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Healthcare Ergonomics: What is It and Why is It Important?

Caring Enough to Prevent Injury for Those Who Care For Us 

Reducing the Risk of Injury to Healthcare Workers

Healthcare workers (HCWs) are the backbone of the medical industry, and their well-being is crucial to ensuring that patients receive the best care possible. Unfortunately, the risk of injury is a persistent threat in this field. Chronic injuries, particularly sprains and strains of the upper body and back, are the most prevalent among healthcare professionals. A problem that has only been intensified since the onset of COVID-19 due to an increased patient load in hospitals, necessitating more transportation of patients and equipment. This heightened activity comes when the industry is already experiencing a shortage of healthcare professionals, exacerbating the risk of injury. 

Common Injuries

According to a poignant case study in the Perioperative Setting by Gurb and Dockery, which conducted an ergonomic assessment in a 14-room surgical suite, 79% of registered nurses had sustained back injuries, with a significant number of the injuries being career-ending. Surgical technologists and/or assistants accounted for 21% of these injuries.

As the study identified, there are five key activities that contributed to these injuries:

  1. Moving patients
  2. Maneuvering heavy carts
  3. Lifting
  4. Walking on wet floors
  5. Reaching for power outlets

To maintain a functional and effective healthcare system it is crucial that we integrate ergonomic principles into everyday healthcare practices. As we continue to rely on the tireless efforts of HCWs, especially in times of crisis, it is imperative that we invest in their safety and health with the same fervor with which they care for us.

Healthcare Ergonomics Best Practices and Resources

Nursing Home Ergonomics

Many patients in nursing homes are reliant on healthcare providers for basic day-to-day activities. These types of activities put physical strain on healthcare workers – multiple times a day, as they require lifting and transferring patients safely. 

To help avoid healthcare worker injuries, employers should ensure: 

  • Workplace analysis to identify and correct workplace hazards and exposure to ergonomic stressors. 
  • Injury recording and analysis to identify injury patterns, allowing visibility to correct unforeseen risks. 
  • Hazard prevention and control including administrative and engineering controls. Administrative controls ensure adequate staffing and assessment of needs. Engineering controls cover design, training and use of tools and equipment to reduce injuries to healthcare providers, e.g. equipment used to lift patients. 
  • Training programs to ensure continual education is in place and performed by a qualified trainer. Successful training programs confirm that both new and existing employees are up-to-date on ergonomic risks in the workplace. 

Lifting guidelines are particularly relevant for healthcare workers in a nursing home environment. The United States Department of Labor – Occupational Safety & Health Administration (OSHA) provides the following lifting guidelines: 

  • Never transfer patients/residents when off balance. 
  • Lift loads close to the body. 
  • Never lift alone, particularly fallen patients/residents, use team lifts or use mechanical assistance. 
  • Limit the number of allowed lifts per worker per day. 
  • Avoid heavy lifting especially with spine rotated. 
  • Training in when and how to use mechanical assistance. 

OSHA also offers recommendations around Patient Handling Programs and Patient Handling Controls.

Laboratory Ergonomics

Laboratories lend themselves towards ergonomic risks due to their focus on efficiency which can distract from safe working practices. There are many resources created by UCLA Ergonomics that offer best practices for healthcare ergonomics in a laboratory setting: 

Recommendations for Pushing and Pulling Tasks

Most healthcare environments possess many large, heavy equipment. This medical equipment must be mobile, so it can be moved where needed across the healthcare facility. Additionally, medical equipment must frequently be maneuvered quickly and safely in a variety of environments (wet, hazardous materials, over cords, etc.). Finally, noise considerations must be considered as patients require rest and cannot be bombarded by noisy equipment constantly being moved around. That’s a tall order for medical equipment designers. 

The AORN Safe Patient Handling Guide provides several task recommendations to mitigate risk for pushing/pulling tasks:

  • Opt for pushing over pulling equipment 
  • Push at a comfortable “middle” height – about 3ft 
  • Use 2 or more caregivers to complete task together 
  • Use powered transport device 
  • Keep casters/wheels clean and well-maintained to assist in moving equipment more easily  

Additionally, Darcor has identified four best practices to assist medical equipment designers to achieve improved design and mobility of medical equipment and carts:

  1. Low push/pull force
  2. Noise reduction
  3. Reduced shock and impact loading
  4. Adjustable height

Investing in healthcare ergonomics is essential as it not only helps mitigate risks for healthcare workers but also greatly improves patient care. To ensure a healthier tomorrow, we must continue to centre ergonomic programs and practices within the healthcare sector and beyond. To learn more about how ergonomics can help you reduce workplace injuries and transform your bottom line check out our latest guide: “The Economics of Ergonomics”!

The Anatomy of a Caster

Written by Madeline Shoot

Caster Technology

The ins and outs of caster technology are not common knowledge, especially for ergonomists and safety professionals alike who have emerged from a scientific background. All the different components can make casters intimidating, but if we take a step back and relate the anatomy of a caster to that of a human, we can start to sort out the intricacy of casters. To help identify these parallels, we will focus on some of the main bodily systems. Those include the skeletal, muscular, nervous, and cardiovascular systems. We will draw comparisons between our anatomy, and that of a caster, to help us understand the role of each system and how they work together to have a smooth-running system.  

The Skeletal System: The Bones of a Caster

Closely mirroring the human skeletal system, the ‘bones’ of a caster, comprising the top plate or stem, yoke, axle, and wheel core, provide a robust framework made of hard materials like nylon or steel. The top plate or stem of a caster is analogous to the fixed joints in our skulls. These parts, connecting the caster to the cart, are designed to move in unison, offering a stable, unyielding attachment point, much like a fixed joint. Their robustness is crucial, akin to how our joints need to be stable and strong to prevent dislocations. In the same vein, the yoke of the caster serves a purpose similar to our bones under pressure. It acts as the core structure, bearing loads without breaking or fracturing, and providing a framework to which other components are attached. This mirrors the role of our bones in supporting weight and maintaining structural integrity. Finally, the wheel core, crafted from hard materials like nylon or steel, supports and structures the wheel, paralleling the bones in our limbs that provide support and framework for muscles. This comparison highlights the integral role each component plays in the caster’s overall functionality and resilience.  

Muscular System: Wheels 

In the world of casters, the wheels and treads represent the ‘muscular system’. Just as muscles in the human body enable movement and provide the strength to carry loads, wheels in casters are designed for mobility and bearing weight. The material of the wheel, like the type of muscle fiber, determines its suitability for tasks. For instance, softer tread materials, akin to slow-twitch muscle fibers, are better for endurance and smooth operation on uneven surfaces. Let’s think about this pairing like going for a trail run. Your slow-twitch muscle fibers don’t tire quickly, making them perfect for such prolonged exertion. Similarly, softer tread wheels are designed for endurance on uneven and changing surfaces. They absorb shocks and adapt to irregularities, much like how your slow-twitch fibers help you maintain a steady pace over rocky and uneven trails, ensuring a smoother and more consistent run.  

In contrast, hard wheel materials in casters are comparable to fast-twitch muscle fibers in the human body, which are essential for power and strength. Imagine a weightlifter performing a heavy lift, such as a deadlift. Fast-twitch fibers are activated to generate a powerful and explosive force. These muscle fibers are designed for high-intensity efforts, providing the strength needed to lift heavy weights. Similarly, hard wheel materials on casters are tailored for situations that demand robust strength and durability. They are particularly effective for supporting heavy loads, maintaining stability, and resisting wear under significant pressure. Just like the weightlifter relies on fast-twitch fibers to power through a challenging lift, hard wheel materials ensure that the caster can withstand the immediate demands of heavy-duty use, efficiently managing the stress of substantial weight without compromising performance.  

The Nervous System: Bearings and Swivels 

The nervous system of a caster comprises features that translate external information into responsive action. Bearings, for instance, facilitate the smooth rotation of the wheel and swivel action. Much like the human nervous system sending signals to coordinate muscle movement, bearings enable precise control and ease of movement. They allow the caster to respond to directional changes quickly and accurately, mirroring how nerves transmit information to the brain. The swivel head, allowing a 360-degree rotation, responds to directional changes comparable to the nervous system’s processing of sensory input. Locking mechanisms, too, play a role similar to the nervous system’s control of movement, where it can initiate, inhibit, or modulate motion based on feedback. Lastly, features like spring loading or shock absorption in a caster can be likened to the reflexes controlled by the nervous system, showcasing adaptability and response to external stimuli. 

The Circulatory System: Lubrication & Maintenance  

The circulatory system of a caster is found in its lubrication and maintenance routines. Just as the human circulatory system is essential for delivering nutrients and removing waste to keep our bodies functioning smoothly, regular lubrication and maintenance are crucial for the health of a caster. Lubrication reduces friction in the moving parts, akin to how our blood reduces friction in our joints, ensuring smooth operation and extending the lifespan of the caster. Maintenance, much like regular health check-ups, involves inspecting the caster for wear and tear, ensuring that all parts are functioning correctly, and making adjustments or replacements as necessary. This routine care is vital to prevent breakdowns, just as a well-maintained circulatory system helps prevent health issues in the human body. 

Caster technology exemplifies the synergy of well-aligned components. Each element, from the sturdy structure to the adaptable wheels and precise control mechanisms, plays a critical role. When these parts function in unison, the caster operates at its peak, showcasing a balance of stability, mobility, and responsiveness. This balanced integration underlines the caster’s efficiency, akin to a well-oiled machine, where every component’s alignment ensures superior performance.

The Economics of Ergonomics: Unlocking the Hidden Benefits

You Don’t Have to Reinvent the Wheel, But You Do Need the Right Caster for the Job!  

When it comes to ergonomics, we often only hear discussions about the value of injury avoidance and prevention. At Darcor, we talk extensively about the importance of ergonomics in the workplace, but we aren’t just talking about injury avoidance… we believe in taking a more proactive approach! 

In terms of transporting heavy loads with manual material handling carts, having the right cart design and caster selection for the specific application doesn’t just reduce the rate of injury. The right cart design can also create a ripple effect that offers benefits for the business in every aspect of operational efficiency and productivity. 

It’s Not Just About Injury Avoidance 

Overexertion injuries, such as those that involve pushing and pulling, are the costliest for employers. According to the 2023 Liberty Mutual Workplace Safety Index (WSI), overexertion costs businesses $12.84 billion in direct costs! That does not include indirect costs that can be anywhere from 4-10x more. We know that workplace injuries can be costly for any business, but a cart that prioritizes ergonomics and ease of use goes beyond injury avoidance. 

A well-designed cart with quality casters makes it easier for the worker to do their job. In fact, a 2019 study of ten workers conducted by Darcor found that doing a repeated task with a well-designed cart was so much easier and more efficient than without, that over time it was like adding an 11th person to the production line. 

A well-designed cart doesn’t just save you the unpredictable and costly consequences of a workplace injury, it can also increase efficiency and productivity, improving the bottom line for your business. 

The Caster’s Hidden Value 

While it may be difficult for a company to justify spending more on their cart program, something as small and simple as casters can make a big difference in productivity. Just like the tires on your car, casters are the only point of contact with the surface you’re on. They impact the ease of movement the cart operator has, how quickly they can stop, and how easily they’re able to turn. Carts that are hard to maneuver can slow down productivity and increase the risk of injury to the worker.  

Type of floor and cart load weight are just two of the key factors that affect caster selection. Simply choosing the right casters can increase operational efficiency by improving operator mobility and decrease production downtime due to less mechanical breakdown resulting from low quality cart components. 

Avoid Breakdowns by Finding the Right Caster

There are several ways that casters can break down, such as exceeding load capacity; environmental conditions, like high workplace temperature or presence of floor debris; and impact loading, which occurs when a caster hits an obstacle. But the most common cause of caster malfunction is that the wrong caster was used in the first place. The reason for caster misuse, most often comes down to price.  

One Darcor client that relies exclusively on cart usage was able to justify purchasing high-quality casters for their carts by looking at the avoided maintenance costs and the resulting operational slowdowns for replacement and fixes. Even one broken cart can have a profound impact on the business by slowing down delivery and putting customer service at risk to the point of losing customers to a competitor. 

Making the Investment 

Choosing the most inexpensive caster may seem like a good way to reduce costs, but it can end up affecting the company’s bottom line when equipment goes down and productivity comes to a halt. Cheap casters can negatively impact your business and competitiveness. It is much more cost-effective to take the long-term view and make a better investment up front. You don’t have to “reinvent the wheel,” but you do need the right caster for the job. 

If you would like to learn more about how cart design can improve the bottom line in your organization or how to tackle the top for your organization, download our Guide to Designing Manual Materials Carts. 

Caster Problems: 10 Reasons Casters Fail

warehouse corridor and handcart, carton stockAlthough casters are one of the smaller parts that make up a material handling cart, they play an integral role in how that cart will move efficiently and safely. Also, premature caster failure can impact the company’s bottom line.

Caster technology has come a long way in the last several decades. Yet, still companies are challenged by caster problems which occur during manual material handling tasks. Caster problems can negatively impact ROI due to the recurring cost for caster replacement. Additionally, caster replacement can mean impaired productivity due to machine downtime.

There are many reasons a caster can fail but the one that comes up most often is: choosing the wrong caster in the first place. Many times, casters are selected based on upfront cost. What is not taken into account is that an inexpensive caster purchase can cost you much more in the long run if it is not the right caster for the application.

Multiply the caster replacement cost by the number of that specific caster you own and add in the loss of productivity when those carts or equipment are down… you may find that you had wished you had done more research to choose the correct caster at the beginning.

10 Reasons Casters Fail and How to Avoid Them

Generally speaking, caster failure is not due to the design or defect in the caster itself. It is generally because some key characteristics were not considered when the caster was purchased and/or installed. Here are the top 10 reasons casters fail:

1. Caster Capacity Overload

The main reason that casters fail in the field is the load capacity applied to the caster exceeds its rated capacity. To avoid this pitfall, consider the heaviest load that will be used in the application. Due to situations arising from uneven floors or bumps etc. it is possible that a four wheeled cart may have only three wheels actually absorbing the full load. A safety factor based on the use of three casters is therefore used to address this which means that if the load capacity is 2,000 lbs., a caster with a load rating of at least 667 lbs. is recommended.

2. Impact Loading

Impact loading occurs when a caster hits a large obstacle or bump and experiences the resulting g-forces. This means that if a caster with a load capacity of 100 lbs. hits a bump and experiences 5 g, it’s as if the caster is carrying 500 lbs. at that moment.

This impact load can cause a catastrophic failure of the caster due to the peak g-forces which cause the caster to bear a higher load than its rated load capacity.

3. Brinelling

Brinelling is the dent or “wear” that is pressed into a hard surface. Brinelling occurs in a caster when the ball bearings in the swivel head begin to develop grooves in the hard cap. Brinelling affects the performance of the swivel of the caster by increasing the swivel force. Swivelling forces are typically the largest mobility force that a material handling cart will experience.

4. Excess Swivel Offset

Excess swivel offset in a caster is generally due to a design flaw. It refers to the distance between the center of the axle and the center of the king pin or main rivet being too great. Having an excessive swivel offset creates a situation that when a load is applied, the legs of the yoke may break away from the swivel. There is a fine balance between a large enough offset that ensures ergonomic efficiency while short enough to ensure joint strength is not compromised. Working with a competent design and engineering team can assist in ensuring optimal offset is achieved.

5. Wrong Bearing Type

Bearings are the part of the caster that limits movement to preferred motion and reduces friction between the moving parts within the caster. Using the wrong bearing type for a specific application can also be a cause of failure. For example, an application experiencing high side thrust. A tapered bearing would best be utilized. Improper bearing selection will cause premature failure of the caster. Various considerations should be made such as; bearing material, race construction and accessibility for maintenance if required.

6. Environmental Conditions

Environmental conditions can cause a caster to fail. In wet environments, using casters that don’t have stainless steel or chrome finishes, which are well-suited to these environments can lead to to corrosion. With corrosion comes the weakening of the caster components and increased risk of caster failure. Other environmental considerations include: surface characteristics (rough, uneven, slope etc.) and debris or other contaminants. Our Workplace Ergonomics Guide sheds light on more environmental conditions that could impact your choice of caster.

7. High speeds

High speeds can cause many issues with casters that weren’t designed for that specific application. Catastrophic failures can occur due to caster overheating, damage to the caster wheel hub, or damage to the bearings. Understanding the speed at which the caster will be used in its intended application will help you choose the right caster. For instance, you would need a much different caster for a manual material handling cart vs. a towable cart which can experience speeds in excess of 5 miles per hour.

8. Soft Top Plates

The function of the top plate of a caster is to provide secure attachment to the structure, protect the wheel and ensure the wheel direction is maintained. Having a thin top plate or one that isn’t hardened steel can make it very easy for it to bend out of shape potentially compromising both the load capacity and the directional intent of the caster. This condition mainly occurs when a caster goes over an obstacle and is damaged by the resultant impact. More robust and hardened top plates eliminate this issue.

9. King Bolt/Rivet Failure

Many casters are designed with the use of a rivet or kingpin bolt. These components generally have much of the stress concentrated on them when a high load is applied. Because of this, they are prone to failure when used in the wrong application. The solution to this potential issue is to use a Kingpinless caster that distributes the stress over a larger area on the caster.

10. Extreme Temperatures

Extreme temperatures can greatly affect the mobility performance of a caster. Many caster wheels are made from a variety of polymers and rubbers, which tend to lose their material properties when introduced to extreme temperature changes. Choosing the right wheel material to correspond with the temperature of the operating environment is the key when deciding on the right caster to use. A great example is caster use in food and freezer environments, which require dependable performance in extreme temperature conditions.

Choose the Right Caster the First Time to Reduce Caster Changeover and Costs

Caster changeover can be costly and can impact your business operations. Your business needs to cut costs and keep downtime low in order to improve. Choosing the right caster may seem like a minor decision, but by doing it right the first time, you can avoid costly caster maintenance and replacement down the road.

By considering the 10 caster pitfalls, you can avoid them in order to choose the right caster for your specific application.

To get some guidance on how to choose the right caster for your particular application, check out caster solutions by industry to help you understand how different industry applications require different caster solutions.

Don’t forget to download the The Economics of Ergonomics in the Manual Material Handling Industry Guide to get started!


This blog was originally published in April 2015.

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