Dynamic Seating
What is Dynamic Seating?
Dynamic seating is movement which occurs within the seat and/or wheelchair frame in response to force from the client. Dynamic components absorb force which, in turn, assists the client back to a starting position.
https://www.seatingdynamics.com/2020/05/05/dynamic-seating-definition/
Who would benefit from using dynamic seating?
Dynamic seating is often used with clients who have increased muscle tone. The dynamic components absorb extensor forces that could otherwise lead to client injury, equipment breakage, decreased sitting tolerance, increased agitation, decreased function, further increases in extension and quite a bit of energy exertion.
https://www.seatingdynamics.com/2020/07/28/dynamic-seating-clinical-indicators/
Which clients benefit from dynamic seating by diagnosis?
As dynamic seating is often used by clients who have increased muscle tone, clients with the following diagnoses often benefit from this technology:
- Cerebral palsy
- Traumatic brain injury
- Spinal cord injury (when spasms are present)
- Huntington’s Chorea
- Other diagnoses where increased tone is present
- Cerebral palsy
- Developmental disabilities
- Sensory processing disorder (when a wheelchair is also required)
- Other diagnoses where the client seeks out movement
For what ages is dynamic seating appropriate?
Dynamic seating is appropriate for children and adults who would benefit from movement within the wheelchair. Please refer to “Who would benefit from using dynamic seating” above.
What are the clinical goals of using dynamic seating?
Clinical goals include:
- To protect the client from injury
- To protect wheelchair and seating hardware from breakage
- To increase sitting tolerance and compliance
- To provide vestibular input
- To provide active range of motion
- To increase alertness
- To decrease agitation
- To increase function
- To increase strength and postural control
- To reduce active extension
- To reduce energy exertion
When is dynamic seating not clinically indicated?
It is important to ensure the client can return to upright after activating the dynamic component. If not, the component resistance can be changed. If this is not adequate to return the client to upright, dynamic options may not be appropriate.
It is also important to ensure the client return to an appropriate posture. For example, a client may return to upright after extending at the hips, but assume a posterior pelvic tilt. Individual manufacturer’s dynamic components work differently and may vary in ability to return the client to an optimal posture.
Some clients may experience increased extensor tone and/or postural insecurity and anxiety in response to dynamic movement. Decreasing the amount of movement may help.
Is there any research demonstrating the efficacy of dynamic seating?
Research has been done on dynamic seating and we have a literature review available. More research is needed and Seating Dynamics is collecting case studies at this time.
http://www.seatingdynamics.com/category/dynamic-seating-research/
Where does dynamic movement occur?
Dynamic seating may allow movement at the hips, knees and neck into extension. The dynamic components then assist the client back to a more upright position.
http://www.seatingdynamics.com/2019/03/12/using-multiple-dynamic-seating-components/
How do I determine how much resistance is needed in the dynamic component?
The client should be able to move the component and readily return to a starting position. If the component does not move, less resistance may be required. If the component moves, but does not return to a starting position readily, more resistance may be required.
http://www.seatingdynamics.com/category/determining-resistance/
Can dynamic seating be used on any wheelchair?
Some dynamic seating systems are a part of a dedicated wheelchair and cannot be moved to another wheelchair frame. Other dynamic seating is modular and is offered as separate components that provide movement at one body area. One component or several can be used on one wheelchair frame to match a client’s needs at one or more body areas. These modular components typically can be used on many types of wheelchair frames. Seating Dynamics components are modular.
Please see our Product Compatibility Matrix: https://www.seatingdynamics.com/wheelchair-compatibility/
Please see our Product Compatibility Matrix: https://www.seatingdynamics.com/wheelchair-compatibility/
I would like to learn more about dynamic seating so that I can use this technology with my clients. Where can I find more training?
Dynamic seating is a relatively new area of wheelchair seating. We have a number of resources available on this website, including links to articles, recorded webinars and a bi-monthly blog (see the Resources Tab above). You may also contact us for further information and product specific training needs.
I know a client who could benefit from dynamic seating. Where do I start?
A good place to start is to seek out a wheelchair seating evaluation with a team of clinicians and suppliers who are familiar with dynamic seating options and applications. If you can’t find resources in your area, give us a call and we will be happy to help you identify someone in your area.
http://www.seatingdynamics.com/2019/04/30/evaluation-simulation-and-dynamic-seating-trials/
I am working with a client who uses dynamic seating. The client has had a medical change. Is re-evaluation indicated?
If the medical change has resulted in a difference in how the dynamic seating responds to the client, then re-evaluation is indicated. For example, a client who has started or changed a tone management program may require an elastomer with less resistance.
How do I find a company near me to answer my questions about dynamic products?
Call us at 303-848-3838 and we can give you contact information for suppliers in your area.
Is funding available for dynamic seating?
This, of course, depends on the funding source. However, with proper justification, dynamic seating is often approved. Access sample justification wording.
Medicare is a nationwide payer and funding dynamic components can be difficult. Please contact your local supplier or ATP for up-to-date funding requirements and assistance.
Medicaid varies from state to state and pays for dynamic components in many cases. A prior approval is often required before the product is ordered.
Insurance companies vary by company and specific plan. Dynamic seating is a rehabilitation product which many insurance carriers are not familiar with. Therefore you should contact a supplier who is familiar with your insurance requirements and can provide necessary documentation.
http://www.seatingdynamics.com/blog-funding/
Dynamic Rocker Back interface (DRBi)
Compatibility:
Can a Dynamic Rocker Back interface be installed on any wheelchair?
Currently there are over 50 different manual and power wheelchair models on which we can install a DRBi. For a full list of compatible wheelchairs, please click here.
Can a Dynamic Rocker Back interface be installed on a power wheelchair?
Yes, we can supply a DRBi on some power wheelchairs. For a full list of compatible wheelchairs, please click here.
http://www.seatingdynamics.com/2019/01/15/faq-can-dynamic-seating-be-used-on-a-power-wheelchair-yes-lets-talk-compatibility/
http://www.seatingdynamics.com/2019/01/15/faq-can-dynamic-seating-be-used-on-a-power-wheelchair-yes-lets-talk-compatibility/
Can a Dynamic Rocker Back interface be installed on a wheelchair that is not new?
Yes, a DRBi is very often installed on wheelchairs which are not new.
http://www.seatingdynamics.com/2019/05/28/dynamic-seating-a-cost-benefit-analysis/
Can a Dynamic Rocker Back interface be used with a Recliner?
No. A recliner back and a DRBi cannot be used together.
Can a Dynamic Rocker Back interface be used with a tilt-in-space wheelchair?
Yes. DRBis are used very often on tilt-in-space wheelchairs.
http://www.seatingdynamics.com/2018/02/06/much-much-choosing-resistance/
Can a Dynamic Rocker Back interface be used with a one-piece molded seating system?
The back of the seating system must move separately from the seat in order to activate the DRBi. If the molded seating system is available in two pieces, this can be used with a DRBi. The Aspen Seating Orthosis is available with a limited recline to accommodate a DRBi.
http://www.seatingdynamics.com/2016/12/19/oil-water-molded-backs-dynamic-seating-mix/
Can a molded back be used with the Dynamic Rocker Back Interface?
A molded back can generally be used with a Dynamic Rocker Back Interface for two reasons. First, the seat to back angle only opens approximately 10-15 degrees. This amount of movement leads to a minimal amount of shear, allowing the client to remain in alignment with the contours of the back. Second, the Dynamic Rocker Back is mounted with a pivot point that further reduces shear, again, allowing the client to remain in alignment with the contours of the back.
http://www.seatingdynamics.com/2016/12/19/oil-water-molded-backs-dynamic-seating-mix/
Can I install custom seating when using a Dynamic Rocker Back interface?
Yes. Custom seating is frequently used for clients needing a dynamic back. The DRBi allows for the seating back to be mounted approximately 7” above the seat rail. This measurement varies slightly, depending on the model of wheelchair for which the DRBi is installed.
http://www.seatingdynamics.com/2019/06/11/wheelchair-seating-surface-cushions-dynamic-seating/
The wheelchair I am ordering for a client has a fold down back. Will the back still fold?
No. Due to the necessity for strength and durability clients using a dynamic back need, the non-folding dynamic back is necessary.
Installation and Adjustment:
Does a Dynamic Rocker Back interface take long to install?
Depending on the wheelchair model, installation usually takes an hour or less. The PN 6100 Back Cane Saw and Drill Jig speeds things up.
https://www.seatingdynamics.com/how-to-install-dynamic-rocker-back/
When I order a Dynamic Rocker Back interface, can I change the seat to back angle?
Yes. The seat to back angle is adjustable through the wheelchair manufacturer brackets, if this is a standard or added feature. If Seating Dynamic brackets are used, the seat to back angle can be adjusted 80 – 120 degrees, depending on the base.
Does the Dynamic Rocker Back interface take up any seat depth?
No, a DRBi is flush with the front of the back post.
The armrests attach to the back canes on the wheelchair. Can I use this configuration with the Dynamic Rocker Back interface?
No, the armrests which attach to the back canes (flip-up) must be removed. These can be replaced with a single or dual post armrest.
If my back canes are broken, can a Dynamic Rocker Back interface be installed on the wheelchair?
Yes. New back canes need to be ordered either from the wheelchair manufacturer or from Seating Dynamics, after which the DRBi can be installed.
Does the Dynamic Rocker Back interface require any maintenance?
The elastomers last approximately 2 years, depending on the frequency and forces applied. We have a “re-build kit” which includes upper and lower elastomers, as well as plastic caps for the top of the elastomers. These can be purchased and installed by your wheelchair supplier.
https://www.seatingdynamics.com/2017/05/09/elastomer-goes-flat-story-j-flattened-elastomers/
What should I do if the Dynamic Rocker Back interface seems out of adjustment or is not working?
Call or visit your supplier.
Elastomers:
How do I determine the correct resistance for a Dynamic Rocker Back interface?
The DRBi includes a range of elastomers to change the resistance without having to order more equipment. The elastomers should allow the client to move the back and then assist the client back to an upright position. The least amount of resistance is the Yellow (soft) elastomer. The strength of the elastomer initially installed in a new DRBi is Clear (Medium). If the client is able to completely compress the clear (Medium) elastomer, then the Blue (Firm) should be evaluated. The next step is to evaluate the green (Extra Firm) elastomer.
http://www.seatingdynamics.com/2018/02/06/much-much-choosing-resistance/
I know a client who is a very hard “rocker” and contacts the back with a lot of force. Should I start with the extra firm elastomer?
An extra firm elastomer may not provide enough shock absorption and movement. Some clients who have started with too firm of an elastomer calmed upon changing to the correct elastomer.
How do I change out the elastomers? How long does it take?
We have an easy to follow instruction guide on how to change the DRBi elastomers. To access this guide, click here.
Can I have a different color or strength Elastomer on one side?
No, the color/strength of the elastomers should be the same on each side. Having different colors/strength will cause possible failure or breakage of the back and the back seating system.
Latch (lock out):
When should I latch (lock out) the Dynamic Rocker Back interface?
The DRBi should be unlatched all the time, except when the wheelchair is being transported with the client in the chair. Remember to unlatch the back as soon as the wheelchair and client leave the vehicle.
Are there any other times when the latch (lock out) should be latched besides transportation?
Occasionally you may want to latch the DRBi when pushing a manual wheelchair over rough terrain to prevent excessive movement, but remember to unlatch as soon as possible to prevent breakage of the DRBi and to allow the client to benefit from the dynamic feature.
I work with schools and developmental group homes and see Dynamic Rocker Back interfaces which are latched all the time. What should I do?
Education about the equipment and how and why it works is essential. A DRBi which is latched when not in transportation is not allowing the client to benefit from the dynamic feature.
Why doesn’t my Dynamic Rocker Back interface latch / unlatch smoothly?
The DRBi needs to be “un-weighted” in order to be latched / unlatched. If there is weight or pressure put on the DRBi, the elastomers are compressed and the back cannot be latched smoothly.
If you are still having difficulty, the DRBi may need adjustment. The supplier may need to adjust the bolt going through the elastomers.
If the DRBi is more than 2 years old, the elastomers may need to be replaced. We have a re-build kit for this, which may be obtained through the supplier. The re-build kit includes upper and lower elastomers as well as plastic caps for the top of the elastomers.
Other:
I noticed that the client is showing less movement after using the Dynamic Rocker Back interface for about a month or two. Is this typical?
For some clients, knowing that movement is possible is enough to decrease the amount of resistance applied to the seating surfaces. As active extension is diffused, it may not persist when using dynamic components.
Is a pelvic positioning belt necessary when using a Dynamic Rocker Back interface?
Yes. The pelvic positioning belt helps to maintain a neutral pelvic position during movement.
http://www.seatingdynamics.com/2017/11/15/bread-butter-dynamic-backs-pelvic-positioning-belts/
If the client uses a pelvic positioning belt, isn’t that considered a restraint?
A positioning device, such as a pelvic positioning belt, is designed to maintain alignment with the support surfaces (i.e. the seat and back), provide stability and postural support and to promote function. A restraint is intended to limit movement to protect the client and/or others.
For specific restraint regulations and documentation requirements to allow provision of necessary postural supports, please refer to “Positioning vs. Restraint”.
http://www.seatingdynamics.com/2017/11/15/bread-butter-dynamic-backs-pelvic-positioning-belts/
Can I hang a backpack on the Dynamic Rocker Back interface?
Carrying any heavy object on the back or looped around the back canes will adversely affect the DRBi function and is not recommended.
If you are still having difficulty, the DRBi may need adjustment. The supplier may need to adjust the bolt going through the elastomers.
If the DRBi is more than 2 years old, the elastomers may need to be replaced. We have a re-build kit for this, which may be obtained through the supplier. The re-build kit includes upper and lower elastomers as well as plastic caps for the top of the elastomers.
Dynamic Footrests
In which directions do the dynamic footrests move?
Seating Dynamics footrests can move in up to three different axes:
- All dynamic footrests have dynamic telescopic movement. In other words, the footrests extend or get longer in response to force, up to 1.5”. When the force lessens, the dynamic footrest will return to its original length. The amount of the resistance can be changed by using different springs. All 3 resistance springs are included in the purchase. Using telescoping movement without knee extension is appropriate for clients who would need dynamic movement, but who may lose hip position when the knee extends. This can be an issue particularly with clients who have very tight hamstrings. This model is not available in the high pivot design.
- Dynamic knee movement which allows the wheelchair user to extend or semi elevate their knee up to 30 degrees. This allows the footrests to be set at a starting point of 90, 80, 70, 60, or 50 degrees of knee flexion. Each footrest can be adjusted separately to meet an individual client’s needs.
- Another option is dynamic plantar and dorsi flexion at the ankle. This option allows up to approximately 17 degrees of movement in either direction. This should not be used when the client has an AFO (ankle foot orthosis), as this will not allow the ankle to move.
As a supplier or clinician, how do I determine which dynamic movements are appropriate for an individual?
Dynamic seating is a relatively new area of wheelchair seating and many providers are needing further information. It is important to identify if the issue is caused by muscular or behavioral conditions. This will assist in determining what needs to be addressed. We have a number of resources on our website and are also happy to speak with you by phone.
In general, use of dynamic footrests that lengthen only is appropriate for clients who may lose the position of the pelvis if the knee also extends, such as clients with very tight hamstrings. If the position of the pelvis can be maintained, lengthening and knee extension provides more movement and active range at the knee. If the client has active ankle dorsi and plantar flexion, providing this option allows movement and active range at the ankle, as well. If the client wears AFOs, this movement will not be possible and so this option is not recommended.
As a parent/caretaker, how do I know which dynamic movements the client needs?
Please contact your local supplier and clinician for evaluation of specific needs. A good starting point is to try to identify the problem. If you are experiencing breakage of the wheelchair components, try to isolate the specific area and see which type of movement caused it. There are two primary movements which tend to cause breakage:
- Extension at the knee which creates a pull between the seat frame and the footrest hanger. This could result in seat frame and/or footrest hanger damage.
- Downward pushing or banging of the foot on the footplate. This could lead to bending or breaking at the footplate, footplate attachment, the footrest hangers and/or the seat frame. This may be first noted as reduced clearance between the footrest / footplate and the front caster.
How do I adjust the resistance in the Dynamic Footrests?
The telescoping feature can be adjusted by changing a spring.
The knee extension feature resistance be adjusted by changing an elastomer.
The plantar/dorsi flexion resistance cannot be changed.
Please read our blog on this topic by clicking here.
Do the client’s feet need to be secured to the footplate when using the dynamic footrests?
Yes, the client’s feet need to be secured using ankle and/or toe straps, “ankle huggers” or shoeholders with straps to maintain contact with the footplate and activate the dynamic footrests. Otherwise, the feet may simply move off of the footplate during movement.
http://www.seatingdynamics.com/2017/12/14/peanut-butter-jelly-dynamic-footrests-securing-feet/
If the client’s feet are secured, isn’t that considered a restraint?
A positioning device, such as an ankle strap, is designed to maintain alignment with the support surfaces (i.e. a footplate), provide stability and postural support and to promote function. A restraint is intended to limit movement to protect the client and/or others.
For specific restraint regulations and documentation requirements to allow provision of necessary postural supports, please refer to “Positioning vs. Restraint”.
http://www.seatingdynamics.com/2017/12/14/peanut-butter-jelly-dynamic-footrests-securing-feet/
Can dynamic footrests be installed on any wheelchair?
Currently we offer dynamic footrests for approximately 35 different models of wheelchairs. For a full list of compatible wheelchairs, please click here.
Are dynamic footrests available on power wheelchairs with center mount footrests?
Dynamic footrests are available on some power wheelchairs, but are not available at this time for center mount applications. We are able to supply a dynamic footrest for all “side mount” style footrest hangers.
http://www.seatingdynamics.com/2019/01/15/faq-can-dynamic-seating-be-used-on-a-power-wheelchair-yes-lets-talk-compatibility/
Can I take my dynamic footrests off one wheelchair and put them on another wheelchair?
Yes, but in order for the dynamic footrest to properly fit and function there are items which will need to be compared and/or adjusted between the two wheelchairs. This situation comes up when replacing the old wheelchair with a new one and in switching back and forth between a manual and power wheelchair.
The new or second wheelchair must have Seating Dynamics receivers. We suggest you contact us to confirm compatibility between the two. We are happy to speak with you to verify if current dynamic footrests can be reused or if new footrests are indicated.
How do the dynamic footrests mount to the wheelchair?
We provide a “receiver” for the footrest. This receiver mounts to the wheelchair, typically to the seat frame. Each receiver is designed for a specific model wheelchair.
Do the dynamic footrests swing away for client transfers?
Yes, the Seating Dynamics footrests will swing away (in or out) or lift out from the wheelchair by simply sliding the release button located on the outside of the receiver to the rear. Swinging inward allows the footrest to move out of the way for a transfer even if there is not room to the side of the wheelchair for the traditional swing-out style of footrest hanger.
Are the dynamic footrests adjustable in length?
Yes, the dynamic footrests have 2.5 inches of length adjustment in the standard models. The high pivot model, which is used with a shorter seat pan to foot plate length, has an additional 2 inches of vertical adjustment available in the hanger.
What is the longest dynamic footrest I can order?
The longest dynamic footrest is approximately 21 inches from the seat pan to the footplate. This will vary depending on the type of wheelchair, as some receivers sit above the seat pan and will affect the overall length.
VERY IMPORTANT: when using the longer length dynamic footrests, the seat to floor height of the wheelchair must be considered. The dynamic footrest will extend (telescope) up to 1.5 inches. Therefore, overall length of the dynamic footrests on the wheelchair equals the leg length PLUS the 1.5” telescopic movement. This must be within the available seat to floor height. Additionally, the knee angle becomes very important to consider as a longer length can be used at a 60 degree angle than at a 90 degree angle.
What is the shortest dynamic footrest available?
The shortest dynamic footrest is 5.25 inches from seat pan to top of footplate. The actual measurement may vary depending on the wheelchair model.
What part numbers do I need to order a pair of dynamic footrests?
Please use our online quote tool here.
Which receiver do I need to order?
Seating Dynamics offers a number of receivers to fit a variety of wheelchair bases and to address specific scenarios. More information can be found on the Dynamic Footrests webpage. Some receivers extend above the level of the seat pan and may require the seat to be notched at both front corners.
Please use our online quote tool here.
Why are left and right screws different on the dynamic footrests?
The left and right footrests utilize the exact same parts. The screws are facing different directions due to the assembly process.
Can a one piece footboard be used with the dynamic footrests?
A one piece footboard can be added to the dynamic footrests as a custom modification. A one piece footboard does limit the ability of each footrest to respond independently. Many clients with increased tone may have higher tone or more movement on one side of the body. By using separate footplates, movement can occur when and to the degree required on each side of the body. The one piece footboard flips up for transfers.
The footplates are rotating, what do I do?
If the footplates are rotating, the anti-rotation screw needs to be tightened. This is the large flat screw on the outer portion of the collar, just above the lower portion of the Dynamic Footrest.
https://www.seatingdynamics.com/2018/09/28/seating-dynamics-how-to-adjust-the-anti-rotation-screw/
https://www.seatingdynamics.com/2018/09/28/seating-dynamics-how-to-adjust-the-anti-rotation-screw/
Static Heavy Duty Footrests
What types of Static Footrests does Seating Dynamics offer?
Sometimes a dynamic footrest is not appropriate due to a client’s lack of range or atypical leg and/or foot postures. Typically, a standard footrest hanger and footplate are appropriate. Occasionally, more specific and Heavy Duty designs are required.
Our Adjustable Knee upper footrest hardware provides a wider range of knee angles using hardware that is very durable and will not lose position due to the clamping method. Adjustment is accomplished using male/female steel splines.
Our Adjustable Windswept upper footrest hardware is designed to accommodate increased hip adduction on one side and increased hip abduction on the other side.
Our Adjustable Super Contracture upper footrest hardware is designed to accommodate significant knee flexion.
Seating Dynamics also provides adjustable plantar and dorsi flexion extensions.
A client I am working with requires more specific knee angle adjustments than those available from the wheelchair manufacturer. Do you offer an option to address this need?
Yes, our Adjustable Knee upper footrest hardware provides a wider range of knee angles using hardware that is very durable and will not lose position.
A client I am working with has a “windswept tendency” that I cannot accommodate using standard footrest hangers. Do you offer an option to address this need?
Yes, our Adjustable Windswept upper footrest hardware is designed to accommodate increased hip adduction on one side and increased hip abduction on the other side. This hardware can also accommodate bilateral hip adduction or abduction.
A client I am working with has very limited knee extension and I cannot find a footrest hanger that addresses this. Do you offer an option to address this need?
Yes, our Adjustable Super Contracture upper footrest hardware is designed to accommodate significant knee flexion.
A client I am working with has unusual foot placement that I cannot accommodate on separate footplates. Do you offer a one piece footboard? Does it move for transfers?
Yes, we do offer a one piece footboard that also flips-up for transfers. A one piece footboard provides a wider space to accommodate the feet where needed and also will not “sag” medially as many footplates tend to do over time and under force. This also prevents the feet from falling into the space between the footplates.
Dynamic Head Support Hardware
Which dynamic head support hardware should I recommend?
The Single Axis dynamic head support hardware provides approximately 8 degrees of movement posteriorly. The resistance can be changed using different elastomers.
The Multi Axis dynamic headrest provides movement posteriorly and laterally, allowing this to respond to rotational movement. If the client does not always extend directly in midline, but has some rotation to their movement, the multi axis dynamic headrest is indicated.
http://www.seatingdynamics.com/2017/03/06/dynamic-head-supports-importance-design-meeting-client-goals/
Which headrest pads are compatible with your dynamic head support hardware?
For a full list of compatible head pads, please click here.
How does the dynamic head support hardware attach to the wheelchair?
Seating Dynamics offers two options:
First is a universal mounting bracket that is attached to the posterior surface of the back of the seating system.
Second, a spreader bar mount is available if the universal mounting bracket will not work, dependent on the type of back used. This is width and depth adjustable.
A quick release mount is available to easily remove the head support.
Where is the ball?
Our Head Support Hardware does not include the typical ball used to connect to the occipital pad. Instead, we use an adapter which attaches directly to the pad. This adapter allows for full adjustment in multiple planes, but holds position much better than a round ball.
http://www.seatingdynamics.com/2018/10/01/maintaining-head-support-position-lets-do-the-math/
Can the resistance of the dynamic head support hardware be adjusted?
The elastomers can be switched to change the level of resistance. The hardware comes standard with Blue (medium) elastomers to provide movement and to return the client to a starting position. If more resistance is needed, Green (firm) elastomers are provided with the unit.
http://www.seatingdynamics.com/2018/03/06/determining-resistance-dynamic-seating-head/
http://www.seatingdynamics.com/2018/09/04/dynamic-head-support-tilt-and-recline-resistance/
How do I adjust the resistance when the client uses a tilt or recline?
If the head support is moving during tilt or recline without force from the client, try a firmer elastomer.
http://www.seatingdynamics.com/2018/09/04/dynamic-head-support-tilt-and-recline-resistance/
Static Head Support Hardware
When would I order Seating Dynamics Static Head Support Hardware?
The Static Head Support Hardware is designed to replace standard hardware with highly adjustable and durable hardware that maintains position. The hardware includes a mounting plate, three links to obtain the height and specific position required, and one interface adapter for common head support pads (pads not included).
http://www.seatingdynamics.com/2018/10/01/maintaining-head-support-position-lets-do-the-math/
