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THE SCIENTIFIC METHOD

1OBSERVATION

2 QUESTION

3 HYPOTHESIS

4 EXPERIMENT

5 ANALYSIS

6 CONCLUSION

OBSERVATION

PEOPLE ARE DISSATISFIED WITH CURRENT ERGONOMIC OFFICE CHAIRS

Do you ever hear people rave about how great their office chair is? Yeah, neither do we!

So we asked ourselves:

CHAIR, SPECIALIZED OR ERGONOMIC: HSA ELIGIBILITY

CHAIR, SPECIALIZED OR ERGONOMIC: REQUIRES A LETTER OF MEDICAL NECESSITY (LMN) TO BE ELIGIBLE WITH A HEALTH SAVINGS ACCOUNT (HSA)

A specialized or ergonomic chair for treatment of a medical condition may be eligible if accompanied with a Letter of Medical Necessity (LMN) with a flexible spending account (FSA), health savings account (HSA) or a health reimbursement arrangement (HRA).

HOW DO I USE MY HSA/FSA ACCOUNT TO PAY FOR MY ANTHROS CHAIR?

Since every insurance carrier is different, the process of using your HSA funds will vary.

Call your HSA Administrator to learn the process for your carrier.

Potential processes:

  1. Get a LMN from a medical professional (MD, PA, NP, Chiropractor)
  2. Use your HSA/FSA to purchase your Anthros chair online
  3. Submit your LMN to your HSA/FSA provider
  4. Get a LMN from a medical professional (MD, PA, NP, Chiropractor)
  5. Pay out of pocket for your Anthros chair
  6. Submit receipt and LMN to your provider
  7. Get reimbursed from your HSA/FSA funds

Have more questions?

QUESTION

CAN WE DESIGN THE WORLD'S BEST OFFICE CHAIR?

HYPOTHESES

  • 1 Prove that we can create a back support that increases disc space and reduces disc pressure
  • 2 Prove that we can create a chair that is capable of improving your posture over time
  • 3 Prove that we can create the world’s most comfortable, lowest pressure cushion
WHAT WE USED TO PROVE OUR HYPOTHESES

EXPERIMENT

Seating Expertise

Digital 3D Human Modeling+ Simulation Software

Medically-graded International Testing Standards

Submission to FDA as orthotic Device

Existing Data on the Science of Sitting

 

What We used to prove our hypotheses

EXPERIMENT

  • Seating Expertise
  • Digital 3D Human Modeling+ Simulation Software
  • Medically-graded International Testing Standards
  • Submission to FDA as orthotic Device
  • Existing Data on the Science of Sitting
HYPOTHESIS

Prove that we can create a back support that increases disc space and reduces disc pressure

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Experiment

Based on 20+ years of designing seating products for wheelchair riders, Anthros imagined an independently adjustable 2 part back system.

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Experiment

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Experiment

It was designed using expertise of the human body and a deep understanding of sitting biomechanics.

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Experiment

According to existing research and experience, we knew that supporting the pelvis in neutral was key to supporting an upright spine with optimal curves and disc space.

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Experiment

We began by building models and testing on human models of various shapes and sizes.

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Experiment

There were multiple iterations to determine and optimize pivot points and contours of the adjustable 2-part back system to achieve our hypothesis.

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Experiment

The effectiveness of this 2 part back system was then validated using 3D human modeling.

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Experiment

We based our testing relative to the Wilke et alstudy which studied the intervertebral pressure of a live person in different positions. They used a pressure transducer that was inserted in the disc at L4-5.

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Experiment

We used human modeling to determine whether disc pressure decreases at L4-5 with the 2 part back system adjusted for an upright position and in a tilted position (seat and back move together).

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Experiment

Based on decades of designing medical seating products for wheelchair users, Anthros imagined an independently adjustable two-part back system to better support and fit the vast differences in human spines. It was designed using a meta analysis of sitting research and a deep understanding of sitting biomechanical principles.

Experiment

According to existing clinical research and decades of medical seating design experience we knew that supporting and leveling the pelvis, L5 and L4 regions was the key ingredient in establishing your natural lumbar curve which in turn also guarantees equal disc spacing throughout your entire spine. We began by building state of the art human models to validate and optimize our two-part back design. Then once perfected with the virtual human environment we prototyped and tested those virtual theories on human subjects of various shapes and sizes.

Experiment

There were years of design iterations to determine and optimize the pivot points, movement patterns and foam shapes of our two-part back system. This dedicated work lead to the development of the most natural human fitment you can experience from any back seating system, a must for the vastly different shapes, comfort and support needs from our extensive panel of human test subjects.

 

The effectiveness of this two-part back system was then validated using 3D human modeling. We based our testing relative to the Wilke et al study which studied intervertebral pressure of a live person in different positions.They used a pressure transducer that was inserted in the disc at L4-5.

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Biomechanical and tissue modeling performed by Simuserv integrated by Abaqus Unified FEA from Dassault Systèmes

We used the most advanced 3D human modeling software system combined with the world renowned Simuserv Human Modeling team to perform all of our human modeling design and analysis. Simuserv helped determine that disc pressure indeed decreases at L4-5 with the Anthros two-part back system when properly adjusted. Simuserv also recorded a dramatic decrease in those L4-5 disc pressures when our two-part back system was used in combination with the Anthros tilt feature.

 

Analysis

The results of the Wilke study showed that an optimal disc pressure in neutral standing is 73 psi.

With the 73 psi value as optimal, we were pleased to see that our two-part back system could achieve and even surpass these values.

Standard Office Chair Standing Anthros Upright Anthros Tilt
102 psi 73 psi 73 psi 44 psi
Standard Office Chair Standing
102 psi 73 psi

Anthros Upright Anthros Tilt
73 psi 44 psi
 
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Conclusion

We were able to show that our two-part back system reduces disc pressure and the reduction of intervertebral disc pressure is correlated to decreased back pain according to research. And the absence of pain can be associated with comfort.

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HYPOTHESIS

Prove that we can create a chair that improves posture

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Experiment

Using 3D human modeling, we wanted to see the effect of supporting the pelvis independently in neutral. The goal was to see the spine follow into an “S” curve, which is a healthy anatomical posture for the intervertebral discs, vertebra, and nerve roots.

Analysis

Existing research shows that supporting the pelvis is the key to achieving and maintaining optimal spinal curves.

Existing research also shows that the body adapts to the position it is in most frequently. This means that sitting poorly all day will result in muscle imbalances and poor posture over time; whereas sitting well all day can help restore muscle balance and improve posture over time. 

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Conclusion

It can be clearly seen in the human modeling simulation that supporting the pelvis with the low back support resulted in the spine elongating and moving into an “S” curve. The upper back support acts to support the upper spine in this position. We can therefore infer, that sitting in the Anthros chair daily will position the body optimally and improve posture over time.

The FDA further validated our hypothesis by registering the Anthros chair as an orthotic device #3021484401, which is used to improve posture.

In legal terms: orthodic device means an apparatus used to support, align, prevent, or correct deformities, or to improve the function of movable parts of the body.

 
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HYPOTHESIS

Prove that we can create the world’s most comfortable, lowest-pressure cushion

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Experiment: Stages of design

With 70+ years designing wheelchair seat cushions, the knowledge and expertise of caring for the most vulnerable sitting population was brought to the Anthros seat cushion. The design began using anthropometric data, then 3D human simulation was used to adjust the design to achieve the lowest peak pressures possible. It began with contours to match the human shape, but we believed we could get lower pressures than we were seeing. We then created empty pressure relief cutouts in the area under the sit bones and saw a drastic reduction of peak pressures. These domes were then perfected in shape and size to ensure that different shapes and sizes of subjects would experience the same benefits.

2" Flat Foam

Contoured Foam

Contoured Foam with Pressure - Relieving Domes

Stages of Design

2” FLAT FOAM
CONTOURED FOAM
CONTOURED FOAM WITH PRESSURE-RELIEVING DOMES
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Experiment

Once we optimized the cushion design using 3D Human modeling to have the lowest sitting pressures (softness), we then validated the virtual design using real foam prototypes at an accredited university. The International Organization for Standardization (ISO) develops standards for all types of products, including wheelchair seat cushions. These standardized tests are established to evaluate how a product performs on measures that impact the user of the product. Anthros chose the University of Pittsburgh School of Health and Rehabilitation Sciences to perform the standardized bench tests on 10 office chair seats to evaluate performance, considering most people sit in these seats for at least 8hrs per day. Since the walking population primarily uses office chairs we focused on the three known measures of perceived tissue comfort based on existing and extensive research: peak sitting pressures, cushion contact area, and tissue shear strain seen from sliding on the cushion.

*Performed on 6/8/22 at the University of Pittsburgh with a rigid load indenter. Human results may vary.

LOW SHEAR

SHEAR Shear is the combination of downward pressure (in sitting, through the buttocks), and horizontal friction (sliding forward in your seat when your skin sticks to the seat and you feel that pull). Imagine a child sliding down a metal slide wearing a bathing suit, with skin sticking to the slide all the way down; this is shear.

HIGH CONTACT AREA

CONTACT AREA Contact area represents how much contact the indenter (or person) is making with the seat surface. A higher contact area is desired as it implies greater pressure distribution and lower peak pressures.

= Comfort

LOW PRESSURE INDEX

PEAK PRESSURE INDEX
Peak pressure implies high pressures in one area. The peak pressure index is what is calculated by averaging the individual sensor results along the simulated IT (sit bones) portion of the testing fixture. Rather than simply taking the single highest value as the peak pressure, one random reading won’t skew the results or the perception of performance. A high peak pressure index is associated with discomfort or pain, so low values are desired.

Analysis

The results of the independent university testing clearly show that the Anthros seat cushion outperforms all other office and gaming chair seat cushions tested—in each measure of comfort. 

Shear

The first test is for shear strain. This simulates the pain one might feel when slouching and sliding off of their seat surface. The higher the shear force number the more one might be able to sense pain over time.

Shear

University of Pittsburgh Study
Low Values are Desirable

Less 0-N
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  • 10
  • 15
  • 20
More 0-25

Pressure Distribution/ Contact Area

The second test is for the cushion contact area. This indicates the amount of tissue from the back of your leg and buttocks that will immerse into the cushion to help reduce sitting pressures. A park bench would have a low number while a large down feather pillow might have a higher number. You can guess which number might lead to greater comfort.

Pressure Distribution/Contact Area

University of Pittsburgh Study
High Values are Desirable

Less 0 mm2
  • 20,000
  • 40,000
  • 60,000
  • 80,000
  • 100,000
More 120,000 mm2

Peak Pressure Index

The third test is to record the sitting pressure your body will make with the various seat designs. Again, think park bench versus a large down feather pillow.

Peak Pressure Index

University of Pittsburgh Study
Low Values are Desirable

Less 0 mmHg
  • 40
  • 80
  • 120
  • 160
More 200 mmHg

Conclusion

Independent university testing proves that Anthros outperforms industry-leading office chairs in measures of comfort. Anthros has created the most comfortable sitting experience with the lowest peak pressures.

DON’T JUST TAKE OUR WORD FOR IT

SEE WHAT SIMUSERV MANAGING DIRECTOR ALEXANDER SIEFERT HAS TO SAY ABOUT ANTHROS

CONCLUSION

SUMMARY

After years of experiments, collecting data, and existing research, we found we COULD:

  • 1 Prove that we can create a back support that increases disc space and reduces disc pressure
  • 2 Prove that we can create a chair that improves posture
  • 3 Prove that we can create the world’s most comfortable, lowest pressure cushion 
 

CAN WE DESIGN THE WORLD’S BEST OFFICE CHAIR? SCIENCE SAYS YES!

Customize Yours Now

DISC SPACE Zhang, L., Helander, M. G., & Drury, C. G. (1996). Identifying factors of comfort and discomfort in sitting. Human Factors, 38(3), 377–389. https://doi.org/10.1518/001872096778701962

Underwood MR, The Use of a Back Teaching Class teaching extension exercises in the treatment of acute low back pain in primary care, Oxford Univ, Great Britain, 1998) (Kreutz, D. (1997). Power tilt, recline or both. Team Rehab Report ,March. 29 – 31.

SUPPORTING THE PELVIS Cohn, 1886; Schoberth, 1969; Branton, 1969; Lee, 2010

Lee H, Yoo W. The mechanical effect of anterior pelvic tilt taping on slump sitting by seated workers. Industrial Health 2011, 49, 403-409.

O’Sullivan P, Dankaerts W, Burnett A, et al. Lumbopelvic kinematics and trunk muscle activity during sitting on stable and unstable surfaces. Journal of Orthopaedic & Sports Physical Therapy 2006b;36(1):19e25

O’Sullivan P, Dankaerts W, Burnett A, et al. Lumbopelvic kinematics and trunk muscle activity during sitting on stable and unstable surfaces. Journal of Orthopaedic & Sports Physical Therapy 2006b;36(1):19e25

Tanoue H, Mitsuhashi T, Sako S, Goto R, Nakai T, Inaba R. Effects of a dynamic chair on pelvic mobility, fatigue, and work efficiency during work performed while sitting: a comparison of dynamic sitting and static sitting. J Phys Ther Sci. 2016 Jun;28(6):1759-63. doi: 10.1589/jpts.28.1759. Epub 2016 Jun 28. PMID: 27390410; PMCID: PMC4932051.

IVD PRESSURE AS IT RELATES TO COMFORT Zhang, L., Helander, M. G., & Drury, C. G. (1996). Identifying factors of comfort and discomfort in sitting. Human Factors, 38(3), 377–389. https://doi.org/10.1518/001872096778701962

Underwood MR, The Use of a Back Teaching Class teaching extension exercises in the treatment of acute low back pain in primary care, Oxford Univ, Great Britain, 1998) (Kreutz, D. (1997). Power tilt, recline or both. Team Rehab Report ,March. 29 – 31.

BODY ADAPTS TO POSTURE OVER TIME Katsman et al. Age-Related Hyperkyphosis: Its Causes, Consequences, and Management. J Orthop Sports Phys Ther. 2010 Jun; 40(6): 352–360.

Kim D, Cho M, Park Y, Yang Y. Effect of an exercise program for posture correction on musculoskeletal pain. J Phys Ther Sci. 2015;27(6):1791-1794. doi:10.1589/jpts.27.1791

Burgess-Limerick, R., A. Plooy, and D. Ankrum, The effect of imposed and self-selected computer monitor height on posture and gaze angle. Clinical Biomechanics, 1998. 13(8): p.584-592.