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Kenneth H. Cooper MD, MPH

 
 

Does Physical Activity Impact the Risk of Musculoskeletal Injuries in Women? The Women’s Injury Study (WIN)

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Tuesday, Jun 19, 2018


The health benefits of regular physical activity are indisputable. The extensive list of positive health outcomes derived from physical activity include a decreased risk of developing and dying prematurely from cardiovascular disease, several types of cancer, type 2 diabetes, and dementia. Accordingly, the U.S. Department of Health and Human Services has long-advocated accumulating a minimum of 150 minutes per week of moderate intensity aerobic activity as well as a minimum of 2 days per week of muscle-strengthening activities. While the upper range of recommended aerobic activity is 300 minutes per week, there is no upper range for muscle-strengthening activities. With increased amounts of physical activity comes an increased risk of musculoskeletal injuries (MSI). Examples of common MSI include joint sprains, muscle strains, tendonitis, and bruises. Surprisingly little is known regarding MSI related to physical activity versus MSI occurring that are unrelated to physical activity. With this in mind, researchers from The Cooper Institute and the University of North Texas teamed up to develop the Women’s Injury Study (WIN).

WIN was a 3-year web-based observational study. Subjects were recruited from the Dallas metropolitan area; the major requirement for inclusion was access to the internet and the ability to self-report data that was relevant to the study. Women who used assistive devices, as well as those with a condition or disease that limited mobility or interfered with physical activity were excluded. The final sample included 909 women between the ages of 20 and 83 years. Prior to study onset, women were trained how to enter their physical activity and MSI data. A baseline assessment was performed, which included measures of body mass index (BMI)*, as well as self-report of medical history, history of injury, and an orthopedic exam by a licensed physical therapist.

All women received pedometers in order to track total weekly steps. Using a secure website and on a weekly basis, participants answered several questions regarding aerobic activity and strength training activities during the previous week. MSI that caused the participant to see a health care provider or interrupted daily activities for 2 or more days were also self-reported via the website; all MSI were confirmed by telephone within 48-72 hours using trained personnel. During the telephone call, information regarding the anatomical location and severity of the injury was obtained, as well as whether or not a health care provider was used, and how the injury occurred (e.g. physical activity-related or not).

It is important to mention that this was not an intervention study. In other words, women were not instructed to become more physically active. They were simply asked to report their physical activity and MSI on a weekly basis. Overall adherence during the study was very good, with an 80% completion rate. Of those who completed the study, more than 95% reported at least 75% of their weekly data. The average age of the women was 53 years; 77% were White and 18% were Black. Only 3% of the sample reported using tobacco, and 65% reported having at least a Bachelor’s degree. There were a total of 323 and 330 MSI reported during the physical activity-related and non-physical activity-related time frames, respectively. Major findings regarding MSI are presented below. We will use the abbreviation PA to denote physical activity from this point forward.

 
  • While 45% of women did not meet recommended PA guidelines for aerobic activity, 27% met guidelines (150-299 minutes per week) and 28% exceeded guidelines (>300 minutes per week).
  • 85% of the women did not meet the recommended PA guidelines for muscle-strengthening activity.
  • Compared to non-PA related MSI, PA-related injuries were more likely to involve the lower and upper limbs.
  • Compared to PA-related MSI, non-PA related MSI were much more likely to involve the head, neck, and jaw
  • Women in the normal weight BMI category were less likely to experience any type of MSI when compared to overweight and obese women.
  • Women who met the PA guidelines were less likely to experience a PA-related MSI when compared to women who did not meet the guidelines and women who exceeded the guidelines.
  • Women who experienced a PA-related MSI were less likely to require treatment from a health care provider compared to women who experienced a non-PA-related MSI
  • Of the PA-related MSI, the majority occurred during free-living walking, jogging, and running. However, this was not unexpected since these activities were the ones most commonly reported.
  • Women who experienced a PA-related MSI were somewhat less likely to miss work or school than women who experienced a non-PA related MSI
To summarize, PA and non-PA-related MSI were very similar in terms of their number, but differed with regard to location of the injuries. Secondly, overweight and obese women were more likely to experience MSI than normal weight women. Finally, PA-related MSI were less likely to require treatment by a health care provider and cause missed days of school/work compared to non-PA-related MSI. Thus, PA-related injuries do not seem to negatively impact quality of life issues beyond that of non-PA-related injuries.

It’s a given that for the overwhelming majority of the population, the benefits of regular PA outweigh the potential risk of MSI. The authors emphasized that PA counseling be part of routine preventive health care. Non-exercisers who wish to become more physically active should increase their activity level slowly and gradually over a period of several weeks in order to help reduce the risk of MSI. While exceeding the PA guidelines for aerobic activity may be helpful for weight loss or athletic performance, such levels of activity are
associated with a somewhat increased risk of MSI in adult women.

*Use this link to determine your BMI.    

Reference
Howard, E., DeFina, L., Leonard, D., Custodio, M., Morrow, J.  (2013). Physical activity and musculoskeletal injuries in women: the Women’s Injury Study. Journal of Women’s Health, 22(12):1038-1042. DOI: 10. 1089/jwh.2013.4287


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