By Glenn Ingle, ANAD Industrial HygieneMarch 8, 2018
ANNISTON ARMY DEPOT, Ala. -- If highly demanding activities are performed for long durations, fatigue and injury will likely occur.
What qualifies as "highly demanding" may surprise you.
Almost every injury reported at Anniston Army Depot can be attributed to an ergonomic risk factor.
Ergonomics is the science of fitting the workplace to the worker. In Ergonomics, we look for risk factors with the potential to damage tissue and cause work-related musculoskeletal disorders.
Frequency, intensity and duration of exposure play a role in how badly an ergonomic risk factors can damage us.
When injuries occur, it's usually not just one risk factor causing tissue damage but multiple risks working synergistically against one area of a worker's body.
Here are some examples:
Forceful Exertion: Many jobs burden the human body with a high amount of force.
As a response to these force requirements, muscle effort increases. This increases associated muscle exhaustion and can lead to injury.
The weight limit for lifting at ANAD is 45 pounds. The amount of force used to push, pull or otherwise move any tool or object should also be limited to this amount of effort.
Keep in mind, this is our limit during "ideal conditions." Adding any other risk factor lowers the amount of force you should use.
Awkward Posture: When joints are worked nearest the mid-range motion, moving the body requires minimum wasted effort. This is known as neutral posture.
Working in awkward postures -- reaching, crouching, twisting or otherwise extending our joints outside mid-range motion -- places undue force on joints and can overwork muscles and tendons around the joint.
When joints operate beyond mid-range repeatedly for continued periods without sufficient recovery time, the risk of work-related musculoskeletal disorders is made greater.
Repetition: When we exercise at the gym, we are free to vary our routine. Given proper time to heal, muscles tear and grow back stronger.
However, most of us are required to perform the same tasks every day when we are at work.
Overusing joints can erode cartilage and inflame tendons, causing internal friction, impaired motion, entrapped nerves and pain.
Repeated motion uses the same muscles and doesn't allow our muscles to heal properly.
Add excessive force and awkward posture and you've got even more muscle healing improperly. These types of injuries happen on a microscopic level and can't be helped with surgery.
Static Loading: If you have ever held a heavy part or tool in place for a long period of time, you know how painful it can be. This is an example of static loading.
Static loads can cause muscle tension and problems with circulation.
If you repeatedly hold a certain posture day after day, this ergonomic stressor can cause injury with or without excessive force.
Contact Stress: This risk factor occurs when a surface or object presses into soft tissues of the body. This can lead to serious injuries over time.
One example of contact stress is when a mechanic has to hold their arm against a chassis to remove a hard to reach part.
There are less obvious examples, such as sitting in a chair for several hours, leaning elbows against a desk or resting wrists on a keyboard while typing.
Vibration: Hand/arm vibration can contribute to carpal tunnel syndrome, Raynaud's syndrome, and other related injuries. Vibration can cause tissue damage in the hands, affect how they feel and move and increase force which must be exerted to grip objects.
Whole-body vibration, such as that experienced by large equipment operators, can injure soft tissues in the spine and cause permanent back pain.
Cold temperatures: Cold can increase the potential of any of the above risk factors for causing a work-related musculoskeletal disorder.
Low temperatures can reduce blood flow, the natural elasticity of the body and the sensation of touch.
This can cause muscles to fatigue when a person exerts more force than is necessary to get the same tactile feedback from an object they touch.
The more risk factors you're exposed to, the higher your chances for injury.
The good news is that removing or reducing just one risk factor can decrease your risk of injury exponentially.
The key is knowing where to start.
Elimination: First, we attempt to remove employees from a task with associated ergonomic hazards. If that cannot be accomplished, we look at engineering controls.
Engineering Controls: Using mechanical assistance, adjustable work surfaces and powered equipment can reduce the need for forceful exertion.
Ergonomic modifications to the workspace can help employees maintain their range of motion in a more neutral posture for vulnerable joints.
Improved seating in vehicles and large equipment can minimize whole-body vibration.
Proper ergonomic tools should be utilized to allow people to hold their bodies in neutral positions.
Eliminating excessive force and awkward posture reduces exhaustion and lets us perform repetitive tasks without significant risk of injury.
Administrative Controls: Providing safer procedures for completing work tasks can reduce work-related musculoskeletal disorders. Employees should be trained to use neutral postures and lift techniques to reduce ergonomic risk factors.
Job rotation is a way to reduce frequency and time exposed to ergonomic risk factors. Workers should cross-train with others in their shop and rotate between workstations to avoid repetitive motion injury.
We should also take rest breaks to give our bodies opportunity for increased circulation needed for recovery.
Personal Protective Equipment: PPE is considered when adequate protection cannot be provided using other methods.
Anti-vibration and impact gloves can minimize the effect of hand and arm vibration.
Special pads can protect the body against contact stress. Clothing can accommodate work in extreme temperatures.
Making sure your team members are physically ready for work reduces injury risk and promotes a healthy and safe team culture.
We should know when a task requires too much effort and either use mechanical means or get help from a co-worker.
We should always be thinking of ways to reduce the frequency, intensity and duration of exposure to ergonomic risk factors.
Recognizing and controlling ergonomic risk factors is an important part of our commitment to providing a safe place of work for all depot employees.