Understanding the Cushion: How the Cushion Works



Last week we talked about the importance of increasing surface area contact to redistribute pressure for skin protection. Today, we will talk about two ways in which we can achieve this pressure redistribution: Immersion and offloading.

Immersion is how much the client sinks into the surface. Immersion works by increasing the surface area contact and therefore redistributing the pressure. Remember from physics in our university that Pressure = Force/Area. The easiest way to describe immersion is to think about how much we sink into a surface, in this case a cushion. When our client sinks into their cushion the amount of surface area contact is increased as opposed to if they are sitting on top of a cushion. A great example of a cushion that works through immersion is a ROHO cushion. ROHO has specific instructions on how to properly adjust the cushion in order to have the full amount of immersion. This is designed to provide the greatest surface area contact and therefore achieve the optimal amount of pressure redistribution. Imagine now if we had a fully inflated ROHO cushion and the client was sitting on top of the cushion… would we still get that immersion into the cushion? No, we would lose the benefits of immersion in this case and decrease the optimal amount of pressure redistribution.
While immersion is a great design not every cushion can work through immersion. Sometimes we don’t want to “sink” down into the cushion, or maybe we can sink down a small amount, but not enough to provide that full amount of pressure redistribution. Let’s take for example a flat foam cushion. Should our client be able to sink down far into a single layer flat piece of foam? If our clients are sinking down far into a single layer flat piece of foam, what is protecting them from bottoming out onto the hard surface under this foam? Foam can often be layered to allow for some immersion on the top while still giving a base for support, but this is why we typically see foam working through the principle of offloading.


Offloading is just what the name suggests! With offloading the cushion is designed to off-load the pressure under a particular area. In this case, typically we see offloading designed to decrease the pressure under the ITs, ischial tuberosities. The ITs, or your sit bones, are one of the points of highest risk of skin breakdown due to it being the lowest point on the pelvis and therefore having the most amount of pressure placed on this area if sitting on for example a flat piece of foam. The easiest way to think about offloading is to think about a tyre. It you were to sit on a car tyre you would have the open ring of the tyre under your ITs and therefore no pressure would be applied to that area. This is true offloading. What we have to remember though is that although we have offloaded in one area, we have decreased the over all surface area contact. Therefore, we have increased the pressure to the areas that have contact, Pressure= Force/Area. These areas might be able to withstand higher pressures, but it is important to keep in mind. What is more common is to provide partial offloading. This is what we see with pelvic/ischial wells, through contouring and material layering. Partial offloading works by trying to load through the femurs first and thereby allowing for partial offloading of the ITs, sacrum, and coccyx.
It is important that you can look at a cushion and understand how a cushion will work for your client. This is how you are able to narrow down the options for your client and determine which cushions may be appropriate.
If you are interested in furthering your knowledge on the materials and principles behind cushions reach out to Rachel Fabiniak at to schedule a clinical education course in your area.



Understanding the Cushion: Why it matters what we are sitting on?



Have you ever been to an event where you had to sit on hard metal benches for hours? They are so uncomfortable that many people bring thin foam cushions to help alleviate pain and discomfort. OR have you had to drive during a long road trip and can barely feel your bottom at the rest stop because it has gone numb? That is why truck drivers often purchase cushions to sit on in their trucks.

What is happening?

The pain that we feel when we sit on a firm, flat surface for long periods of time is due to a buildup of pressure right under our bony prominences. The most common bones are our “sitting bones,” the ischial tuberosities (ITs). As well, we often slouch and can sit right on our sacrum and/or coccygeal bone.

If we do nothing to protect those bony areas pressure builds up, cutting off blood supply, oxygen, and nutrient delivery to that area, leaving the skin and tissue between the seat surface and the bony prominence susceptible to ischemia. As we start to feel our bottom go numb, we begin to move and fidget, trying to relieve the discomfort or numbness.

What about our clients? Can they all move around to relieve this discomfort?  Or, do they even have the sensation to know that they need to move around?

We prescribe our clients a cushion to help assist with pressure relief, but do we understand what that cushion is doing?  It is important to understand the design and theory of how a cushion works to ensure it is the right type of cushion for your client.  If we are looking at a cushion for skin protection, we are looking at cushions to increase surface contact area.

Increasing Surface Contact Area:

We have to step back into our physics course to first understand.  Pressure is equal to Force over Area: P=F/A. Pressure can never truly be eliminated, but it can be redistributed to greater surface areas to produce less pressure. So, our goal should be pressure redistribution over the greatest surface area rather than only through small surface areas that would increase pressure.



How do we redistribute pressure in a skin protection wheelchair cushion?

We know now that we want to increase the surface area that the client contacts when sitting on a cushion. Pressure distribution can be accomplished in one of two cushion designs:

  •          Immersion
  •          Offloading

Next week we will begin our discussion on what these two design principles are and how they work.

Ana Endsjo, MOTR/L, Clinical Education Manager LTC Division Business Region Americas and Rachel Fabiniak, Clinical Education Australia/New Zealand



Mobility is a Human Right?



Mobility is a Human Right. Take a second to think about that statement. How do we define mobility? Is it simply the act of moving from one place to another? The Oxford English Dictionary defines mobility as the ability to move or to be moved freely and easily. I want us to focus on the beginning part of this definition – the ABILITY to move. Then, every individual, whether they are a child, adult, or elderly, that has the ability to move, should be provided the opportunity for mobility.


I had the privilege of attending the Source Kids Expo in Melbourne, Australia this past Friday and Saturday. Source Kids was started by Emma Price, a mom whose eldest child has a disability. Emma created Source Kids as a resource for other parents raising children with a disability. This past weekend I was able to meet families from all around Victoria (and Australia). While some families approached with questions in hand and ideas about what they were looking for, many families came with a blank slate hoping to learn a little more about what resources were available. It was incredible to witness the number of families and therapists that attended this expo.




Throughout these two days, we were able to help several children experience independent mobility with a manual or power wheelchair for the first time. The age of the children that trialed manual or powered wheelchairs ranged from 2.5 years old and up. Some of the parents had wanted to try out a wheelchair while others had never thought it possible for their child to learn and use a wheelchair. I cannot accurately describe the feeling that comes over you when you see a child move around efficiently and independently with a wheelchair for the first time, but their face says it all. It is true happiness. While these amazing moments continued throughout the expo, I couldn’t help but consider all the individuals that have potential for safe, independent mobility but may never have access to this type expo. That is why this week the blog was shifted from a discussion on cushions and is now dedicated to Mobility! We know that not every individual will have the capacity to perform independent mobility even given the best mobility devices on the market, this is why there are so many great options out there for wheelchairs and mobility devices that can be controlled by carers and family. For those individuals that do have the capacity, we have to remember that mobility is a human right. It can be challenging whether you are a carer, parent, family member, friend, or therapist to know if someone is appropriate or the “right age” to trial a mobility device. I want to challenge everyone to stop thinking about if and when someone is appropriate, instead believe that everyone should be given the opportunity for mobility until they prove that they are unable to or would be unsafe.



While we have children on one end, we also have to remember the aged population. These individuals may have had independent mobility their entire lives. Is there an age where we can say it is okay that they no longer should have safe independent mobility? What age is that: 90, 85, 78? Once you hit that age then we should just give you a wheelchair that you can sit in, but are not able to move? Is that independent mobility? Or, have we taken away this human right? There is no age where safe independent mobility should be denied. The key is of course that this mobility is safe. Let us as therapists, families, and as an industry to make sure that we are not denying this potential safe and independent mobility to anyone regardless of their age.


It can be scary to determine if someone is ready for safe, independent mobility, but remember you have resources to help! Never be afraid to ask questions to safely determine if someone has the capacity to trial a mobility device. Giving someone independent mobility who has the ability to move is their human right.



There Are So Many Cushion Options: Where do I start?



Over the next several weeks, we will be discussing cushions and how to choose the right cushion for your client. It can be challenging to pick a cushion for a client when there are so many options out there today. Some of the questions I commonly get are: Where should I start? How do I narrow down the options? What will work best for my client? Can I just keep them on the same cushion they already have?


Let’s start by first considering the client goals and your goals as the therapist. These might include goals such as: positioning goals, skin protection goals, or function-based goals. Often, we might have multiple goals for seating that we are trying to meet. Take a look at the chart below. Here are a few examples of goals that we might be trying to meet with the cushion. We have to remember that one cushion may not be able to achieve all of our goals, but what is most important? Where can we have overlap? How can we achieve the best outcome for our client?




Once you decide what goals you are trying to accomplish then you can begin to look at what design of cushions you should be considering. Let’s consider two examples.
Client 1: The therapist’s goal and the client’s goal are both to maintain the client’s posture thereby allowing the client to have increased function. The current cushion does not maintain the client’s position, allowing the client to collapse into a posterior pelvic tilt and therefore decreasing their range of motion with shoulder flexion for overhead activities.
Client 2: The therapist’s goal is skin protection. The client has a history of multiple pressure injuries on his ischial tuberosities bilaterally. The client has been limited in their sitting tolerance due to pressure and therefore the therapist is looking for the best possible skin protection cushion for their client.

For these examples above would the Client 1 and Client 2 benefit from the same cushion? Perhaps, but not likely. Look at the example of two cushions below. Which cushion would you trial with each client?


You could trial both cushions for each client, but in this case if we had to choose, we would choose the air-cell based cushion for client 2 and the contoured foam cushion for client 1. How did I come to this conclusion?


The next step is to understand the design and materials of cushions to determine when or why you might choose one cushion over another. Next week we will begin with discussing the design behind cushions and how they work.
For this week it is important to remember that there is not one cushion that works for every client! In fact, every client even with the same cushion will have a unique interaction. We can even go as far to say that the same client on the same cushion will likely have a different interaction with that cushion each time they sit on it as they sit slightly different each time and many clients move around throughout their day.


What Causes Pressure Injuries? 



We just finished discussing backrests over the past several blogs.  We will now move onto another support surface: Cushions.  But first, I want to take one step back and discuss pressure. Pressure is one of the reasons that we all spend so much time considering the support surfaces for our clients.  Today we will have a little review on pressure from Ana Endsjo, US Clinical Education Manager LTC Division.
When we talk about wounds caused by pressure, we often only consider the pressure on our bottom. However, pressure can be created by any support surface that comes in contact with the body such as the: the backrest, cushion, arm rests, and head support.
So, let’s clarify the definition of pressure when considering it from the seated posture.
Pressure is a continuous force applied on or against an object through direct contact. In seating, equipment such as the seat and/or back support surface is in constant contact with the body, creating peak pressures.
Peak pressure is a constant pressure directly under or against the bony prominences that will cause a pressure injury without proper pressure redistribution through appropriate cushion and back support choices. Peak pressures are commonly found at the ITs, sacrum, coccyx, and on the spinous process, injuring the skin and underlying tissue, muscle, and, in extreme cases, bone.
 Pressure from a seated posture comes from:
  • downward pressure from gravity
  • upward pressure from the seat surface
  • horizontal pressure along the spine from the back support
When these peak pressures are not addressed through proper pressure redistribution techniques with the appropriate cushion and back support, the skin, tissue, and bone is compromised. Sustained loading against the back support and/or seat surface causes constant compression of that skin and tissue under a bony prominence, leading to a pressure injury. The degree of injury depends on the layers of skin impacted.
It is important that we as therapists begin to understand the critical role that the seated posture plays in the prevention and treatment of pressure injuries.
Thank you Ana.
The next several blogs we will be discussing cushions. From materials of cushions to what type of cushion will be best for your client, cushions can vary greatly, and it can be challenging to look at a room full of cushions and know which ones to pick for your client.


How do I choose a backrest for my client?
We have talked for a couple weeks now about backrests and the importance of choosing the right backrest for our client, but how do we make that final decision? There are so many backrest options out there and typically a client can benefit from more than just one option. Often, I am asked the question, “As a therapist should I know all the backrest options on the market?”  The answer is simple – NO. Your role as the therapist is to know what your client would benefit from for positioning, function, comfort, etc… Then, to communicate those needs to your supplier who can offer specific options. Remember that the client should have options, and your supplier will offer these.
This is not to say that every client should trial 5 different backrest options at the seating appointment, but instead to keep in mind that there are options.  We want to consider what the goals of the seating system are, and then determine when discussing or trialling a backrest option if that option is meeting those goals. Those goals being both your goals as the therapist and the goals of your client.
So now you have looked at a few backrest options and you think you found one that the client is happy with, what’s next?  We want to be able to show that our goals have been achieved. The best way we can do this is by completing outcome measures.  Outcome measures will give us objective feedback to truly show if the goals we were looking to accomplish have been met. Outcome measures are an important tool that we should be utilising during our wheelchair evaluation process, especially when it comes to funding.  Reviewers like to see outcome measures as these are not subjective to your opinion, but instead objectively give insight into the outcomes of the equipment you are trialling.
There are many options for outcome measures and we will have an upcoming blog dedicated to these, but for today let’s think about a few options. For example, we have a client and the goal for this client and his seating system was that he would have less pain in his back.  We could simply have the client complete the numeric pain rating scale in his current seating system and then with this new backrest option depending on how quickly the pain typically starts. This outcome seems simple but showing the difference in the numbers could be powerful or could give you the feedback that perhaps another backrest option is required.
Another example is the client that needs to be positioned well for stability but has to be able to reach within their environment in order to be independent.  Here we can think about a functional outcome measure like the modified functional reach test. This test will allow us to see how far our client can reach forward and can be compared to their previous seating system. It is important to remember that the set-up of the chair and cushion will largely impact this score, so be sure to have considered the whole seating system.  If you have not heard of the modified functional reach test, it is one of my favourites. I included the link to the exam below.
Remember that there are always numerous backrest options out there and likely more than one option will work for your client.
Modified Functional Reach Test:

Is the Standard Sling Back on a Manual Wheelchair a Good Option?



This week we will hear from Ana Endsjo, US clinical education manager for the LTC division, and her great thoughts on the replacing the sling back on a manual wheelchair. Thank you Ana!
I am going to make a bold statement: for every cushion purchased a back support should be purchased with it. No exceptions.

WHAT did she say??? You heard correctly!

I have been asked many times why I feel so strongly about replacing wheelchair sling backs to provide the optimal seating system for our patients. I will provide you with a multitude of reasons, which we will explore in a moment.



Almost immediately after making that statement, I get asked, “Why do manufacturers even bother putting a sling back on the chair if they are so ‘bad?’” Great question, and I use a shoe analogy to explain my reasoning. You can go out and purchase a $50 pair of sneakers from Shoe Depot or go to a specialised running store and purchase a $180 pair of sneakers, and they will have one thing in common: the thin, flimsy foam insert that every manufacturer must supply to release the product to the market. The shoe manufacturer must supply the bare minimum insert to protect a foot from minimal shock and trauma while wearing the shoe. However, the research and time manufacturing the highest quality shoe was not spent in making the foam insert; it was in every other aspect of the shoe.

The technology behind the shoe to allow for a comfortable, efficient, and injury-free stride sets it apart from the lower end models and not the thin, flimsy foam insert! Manufacturers understand that if you have a more complex podiatry need due to plantar fasciitis or Achilles tendonitis, etc, then you will have to replace the manufacturer insert with a more expensive, specialised insert or orthotic that can accommodate or correct the underlying issue. And this is the same situation with the sling back.

The sling back is just like that thin, flimsy foam insert in the shoe. It helps meet qualification for the wheelchair to be sold in the market but cannot accommodate or correct for any type of postural abnormality. Moreover, it will not be able to stabilise or create better pressure redistribution to prevent a fall or pressure injury in a seating system.

This important stability and prevention does not begin and end with the seat of the wheelchair. We have been singing songs since we were children that every bone, joint, and muscle is connected, affecting the movement and stability of the entire body. So, we shouldn’t focus solely on the pelvis and purchase only a cushion to fix a seating issue. It is all connected, and if we want the trunk, head, neck, and extremities to be better aligned, then we need to consider the critical role of the back support and how it affects the movement and stability of the pelvis and everything else below and above it.

A back support can allow you to:
• Optimise the wheelchair configuration by opening or closing seat-to-back angle
• Stabilise the spine/trunk more effectively to maximise alignment for increased independence with functional tasks
• Allow for the ability to immerse and contour to the spine for maximum contact and decreased risk of pressure injury development.

If the back support can do so much, now it is easier to see that the cushion alone cannot solve the seating issue. We should now realise that our patients deserve more than the, “thin, flimsy foam” insert and need a more specialised option that will allow for optimal stability, alignment, and function!


Ana Endsjo, MOTR/L, CLT
US Clinical Education Manager, LTC division
Ana Endsjo has worked as an occupational therapist since 2001 in a variety of treatment settings. She has mainly worked with the geriatric population, dedicated to the betterment of the treatment of the elderly in LTC centers. Her focus has been on seating and positioning and contracture management of the nursing home resident.



The Collapsing Position: Considering the backrest materials


As we continue our discussion on positioning the client in the wheelchair, we will begin looking at how products play a crucial role in the positioning of the client.  Let’s take an example of someone with thoracic kyphosis.  We determine based on our mat assessment that our client has a reducible, or flexible, thoracic kyphosis.  With proper support we are able to achieve a close to neutral, or midline, seated posture. Now we have to choose the backrest, cushion, and other positioning components on the wheelchair, along with the positioning of the chair itself, to maintain this neutral posture.  We want to try to keep our client as close to neutral as possible in order to prevent worsening of the kyphosis and other long-term negative effects. Today, we will focus on the backrest. How do we make sure our client is in this position? What types of products are we looking for?

The first key we have to remember is to not be distracted by what WE think is comfortable.  Each individual will have a unique interaction with their backrest. It is important for us to not just determine the backrest for our client based on what “feels good” to us, but instead to consider the options based on what we need to provide in support for our client.  Now, it is still important and a great idea for you to sit with and feel the products you are considering for your client, so you can see how they will be providing the support you are requesting.
Let’s go back to our client with the flexible kyphosis.  This client will require a backrest that gives them support, support to maintain their neutral posture.  I want to find something that will allow my client to be positioned in neutral without increasing their energy expenditure.  Can you imagine if you had to sit and stand in a perfect posture all day? Could you do it?  For this client, I want to provide a backrest that gives positive support, so that he/she can be in a close to neutral position at rest, requiring less effort by the client.  This is the perfect example of where we need to think about the backrest option for the client and their unique interaction. Often, I see therapists squeeze a backrest cushion and comment on how soft and squishy the cushion feels. While this may feel great for your hand, what happens to our client with kyphosis?
Imagine our client on the left, we have positioned them to neutral and now we stick this “super soft and squishy” backrest behind them.  We have now created the image on the right.  Our client, as they go to relax, will collapse into this backrest, pushing through that soft and squishy foam until they have reached their preferred kyphotic position. It isn’t just the kyphosis.  We may also begin then to see other secondary complications including cervical hyperextension to try to overcome the effects of the kyphosis.
Now, this is not to say that the “super soft and squishy” backrest cannot be used for some clients, but are we considering the needs of the client when choosing this option? We have to be sure that our client is not collapsing into the backrest that we have chosen for them, but instead being supported. Let’s move away from the idea of soft means comfortable for everyone and instead focus on what the needs of your client are and how through different positioning products those needs can be addressed.

What Happens After the Mat Assessment?


What happens after the mat assessment? We have to use the results of the mat assessment and work as a team, utilising the skills of the therapist, the supplier, and the manufacturer to meet the clients’ seating needs. There are many roles and people involved in the seating evaluation process beyond the supplier and therapist including the client, family, teachers, nurses, etc… Today, we will focus on the role of the therapist. As a therapist becomes more experienced and comfortable with mat assessments they may start learning about specific products and the ways those products could work for their clients. Initially though, the role of the therapist is to be able to communicate to the supplier their findings from the mat assessment.


During the mat assessment the therapist should be assessing if their client is in a neutral posture, or if not, where the asymmetry is coming from. This doesn’t mean that you have to remember exactly how to name, for example, a pelvic rotation, but you want to be able to tell the supplier that the client’s pelvis sits further backward on the right side. Once we determine that there is a right hip rotation, then we need to assess if this hip rotation is reducible or non-reducible. You may have also heard this term referred to as fixed or flexible. If the asymmetry that we see can be reduced back towards neutral, it is flexible, or if it is “stuck” and non-reducible, then it is fixed. Knowing if the client has reducible or non-reducible asymmetries is important in determining the best products for the client. If someone has a reducible asymmetry, then we want to make sure products are selected to correct the asymmetry towards neutral. If the asymmetry is non-reducible, then we will have products to accommodate to this asymmetry and assist with prevention of furthering the asymmetry.

The other key questions we need to think about would include: What are the goals of the client? Let’s take for example a client that has scoliosis and is leaning to the right. We determine, based on our mat assessment, that this is a reducible asymmetry and that we can use positioning products to achieve an almost neutral seated posture. However, during our goal setting, the client explains the importance of being able to reach objects off the ground for maintaining his functional independence. How does this goal guide our practice? In this instance, with correcting his posture we may prevent him from leaning side to side to reach the ground. We need to be sure when we are choosing seating and positioning products that we remember MOBILITY is our ULTIMATE GOAL. The goals as the therapist may not match the same goals as the client. For this example, the therapist would need to consider both their positioning goals and the client’s functional goals.

We also need to remember that our clients change over time. Their goals change, their posture changes, and their needs will change. We want to remember that this equipment whether it is the wheelchair, or the seating on the wheelchair, will need to last a reasonable amount of time. Therefore, we need to keep in mind the long-term goals and anticipate any long-term changes that might occur.

Finally, before you choose your solution remember that you need to determine the cause before determining the solution. There will likely be problems that require more than one intervention, or different problems that may utilise the same intervention. Remember to keep the client’s goals and the ultimate goal of mobility in your mind as you work towards finding their seating solution.

Next week we will take a look at specifics behind the design of seating products and how we know what type of product to choose for our client when we are looking at all the options.

It All Begins with the Mat Assessment



We spoke last week about 24-hour positioning and its importance for the client, but how do we know what products to use and how to position our client? This all begins with the mat assessment. The mat assessment is where we will be able to determine any postural asymmetries, decreased range of motion, contractures, muscle tone, and so much more for the client’s seated position. Although the mat assessment typically will be utilised for the seated posture in the wheelchair, it can be beneficial for any surface the client may be on throughout their day. If you have never completed a mat assessment or are still new to the process – the most important piece of advice is to remember to breathe, get hands-on, and write down what you feel/see. Mat assessments can be scary when you first start, but ultimately it will provide you with the information you need to provide the best care to your client. So where do you begin?

Begin first by trying to find a hard surface for your client. Not every therapist will have access to a mat and that’s okay. It is important to try to find a firm surface so that you’re not getting false information back. The client’s safety and well-being are most important, so be sure to make sure your client is safe on the surface you choose.



You want to assess the client in both supine and sitting. The assessment in supine will allow you to not only assess the client without the effect of gravity, but it will also allow you to safely assess the client’s range of motion. I have included a few great resources below on mat assessments and a few helpful forms you can utilise. It is important to either have a form to fill out, or to write down what you see and feel as you go along. The last thing you want to do is finish the mat assessment and then forget what you have just done! Once the supine examination is over then you can complete the sitting examination.

For the sitting examination, be sure your client is safe at all times! You may have to provide support by sitting behind your client or having a second person for safety. The seated examination will give you feedback on the client’s position with gravity, position of their head and trunk, their balance, and so much more. Here is where you can really get hands on and determine how much support the client will need in their wheelchair. I like to use my hands as laterals, chest straps, or as whatever positioning items I am thinking of to mimic their effects. Remember to give your client proper foot support during the sitting examination.



If I can give one piece of advice when learning mat assessments is to PRACTICE! Practice on your family and friends. Practice on other therapists. Feel comfortable with your process before you try to just jump two feet into a complicated mat assessment. The best way we can learn is through practice. Take a look at these great resources below and as always feel free to email/call with any clinical questions! I am here to help you.




Spinal Seating Modules

Mat Assessment Guide

Permobil Seating and Positioning Guide