The question of the value of workplace stretching exercises is one of the hottest debates going in the world of ergonomics and MSD prevention. This is an excellent debate to examine.

Detractors include most engineering-based ergonomists and OSHA regulators. Supporters include physical therapists and occupational therapists who treat workers with MSD problems. Each side presents strong opinions. But that is exactly the point.  Virtually all workplace MSD prevention strategies are almost totally founded on OPINIONS, even most ergonomics methods.  Very little is actually "proven" by sound, controlled scientific research.

Our recommendations what we see has worked or not worked for our 700+ client workplaces.

Exercise opponents fear workplace managers will turn to stretching rather than invest in ergonomic improvements in workplace design to reduce work stresses. They fear stretching may become a cheap way to avoid spending money on improved job design. This is a valid concern.  When ergonomics is bad, that must be the first priority to fix. 

Exercise opponent-detractors say another reason to avoid stretching is workplace stretching has not been proven effective controlled scientific research.  This is a correct observation... to a point.  BUT...neither is the value of ergonomic job re-design supported by controlled research!  One study (Silverstein... see bibliography) that was attempted showed exercises do not work... but they were the wrong exercises!  The study was biased in its design, trying to prove exercises are ineffective.   They selected exercises that actually stress, rather than relieve arm tendons.   Another very large study that we are preparing for publication involves 4200 workers at 11 workplaces in 5 states, using our micro-stretching exercise protocol (takes 2 minutes done every two hours) clearly showed lost time claims reduced 59% and lost days reduced 78%.   The right exercises DO work.

None of the various strategies for MSD prevention in the workplace (engineering-ergonomics controls or administrative controls or work performance controls) have had their value precisely measured by controlled research.  Us experts all base our prevention recommendations on our educated OPINIONS, supported by our professional scientific education and experience.

The nature of all these prevention strategies does not lend itself to investigation by traditional double-blind research design.  We are limited to experience, observation and analysis of what seems to work or not work at various workplaces. There are numerous discussions of the effects of several approaches to workplace exercises in various publications, some supportive and others not, based on the bias of the author (yes, me included).

When we look at large numbers of workplaces that have tried various workplace exercise programs, we see a wide range of outcomes. We do not see a unanimous trend of favorable versus unfavorable effects. Some greatly succeed, while others miserably fail.  This is important.  We must consider why some failed while others succeeded.  There are lessons to be learned here.

This is the issue I have focused on in my 30 years of workplace MSD prevention consulting at more than 700 workplaces nationwide.  I have seen several critical trends.  This led us to develop our MICRO-STRETCHING protocol that ties together repetitive motion stress at the hand with posture stress at the neck.  If we approach MSD as a POSTURE problem, we see a whole new set of controls that seem to work... including brief, frequent micro-stretches.

If stretching is done right... using the right stretches... with good training to motivate workers... with proper commitment and leadership from management... then... stretches become extremely effective for virtually every type of job.

These are just two examples of a typical set of 8 or 9 micro-stretches customized to the job.  BUT employees MUST be effectively trained to select and do these properly for this strategy to work.   Success is based on effective training (both management and workers).

HERE IS THE BASIS FOR WORKPLACE STRETCHING...

MSD problems are the result of reduced circulatory perfusion (blood supply) to muscles, tendons and joint structures. Muscle contraction, tendon tension and joint compression all create mechanical pressures that inhibit circulatory perfusion pressures of these working tissues. Work then shifts to anaerobic metabolism, resulting in excessive accumulation of metabolic waste products in working tissues. These chemicals irritate and damage the musculoskeletal tissues.

MSD is a NUTRIENT PATHWAY DISORDER. It is critical to understand this. We prevent MSD by restoring, maintaining and enhancing the nutrient pathway to working musculoskeletal tissues.

This is accomplished by designing jobs to minimize mechanical compression or tension of posture and movement work that inhibit tissue perfusion. This defines the purpose of engineering controls.

Or we accomplish that objective by administrative controls such as job rotation or switching between sitting and standing to provide posture and movement work variety.

Or we may accomplish that objective with specific targeted stretching techniques that reduce neuro-muscular tension and unload compressed tissues. This is a critical definition of workplace stretching.

The term "stretching" is incorrect. Stretching implies lengthening of a shortened muscle-tendon unit. But this may not be the appropriate or safe objective. Lengthening requires a stretch to be held for 30 seconds. Research implies this is the threshold for optimal lengthening effect. But that is not what we are after. Besides, that calls for stretches that are too time consuming for the workplace to tolerate and too hazardous to teach to large numbers of individuals with individual complications.

What we seek for MSD prevention are exercises that relax neuro-muscular tension in the muscle-tendon units that are deprived of nutrient pathway. A gentle passive stretch for ten seconds can stimulate the Golgi Tendon Organs, nerve endings located within tendons that can reduce motor nerve input to working muscles. The result is decreased muscle tone resulting in increased muscle, tendon and joint surface perfusion. Exercises must target those muscle-tendon units involved in grip, pinch, reach or other loading demands of work.

Another critical issue consideration of the neck region. Repetitive motion problems occur in the upper extremity while the worker is sustained sitting or standing at the workstation. Static posture often leads to forward head posture and a protracted shoulder girdle. This encourages a degree of thoracic outlet compression, where tight lateral neck muscles compress the nerves and vessels running to and from the working upper extremity. This is a major source of reduced nutrient pathway to the brachial plexus nerves to the carpal tunnel, radial tunnel and cubital tunnel. There is also obstruction of vein and lymphatic drainage of the upper extremity in this posture, creating tissue fluid backup throughout the upper extremity. This reduces nutrients feeding working tissue. We, therefore, seek to gently stretch the scaleni at the lateral neck to reduce neck compression of nerves and vessels to the working upper extremity.

There are many bad exercises employed in the workplace and a few good exercises. One cannot judge the value of workplace exercises without specifying which exercises are employed. Potentially hazardous and generally worthless exercises must be eliminated from the discussion. We have consistently seen excellent reductions in MSD problems at hundreds of workplaces where the correct exercises are employed.

Workplace stretching is not a cure-all. It is certainly not an excuse to defer ergonomic improvements. But it is extremely valuable as an added effort to accomplish maximum reduction in MSD problems. It is especially valuable for jobs where ergonomics modifications are just not available.

Another consideration is to address MSD problems not caused by ergonomics hazards. We find that many workers develop MSD not because the job is poorly designed but. Rather, because the worker has poor posture habits, bad body mechanics, poor flexibility or vulnerabilities presented by health issues (pregnancy, diabetes, thyroid dysfunction, etc.). These at-risk workers could benefit from stretching to build their margin of work tolerance.

Workplace Stretching Programs..Yes, they do work!!!.... if you follow certain rules. Hundreds of workplaces have implemented our stretching program...with consistently great success. But ONLY if certain criteria are met. Studies showing poor results with stretching programs violated these criteria. Stretches must address the neck to reduce wrist-hand problems (tight neck muscles squeezing blood supply to wrist-arm tendons). Stretches must be designed by a professional therapist and be customized to the workplace. Workers must be educated as to how and why, and checked on their accuracy of doing them. Management must have the courage to ENFORCE exercises (supervisors must be trained in this and REQUIRED to cooperate). Our program requires only two minutes of total stretch time, done every hour or two. And productivity does NOT go down... it INCREASES according to our client workplaces that track piecework productivity, due to reduced fatigue. Stretching is especially valuable for stressful jobs but have no ergo re-design alternatives.

Re-defining workplace "stretching" exercises

We are guilty of incorrect terminology. We have long been advocating a specific method of workplace "stretching" exercises for the prevention of common MSD problems. We have consistently enjoyed exceptional success with these, contrary to the writings of other ergonomics experts. Why have they been so resistive while we have been so successful?

The answer lies with our faulty terminology and assumptions. First, the other experts decry workplace stretching because it tends to direct attention away from correcting faulty workplace ergonomic design. This is a valid concern. But we refuse to implement workplace exercises in the absence of a workplace ergonomics analysis and corrections efforts. We insist on this as a pre-requisite. Our workplace exercises are an adjunct to that and serve as a rescue vehicle where work demands are stressful but ergonomics alternatives are unavailable.

My concern is our faulty terminology of calling our exercise protocol a "stretching" program. These are not, in strict physical therapy definition, true "stretching" exercises. Stretching exercises are intended to maximize muscle flexibility. That is not the objective of our exercise protocol. Our objective is to restore muscle and tendon perfusion. These is a significant difference between improving flexibility and improving perfusion.

Stretching to restore flexibility calls for a minimum 30 seconds of passive or dynamic stretching of the target muscles. This is time-consuming (thus costly to production) and requires specific individualized worker training to assure safe and correct technique. That is not our objective.

We seek, instead, to restore circulatory perfusion to the working tissues. Muscle contraction and its tendon tension forms a barrier to blood supply for these working tissues. Too much contraction and tissue tension can shift metabolism from aerobic work to anaerobic work. This greatly increase accumulation of metabolic waste chemicals in these tissues. These serve as an irritant than can lead to inflammation. Our exercises are designed to specifically target this process. Prolonged postures and repetitive motion cycles can greatly increase muscle-tendon tension, leading to this process.

Our exercises call for a brief, gentle, ten second passive stretch across the target tissues. This is not enough stretch duration to restore flexibility and that is not our aim. This is a stimulus to golgi tendon organs and other mechanoreceptor nerve endings that respond by inhibiting muscle tension and increasing relaxation. This then allows circulation to be increased, restoring a predominance of aerobic metabolism and irrigation of metabolic wastes from the working tissues. That is our objective.

This protocol of ten-second stretches to key muscle-tendon regions seeks to relax these structures through neurological inhibitory reflexes. Relaxation of the contractile units allows circulatory perfusion to be restored, thus reversing risks for inflammation and improving repair. This is a protocol that is time-efficient so as to avoid impairing production demands. We have, in fact, observed increases in productivity when workers take a minute or two of exercise time every hour, apparently due to reduced worker fatigue and improved output capabilities.

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A STUDY AWAITING PUBLICATION...

Hebert, Lauren:  “Implementation of a “Micro-Stretching” Program for MSD Prevention in Manufacturing Work Settings:  A Multi-Case Report”

Study Design:   Multiple-case report

Background and Purpose:  Worker Compensation claims for musculoskeletal disorders (MSD) are widespread in today’s workplace, resulting in extensive human suffering, costs and lost workdays.  Despite controversy over effectiveness, workplace stretching exercises is one intervention utilized by many workplaces.  This report describes a “micro-stretching” program encompassing 4200 manufacturing workers at 11 workplaces provided by four physical therapists in five states and the implications of the outcomes.

Case Description:  11 manufacturing workplaces experiencing high rates of MSD claims and lost workdays employed physical therapists to introduce a structured stretching program seeking to reduce incidence, severity and costs of work-related MSD.  These workplaces had a predominance of jobs requiring repetitive tasks performed in fixed postures (sustained standing or sitting).  It was assumed that these work demands led to high rates of claims for MSD.

Intervention:   Physical therapists designed a “micro-stretching” program of brief but frequent stretching to neuromusculoskeletal structures at the neck, upper extremity and lower back.  This program was implemented via a structured training process provided first to company leadership to gain implementation commitment, followed by employee training on how and why to perform these exercises.   Micro-stretching was performed over a two-minute period every two hours during the workday, seeking to restore nutrient pathway and perfusion to neuromusculoskeletal tissues under posture, movement and loading demands.

Outcomes:   MSD claims and lost days were measured from workplace injury records for the year prior to implementation and compared to the year following implementation.  MSD claims declined 37 percent.  Lost-time claims declined 59 percent.  Lost workdays declined 78 percent.

Discussion:  Preventive stretching in the workplace is a controversial issue.  Although evidence is lacking, stretching offers potential value to MSD prevention, particularly where ergonomics controls may not be viable options.  Key prerequisites to an effective preventive stretching program include proper exercise design by qualified experts such as physical therapists who understand pathomechanics of MSD, management commitment to making the exercises happen, and effective employee education to foster motivation and skills to perform the stretching exercises.

Keywords:  workplace stretching exercises, MSD prevention