By Thomas B. Gilliam, Ph.D. President, IPCS
The historical analysis of the IPCS strength database, consisting of over 600,000 industrial workers from 2005-2019, shows the worker, on average, has lost about 1 % of muscular strength each year since 2005. However, the loss of muscular strength due to the COVID lockdown from 2019 to 2021 was 8 times greater for females and 10 times greater for males compared with the historical analysis. This significant loss of strength will be difficult to make up. Intuitively, it would appear that the industry should expect an increase in musculoskeletal (MSK) injuries and an increase in lifestyle-related diseases such as diabetes, hypertension, cardiovascular disease, and certain cancers. It is critical for occupational medicine programs to address this risk factor with preventative programs.
Over the last couple of years, I have written several papers discussing the impact that COVID-19 has had on the workforce as a result of the lockdown.
IPCS is in a unique position to measure retrospectively the impact that the lockdown had on physical strength, strength-to-body weight ratio, and body mass index. IPCS conducts muscular strength tests for new hire applicants for physically demanding jobs for a number of industries across the United States.
To measure this impact, the new hire strength data in the IPCS database was statistically analyzed from January 1, 2019, to November 30, 2019 (Pre-COVID) and compared to the new hire strength data collected from January 1, 2021, to November 30, 2021 (Post-COVID). Obviously, data collected in 2020 was an aberration due to COVID and therefore not included in the analysis.
- There were 18,403 strength tests pre-COVID (6,221 females and 12,182 males) completed.
- There were 17,233 strength tests done post-COVID (5,254 females and 11,979 males).
- There was statistical significance (p<.05) between males and females, so the male and female data were analyzed independently.
- The same industries were involved in both years representing transportation (airline, railroad, trucking), hospitals, warehouse distribution, furniture/appliance, manufacturing, utilities, and public schools.
The results of the initial analysis can be found at the link: http://www.ipcs-inc.com/home/ipcs-data-on-the-lockdown/
A second analysis was completed looking at changes in strength Pre/Post COVID by gender and by age group. The tables below show the physical characteristics of the males and females completing the strength test.
The body weight and body mass index (BMI) increased significantly (p<.05) pre- to post-COVID. There is about a 3-year age difference for the female group. A synopsis of the first statistical analysis presented in an earlier paper on the impact COVID had on muscular strength in the workplace is as follows:
- Overall muscle strength decreased between 4% to 7% depending on gender and body part.
- The frequency of morbid obesity (BMI >=40) increased by 9% for females and 20% for males.
- Strength-to-Body Weight (a measure of muscle health) decreased by as much as 17% post-COVID for those in the Excellent category shifting to the Very Poor category.
Results: Changes in absolute strength
Chart 1 shows the changes in absolute strength as measured by an isokinetic dynamometer across 5 different age groups for females. Absolute strength is a measure of shoulder and knee strength.
Previous analyses have shown that strength in the workforce decreases with age. The pre-post COVID analysis by age group is no different. When comparing 2019 vs. 2021, the data shows on average a 4.5% decrease in strength which is statistically significant (p<.05). It should be noted that the greatest strength difference was observed for the >59-year-old age group which could have occurred because of the smaller number of females in that group.
Like that of the female population, the male worker (Chart 2) also shows a loss in strength post-COVID. The downward trend in strength with age is more apparent with the male data and with a greater difference between pre/post-COVID results (about 5.5%) compared to the female data. It should be noted that the greatest decrease in male strength post-COVID occurred in the age group 20-29 years old.
Results: Changes in strength due to COVID vs. expected changes.
Chart 3 shows the changes in female absolute strength on a percentage basis due to the COVID lockdown compared to the historical analysis for the past 15 years (2005-2019) by age group.
The average decrease in absolute strength each year from 2005 to 2019 for females is about 0.6% across age groups. As Chart 3 shows, the loss of strength that occurred during the lockdown for the female group is about 8 times greater compared to the historical change from year to year (2005-2019).
Chart 4 shows the changes in male strength on a percentage basis due to the COVID lockdown compared to the historical analysis for the past 15 years (2005-2019) by age group.
The average decrease in absolute strength each year from 2005 to 2019 for the male worker is about 0.7% across age groups. As Chart 4 shows, the loss of strength that occurred during the lockdown for the male worker is about 10 times greater than what the historical change shows from year to year.
As I have reported previously, the absolute strength of the industrial worker has decreased substantially over the last 15 years. This in itself does not bode well for industry. One of the body parts evaluated by IPSCS is the shoulder region. One of the reasons why the number of shoulder MSK injuries has increased over the years is because of the loss of shoulder strength. In some industries, shoulder injuries have become the number one MSK and the most costly (more than the low back).
The significant loss of strength due to the COVID will put the worker at even greater risk of shoulder injuries as well as other MSK’s.
The research also shows a strong relationship between strength and certain lifestyle diseases such as diabetes, hypertension, cardiovascular disease, and certain cancers. Again, one can only intuitively predict with the loss of strength due to the lockdown that there will be an increase in certain lifestyle diseases.
Occupational medicine clinics should play a critical role in promoting preventative programs in the industry including strength training programs to mitigate the increased risk of MSK injuries and certain lifestyle diseases.
