening or yard work?" "Yes" or "no" responses for each activity were recorded. Those who
responded "yes" to an activity were read a series of questions specifically mentioning that
activity. For example, if someone responded that he/she had done weightlifting, he/she was
asked, "In the past 30 days, were you injured while you were weightlifting." If "yes," the
respondent was asked, "During the past 30 days, on how many occasions when you were
weightlifting did you get injured severely enough that you stopped or reduced the amount of time
you spent weightlifting?" Regardless of the answer about stopping or reducing time, he/she was
asked, "During the past 30 days, on how many occasions when you were weightlifting were you
injured severely enough that you went for medical care or missed one-half day or more of work,
housework, or school?"
Data were weighted to generate national estimates. Weights include both a selection probability
weight and a poststratification weight. Selection probability weights were the inverse of the
probability of selecting a particular household type and the number of telephone numbers in the
household.
Poststratification weights were ratio adjustments based on the March 1994 Current Population
Survey number of households and the study estimates by age, race, sex, Census region, and
location within a metropolitan statistical area.
To account for the complex survey design, we used SUDAAN software (12) to generate
weighted estimates, percents, and 95% confidence intervals (CI). If the coefficient of variation
exceeded 35%, the national estimate and 95% CI are not reported. The Pearson chi-square test
was used to assess the association between sex and age-group characteristics of our study
population and participation and injury prevalence.
RESULTS
Of 9,342 answered calls, 3,630 respondents refused participation and 474 interviews were
incomplete. The final sample was 5,238 completed interviews (response rate, 56.1%).
Participation. Participation in the five activities in the late spring and summer of 1994 was
common, ranging from an estimated 14.5% of the population for aerobics (nearly 30 million
people) to 73.0% for walking (about 138 million
people) (Table 1). Men were more likely than women to participate in gardening or yard work,
weightlifting, and outdoor bicycle riding and less than likely than women to walk for exercise or
do aerobics (PP
Self-reported injury. Among participants, the activity-specific 30-day prevalences of injury were
low, ranging from 0.9% for outdoor bicycle riding to 2.4% for weight-lifting (Table 1). The
estimated number of people injured nationwide in the 30 d before their interview ranged from
330,000 for outdoor bicycle riding to 2.1 million for gardening or yard work. Despite the low
injury rates, sex- and age-group-specific injury rates could be calculated for walking and
gardening. Men and women had similar injury rates for walking and for gardening; however, the
prevalence of injuries among younger people was about twice as high as for older people (P
Injuries requiring reduction in activity, time-loss, or treatment. Incidence rates per 100
participants for injuries causing reduced participation in the activity were 1.1 +/- 0.5 per 30 d for
walking, 1.1 +/- 0.4 for gardening, and
3.3+/- 1.9 for weightlifting. There were too few activity-reducing injuries to calculate incidence
rates for outdoor bicycling and aerobics. There were too few time-loss injuries or injuries
requiring treatment to calculate incidence rates for any of the activities.
Many of the reported injuries apparently were slight. Based on unweighted numbers, about half
of the people who reported an injury from walking, gardening, or bicycling said that the injury
required no change in activity, time off, or medical care (Fig. 1). Roughly 30% of these people
reduced or stopped participating in the activity but did not seek care or take time off; about 20%
either sought medical care or missed one-half day or more of work, housework, or school. For
weightlifting and aerobics nearly everyone who reported an injury reduced the level of their
participation, and 25-30% sought medical care or missed one-half day or more of work,
housework, or school.
DISCUSSION
These data suggest that the proportion of participants who suffer an activity-related injury over a
30-d period while walking, gardening, weightlifting, outdoor bicycling, and performing aerobics
is low (0.9% to 2.4%), and that the 30-d incidence of injuries for walking, gardening, and
weightlifting are 1.1, 1.1, and 3.3 per 100 participants, respectively. The data also indicate that
about half of the self-reported injuries for walking, gardening, and bicycling did not require a
reduction in participation, a visit to a medical professional, or loss of at least one-half day from
work, housework, or school. Persons 45 yr or older were significantly less likely to be injured
than younger persons while walking or gardening.
Although the proportion of participants reporting injuries is low, on a national scale the high
participation rates yield a large number of injured people over the 30-d period, ranging from an
estimated 330,000 for outdoor bicycling to 2.1 million for gardening or yard work. The number
of people injured annually would, of course, be even higher; however, we chose not to project
annual rates because participation in gardening, outdoor bicycling, and perhaps walking are
likely to be lower from October to March.
The limited number of questions we asked led to three important limitations of our data. First, we
have no information about the amount of participation (i.e., we know only that the respondent
did the activity at least once in the preceding
30 d). Because time spent on activity is one of the most consistently observed risk factors for
injury, injury rate estimates based upon the amount of participation would be more informative.
Second, we have no information about the type and location of the injury. Third, we know
nothing about the causes of the injuries, which may be intrinsic to the activity, equipment-
related, or arise from conditions unrelated to the activity itself. Intrinsic injuries would include
problems arising directly from the movements of the activity and would include acute strains and
tears as well as "overuse" injuries. Equipment injuries would include dropping a weight on one's
foot or falling because of a wet surface. Extrinsic injuries would include dog bites or collisions
with motor vehicles. Rational injury-prevention activities will depend upon more information
about the actual causes of the injuries.
We were surprised by the high participation rates reported for the five activities but found few
data for comparison. A 1991 survey yielded an estimate that about 18% of people over 20 yr of
age had ridden a bicycle (presumably
outdoors) during the preceding 12 months (11); we estimated 20% of people older than 17 had
ridden during the preceding 30 d. For the other four activities, the survey most similar to ours is
the 1991 National Health Interview Survey (NHIS) (14). Comparing the NHIS with ICARIS,
participation rates are lower in NHIS for walking for exercise (44% vs 73%), gardening or yard
work (29% vs 71%), weightlifting (14% vs 21%), and aerobics or aerobic dance (7% vs 14%).
The higher participation rates in our survey may result from a longer time period of inquiry (30 d
vs 2 wk), more clement weather (April through September vs year-round), or attitude changes
between 1991 and 1994 about how much activity justifies a positive response. Generally, self-
reported physical activity data have been found reliable, but high-intensity activities appear to be
more accurately recalled and reported than activities of light or moderate intensity (2,5,15).
We are unaware of similar population-based estimates for activity-specific injury rates for
common physical activities, and confirmation in other studies is needed. Two studies of walkers
reported injury rates of 2.5% and 3.9% when converted to monthly injury rates (3,13), both
higher than our rate of 1.4%. The walkers in those studies walked 3-6 d[middle dot]wk-1, and
the injury rates represent injuries severe enough to stop or reduce participation. Our walkers
probably averaged less walking, and about half of the injuries did not require any reduction in
participation.
The information about the self-reported frequency and severity of injuries associated with five
common physical activities of moderate intensity brings different messages to different groups.
For the public, the message is that injuries associated with these activities are uncommon and
many of them so minor as to require no treatment or activity reduction. This is good news for the
general population. For the medical, research, and health promotion communities there is, in
addition to this primary positive message, a secondary and challenging one. The number of
people doing these activities is large and, hopefully, will get larger. Therefore, although the rates
of injury are low, the number of injured is large. A few of the injuries may be severe, more will
require care or activity reductions, thereby burdening both the health care system and the injured
individuals. Some of the injured will stop participating in physical activities altogether and will
not benefit from a predominantly healthy behavior. Clearly, further study of injuries caused by
commonly performed activities such as walking for exercise or gardening or yard work should be
done. Such research should enable greater understanding of the frequency and risk factors for
such injuries and facilitate the design of prevention efforts.
REFERENCES
1. Blair, S. N., K. E. Powell, and R. L. Bazzarre, et al. Physical inactivity.
Workshop V. AHA Prevention Conference III. Behavior change and compliance: keys to
improving cardiovascular health. Circulation 88:1402-5, 1993.
2. Booth, M. L., N. Owen, A. E. Bauman, and C. J. Gore. Retest reliability of recall measures of
leisure-time physical activity in Australian adults. Int. J.
Epidemiol. 25:153-159, 1996.
3. Carroll, J. F., M. L. Pollock, J. E. Graves, S. H. Leggett, D. L. Spitler, and D. T. Lowenthal.
Incidence of injury during moderate- and high-intensity walking training in the elderly. J.
Gerontol. Med. Sci. 47:M61-6, 1992.
ExternalResolverBasic Bibliographic Links Library Holdings
4. Frank, E., P. Frankel, R. F. Mullins, and N. Taylor. Injuries resulting from bicycle
collisions.Acad. Emerg. Med. 2:200-203, 1995. ExternalResolverBasic Bibliographic Links
Library Holdings
5. Jacobs, D. R., B. E. Ainsworth, T. J. Hartman, and A. S. Leon. A simultaneous evaluation of
10 commonly used physical activity questionnaires. Med. Sci.
Sports Exerc. 25:81-91, 1993. Ovid Full Text ExternalResolverBasic Bibliographic Links
Library Holdings
6. Koplan, J. P., D. S. Siscovick, and G. M. Goldbaum. The risks of exercise: a public health
view of injuries and hazards.Public Health Rep. 100:189-94, 1985.
ExternalResolverBasic Full Text Bibliographic Links Library Holdings
7. Koplan, J. P., R. B. Rothenberg, and E. L. Jones. The natural history of
exercise: a 10-year follow-up of a cohort of runners. Med. Sci. Sports Exerc.
27:1180-4, 1995. Ovid Full Text ExternalResolverBasic Bibliographic Links Library Holdings
8. NIH Consensus Conference. Physical Activity and Health. NIH Consensus Development
Panel on Physical Activity and Cardiovascular Health. JAMA 276:241-6, 1996.
9. Pate, R. R., and C. A. Macera. Risks of exercising: musculoskeletal injuries.
In: Physical Activity, Fitness, and Health: International Proceedings and Consensus Statement.
Bouchard, C., R. J. Shephard, and T. Stephens (Eds.).
Champaign, IL: Human Kinetics Publishers, 1994, pp. 180-202.
10. Pate, R. R., M. Pratt, and S. N. Blair, et al. Physical activity and public
health: a recommendation from the Centers for Disease Control and Prevention and the
American College of Sports Medicine. JAMA 273:402-7, 1995. ExternalResolverBasic Full Text
Bibliographic Links Library Holdings
11. Rodgers, G. B. The characteristics and use patterns of bicycle riders in the United States.J.
Safety Res. 25:83-96, 1994. ExternalResolverBasic Bibliographic Links Library Holdings
12. Shah, B. V. Software for Survey Data Analysis (SUDAAN) Version 6.10.
Research Triangle Park, NC: Research Triangle Institute, 1993.
13.Suter, E., B. Marti, and F. Gutzwiller. Jogging or walking: comparison of health effects. Ann.
Epidemiol. 4:375-81, 1994.
14.US Department of Health and Human Services. Physical Activity and Health: A Report of the
Surgeon General. Atlanta, GA: US DHHS, Centers for Disease Control and Prevention, National
Center for Chronic Disease Prevention and Health Promotion, 1996.
15. Wolf, A. M., D. J. Hunter, and G. A. Colditz, et al. Reproducibility and validity of a self-
administered physical activity questionnaire.Int. J.
Epidemiol. 23:991-9, 1994. ExternalResolverBasic Bibliographic Links Library Holdings
Key Words: INJURY RATES; PHYSICAL ACTIVITY
----------------------------------------------