Questioning Stretching Programs

DEPARTMENTS

ERGONOMICS

Scott Schneider, CIH, is director of Occupational Safety and Health for the Laborers’ Health and Safety Fund of North America. He can be reached at (202) 628-5465 or schneider@lhsfna.org.

Mary O’Reilly, PhD, CIH, CPE, is adjunct faculty at the SUNY School of Public Health and Empire State College School of Business, and Principal, ARLS Consultants, Inc. She can be reached at (315) 682-3064 or moreilly@albany.edu.

In recent years, many companies have introduced stretching programs for employees as a means of reducing musculoskeletal injuries. Stretching programs seem particularly popular in industries like construction, where the work is physically demanding and workers are at high risk of musculoskeletal injuries.

Despite these risks, few construction companies have developed or implemented comprehensive ergonomic programs. Some have instead implemented pre-work stretching programs. While these programs may have ancillary benefits, there is little evidence that they prevent injuries.

Is stretching the new “back belt,” an unproven solution that may not be effective? A review of the research is inconclusive. Results are often difficult to interpret due to less-than-ideal study design and the questionable influence of other variables. And, as with many ergonomic interventions, some workers seem to be at increased risk while others seem relatively resistant to injury regardless of preventive strategies.

Is Stretching the New “Back Belt”?

Questioning the Benefits of Stretching Programs

BY SCOTT SCHNEIDER AND MARY O’REILLY

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This article was developed from the “Stretching: The Truth” session at AIHce 2013 in Montreal. Participants in the session included a wide range of views and expertise:

Richard Donze, DO, MPH, an occupational physician and medical director at The Occupational Health Center in West Chester, Penn.
Sean Gallagher, PhD, CPE, associate professor at Auburn University and a professional ergonomist specializing in anatomy
Marjorie Werrell, PT,CIE, CPEE, a physical therapist with ERGOWORKS Consulting, LLC in Gaithersburg, Md.
Blake McGowan, CPE, managing consultant and ergonomics engineer at Humantech, Inc. in Ann Arbor, Mich.
Jennifer A. Hess, DC, MPH, PhD, an ergonomist and chiropractor at the University of Oregon Labor Education and Research Center
Scott Schneider, CIH, an industrial hygienist specializing in construction and director of Occupational Safety and Health for the Laborers’ Health and Safety Fund of North America
Seunghon (“Tony”) Ham, MPH, an ergonomist from Seoul National University
Mary O’Reilly, PhD., CIH, CPE, adjunct faculty at SUNY School of Public Health

Little research shows that stretching has value as a preventative measure, especially in isolation.

Most stretching programs are implemented simultaneously with ergonomics programs that address workplace hazards, so statistics that evaluate standalone stretching programs are difficult to find. Motorola, L.L.Bean, and other companies have achieved some success with ergonomics programs that include breaks for stretching. Reports from these companies indicate reluctance, due to positive employee feedback, to remove the stretching component of the program. STRETCHING VS. DESIGN In accordance with fatigue failure theory, the amount of force imposed on tissues influences the number of repetitions a person can sustain before injury occurs. Reducing forces through ergonomic redesign of the workplace can greatly increase the number of cycles to tissue failure and thus provide protection from musculoskeletal injury.

High force is associated with musculoskeletal injury, and there is no evidence that stretching increases the ability of musculoskeletal tissues to withstand high force exertions. Studies of stretching have not involved controlled loading, so the true effect of stretching is not known, nor is a theoretical basis clear. However, a strong theoretical basis supports the idea that reducing forces through ergonomic design can protect musculoskeletal tissues.

Reported conclusions differ on how range of motion, muscle-tendon lengthening, and strength prevent musculoskeletal injuries in the workplace and where stretching fits into the mix. Discrepancies abound over what type of stretching is best, when and how one should stretch, and exactly how stretching is defined in the workplace. Because many companies include stretching as one small piece of their ergonomic program, identifying benefits is difficult. Each company tends to define stretching differently, with some companies using a pre-work stretching program while others employ a “stretch break” that incorporates physiological movement into neutral positions with the goal of reducing tension and fatigue.

While scientific evidence is inconclusive, some companies have had positive responses to stretch breaks. But the apparent success of stretch breaks may be due more to the benefits of rest, improved well-being, and ergonomic awareness. Similarly, stretching before work gives workers the opportunity to communicate with each other and to function as a team—benefits that are independent of stretching and which may contribute more to reduced injury and increased productivity. COSTS VS. BENEFITS The actual costs of a daily morning stretch break can be calculated in terms of work time (based on an hourly rate) and lost productivity for a full crew. From this perspective, stretching turns out to be a fairly costly intervention. Such an investment might be better directed toward making ergonomic changes to the work process.

Some promoters of stretching programs have plucked stretching out of the fitness continuum in lieu of implementing ergonomics solutions. This approach is like trying to determine a healthy diet solely by adding up calories. Studies suggest that other aspects of fitness such as warming up, endurance training, and improving core strength and dynamic stability may be more effective in preventing musculoskeletal injury than stretching alone.

Physiologically, it’s best to warm up before performing exercise. Warming up involves moving large groups of muscles (like extensors and flexors associated with arms and legs) to increase circulation and generate heat. Current thought recommends stretching after warming up and not first thing in the morning. Most stretching programs do not follow this protocol. Overall fitness may be more important in terms of injury prevention than stretching certain muscles. Yet this message hasn’t reached the workplace, where some programs continue to focus solely on five minutes of morning stretching.

Total worker health and safety depends upon moving beyond stretching programs, toward development of dynamic fitness programs integrated with comprehensive ergonomic controls. Such an approach has evolved in other countries. The Korean Traditional Mask Dance (KTMD) is being used to address musculoskeletal disorders (MSDs) in the cosmetic manufacturing industry in the Republic of Korea. Physiologically, the dance strengthens core muscles and improves balance, and in these respects is different than typical Western stretching programs. THE VALUE OF STRETCHING Understanding the effects of stretching on musculoskeletal injury prevention is complicated by imprecise terminology, lack of specific and controlled scientific data, the complexity of workers and organizations, and Hawthorne or placebo effects. By focusing prevention efforts on improving individual workers rather than changing the work and reducing the risk, stretching programs embrace a “blame the victim” approach. Overall, little research shows that stretching has value as a preventative measure, especially in isolation. More conclusive studies have been done on the benefits of rest breaks and micropauses.

In the hierarchy of controls for ergonomic risk, stretching, if it is anywhere, would be at the bottom, even below PPE. If stretching is used, it needs to be incorporated into a comprehensive ergonomic and fitness program. Stretching is not a substitute for implementing proven ergonomics solutions, and ergonomic changes in the work process will likely be more cost-effective.