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The Hoerner Report

Answers to Dr. Hoerner questions about the APAS system

 

Dr.  Earl F. Hoerner, M.D. requested information from the Biomch-L list to assist him in evaluation of the APAS system.  His message reads as follows:

An:   BIOMCH-L@NIC.SURFNET.NL
Betreff:   Movement Analysis Systems

Dear Biomch-L,
I have been retained to evaluate movement analysis software by a large
provider of physical medicine services. The equipment will be used for
various applications including functional capacity evaluations,
rehabilitation, sports analysis and independent medical evaluations.
The proposed budget for the project was $100,000. I have anticipated
purchase of a full movement analysis system with 2 high speed cameras,
analog capability, 2 force plates, EMG, etc. Upon performing my
initial "due diligence," research, I started to wonder if I grossly
underestimated my proposed budget. I eventually reviewed a paper
presented at the recent 3D conference of Human Movement. One of the
systems reviewed is called APAS. The vendor provides a trial download
over the internet. The web site for download is
/

My colleagues and I have been using the APAS software for approximately
two weeks. We have performed studies for gait, running, jumping. We
are able to interface a force plate and collect EMG. I was pleasantly
surprised at the relative ease of learning and operating this system.
It allows direct hard disk capture with any video source, including live
camera and 8 mm, without a dedicated VCR, through an inexpensive video
frame grabbing board. You can trim and synchronize your video on the
computer. There are multiple reporting formats, utilizing forms and
graphs. You can export the data to programs such as MathLab, Excel,
Etc.

It appears that the full purchase price of this system is only $5,000,
utilizing my computer, cameras, and peripheral equipment. This is a
fraction of the cost of other vendors. My question to the LIST is
"what am I missing?" This sounds too good to be true. I would
appreciate feedback from anyone familiar with APAS or any information
that will be helpful, before I commit to a system. Does anyone know of
other manufacturers that provide similar trial software downloads?

I am looking forward to your replies. I will forward a synopsis of
replies to the LIST.

Earl F. Hoerner, M.D.
Biomotion, Inc.

-------------------------------------------------------------------
To unsubscribe send UNSUBSCRIBE BIOMCH-L to LISTSERV@nic.surfnet.nl
For information and archives: http://www.lri.ccf.org/isb/biomch-l
-------------------------------------------------------------------


Following are the answers received to date, 11-17-1998

(A response from Mr. Gary Scheirman of Peak and an Answer from Dr. Ariel, were posted seperately)

From: "Erik B. Simonsen" <E.Simonsen@mai.ku.dk>
Subject: APAS

Dear Dr. Hoerner,

I do not believe you miss anything if you choose to use an APAS system for
movement analysis. Here at the university of Copenhagen we have used the
APAS for about 4 years now and we have been very satisfied all the way.

We use the system on a daily basis for gait analysis. We use 5 video cameras
(50 Hz) and 2 AMTI platforms, which we had before we bought APAS. We use
also EMG recordings from various EMG-systems. For digitizing we use the
system semi-automatically, which means that it takes a little less than 60
min to digitize 5 camera views (there are about 80 frames per view meaning a
total of 400 frames). However, we run the APAS system on several computers,
so often several staff members work on the same project at the same time,
which may further cut down time consumption for the total offline analysis.

Normally, we calculate 3-D inverse dynamics by importing the 3D coordinates
and the force plate signals from APAS to Matlab.

An interesting alternative is to invest in an online system. I haven't any
experience with such a system, but it is my impression that you often run
into technical problems during experiments, so you may end up spending more
time in the lab. Also after experiments you may spent some time with the
data from online systems because these systems often mix the markers (see
the Chattanooga presentation about marker confusion).

I hope you can use our experience and you are welcome to return with
specific questions.

Erik B. Simonsen, associate professor, Ph.D.


++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Erik B. Simonsen, Associate Professor, M.Sc. Ph.D.
Institute of Medical Anatomy section C.
Panum Institute. University of Copenhagen
Blegdamsvej 3., DK-2200 Copenhagen N
DENMARK
Phone: +45 35 32 72 30 (work) Fax: +45 35 32 72 17
Phone: +45 45 80 93 04 (home)
http://www.biomechanics.mai.ku.dk/ebs.htm
E-mail: E.Simonsen@mai.ku.dk
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++


From:   Sun G. Chung, INTERNET:suncg@medicine.snu.ac.kr
To:   "Earl F. Hoerner, M.D.", [70314,2171]
  
Date:   11/11/98 11:47 PM

RE:   Re: Movement Analysis Systems

Sender: suncg@medicine.snu.ac.kr


Dear Dr. Hoerner:


Yes, you are missing something very important.
You are missing negative balance due to so much money for sales, advertisement, company maintenance fee and some bubbles.:-)

If you are so busy and have no time, you may stop here just after knowing nothing to miss. Somewhat long phrase are here.

I am an M.D.(physiatrist) and used APAS since 1994 in Korea. I analyzed the motions of baseball players and abnormal gait patients with APAS since it was DOS version. As your experience, it works so fine, is accurate and has user friendly interface. Most of all, the APAS is very powerful. The more know you about the APAS, the greater power may you feel. I think the power of the system may come from the opened nature. No black box there.

What would be left to be desired for the system? Dynamic EMG?, Forceplate? Do you know the analog module of APAS with AD converter can be used as an polygraph equipped with powerful signal processing ability? You may know some kind of commercialized digital polygraph system is sold at the price of more than $10,000.

If you think that I may have some relation with the APAS company, the relation would be maintained by only below idea.

How much, do you think, would be appropriate for a motion analysis system? $200,000, $300,000 ... ...
Why do you think that it would be?

I have two simple estimation - forward and inverse.

Forward : The price for making the motion analysis system per se.
1. It should depend on the hardwares. The price of hardwares will inversely correlate to the number of consumer. Which consumer group would be larger, the consumer group of common camcorder or that of specialized CCD camera? If a motion system try to have its own hardware, the price may go up steeply. The black box may give some convenience but sometimes it provokes many troubles and prevents extensibility and power.

2. It should depend on the technology. How much should the company pay for adopting the DLT, various smoothing algorithm, Euler/Cardan angles, inverse dynamics and other signal processing algorithm? None!! Except for several hundred dollars for the books and articles.

3. It should depend on the software to assemble all the calculation, processing and driving the hardware. They may pay far more money to build user friendly interface than to assemble the modules and hardware. You can compare the system by system about the feature.

4. There remains may be what you are missing.


Inverse : The price for the patient or client to pay for the analysis(information)
In Korea, Magnetic Resonance Imaging on a body segment as brain, C-spine... costs about $500, provided that the exchange rate is 1:1000(really 1: 1300-1400). The gait analysis by the motion analysis system that you think nothing to miss, costs about $500 - $600. This price can be accepted if the information is so critical for clinical decision with invasive procedure. But, far more often, we meet the situation that the gait analysis data is not so critical as for following up the treatment course, for minor orthotic change, dosage change of antispastic drugs etc. Few patients can afford that price for their weekly or monthly follow-up or for the minor clinical decision. Of course, I think, as a rehabilitation doctor, we should work and study harder to make the information from gait analysis more valuable than now. But the price should be down and cheaper information could be supplied. Why not?

This "inverse estimation" is not exactly applicable to the research institute or other rich country as the "inverse dynamics" cannot show the real joint kinetics including bone on bone force. :-)

My idea is that more patients, clients or sports men should be helped with biomechanic knowledge which is build up of so many scientists' sincere and brilliant works. Maybe I meet with the APAS company at this point.

Thank you for reading my clumsy words.

Sincerely,

===================================================
Sun G. Chung M.D., Ph.D.
Dept Rehab Med
Seoul National University College of Medicine
Chong Ro Ku YeonGeon Dong Seoul
South Korea
(TEL)82-2-760-2619 (FAX)82-2-743-7473
suncg@medicine.snu.ac.kr


From: "PMUSERS" <pmfinch@scifac.indstate.edu>
Organization: Indiana State University
To: Gideon Ariel<gideon@arielnet.com>
Date: Mon, 23 Nov 1998 12:51:40 -0500
Subject: (Fwd) (Fwd) Ariel APAS Systems

Forwarded message:
From: Self <Single-user mode>
To: "Earl F. Hoerner,M.D."<70314.2171@compuserve.com>
Subject: Ariel APAS Systems
Date: Sun, 22 Nov 1998 23:40:19

Dear Dr. Hoerner,
I saw your posting on Biomech-L requesting feedback about the APAS
system and I would like to share my experiences with the Ariel APAS.
I bought my first Ariel APAS 386 collection system in 1990. I have
used the APAS for 3- D video analysis (kinematic & kinetic), force
platform analysis with a Kistler plate (gait & jump analyses) and 16
channel EMG analysis in a Physical Education undergraduate and
graduate environment. Also, I have used the EMG system to teach real
time EMG responses during different neuromuscular conditions at the
medical school. We regularly perform simultaneous video analysis,
force platform and EMG analyses on research & design evaluation of an
active traction rehabilitation prototype and master's
thesis projects. I have used up to 4 video cameras (60 HZ) and a
LoCam cinematographical camera (500 fps) for video analysis and I
have verified the accuracy of the system with known measures. The
accuracy I found to be similar to those reported in this year's 3D
conference at Tennesee. Also, I have used theDynamic Lift Task
Analysis (DELTA) software, Jump software, and GAIT software on
various research projects. Presently, I am working with the panning
module on a track & field project and last summer at the ISBS at
Konstanz, I used the APASview software to present the results from
the Track & Field competition at the 1996 Olympic Games. Since
purchasing my original system I have acquired another full APAS
desktop analog collection unit and an APAS laptop with A/D
capabilities and an Computerized Exercise Strength unit (CES). Also,
I have personally acquired an APAS laptop with A/D and I just
downloaded the new APAS light software for my home desktop computer
for my consulting business. All the systems have worked
exceptionally well and each machine generation has gotten better with
improvements in the software and hardware while decreasing in cost.
New versions of the software can be downloaded from the server and
the open architecture has made it a very powerful and versatile
analysis tool, that is a great bargain. My undergraduate and
graduate students finds the software easy to learn and well
documented with good help screens. Furthermore, if any technical
problems arise, John Probe, head of technical support will promptly
and accurately resolve the difficulty. The international APAS users
group is very helpful in sharing ideas, information on current and
new analysis applications.   Your concern about the potential catch
about the low price is unfounded because Ariel does not believe in
using expensive proprietary hardware when comparable hardware is
available at a fraction of the cost. The only thing you are missing
is the time you will save completing your research projects using
these great systems.
   I am so confident about these systems that I plan on personally
acquiring a new APAS notebook, hopefully in the next year.
   If you have any further questions concerning the systems please feel
free to contact me at
   pmfinch@scifac.indstate.edu
or if you want to see some of the projects completed using an APAS
check out the Magin Putter project or the Olympic Discus project @
/  

Sincerely,
Alfred Finch,Ph.D.
Professor Biomechanics
Physical Education Department
Indiana State University




From:   "B.J. Fregly", INTERNET:bj@sj.ptc.com

Dr. Hoerner,

I agree that this sounds almost too good to be true, but unfortunately I
do not have enough experience to tell you whether or not you are missing
something.

I will look foward to hearing what responses you receive from members of
the BIOMCH-L newsgroup.

B.J. Fregly

----------------------------------
Benjamin J. Fregly, Ph.D.
Research and Development Engineer
Pro/MECHANICA MOTION Analysis Technology
Parametric Technology Corporation
2590 North First Street, Suite 200
San Jose, CA 95131
Tel: 408/953-8650
E-mail: bj@sj.ptc.com


From:   Daina Sturnieks, INTERNET:Daina.Sturnieks@rmit.EDU.AU

Dear Earl,

Our department is also planning to purchase a motion analysis system. We
have looked into the APAS and I agree that the price does seem extremely
reasonable. However, we have been looking into the specifics of the system
and are yet to find anything to put us off. I don't have the knowledge to
completely answer your query. However, I would recommend that you check
the sampling frequency as some systems sample at an insuffiecent rate to
analyse very fast movements (particularly in sporting situations).
Obviously this depends on what you will analyse.

Would you please send me a summary of your replies as I would appreciate
reading these before we purchase the APAS.

Kind regards,

Daina Sturnieks.


From:   Leonard Elbaum, INTERNET:elbauml@servax.fiu.edu
To:   "Earl F. Hoerner, M.D.", [70314,2171]
  
Date:   11/11/98 7:58 PM

RE:   Re: Movement Analysis Systems

To: "Earl F. Hoerner, M.D." <70314.2171@compuserve.com>
Subject: Re: Movement Analysis Systems
References: <199811110951_MC2-5FD9-9D71@compuserve.com>
Content-Type: text/plain; charset=iso-8859-1
Content-Transfer-Encoding: 8bit

I am a long time user of the apas system, and would be happy to discuss it
further with you. Basically, it is what it is, quite robust and accurate,
and will probably serve you quite well..

best wishes with your venture.

Leonard Elbaum
Associate Professor
Department or Physical Therapy
FIU / Miami, FL


From:   Ed Lemaire, INTERNET:ELemaire@rohcg.on.ca

Hello Earl Hoerner,

We have been using APAS for a few years now and we have been
very satisfied. Once we sorted out our data collection space (i.e.,
painting walls black and adding dark flour tiles) APAS was extremely
capable of detecting marker positions. Support from Ariel Dynamics has
also been fine. We are still using the old DOS system but are planning to
move to the new software. Interfacing the APAS system with our other
hardware has been relatively easy (EMG, force plate, bioamps, etc.).

While we will always have a need for the APAS system (we can video
away from our gait lab and process later), we would also like to have an
automatic digitizing system (Vicon, etc.) to speed up our data processing
time. APAS is great for our clinical and R&D efforts; however, the
digitizing time for 3 cameras at 150-300 frames limits the volume of
clinical referrals that we can handle (since we deal with physical
disabilities, our client's walk very slowly). In Canadian $ the automatic
digitizing setup we need would cost around $200,000.00. This is purely
a speed of data processing concern - not a comment on data
reliability/validity.

In conclusion, I think that any new lab should have an APAS installation.
This is a very flexible system with a very reasonable price. I would
suggest that you get three cameras, instead of two. In addition to being
able to pickup most marker positions, we have been saved by having
some video-taping redundancy (i.e., when one camera did not record).
Also, factor in the cost of setting up the lab so that all cameras can be
turned on at one location - preferably beside main the data collection
computer (we are still working on this one!).

Please let me know how thing are progressing with your lab - our group
is always interested in sharing/learning with other physical rehab
facilities.

Edward Lemaire, PhD
Clinical Researcher
The Rehabilitation Centre
(613) 737-7350 x5592


From:   "Rebecca Stine", INTERNET:rebecca.stine@motionanalysis.com

Dr. Hoerner,

I would like to speak with you regarding our products and the integration of the APAS system with our system. If you could let me know a phone number and a convenient time to reach you, I would be happy to discuss your options. I look forward to speaking with you.


Rebecca Stine
Motion Analysis Corp.
Sales and Training Manager
(606) 276-1744 ph.
(606) 277-3565 fax


X-Sender: bi_sinclair@mailbox.cchs.usyd.edu.au
Date: Fri, 20 Nov 1998 11:18:16
To: gideon@arielnet.com
From: Peter Sinclair <p.sinclair@cchs.usyd.edu.au>
Subject: APAS problem

Dear Dr Ariel,

My name is Peter Sinclair. I teach Biomechanics at the University of Sydney
in the School of Exercise and Sport Science.

We have been using an APAS system under Win95 running projects for
undergraduate students here. The system has behaved very well once I
realised how it works. I was particularly impressed by its ability to cope
with students making mistakes and stopping half-way to attend classes
before continuing later. The system always let them pick up again where
they had left off without starting again. This is a big improvement on
other systems I have had experience with.

We have been using a combination of Win95 and DOS based modules for data
processing. This is because, although the Windows software is very friendly
to use.

Yours faithfully,

Peter Sinclair

School of Exercise and Sport Science
The University of Sydney
East St E-mail: p.sinclair@cchs.usyd.edu.au
Lidcombe NSW 1825 Phone: 61 2 9351 9137
Australia Fax: 61 2 9351 9204


Return-Path: <Normand.Teasdale@pmh.ulaval.ca>
X-Sender: teasdale@sntpmh.pmh.ulaval.ca
Date: Fri, 20 Nov 1998 13:49:12 -0500
To: Gideon Ariel <ariel1@ix8.ix.netcom.com>
From: Normand.Teasdale@pmh.ulaval.ca (Normand Teasdale)
Subject: site codes

Hi Gideon;

Thanks for all the answers. I'm really excited about the products and I do hope to build a biomechanical empire!!!

Here are 5 site codes and sites keys I would need to keep me going for a while and to allow some late nights and weekends digitizing for some of my grad students!!! This should be enough for my graduate level classes and research. If and when I decide to go ahead an implement undergraduate classes with APAS I'll have the University buy a site license! I have a programmer of my own here and I fully appreciate all the efforts involved in developping such complex software.

Thanks in advance

Normand

Normand Teasdale (Normand.Teasdale@kin.msp.ulaval.ca)
Universit Laval, Laboratoire de performance motrice humaine, PEPS
Facult de mdecine
Dpartement de mdecine sociale et prventive
division de Kinsiologie
Qubec, Qubec G1K 7P4
Tl: (418) 656-2147
Fax: (418) 656-2441


From:   "Marco Cardinale, M.S.S.", INTERNET:marcar@meda.it
To:   "Earl F. Hoerner, M.D.", [70314,2171]
  
Date:   11/18/98 11:44 AM

RE:   Re: Movement Analysis Systems


Dr. Hoerner,
I utilized the system during my year of study in USA at the United States
Sports Acdemy. I used it also for my thesis project. I am using it here in
Italy with Technogym for perfoming biomech. analyses.
I found it extremely good. It is very easy to use once the procedure has
been properly memorized and the new software for win98 is much more
user-friendly than the old versions.
My rating of APAS is very high. I think the ratio costs-benefits determine
APAS to be the best currently available on the market.

If you need further and more detailed info,
feel free of contacting me via email.

Regards,
Marco Cardinale
______________________________
Marco Cardinale, M.S.S.
Associate Editor
Coaching and Sport Science journal
Via G.Guinizzelli 56- 00190 Roma (Italy)
Phone: +39-335-6773389
Fax: +39-0771-500932
Email:marcar@meda.it
_______________________


From:   "Motion Analysis: Dan India", INTERNET:Dan.India@motionanalysis.com
To:   "Earl F. Hoerner, M.D.", [70314,2171]
  
Date:   11/21/98 6:43 AM

RE:   Re: Movement Analysis Systems

Sender: dan.india@motionanalysis.com


Congratualations on purchasing a APAS system. I am very much aware of its
features and benefits. If Motion Analysis can be of assistance in the
future please feel free to contact me or Gideon Ariel and he can forward to
me.

Much success

Motion Analysis Corporation
Daniel India, Vice President
3617 Westwind Blvd
Santa Rosa, CA 95403 USA
HQ Tel: 707-579-6500 Direct 847-945-1411
HQ Fax 707-526-0629 Direct 847-945-1442
www.motionanalysis.com
Dan.India@motionanalysis.com


Return-Path: <owner-biomch-l@NIC.SURFNET.NL>
Content-Disposition: inline
Approved-By: "Earl F. Hoerner, M.D." <70314.2171@COMPUSERVE.COM>
Newsgroups: bit.listserv.biomch-l
Date: Thu, 3 Dec 1998 12:01:26 -0500
Reply-To: "Earl F. Hoerner, M.D." <70314.2171@compuserve.com>
Sender: Biomechanics and Movement Science listserver <BIOMCH-L@NIC.SURFNET.NL>
From: "Earl F. Hoerner, M.D." <70314.2171@compuserve.com>
Subject: Motion Analysis Systems
To: BIOMCH-L@NIC.SURFNET.NL
X-MIME-Autoconverted: from quoted-printable to 8bit by ixmail8.ix.netcom.com id JAA29223

Dear Subscribers,
The following is a summary of responses received to my posting regarding
motion analysis systems and, in particular, the APAS system:

Dear Dr. Hoerner,
I saw your posting on Biomech-L requesting feedback about the APAS
system and I would like to share my experiences with the Ariel APAS.
I bought my first Ariel APAS 386 collection system in 1990. I have
used the APAS for 3- D video analysis (kinematic & kinetic), force
platform analysis with a Kistler plate (gait & jump analyses) and 16
channel EMG analysis in a Physical Education undergraduate and
graduate environment. Also, I have used the EMG system to teach real
time EMG responses during different neuromuscular conditions at the
medical school. We regularly perform simultaneous video analysis,
force platform and EMG analyses on research & design evaluation of an
active traction rehabilitation prototype and master's
thesis projects. I have used up to 4 video cameras (60 HZ) and a
LoCam cinematographical camera (500 fps) for video analysis and I
have verified the accuracy of the system with known measures. The
accuracy I found to be similar to those reported in this year's 3D
conference at Tennesee. Also, I have used theDynamic Lift Task
Analysis (DELTA) software, Jump software, and GAIT software on
various research projects. Presently, I am working with the panning
module on a track & field project and last summer at the ISBS at
Konstanz, I used the APASview software to present the results from
the Track & Field competition at the 1996 Olympic Games. Since
purchasing my original system I have acquired another full APAS
desktop analog collection unit and an APAS laptop with A/D
capabilities and an Computerized Exercise Strength unit (CES). Also,
I have personally acquired an APAS laptop with A/D and I just
downloaded the new APAS light software for my home desktop computer
for my consulting business. All the systems have worked
exceptionally well and each machine generation has gotten better with
improvements in the software and hardware while decreasing in cost.
New versions of the software can be downloaded from the server and
the open architecture has made it a very powerful and versatile
analysis tool, that is a great bargain. My undergraduate and
graduate students finds the software easy to learn and well
documented with good help screens. Furthermore, if any technical
problems arise, John Probe, head of technical support will promptly
and accurately resolve the difficulty. The international APAS users
group is very helpful in sharing ideas, information on current and
new analysis applications. Your concern about the potential catch
about the low price is unfounded because Ariel does not believe in
using expensive proprietary hardware when comparable hardware is
available at a fraction of the cost. The only thing you are missing
is the time you will save completing your research projects using
these great systems.
I am so confident about these systems that I plan on personally
acquiring a new APAS notebook, hopefully in the next year.
If you have any further questions concerning the systems please
feel
free to contact me at
pmfinch@scifac.indstate.edu
or if you want to see some of the projects completed using an APAS
check out the Magin Putter project or the Olympic Discus project @
/

Sincerely,
Alfred Finch,Ph.D.
Professor Biomechanics
Physical Education Department
Indiana State University

Dr. Hoerner,
I utilized the system during my year of study in USA at the United States
Sports Acdemy. I used it also for my thesis project. I am using it here in
Italy with Technogym for perfoming biomech. analyses.
I found it extremely good. It is very easy to use once the procedure has
been properly memorized and the new software for win98 is much more
user-friendly than the old versions.
My rating of APAS is very high. I think the ratio costs-benefits determine
APAS to be the best currently available on the market.

If you need further and more detailed info,
feel free of contacting me via email.

Regards,
Marco Cardinale

Dear Dr. Hoerner,

I do not believe you miss anything if you choose to use an APAS system for
movement analysis. Here at the university of Copenhagen we have used the
APAS for about 4 years now and we have been very satisfied all the way.

We use the system on a daily basis for gait analysis. We use 5 video
cameras
(50 Hz) and 2 AMTI platforms, which we had before we bought APAS. We use
also EMG recordings from various EMG-systems. For digitizing we use the
system semi-automatically, which means that it takes a little less than 60
min to digitize 5 camera views (there are about 80 frames per view meaning
a
total of 400 frames). However, we run the APAS system on several computers,
so often several staff members work on the same project at the same time,
which may further cut down time consumption for the total offline analysis.

Normally, we calculate 3-D inverse dynamics by importing the 3D coordinates
and the force plate signals from APAS to Matlab.

An interesting alternative is to invest in an online system. I haven't any
experience with such a system, but it is my impression that you often run
into technical problems during experiments, so you may end up spending more
time in the lab. Also after experiments you may spent some time with the
data from online systems because these systems often mix the markers (see
the Chattanooga presentation about marker confusion).

I hope you can use our experience and you are welcome to return with
specific questions.

Erik B. Simonsen, associate professor, Ph.D.


++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Erik B. Simonsen, Associate Professor, M.Sc. Ph.D.
Institute of Medical Anatomy section C.
Panum Institute. University of Copenhagen
Blegdamsvej 3., DK-2200 Copenhagen N
DENMARK
Phone: +45 35 32 72 30 (work) Fax: +45 35 32 72 17
Phone: +45 45 80 93 04 (home)
http://www.biomechanics.mai.ku.dk/ebs.htm
E-mail: E.Simonsen@mai.ku.dk

Dear Dr. Hoerner:


Yes, you are missing something very important.
You are missing negative balance due to so much money for sales,
advertisement,
company
maintenance fee and some bubbles.:-)

If you are so busy and have no time, you may stop here just after knowing
nothing
to miss.
Somewhat long phrase are here.

I am an M.D.(physiatrist) and used APAS since 1994 in Korea. I analyzed the
motions of baseball
players and abnormal gait patients with APAS since it was DOS version. As
your
experience, it
works so fine, is accurate and has user friendly interface. Most of all,
the APAS
is very
powerful. The more know you about the APAS, the greater power may you feel.
I
think the power
of the system may come from the opened nature. No black box there.

What would be left to be desired for the system? Dynamic EMG?, Forceplate?
Do you
know the
analog module of APAS with AD converter can be used as an polygraph
equipped with
powerful
signal processing ability? You may know some kind of commercialized digital
polygraph system is
sold at the price of more than $10,000.

If you think that I may have some relation with the APAS company, the
relation
would be
maintained by only below idea.

How much, do you think, would be appropriate for a motion analysis system?
$200,000, $300,000
... ...
Why do you think that it would be?

I have two simple estimation - forward and inverse.

Forward : The price for making the motion analysis system per se.
1. It should depend on the hardwares. The price of hardwares will
inversely
correlate to
the number of consumer. Which consumer group would be larger, the consumer
group
of common
camcorder or that of specialized CCD camera? If a motion system try to have
its
own hardware,
the price may go up steeply. The black box may give some convenience but
sometimes
it provokes
many troubles and prevents extensibility and power.

2. It should depend on the technology. How much should the company pay
for
adopting the
DLT, various smoothing algorithm, Euler/Cardan angles, inverse dynamics and
other
signal
processing algorithm? None!! Except for several hundred dollars for the
books and
articles.

3. It should depend on the software to assemble all the calculation,
processing and driving
the hardware. They may pay far more money to build user friendly interface
than to
assemble the
modules and hardware. You can compare the system by system about the
feature.

4. There remains may be what you are missing.


Inverse : The price for the patient or client to pay for the
analysis(information)

In Korea, Magnetic Resonance Imaging on a body segment as brain,
C-spine...
costs about
$500, provided that the exchange rate is 1:1000(really 1: 1300-1400). The
gait
analysis by the
motion analysis system that you think nothing to miss, costs about $500 -
$600.
This price can
be accepted if the information is so critical for clinical decision with
invasive
procedure.
But, far more often, we meet the situation that the gait analysis data is
not so
critical as
for following up the treatment course, for minor orthotic change, dosage
change of
antispastic
drugs etc. Few patients can afford that price for their weekly or monthly
follow-up or for the
minor clinical decision. Of course, I think, as a rehabilitation doctor, we
should
work and
study harder to make the information from gait analysis more valuable than
now.
But the price
should be down and cheaper information could be supplied. Why not?

This "inverse estimation" is not exactly applicable to the research
institute or
other rich
country as the "inverse dynamics" cannot show the real joint kinetics
including
bone on bone
force. :-)

My idea is that more patients, clients or sports men should be helped with
biomechanic
knowledge which is build up of so many scientists' sincere and brilliant
works.
Maybe I meet
with the APAS company at this point.

Thank you for reading my clumsy words.

Sincerely,

===================================================
Sun G. Chung M.D., Ph.D.
Dept Rehab Med
Seoul National University College of Medicine
Chong Ro Ku YeonGeon Dong Seoul
South Korea
(TEL)82-2-760-2619 (FAX)82-2-743-7473
suncg@medicine.snu.ac.kr

Dear Earl,

Our department is also planning to purchase a motion analysis system. We
have looked into the APAS and I agree that the price does seem extremely
reasonable. However, we have been looking into the specifics of the system
and are yet to find anything to put us off. I don't have the knowledge to
completely answer your query. However, I would recommend that you check
the sampling frequency as some systems sample at an insuffiecent rate to
analyse very fast movements (particularly in sporting situations).
Obviously this depends on what you will analyse.

Would you please send me a summary of your replies as I would appreciate
reading these before we purchase the APAS.

Kind regards,

Daina Sturnieks.






Daina Sturnieks, B.App.Sc. (Hons)
Department of Human Biology and Movement Science
RMIT University
PO Box 71
Bundoora
Victoria, 3083
Australia
Ph. +61 3 9925 7682
Fax +61 3 9467 8181

I am a long time user of the apas system, and would be happy to discuss it
further with you. Basically, it is what it is, quite robust and accurate,
and will probably serve you quite well..

best wishes with your venture.

Leonard Elbaum
Associate Professor
Department or Physical Therapy
FIU / Miami, FL

Hello Earl Hoerner,

We have been using APAS for a few years now and we have been
very satisfied. Once we sorted out our data collection space (i.e.,
painting walls black and adding dark flour tiles) APAS was extremely
capable of detecting marker positions. Support from Ariel Dynamics has
also been fine. We are still using the old DOS system but are planning to
move to the new software. Interfacing the APAS system with our other
hardware has been relatively easy (EMG, force plate, bioamps, etc.).

While we will always have a need for the APAS system (we can video
away from our gait lab and process later), we would also like to have an
automatic digitizing system (Vicon, etc.) to speed up our data processing
time. APAS is great for our clinical and R&D efforts; however, the
digitizing time for 3 cameras at 150-300 frames limits the volume of
clinical referrals that we can handle (since we deal with physical
disabilities, our client's walk very slowly). In Canadian $ the automatic
digitizing setup we need would cost around $200,000.00. This is purely
a speed of data processing concern - not a comment on data
reliability/validity.

In conclusion, I think that any new lab should have an APAS installation.
This is a very flexible system with a very reasonable price. I would
suggest that you get three cameras, instead of two. In addition to being
able to pickup most marker positions, we have been saved by having
some video-taping redundancy (i.e., when one camera did not record).
Also, factor in the cost of setting up the lab so that all cameras can be
turned on at one location - preferably beside main the data collection
computer (we are still working on this one!).

Please let me know how thing are progressing with your lab - our group
is always interested in sharing/learning with other physical rehab
facilities.

Edward Lemaire, PhD
Clinical Researcher
The Rehabilitation Centre
(613) 737-7350 x5592

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Return-Path: <osa10@cc.keele.ac.uk>
From: "A. Rahmatalla" <osa10@cc.keele.ac.uk>
Subject: Season's greetings
To: ariel1@ix.netcom.com
Date: Mon, 21 Dec 1998 17:07:03 +0000 (GMT)

Dears: Gideon, John, and all ariel crew
As we approach a new year, may I take this opportunity to thank every one in
the Ariel Dynamics for their endless efforts in helping us in the past, and
looking forwards for a prosperous and fruitful new year. having nice time
in Christmas and best wishes for the comming year.

Sincerely
Aziz Rahmatalla


An Open Response to Mr.  Gary Scheirman's, Peak Performance Technologies, answer to the informational query from Dr. Earl Hoerner

 

     Following Dr. Hoerner's published inquiry about the Ariel Dynamics APAS system on BiomechL, many responses were forwarded to me for response. Some of these have been published on our website. In addition, a recent response came from Mr. Scheirman, Vice President of Peak Performance Technologies.  The following points are my response to Mr. Scheirman letter.

    (1)  Mr. Scheirman compared pricing "motion capture systems" to selling  automobiles.   He compared the automotive market having a range of prices but that some automobile are twenty times more expensive then others.  Mr. Scheirman's letter suggested that the basic hardware for automobiles, such as wheels, engines, seats, steering wheels, etc., could be constructed of different quality and, therefore, account for the large discrepancy in prices. This is true for the automobile, but is a relative useless comparison for computer hardware.  Today's computers consist of several essential components: (1)  the processors, which are made primarily by Intel, AMD, or Cyrix, (2) the size of the storage capacity, and (3) the amount of memory.  The computer's "box" can sit on your desk or stand up beside or underneath it, the colors generally vary in shades of cream or beige, and the prices usually range from $800.00 to $1500.00 depending on the brand name selected.  But the most important point to understand is that the price is unrelated to the quality or the functionality of the hardware.  There are only minute differences in computers and relatively minor differences in prices if you are trying to use the automotive industry as your comparative analogy.  There are not vastly different component qualities nor extremes in prices.  In summary, there are huge differences in quality and pricing in cars and tiny differences in quality and pricing in computer hardware.

In addition, since you can download the software to your own hardware, you can select any hardware you wish. You can install it on a Windows base machines or an NT based machines or combination.  Not only you utilize hardware that you already own, but you save all the shipping charges and all the taxes applied to this hardware.  You cannot do this with cars... And you can install the software on any number machines that you want.  General Motor Corp. will not give you any number of cars for the one you purchase...

    (2)  Mr. Scheirman stated that "the most expensive and critical component is software.  I believe that this is absolutely correct!  We at Ariel Dynamics Inc. developed the first commercial available biomechanical quantification system. As our biomechanical system evolved, we learned from Hatze, Woods, Jennings, Shapiro, Walton, Wise and others.   Some of them were fellow students with me at the University of Massachusetts during the 1970s.  Our staff consists of  Ph.Ds from many diverse backgrounds including biomechanics, nuclear physics, mathematics, and engineering.  The power of our software is derived from the strength of the scientists and programmers who have worked together for almost 30 years to develop the most powerful biomechanical system in the world.

    (3)  Software is power!   Biomechanics, academically and in various applications, has grown and developed quite remarkably in the last 25 years.  From film to video to digital cameras, from main frames to PC to laptops on the field, from 2D to 3D to synchronized kinematics, EMG, and force plate measurements.  Ariel Dynamics has been the leader in innovations in these areas.  Ariel Dynamics continuously develops commercially available products which include new algorithms, new software-controlled hardware choices, and consumer generated requests.  Our goal is to provide the best and most accurate biomechanical system for the best price.  The Ariel Performance Analysis System (APAS) has been proved repeatedly to have the best options, the most extensive choices, as well as being the leader in new technologies --- always and all ways for the best price.

     (4) Mr. Scheirman mentioned service.  There is no better service company in the world than Ariel Dynamics, Inc. Check with our customers and find that our service is both free and quick.  Call other companies and ask the price for service. Try to ask for advice and you will learn what it will cost. The Ariel Dynamics APAS biomechanical package has "Help" screens available for every option selection for every program.  In addition, there are manuals included with the computer and, if you own your own computer and merely download the software, the manuals are included as well.  Customers can call the Ariel Dynamics office or send inquires by e-mail if they want these more information.  Most importantly, if customers have software requests, such as changing the color of the cursor during the digitizing phase, our staff can incorporate these improvements at no additional charge to the customer.  In addition, these software changes are then made available to other customers at no additional cost to them.

     (5)  The last item, of course, is cost!  The APAS biomechanical system provides everything the scientist, physical therapist,  coach or athlete, physician, and even the industrialist could want for the lowest price --- the BEST for LESS.   In addition, Ariel Dynamics does not charge for software upgrades. Call other companies and ask what they charge for software upgrades.  Try to upgrade the software and you will discover what it will cost you.  Ariel Dynamics offers free demonstration systems.  Call other companies and ask them for a free demonstration system. Ariel Dynamics provides free workstations on other computers at the customer's site. In other words, buy one and you can have all of your other computers operating as free workstations.  Call other companies and ask the price for their systems for every computer at your site.

     Check the APAS.  You can link to our website at:  / and download the software for free. Try it out; what do you have to lose?  It's free to try.  Check all the functions.  Call (619) 874-2547 or send a e-mail to: ariel1@ix.netcom.com.  Our staff will help you should there be questions. Imagine having the BEST biomechanical quantification system on your desk and at the VERY LOWEST PRICE.  If you do not like it, you can always buy another product --- with fewer functions and higher prices.

  Sincerely,

  Gideon Ariel, Ph.D. and the staff at Ariel Dynamics, Inc.

 

Why Should You Select the Ariel Performance Analysis System for Your Movement Quantification Needs?

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