Sutherland 2

8/6/2019 Sutherland 2

http://slidepdf.com/reader/full/sutherland-2 1/21

Gait and Posture 16 (2002) 159–179

The evolution of clinical gait analysisPart II Kinematics

D.H. Sutherland *

Children’ s Hospital San Diego, 3020 Children’ s Way MC 5054 , San Diego, CA, USA 92123 -4282

Accepted 18 December 2001

Abstract

Kinematics is treated as a single topic in this manuscript and the emphasis is on early history, just as it was in Part I,

Electromyography. Needless to say, neither kinematics nor electromyography, nor kinetics and energy (the latter to be included

in Part III) are stand-alone components of clinical gait analysis. The only reason for this selective format is that it lessens my task

to be able to write about one subject at a time. One of the consequences of this arbitrary separation is that some contributors,

who have enriched more than one portion of clinical gait analysis, are highlighted only in the area in which they have contributed

the most. I began with Kinesiological Electromyography in Part I because the earliest stirrings of the dream of clinical gait

analysis were expressed in the development of KEMG (kinesiological electromyography). The early investigators realized that very

little could be said about the dynamic action of muscles without KEMG. Next, in chronological order, came kinematics. I have

been an active participant and eyewitness, and take full responsibility for attempting to write an early history at a time when most

of the contributors are still alive. Ordinarily, history is written much later, in order to fully grasp the significance of individual

contributions in the tapestry of the whole. As stated in Part I, Electromyography, the emphasis has been placed on the early

history. The application of motion analysis to sports medicine, and sports medicine functional analysis, is covered only lightlyhere, and this should not be interpreted as minimizing its importance. The literature on this subject is now quite voluminous and

it would not be possible to cover it adequately in this manuscript. Later historical writings may differ significantly and will

hopefully give more recognition to pioneers in later generations: those physicians, engineers, physical therapists and kinesiologists

who are lifting the level of clinical gait analysis and directing their energies in expanding clinical directions. It is hoped that this

manuscript will prompt additional manuscripts, as well as letters to the editor of Gait and Posture on the content of this review

paper. © 2002 Published by Elsevier Science B.V.

Keywords: History; Kinematics; Clinical gait analysis

www.elsevier.com/locate/gaitpost

1. Introduction

Accurate measurement of motion is central in any

scientific method of gait analysis. Measurements of

individual joint angular rotations, as well as transla-

tions of segments and of whole body mass, allow the

comparisons with normal that are necessary to distin-

guish pathological from normal gait. Complex hard-

ware and software are necessary to accomplish this task

with accuracy and reliability. This component of clini-

cal gait analysis has proven to be very challenging and

the evolutionary process continues to this day.

The individual joint angles and the displacements of

segments and of the whole body mass were recognized

to be essential measurement requirements in the late

1800s by Braun and Fischer [1– 5]. Their clever ap-

Note from re6iew editor: This article is the second in a series of

three historical narratives that Dr Sutherland has very kindly agreed

to author for Gait and Posture. As Dr Sutherland indicated in his

abstract for Part I, these are very personal accounts that focus

primarily, although not exclusively, on the early history of clinical

motion analysis. He further acknowledged that not all important

contributors or events may be chronicled or weighted in the same

manner as others might have done. Still, these accounts are extremely

valuable because they provide a very alive ‘behind the scenes’ view of

how our field has progressed over the years as told by one of its true

pioneers, with a richness that could never be captured by a mere

listing of names or documented events.

* Tel.: +1-858-966-5807; fax: +1-858-966-7494

E -mail address: [email protected] (D.H. Sutherland).

0966-6362/02/$ - see front matter © 2002 Published by Elsevier Science B.V.

PII: S 0 9 6 6 - 6 3 6 2 ( 0 2 ) 0 0 0 0 4 - 8



D.H . Sutherland / Gait and Posture 16 (2002) 159 – 179 160

proach to kinematic analysis was to apply Geissler

tubes to the limb segments, interrupt the illumination at

regular intervals by a large tuning fork, and pho-

tograph the subject walking in total darkness with four

cameras while the lenses were open. One camera was

positioned in front of the subject, one behind, and oneon each side, making their measurements tri-dimen-

sional. The subjects were protected from electrical

shock by wearing rubber suits resembling wet suits. The

process of collecting data required 8 or 10 hours per

subject and then it involved months of work to reduce

the data and calculate kinematic measurements. This

was a fantastic scientific achievement, however, because

it was so time consuming, Braun and Fischer’s method

could only be applied in gait research.

One of the methods used by Eberhardt and Inman [6]

in the 1940s also included the use of interrupted light.

A photograph was obtained with the subject walking in

front of the open lens of a camera while carrying small

light bulbs located at the hip, knee, ankle and foot. A

slotted disk was rotated in front of the camera, produc-

ing a series of white dots at equal time intervals. These

dots could be laboriously connected to provide joint

angles that could be manually measured. Again, this

was a slow and labor-intensive process, not suitable for

clinical application. In order to examine transverse

plane rotations, Vern Inman, MD, PhD, drilled pins

into the pelvis, femur, and tibia, and recorded pin

rotation with the aid of a movie camera located above

the subject [7]. One of his subjects, David Chadwick,

MD, then a student at the University of California,Berkeley, later became the Medical Director of Chil-

dren’s Hospital of San Diego. He described his experi-

ence as ‘very painful’, something he would not have

agreed to had he understood ‘what it would be like’.

Needless to say, this technique gained very few follow-

ers, although there has been some recent use of pins

inserted into bones in normal subjects for a different

purpose, i.e. to determine the difference between move-

ment of markers taped to the skin surface and those

placed into the skeleton.

2. Early pioneers and techniques (post Inman)

2 .1. Strobe light, reflecti 6e strips and manual

goniometer

Mary Pat Murray, PhD, working at the Veteran’s

Administration Hospital in Milwaukee, Wisconsin, de-

vised a simple, effective, and low cost way to record

and measure movements. She and her team attached

reflective targets (including reflective strips in the lower

extremity) to specific anatomic landmarks and the sub-

jects walked in the illumination of a strobe light. The

resultant photograph was used to make measurements

of the individual segments. Her method did include

upper extremity and trunk markers, as well as pelvis

and lower extremity. She successfully used this method

to produce landmark articles in the 1960s, 70s and 80s

outlining the walking patterns, first of normal men [8],

then of normal women [9], and then patients withpathological conditions [10 – 12]. Although, viewed by

today’s standards, this appeared to be a crude method,

the sagittal plane joint angle measurements of normal

subjects in her publications are very similar to those

obtained with current technology, (see Fig. 1) [9]. The

primary problems with Dr Murray’s method were the

need for manual measurements of all the joint angles

and the inherent dif ficulty with the method in providing

hip, knee, and ankle joint rotations in the transverse

plane.

2 .2 . Electrogoniometry

There was a flurry of enthusiasm for recording joint

angles with electrogoniometers. The Karpovich broth-

ers were early contributors who used goniometers to

record joint angles. Their reason for using electrogo-

Fig. 1. Sagittal measurements of pelvis, hip, knee and ankle in normal

women. Reprinted from the Archives of Physical Medicine and

Rehabilitation, with permission from W.B. Saunders Company [9].




Fig. 2. Triaxial Goniometer as applied to a subject for bilateral hip

and ankle joint motion analysis. Reprinted from the Journal of Biomechanics, vol. 13, 1980, pp. 989 – 1006, Chao: ‘Justi fication of

triaxial goniometer for the measurement of joint rotation ’; with permis-

sion from Elsevier Science [22].

the necessity for matching the size of the individual

with the appropriate goniometers, the offset of the

recording device to the side of the limb segments, and

the inability to obtain simultaneous measurements of

all of the moving segments. Quoting from Dr Chao’s

article entitled, Justi fication of Triaxial Goniometer forthe Measurement of Joint Rotation, ‘‘This paper at-

tempts to provide the theoretical and experimental jus-

tifications of the existing triaxial goniometer design so

that these potential problems can be resolved’’ [22]. The

experimental device used for the justification was a

mechanical model, thus any problems with skin motion

were not considered. Quoting further, in the ‘Discus-

sions’ section of the article, Dr Chao states, ‘‘Although

the triaxial goniometer is the only instrument that can

provide instantaneous angular motion of a joint in

three dimensions, its user must realize the potential

drawbacks of the method in order to avoid unnecessary

complications. First of all, the external attachment of

the device could introduce error in the data due to

relative movement of the underlying soft tissues’’. Chao

goes on to mention other critical points to consider in

the use of the triaxial goniometers relating to align-

ment, lateral projection, and the weight of the measur-

ing device. Although these dif ficulties have prevented

widespread adoption of electrogoniometers for routine

clinical gait analysis, goniometers are effective when

multiple recordings are required, when studies are being

carried out outside of a motion analysis laboratory, and

when sagittal movements are suf ficient for data acquisi-

tion. A final objection yet remains: moment studiescannot be made without the measurements of the posi-

tion of joint centers in space, something that goniome-

ters do not provide.

2 .3 . Cine film and passi 6e marker systems with manual

entry of marker positions

2 .3 .1. Vanguard Motion Analyzer

Other investigators concentrated on developing pho-

tographic techniques for gait analysis. Photographic

methods have a key advantage over other techniques in

that the whole body can be included and the relation-

ship of each extremity and the trunk can be simulta-

neously viewed. The opportunities for measurement are

thus greatly expanded over prior techniques. A further

advantage is that individuals of all sizes are suitable for

clinical analysis. Initially, however, there were

formidable obstacles, including the need for excessive

time spent in reducing the data and the absence of

computer availability for storing data and performing

voluminous mathematical computations.

While casually scanning a technical journal, my eyes

focused on an advertisement for a Vanguard Motion

Analyzer. The very name was intriguing and its capabil-

ity for projection of movie film on a backlit screen for

niometers was that many gait cycles could be collected

quickly, and analog graphs of motion could be dis-

played, without the need for data reduction by hand

[13]. In 1976, Bajd et al. [14] published an article

describing online electrogoniometric gait analysis using

six precision potentiometers, giving time-dependent an-

gles in hip, knee, and ankle of both legs in the sagittal

plane. Their reasons for choosing this method of instru-

mentation were that it was suitable for online process-ing of measured data, and was simple, reliable and

inexpensive. Other important contributors to electrogo-

niometry are McLeod [15], Tata [16], Johnston and

Smidt [17], Lamoreux [18], Kinzel et al. [19] and

Townsend et al. [20]. Foort presented the electronic

recording of joint function with analog recordings of

three-dimensional hip, knee, and ankle joint motion

[21] at a workshop on Human Locomotion and Clinical

Analysis of Gait in Philadelphia, in 1976. Edmund Y.S.

Chao, PhD published a report in 1980 on the design of

a triaxial goniometer, based on the gyroscope concept

utilizing Eulerian angles in the computation of the

measurements (see Fig. 2) [22]. Again, this did not gain

wide acceptance, arguably because of the dif ficulty in

preventing cross talk from the three motion axes. An

anecdotal description by Jacquelin Perry (unpublished)

of significant motion recorded in the hip joint of a

patient with a solid hip fusion did not help promote

adoption of this method. At first glance, the goniomet-

ric method holds great appeal. However, with the

tremendous range of height and weight of subjects, and

the dif ficulty for small subjects to walk comfortably

with this amount of hardware, widespread adoption of

this technique never occurred. The dif ficulties encoun-

tered with the use of goniometers, then and now, are




easy frame-by-frame viewing, and measurement of se-

lected points with x and y coordinates, was most ap-

pealing. Dick Freeborg, later President of

Instrumentation Marketing Corporation and now a

Vice-President in the Kodak Corporation, suggested

that I contact Ray Linder at Lockheed Aircraft Corpo-ration Missiles and Space Company, Sunnyvale, Cali-

fornia. Ray Linder was the leader of a section charged

with making measurements of machines, rocket trajec-

tories, etc. In 1965, he published a description of the

methods that he and his team had developed to mea-

sure pitch, yaw, and roll, using mathematical formulae,

two or more cameras, and a two-dimensional coordi-

nate system of measurements [23]. After a telephone

call and a letter from me, Ray Linder invited me to

come to his section during their lunch hour and explain

the need for human gait measurements. Roger Mann,

MD, accompanied me. Ray Linder made a prescient

comment after our presentation to the group, ‘‘You

mean you would like to measure the movements of the

skeleton from surface markers with skin movements

confounding the interpretation. Is not that like trying

to measure the movements of a broomstick within a

gunny sack?’’ Nothing daunted, we were fascinated to

see about 17 Vanguard Motion Analyzers in one room.

We were introduced to an interested and bright group

of people employed at the task of making measure-

ments of pitch, yaw and roll. Their level of interest in

our project was very exciting. Out of this contact, John

Hagy and Richard Oyama came forward as volunteers

to the Shriners Hospital in San Francisco, bringingwith them high-speed movie cameras, generously

loaned by Lockheed Missiles and Space Company. In a

relatively short time, Hagy, Oyama, and Keller helped

us establish a system to add kinematics to the elec-

tromyography already in clinical use in our laboratory.

Hagy assisted during evenings and weekends until we

were able to persuade him to come full-time in April of

1971. John Hagy and Cecil Keller, also a Lockheed

employee, assisted in the development of our movement

measurement system, first reported in 1967 in the arti-

cle, ‘Measurement of Movements and Timing of Mus-

cle Contraction from Movie Film’ [24]. Initially, our

methods of computation were very time consuming.

After recording x and y coordinate measurements from

the cine film displayed on the Vanguard Motion Ana-

lyzer, we used a slide rule to perform the trigonometric

computations. Later, an optical encoder was added to

replace the necessity of manually recording the x and y

coordinates. This task was further simplified by utiliz-

ing a sonic digitizer to input the data (see Fig. 3) [25].

Significant progress in time reduction came when a

computer was added to store and perform the mathe-

matical calculations, (see description of our first use of

a dedicated computer by Electronic Processors, Inc. in

Appendix C). We used this method for many years, but

hand digitizing continued to be an obstacle. Individuals

were trained and employed to do the digitizing. They

were enthusiastic, but in time became bored with the

repetitious nature of their task. The average length of

time for a technician to be employed in our laboratory

was 2 – 4 years; many used this opportunity as a step-ping stone in their career.

We made use of these gait analysis data to provide

treatment recommendations and to study the outcome

of treatment intervention. Some of the papers from our

laboratory were on the subjects of crouch gait [26], gait

analysis in cerebral palsy [27], the role of the ankle

plantar flexors [28], and the pathomechanics of gait in

Duchenne muscular dystrophy [29]. When our methods

and results were given, many were enthusiastic about

the possibilities for further development of this emerg-

ing application of science, but very few were willing to

undertake such a labor-intensive effort. The real break-

through, needed to bring about widespread adoption of

three-dimensional movement measurements for clinical

gait analysis, was yet to come when the measurements

could be automated. In fact, had there been no further

improvements in technology, clinical motion analysis

might have continued in only a few locations. The time

and energy required to digitize film prevented many

centers from using gait analysis as a clinical tool. In

spite of the dif ficulties, the stage was set for

automation.

2 .4 . A turning point! Fully automated mo6ement

measurements

2 .4 .1. European contributors and techniques

Engineers and physicists deserve full credit for devel-

oping methods to automate human movement measure-

Fig. 3. Vanguard motion analyzer and Graf-Pen sonic digitizer used

to determine the X and Y coordinates of the markers shown on the

viewing screen. Reprinted with permission from the Journal of Bone

and Joint Surgery [25].




Fig. 4. Cat on a treadmill with reflective markers. Reprinted with

permission from Dr Hans Furnee [30].

Measurement Systems: Aspects of Data Acquisition,

Signal Processing and Performance’ [36].

J. Paul, PhD, who started his kinematic measurementswith two orthogonal Bolex cine film cameras driven by

synchronous electric motors at 50 Hz and a homemade

ground-to-foot force platform, wrote this personal letterto me in response to some questions I had posed:

‘‘As you may imagine, the processing of the cine film

and hand digitizing was an onerous procedure, and I

was therefore very excited when, in 1967, I saw the

presentation of Furnee, hybrid instrumentation inProsthetics Research Proceedings in the 7th Interna-

tional Conference on Medical and Biomedical Engi-

neering in Stockholm. Furnee presented his invention

of a single camera television system for 2-D move-

ment analysis. As soon as possible thereafter, I gottwo of our research students to develop a 2-camera

system for 3-D video/computer movement analysis.In 1972, M.O. Jarrett, and B.J. Andrews started their

PhD studies with the remit of developing the system.

Between them, they got our system up and runningbased on a PDP-12 computer, which allowed us a

total of 36 analog inputs. Brian Andrews did not

complete his PhD at that time, but came back to us

in 1980 as a member of the staff. At that time, he did

further development on the system to allow it towork with a PDP-11 computer and took the opportu-

nity to try the use of shutters on the camera to

improve definition, but then implemented what I

believe was the first application of strobe infrared

lighting.’’

‘‘When Jarrett finished his studentship, he was em-

ployed jointly by ourselves and George Murdoch at

Dundee to develop a system for implementation atDundee. He did this, but to my great astonishment,

implemented a two-dimensional system there, and

Julian Morris became aware of this, and went on to

develop the Oxford Metrics System, which was devel-

oped to be three-dimensional. Julian was very sur-prised, at a later date, to find that our first and only

computer television movement analysis system had

been three-dimensional. Apparently Jarrett, withwhom he was interacting had not told him!’’

‘‘At that time, we were not very assiduous at publica-

tion of our work, and the only one which I can cite

is, Jarrett, Andrews and Paul, 1976, which is the text

of a conference presentation as you will see on mypublication list [37 – 39]’’.

From the letters of Hans Furnee and J. Paul, andtheir publications, there is an unmistakable sequence

of interweaving paths and shared enthusiasm for au-

tomating gait analysis. Hans Furnee led the effort; J. Paul

ments. E.H. Furnee, PhD, Faculty of Applied Physics,

Technical University, Delft, The Netherlands, began

around 1967 to develop TV/motion analysis systems withautomated recording of reflective marker positions. His

experiment, capturing multiple joint angles of a cat

running on a treadmill, was a strong portent of the future

widespread adoption of the photo-electronic method to

measure the kinematics of human walking. The markers

used by Furnee were passive paper disks that were

brightly visible in ultraviolet light, and the ultraviolet

light was pulsed to prevent ‘smearing’, (see Figs. 4 and

5) [30].

Prior to the first publication directly authored by

Furnee [31,32], a student of Furnee, P.C. Steilberg,

reported the method more completely as BS and MSthesis work in 1967 and 1968 [33,34]. Furnee is the

originator of the Primas System, from the Motion

Studies Lab, Delft University of Technology. The current

Primas system emphasizes real-time marker identifica-

tion and real-time marker centers by circle fitting (pilot),

developed, respectively at Delft University in 1990 and

1992. Additional publications authored by Dr Furnee

include: ‘TV/Computer Motion Analysis Systems: The

First Two Decades’ [35] and ‘Opto-Electronic Movement

Fig. 5. Variation of angles at shoulder, elbow, hip and knee of limbs

of same side during stepping on treadmill at 2.0 m s−1. Upward

excursion indicates extension, downward flexion. Reprinted with per-

mission from Dr Hans Furnee [30].




was excited by his work and set graduate students,

Andrews and Jarrett, to work, with the resultant pro-

duction of a 3-D automated video camera system for

movement measurement. Prior to his entry into auto-

mated movement measurements, J. Paul had already

become an expert in gait analysis, using a digitizedcine-film system for movement measurements. His pub-

lications cover a wide range of clinical subjects, with a

special emphasis on the gait of amputees. A large

number of students of Dr Paul are spread worldwide

and it is fair to say that he has been a central figure in

the development and expansion of clinical motion

analysis.

In response to questions posed to Julian Morris,

DPhil, I received a personal correspondence dated

April 13, 1996. The following correspondence is printed

in its entirety.

The history of the development of Oxford Metrics

and VICON is as follows:

‘‘I first met Mick Jarrett at an ISPO1973

conference in Montreux,

Switzerland, while he and I were

both graduate students. He was

working (together with Brian

Andrews, now in Edmonton,

Alberta) on a 2-D TV computer

system and I was using

accelerometers for measuring gait.Mick and I both presented our

doctoral theses later the same year,

his to Strathclyde University and

mine to Oxford.

Mick was by now working with1974 –75

David Condie in University of

Dundee, and I was working at the

Nuf field Orthopaedic Centre in

University of Oxford. We both

wanted to set up automated,

non-cine gait analysis facilities in

our respective hospitals.

I arranged for an Oxford

engineering friend of mine, Malcolm

Herring, who was a far more

experienced electronics designer than

either of us, to redesign Mick’s

prototype from Strathclyde. Three of

these (multi-camera but still 2-D)

systems were built — one for

Strathclyde, one for Dundee, and

one for Oxford.

Having left the Nuf field Orthopaedic1979

in 1977 (Mike Whittle took over my

job), I was now Technical Director

of Oxford Medical Systems, part of

the Oxford instruments group.

Although our main product range

was for cardiology (Holter

monitors), I believed that there was

a commercial market for anautomatic 3-D gait analysis system.

I hired Malcolm Herring (see

above), Graham Klyne, and Annabel

MacLeod as the development team,

and made a licensing deal with

Universities of Strathclyde, Dundee,

and Mick Jarrett personally, for the

existing technology. Over the next 2

years, the VICON (the name derives

from video-converter) development

team redesigned the hardware and

wrote the first 3-D photogrammetry

software applied to this field. The

first system was shipped to Eric

Radin, MD, in West Virginia in

1980, and the second to Sheldon

Simon, MD, Boston Children’s

Hospital, a few months later.

The Oxford Instruments Group1983 –84

decided to float on the London

Stock Market and focus on their

core businesses, primarily building

cryogenic magnets for MRI. They

‘spun-off ’ the biomechanics business,

by then called Oxford Dynamics,which was sold to myself and other

members of the VICON

development team. We renamed the

company, Oxford Metrics Ltd.

(Graham Klyne won a bottle of

wine for the name).

During the 70s I was aware, through

publications, of the work of Hans

Furnee and David Winter. However,

I do not think I first met either of

them until after VICON was

launched. To my knowledge, Hans

did not ever spend time working in

Oxford.

The connection between Hans and

VICON is largely technical, rather

than historical. The hardware tech-

nology used by VICON is basically

the same as that developed by Hans.

Whether either one derived from the

other is hard to say. Certainly, I

believe that Hans published his early

work and may have been visited in

Holland by Mick Jarrett while the

latter was a graduate student.’’




Author’s comment: In a letter to me, Hans Furnee

confirmed the visit of M.O. Jarrett to his laboratory

and stated that he had freely shared information with

Jarrett.

Again, back to Julian Morris’ letter:

‘‘Although they both use video, there is minimal

technical connection between what David Winter

published and VICON. I certainly believe that Hans

and David developed video-based systems a year or

two ahead of Mick, but as you imply, this is, for

some, a sensitive area! Mick Jarrett and Brian An-

drews, I believe, wrote most of the software for the

1973 Strathclyde TV system jointly. However, the

VICON development team never saw or used any of

it. The first true VICON 3-D software was designed

by Graham Klyne and myself, and written entirely

by Graham. We drew on the published ideas of

many others, including Herman Woltring.’’

Eric Radin, MD, used the technology supplied by

VICON to study the running and walking gait of

sheep on a treadmill. In 1983, along with gait col-

leagues from San Diego, Ed Biden, and Marilynn Wy-

att, I visited Eric Radin’s Laboratory in Morgantown,

West Virginia. The Laboratory provided an extraordi-

nary scene of stacked bales of straw, sheep in a pen at

the side of the room, and the odor of sheep lying like

a pall over all. I asked Dr Radin, ‘Eric, do you do

any studies of human patients?’ Eric, in his inimitablestyle, said, ‘‘Well, yes, of course, but we only let

people in on Fridays’’. I silently wondered how well

human subjects responded to being studied in this

environment! Following this visit, we purchased VI-

CON hardware and Ed Biden, DPhil, wrote custom

software in 1984 for clinical application in our San

Diego Gait Laboratory. After a period of comparison

of studies on normal individuals with cine-film digi-

tization, and data collected on the same individuals

with the VICON hardware and Ed Biden’s software,

we made the transition from film digitization to auto-

mated data capture. The initial problems were associ-

ated with the dif ficulty of identifying and tracking

markers; this was initially done in two dimensions. A

tremendous move forward occurred with the contribu-

tion of Andrew Dainis, who wrote three-dimensional

tracking software (details to follow later).

Michael Whittle, MD, PhD, spent 2 years doing

surgical research after internship, which led to a mas-

ter’s degree in biomechanics. As a research medical

of ficer in the Royal Air Force, he was loaned for 3

years to NASA in Houston to supervise the muscu-

loskeletal experiments on the Skylab Space Station.

One of these experiments was on the 3-D measure-

ments of the astronaut’s body form [40], and this

became the subject of his PhD dissertation, which he

obtained after he returned to Great Britain. He took

over the directorship of the Motion Laboratory at

Oxford after Julian Morris left to found Oxford Met-

rics. The only software available for the new Oxford

Metrics system was for data capture, so Dr Whittlewrote full 3-D motion capture software, ‘‘So, in effect,

we had the first 3-D TV computer system in the

world’’. (Author’s comment: Communication from J.

Paul indicates earlier 3-D development in Strathclyde.)

Michael Whittle now holds the Cline Chair of Reha-

bilitation Technology at the University of Tennessee at

Chattanooga. He is author of a book entitled, ‘Gait

Analysis: An Introduction’, which is now in its 2nd

edition [41].

Another important player in the exciting world of

motion capture is the Bioengineering Technology Sys-

tems, or BTS, which is home-based in Milan, Italy.

BTS traces its origins to the contribution of the bio-

engineering center of the Pro Juventute Foundation

and the Politecnico di Milano. The company was

formed in 1986. The engineering contributions of Fer-

rigno, Pedotti, and Cappozzo were key in the develop-

ment of the ELITE System [42 – 44]. BTS rapidly

expanded into the complete world of clinical gait anal-

ysis, combining kinematics, kinetics, and electromyo-

graphy in a robust, all-inclusive approach to clinical

gait analysis and research in motor skeletal function.

In point of time, BTS entered the field of clinical

motion analysis after Oxford Metrics, Inc. and Motion

Analysis Corporation.The story does not stop here. The entry of many

new companies and new systems of motion capture

attests to the enduring fascination with movement

analysis. The competition between the companies now

marketing motion capture systems has resulted in

more rapid processing of information, new methods of

displaying the data, and a surging interest in clinical

gait analysis. Laboratories are now available in all of

the developed countries and in many of the developing

countries.

2 .5 . Automated mo6ement measurements

2 .5 .1. North American early contributors and

techniques

While the early advances in gait analysis and auto-

mated movement measurements were occurring in the

Netherlands, England, and Scotland, exciting activities

were also taking place in Canada. Robert K. Green-

law, MD, then the Chief Surgeon of the Shriners Hos-

pital, Winnipeg, Canada, and a former resident in the

Shriners Hospital in San Francisco, was aware of Dr

Inman’s work and of my work in the San Francisco

Shriners Hospital Gait Laboratory. It was not obvious




Fig. 6. Gait studies data acquisition system. ‘Locomotion studies as an aid in clinical assessment of childhood gait ’—reprinted from, by permission

of the publisher, CMAJ , 1975; 112 (9), pp. 1091 – www.cma.ca [46].

to me then that orthopedic resident Greenlaw had an

interest in motion analysis, but the events that followed

proved otherwise. He had the good judgment to ask

David Winter, PhD, to design the first gait analysis

laboratory in the Shriners system in Canada.

David Winter, PhD, then with the Department of

Electrical Engineering and the Department of Surgery,

University of Manitoba, Winnipeg, designed a Gait

Laboratory for the Winnipeg Shriners Hospital. Dinn

et al. submitted a manuscript in 1969 entitled, ‘Com-

puter Interface for Television’, which was ultimately

published in IEEE Transaction of Computers in 1970

[45]. In a letter to me, Dr Winter states, ‘‘Our first

routine use of the interface began early in 1970 at the

Shriners Hospital in Winnipeg. For the 5 years I was

there it was the backbone of all our kinematic data

collection. Actually, it goes back to the time of Furnee.

Our first operational TV interface was reported at

biomedical engineering conferences on this side of the

Atlantic at the same time (unknown to us) as he was

reporting in The Netherlands’’, (see Fig. 6), [46]. Winter

et al. subsequently published an article entitled: ‘Televi-

sion – Computer Analysis of Kinematics of Human

Gait’ in Computer and Biomedical Research in 1972 [47].

Winter et al. published an important study of the

kinematics of normal locomotion in the Journal of

Biomechanics in 1974 [48]. Doctor Winter’s publications

since that time are legendary [49]. He has profoundly

influenced the course of clinical gait analysis through

his scientific studies, teaching, mentoring of many grad-

uate students and his many publications. His book

entitled, ‘Biomechanics and Motor Control of Human

Movement’, now in its 2nd edition, is a ‘must read’ for

all who are interested in gait analysis [50].

Sheldon Simon, MD, obtained his medical degree

from Harvard and his residency training was completed

in the Harvard Training Program. During his residency

training, he worked in the laboratory of Robert Mann,

PhD, at the Massachusetts Institute of Technology. He

received a Cave Traveling Fellowship and, in January

through June 1974, divided his time between the San

Francisco Shriners Gait Analysis Laboratory, then di-

rected by Roger Mann, MD, and the Pathokinesiology

Laboratory at Rancho Los Amigos, directed by

Jacquelin Perry, MD. He says that he was very im-

pressed by the electromyographic studies at Rancho

and the force and kinematic studies in San Francisco.

By the time of his return, the Kistler force plate was

available as a commercial product, but the price was

steep for his budget in Boston. He persuaded Walt

Synutis, President and CEO of AMTI, to design a new

strain-gauge force plate at a price within his budget.

The space available for him in Boston was small and he

realized that a three-dimensional coordinate software

system for kinematic measurements should be devel-

oped. The laboratory opened in Boston Children’s Hos-

pital in September 1974, with two AMTI strain gauge

force plates, a three-camera 16 mm high speed camera

system, a Vanguard Motion Analyzer and a computer

which stored the measurements from force plates and

electromyograph simultaneously. The software for kine-

matic measurements utilizing a three-dimensional coor-

dinate system from film was conceived by Dr Simon

and written by Roy Nuzzo, MD, an orthopaedic resi-

dent at the time [51]. Mick Jarrett, PhD spent a good

deal of time at Boston Children’s Hospital in 1982

perfecting software for clinical application of the VI-

CON system. According to Dr Simon, initially it took




just as long to process 3-D VICON measurements as

3-D film measurements. Nonetheless, it was clear that

further developments would establish automated video

measurements and there would be no turning back. In

1986, Dr Simon moved to Ohio State University, where

he held the positions of Chairman of the Department of Orthopedic Surgery and Medical Director of the new

Motion Analysis Laboratory. Numerous clinical and

research publications have followed [52]. One of Dr

Simon’s many interests has been the application of

artificial intelligence to gait data. He says that he

realized that interpretation would continue to offer the

greatest challenge and, in 1984, began work on an

artificial intelligence application. This work has contin-

ued to this time and a system, which can be separately

used as a decision helper and as a trainer, is currently

being tested. Dr Simon is the editor of a book entitled,

‘Orthopaedic Basic Science’, published by the American

Academy of Orthopaedic Surgeons [53]. He now resides

in New York City and continues his career-long interest

in clinical gait analysis.

In 1978, James R. Gage, MD, visited Eugene Bleck’s

Gait Laboratory at Stanford Children’s Hospital,

Jacquelin Perry’s laboratory at Rancho Los Amigos

Hospital, and my laboratory at San Diego Children’s

Hospital, in preparation for beginning his first labora-

tory at Newington Children’s Hospital. United Tech-

nology Research Corporation, located in Newington,

Connecticut, had offered extraordinary engineering and

financial support for the establishment of a Gait Labo-

ratory. In early 1980, Gage returned to the San DiegoLaboratory for an in-depth look, bringing with him

Ken Taylor, United Technology Project Engineer, and

Jim Clark, Manager of the Newington Gait Laboratory

project. The three men asked many questions, including

what we would do if we were starting another labora-

tory with optimal funding and full technical assistance.

We answered openly, even with ideas that were not yet

fully realized in our own laboratory. This cooperation

and sharing of information continued during the devel-

opment of the Newington Laboratory. The Newington

Gait Laboratory opened in July 1981. Special features

of this laboratory included synchronization of all gait

data, full custom clinical software and rapid processing

of data. Scott Tashman, MS (now PhD), validated and

continued the United Technologies software package.

Follow-up gait studies were regularly performed on

patients who had undergone preoperative gait studies,

thus opening the way for a great many clinical papers

[54 – 59] and a book entitled ‘Gait Analysis in Cerebral

Palsy’ [60].

Following Dr Gage’s move to Gillette Children’s

Hospital in 1990, the Newington laboratory continued

under Peter DeLuca, MD, as Medical Director, with

Roy B. Davis, PhD, as Director until 1998. Sylvia

O . unpuu, M Sc., a prior student of David Winter, is the

current Director. The Newington Gait Laboratory

moved to Hartford Connecticut, with the opening of

Children’s Hospital of Connecticut as an integral part

of the University of Connecticut Medical Center. Many

papers have been published both by Gillette Children’s

Hospital and Newington/Children’s Hospital of Con-necticut covering a variety of subjects, including: run-

ning patterns of normal children [61] [62], outcome of

multilevel surgery in cerebral palsy [63], stiff-knee gait

[64,65], the utility of basing treatment decisions in

cerebral palsy on preoperative gait analysis, [66], and a

gait analysis data collection and reduction technique,

which includes Davis’ much referenced joint center

determination method [67]. Gage has pushed the envel-

ope in advocating gait analysis routinely in patients

with cerebral palsy [60]. Some surgeons, none of whom

have gait laboratories, have criticized this. An anecdote

illustrating this point follows:

At a course jointly sponsored by the American

Academy of Orthopaedic Surgeons (AAOS) and the

Pediatric Orthopaedic Society of North America

(POSNA) in San Francisco, May 6, 1990, entitled Con-

troversies in the Treatment of Cerebral Palsy, the

course chairpersons were Dr Michael Sussman and Dr

Walter Greene, myself, Dr Simon, and Dr Gage, in that

order. We had just finished giving views on the impor-

tance of clinical gait analysis when, from near the back

row, Hugh Watts, MD, a pediatric orthopaedist and

friend, but never one to avoid controversy, rose to

challenge the clinical usefulness of gait analysis. Heclaimed that the gait laboratory setting is not a suitable

environment for arriving at the true walking patterns of

children with cerebral palsy. He implied that observa-

tional analysis of children in the playground, or in

other familiar surroundings, is better. The entire back

section of the auditorium, filled mostly with ortho-

paedists, burst into spontaneous applause. The heated

discussion that followed resulted in back-to-back edito-

rials by Gage and Watts in the Journal of Pediatric

Orthopaedics [59,68]. Be that as it may, acceptance of

clinical gait analysis has steadily increased and new

laboratories are being established throughout theworld. The new generation of orthopaedic surgeons,

introduced to gait analysis in their training, increasingly

demands functional analysis, before and after treat-

ment, in order to better understand the magnitude of

the disability and to ascertain the impact of their inter-

vention. As my ‘parting shot over the bow’ on this

subject, I would like to quote Max Planck, the famous

German physicist, who pioneered modern physics by

proposing the quantum theory and won the 1918 Nobel

Prize. He said, ‘‘An important scientific innovation

rarely makes its way by gradually winning over and

converting its opponents. What does happen is that the

opponents gradually die out’’ [69].




Murali Kadaba, PhD, became interested in gait anal-

ysis when he joined Helen Hayes Hospital as a research

scientist in 1979. Dr George Van Cochran was influen-

tial in his decision to work in the area of clinical gait

analysis. Dr Kadaba states that his interest was inten-sified after a visit with Dr Perry at Rancho Los Amigos

Pathokinesiology Laboratory in Downey, California,

and with me at the Motion Analysis Laboratory at San

Diego Children’s Hospital. He received a NIH grant in

1984 to study the reproducibility and reliability of gait

data [70]. Following completion of this study, he be-

came interested in the numerical representation of kine-

matic and kinetic data for pattern recognition in spastic

diplegia [71]. The Helen Hayes clinical software was

completed in 1985. ‘‘This was a cooperative effort; the

other team members were H.K. Ramakrishnan, Mary

Wootten, Janet Burn (Gainey) and Dr Van B.Cochran’’ [72]. This clinical software served a critical

need for software to be used in a clinical setting. It was

implemented at the following centers: Richmond Chil-

dren’s; Shriners Hospital, Houston Unit; Methodist

Hospital, Houston, Texas; Children’s Memorial Hospi-

tal, Chicago; Children’s Milwaukee; and Shriners Hos-

pital, Portland Unit. The Helen Hayes Team, under the

leadership of Dr Kadaba, deserve great credit for devel-

oping and supporting clinical software (no small task),

in the precarious early years. At that time, the writers

of commercial software were attuned to the diverse

needs of researchers, but they lacked confidence in the

ability of clinical laboratories to agree on nomenclatureand formats for data presentation. As a consequence,

new laboratories were forced to adapt commercial soft-

ware to their own tastes. The Helen Hayes Software

helped fill this temporary void. Happily, the common

needs of most of us are now met with commercially

available software.

The original Helen Hayes software could now be

named the Helen Hayes marker set as software is

available that can handle both the Helen Hayes marker

set and the Cleveland Clinic marker set. The competing

marker set is the Cleveland Clinic, credited to Kevin

Campbell of the Cleveland Clinic Foundation. Thedifferences in the two marker sets are briefly outlined as

follows:

Both marker sets are used to define joint centers and

segmental coordinate systems (SCS) needed to calculate

angular kinematics. The main difference between both

sets is in the way the joint centers and coordinate

systems are defined. Helen Hayes (HH) is a ‘wand-

based’ marker set, in which joint centers and segmental

coordinate systems are defined using a wand marker on

each segment (i.e. thigh and shank). As joint markers

are shared between segments and, therefore, each seg-

ment has at least three markers for its definition, the

Helen Hayes is considered a simplified marker set,

which along with a static trial of markers on the medial

and lateral sides of each joint (ankle and knee), gives

everything that is needed to calculate joint angles (i.e.

location and orientation of each joint axis) [73].The Cleveland Clinic Foundation (CCF) marker set

is a ‘cluster-based’ marker set, in which clusters or

arrays of three (or sometimes four) markers are used to

define joint centers and segmental coordinate systems.

With this marker set, the clusters are placed on each

segment along with the medial and lateral markers,

which define the flexion-extension axis of each joint,

during the static trial. As the clusters define a coordi-

nate system to reference the positions of the medial and

lateral markers, all medial and lateral joint markers can

be removed after the static trial, and a dynamic trial

can be collected, while still maintaining the location

and orientation of each joint axis [74].

The advantage of the Helen Hayes marker set is that

it is relatively simple to use and more applicable to gait

analysis of children. The arrays used in the Cleveland

Clinic marker set have been known to hit each other in

smaller children. In a recent comparison study, con-

ducted in our Motion Analysis Laboratory by Arnel

Aguinaldo, MA, ATC, and the laboratory team, we

observed less variability in the transverse plane kine-

matics with the Cleveland Clinic marker set. This was

probably because there was less marker movement, due

to the fact that there are at least three markers fixed to

a rigid frame, although skin motion over the segmentdefined by the array is still a factor.

2 .6 . Methods of joint angle calculation

Although, there are two methods of joint angle calcu-

lation most frequently used: Euler/Cardan and Helical

screw axis, there are at least three additional methods,

with definitions and pros and cons noted in Table 1.

Further use and description of joint movement and

rotational three-dimensional motion by Kenton Kauf-

man, PhD, includes the transformation matrix method

for complete representation [78]. The Euler/Cardan

method lends itself well to clinical interpretation.

Therefore, we utilize it for most of our clinical studies

that do not involve translational movement, such as

that found in patients with anterior cruciate insuf fi-

ciency. For persons with knee instability, which may

add more than normal translation to angular rotation,

the use of the helical screw axis method of joint angle

calculation is more appropriate.

John Greaves, PhD, a graduate in electrical engineer-

ing from the University of California, Santa Barbara,

while he was a student with Glen Culler, worked on a

project they dubbed ‘the bug watcher’. The researchers

in the biological sciences department were interested in




monitoring the motion of the microscopic marine

plankton known as dynoflagellates. Greaves tackled the

problem for them by designing and building a system

using a video camera to look into a microscope coupled

with a computer to process the video signals and

provide position and velocity information about thedynoflagellates. The system worked. After some inter-

vening post-doctoral activities, John Greaves founded

Motion Analysis Corporation; a company that provides

3-D motion capture systems for many clinical gait

laboratories, sports analysis research facilities, and

equipment for use in the movie industry. This company

utilizes ORTHOTRAK software for processing of move-

ment, developed jointly by the Cleveland Clinic Foun-

dation and Motion Analysis Corporation, in

conjunction with Chet Tylkowski, MD, then at the

Human Motion Laboratory, Department of Ortho-

paedics, University of Florida, Gainesville. The current

version is a joint development effort with James

Richards, PhD, Freeman Miller, MD, and Patrick Cas-

tagno, MS, from the University of Delaware and the

Alfred I. duPont Hospital for Children.

Chester Tylkowski, MD, became interested in gait

analysis while working as a fellow with Dr Sheldon

Simon at Boston Children’s Hospital, 1978 – 79. He set

up a clinical gait laboratory at the University of Flor-

ida, Gainesville, in 1980. Subsequently, in 1989, Dr

Tylkowski and the laboratory moved to the Miami

Children’s Hospital. His third move was to the Shriners

Hospital, Lexington, Kentucky, in 1995, where he holds

the position of Chief of Staff. He holds the unof ficialrecord for the physician responsible for forming the

largest number of clinical gait laboratories. This is an

indication of his commitment to the importance of

clinical gait analysis throughout his orthopaedic career

[79 – 81]. A kinesiologist, Susan Sienko Thomas, MA, a

former student of David Winter, holds a similar record

for involvement in three gait laboratories. In 1985,

Susan was hired to oversee the operation of the South-

ern Illinois University Motion Analysis Laboratory in

Springfield, Illinois, after the tragic death of Maxine

Covert. The laboratory had been established with a

VICON system in 1983. In 1989, she assisted in the set

up and operation of the Motion Analysis Laboratory at

Children’s Memorial Hospital, Chicago, where the He-

len Hayes clinical software package was used. She

currently holds the position of Clinical Research Coor-

dinator at the Shriners Hospital in Portland, Oregon

[82,83].

Steven J. Stanhope, PhD, from the Biomechanics

Laboratory, National Institutes of Health, has stronglyadvocated inter-laboratory reliability and the need for

demonstrating proven means of testing kinematic

movement measurements. His efforts have lifted the

standards for all gait laboratories in the U.S. Similar

efforts are occurring in Europe under initial funding by

the European Union. The testing of laboratories should

be a requirement for certification. Although many ef-

forts have been exerted to move this important task

forward, it still remains in the discussion stage. There

should be no objection to the concept that patients,

referring physicians, and payers have a right to know

that a laboratory is capable of providing accurate and

reliable data. There is little doubt that testing and

certification will be instituted, hopefully in the near

future.

The majority of clinical patients seen at the Biome-

chanics Laboratory, National Institutes of Health, are

adults referred by physiatrists or internists. Thus, the

clinical applications have been primarily for subjects

with rheumatoid arthritis, osteoarthritis, limb defi-

ciency, diabetes, stroke, and neuromuscular disorders

[84 – 86]. The establishment of a three-dimensional mus-

culoskeletal database is a research effort that will con-

tribute greatly to clinical applications [87]. Software for

clinical applications, as well as for research, were devel-oped in this laboratory, and provided to laboratories

throughout the world. The program is called Move 3D.

This software is very robust and, according to Dr

Stanhope, is the first software to provide six degrees of

freedom gait measurements.

3. Shriners network of gait laboratories

There are 19 orthopedic Shriners Hospitals in the

U.S., Canada and Mexico. Of these, 12 currently have

gait laboratories, with a 13th laboratory being estab-

lished in Tampa, all of them carrying out clinical

analysis before and after treatment. In addition, they

Table 1

Methods of joint angle calculation (A. Aguinaldo, MA, ATC, Motion Analysis Laboratory, Children ’s Hospital, San Diego)

Method Pros ConsDefinition

Angles projected onto plane Simple ParallaxPlane projections

Not clinically relevantComplete representationDirection cosines Transformation matrix

Gimbal locksEuler/Cardan Sequence of rotations Clinical interpretation

Euler with floating axis Not suitable for kineticsSequence independentGrood and Suntay

Screw axisHelical Rotation and translation Sensitive to noise

References: [75,76,73,77].




are involved in collaborative research. This confirma-

tion of the usefulness of clinical gait laboratories has

not gone unnoticed by physicians in the children’s

hospitals of North America. This powerful statement

by a major block of children’s hospitals may well

have helped spur the establishment of centers foranalysis in the other Children’s Hospitals, both pri-

vate and University af filiated.

3 .1. Acti 6e marker systems

The Selcom Company of Sweden developed the

Selspot System, which used active markers taped to

the limb segments, prior to the advent of VICON and

Motion Analysis Corporation. The first Selspot move-

ment capture systems in the U.S. were installed in the

laboratory of Thomas Andriacchi, PhD, at Rush

Presbyterian Medical Center in Chicago, and in the

laboratory of Robert Mann, PhD, at Massachusetts

Institute of Technology, Cambridge, MA. Herman

Woltring, PhD, did some of the early work with the

Selspot System as did Andrew Dainas. Robert Mann,

PhD, and Eric Antonsson, PhD, established a clinical

laboratory at Massachusetts General Hospital in 1984,

along with several orthopedists, William Harris, MD,

Henry Mankin, MD, Donald Madeiras, MD, and

Michael Erlich, MD, PhD. Their system was designed

for cerebral palsy gait analysis. David Krebs, PhD,

PT, continues this work, collecting data on human

subjects with a variety of problems, including cerebralpalsy and disorders of posture and balance. This lab-

oratory utilizes Selspot active markers, arranged in

clusters on a fixed base, applied to each of the body

segments being studied. A large database of children

and adults with neuromuscular disorders, including

many with problems of balance, has been established.

One area of investigation is sitting-to-stand move-

ments.

Although the Selspot system eliminates the need for

marker identification and tracking, it contains other

less positive features including its propensity to pick

up reflections, the necessity for the subjects to carrycumbersome apparatus, and the trade-off between

sampling rate and the number of markers. These in-

herent drawbacks in this active marker system served

to energize the proponents of passive marker systems

and to keep them working to solve the dif ficulties

with marker identification and tracking. In spite of

the current preponderance of passive marker systems,

some active marker systems are emerging to compete

with the passive models. Examples of active marker

systems are those by CODA and Skill Technologies,

(see Appendix A). The brief discussion contained in

this manuscript will be useful to clinicians, but engi-

neers and physicists will be well served by reading

Furnee’s very complete, and highly technical, descrip-

tions of passive and active motion capture systems

[35,36].

3 .2 . Three-dimensional marker identi fication and

tracking

Andrew Dainas deserves much credit, along with

Doug McGuire, for more ef ficient processing of raw

TV data to 3-D coordinates. In a personal communi-

cation Dainas writes,

‘‘By 1988 we had finished the first version of the

AMASS software. The software development was

carried independently of NIH, and was not sup-

ported by NIH. At that time, we installed it on theNIH VICON system and offered it as a replace-

ment to Oxford Metrics for their aged system. As it

turned out, in 1988, Oxford Metrics had completed

their new VAX – VX hardware system but lacked

appropriate software, and they agreed to market

AMASS with their systems. Between 1988 and 1993,

Oxford Metrics sold some 70 VICON systems bun-

dled with the AMASS hardware. In 1993, Oxford

Metrics announced the VICON 370 system, with

their own software (which replicates many functions

of AMASS). We (at ADTECH) in turn ported

AMASS to the PC computer, and adapted it to workwith raw data from both Motion Analysis Corpora-

tion systems and ELITE systems. Currently, we of-

fer AMASS as alternative software for these systems.

AMASS can claim to be the first software used in

clinical and gait applications to provide:

1. Intelligent marker reduction to 2-D centers in the

camera image data by fitting circles to the pixels

outlining the markers.

2. Provide the user with the ability to linearize each

camera for distortions, etc.

3. Do automatic identification of reference markers

in the 3-D camera calibration process.4. Do completely hands-off 3-D reconstruction and

tracking of unidentified camera image data.

In 1994, I wrote and incorporated into AMASS the

first program to carry out the 3-D camera system

calibrations using a large number of markers whose

locations in 3-D space need not be measured before-

hand. This technique does away with the need for

rigid calibration objects, or hanging strings or rods,

and is capable of eliminating a chief source of inaccu-

racies in most currently used 3-D measurement sys-

tems. The method has since been also implemented

by Oxford Metrics.’’




3 .3 . Present reality

Commercial hardware and software now available

have nearly eliminated problems with marker identifica-

tion and tracking, thus removing the chief objection to

passive marker systems. As a consequence, the develop-ment and utilization of active marker systems was on

hold for a time. In today’s state-of-the-art laboratory, a

subject can be fitted with appropriate reflective markers

and walk down a calibrated walkway, while the mark-

ers are automatically tracked and thousands of compu-

tations are performed by a dedicated high-end PC

computer or a computer work station. The resultant

joint angles can be viewed within minutes from the end

of collection of the data. An increase in the number of

cameras, plus 3-D identification and tracking of mark-

ers, now enable laboratory personnel to examine the

data for reliability and potential errors while the subject

is still present in the laboratory. This represents an

enormous evolution in automated movement measure-

ments in the 34 plus years since the technology was first

developed. There are still some problems to be worked

out. For example, accurate timing of toe-off is prob-

lematic with kinematic methods. The incorporation of

force platform input establishes the events of foot-strike

and toe-off accurately for those patients able to contact

two or more force platforms. However, it is the slow

walkers, using crutches or a walker, who often exhibit

variable or even inaccurate foot-contact times, as calcu-

lated from the trajectory velocities of markers on the

foot. Yet another problem is that of marker movementdue to skin movements over the underlying skeleton. A

number of research studies address this problem, but

none have discovered a way to totally eliminate inaccu-

racies due to skin movement [88 – 95].

If these reasons are not enough to convince the

reader of the need for additional research, or even

investigation of other methods of measuring movement,

there is yet another problem, that of placing markers

accurately and reliably. Mistakes can alter the calcula-

tions of joint centers. The models for establishing hip

center, used in all of the commercial software systems,

have come from cadaver studies and are not patient

specific. This inherent flaw in patients with pathology

of the hip makes moment and power calculation of the

hip suspect. Discussion of this topic will be included in

The Evolution of Clinical Gait Analysis Part III, Kinet-

ics and Energy.

3 .4 . Future

It would be a mistake to assume from the rapid

development of 3-D passive marker systems that tech-

nological advances in active marker systems are not

occurring. There are currently several companies em-

ploying active marker systems. Why, with good passive

systems dominating the field, is this occurring? The

passive marker systems are expensive, considerable

training is still required for optimal use of the hardware

and software, and flexibility in programming for special

studies requires the talents of engineers. Our laboratory

currently uses an 8-camera, passive marker system, andeven larger camera arrays are in use in some

laboratories.

Possible developments in the next decade are:

(1) The elimination of the need for either passive or

active targets and a reduction in the number of cameras

now in use. With increasing computer memory and disc

capacity, markerless measurements of 3-D motion loom

on the horizon as a possibility.

(2) The development of an active marker system with

radio-frequency active emitters is a promising approach

for the economics of gait analysis hardware. This wouldbring about economies in the number of cameras re-

quired. The technology for 3-D identification of radio-

frequency signals is already well established in military

applications. The active emitters are lightweight and

relatively inexpensive and there is little to prevent the

use of a large number of markers. If such a system is to

be implemented, there must be initial research and

development investment, following which the costs for

purchase of software and hardware would be well

below the present costs for passive marker systems.

(Tera Research has a patent pending for this technol-

ogy. For further information, contact Dr Walter Heine

at [email protected].)

(3) Better methods of defining joint centers, especially

with regard to hip joint center, will be required, possi-

bly with the aid of CT and MRI scanning. Moment

measurements are sensitive to the accuracy of joint

center calculations; consequently, errors in joint centers

degrade the accuracy of moment calculations.

(4) The use of neural network statistical analysis is

still in its infancy in clinical gait analysis [96] and

computer assisted diagnostic and problem identification

[97] will surely expand in the next decade.

(5) In addition to whole body gait analysis, foot

models are emerging. Analyzing joints distal to theankle remains a major challenge for the future [98,99].

The treatment of individuals with pathological gait

will steadily change as data are gathered and published

from multiple sources. A quantum change has already

occurred in the treatment of cerebral palsy. A new

generation of multidisciplinary motion analysis teams is

forging new standards of quality and pushing the limits

of application to a wide variety of disabilities. Rapid

changes are occurring in the treatment of myelodys-

plasia, and improvements in the recognition and treat-

ment of a large variety of neurological disorders are on




the horizon. We now have the tools to perform func-

tional analysis and to replace guesswork with a scien-

tific framework for evaluation and treatment. Oral drug

treatment, injections of Botulinum Toxin Type A, in-

trathecal baclofen pump, physical therapy, orthotic

management, orthopedic and neurosurgery must all beevaluated on both a short and long term basis, and gait

analysis must play a pivotal role. The changes in treat-

ment will be incremental, wide-ranging, and will come

from all parts of the globe. There is much work to do

and the beneficiaries will be patients with disorders of

movement. It is a source of great satisfaction to pa-

tients, their parents, and their physicians to know that

locomotion and movement disorders are at last receiv-

ing the attention they deserve.

Acknowledgements

My special thanks to all of the individuals who

responded to my letters and phone calls, supplying

details that give life to this account. For the administra-

tive assistance provided by Sherill Marciano, Jill Jor-

dano, and Kit Holm, who put up with my many

changes to the manuscript, and for Kit’s tenacity with

research, which helped immensely with reviewer re-

sponse and final publication requirements. To bioengi-

neer, Arnel Aguinaldo, and physical therapists,

Marilynn Wyatt and Janet Buttermore, for their assis-

tance with the search for details and review of the

manuscript. To John Hagy who filed and saved corre-spondence and other documents from the early days of

the San Francisco Gait Lab. Finally, my thanks to Dr

Hank Chambers, Medical Director of the Motion Anal-

ysis Laboratory at Children’s Hospital, San Diego, for

his helpful comments.

Appendix A. A partial list of commercial kinematic

systems

Ariel dynamics

6 Alicante Street

Trabuco Canyon, CA 92679

USA

Tel.: (949) 858 4216

Fax: (949) 858 5022

BTS

Via C. Columbo, 1A 20094 Corsico

Milano, Italy

Tel.: +39 02458751

Fax: +39 0245867074

CODA

Charnwood Dynamics Ltd.

17 South Street, Barrow on Soar

Leicestershire, LE12 8LY

Tel.: +44 (0) 116 230 1060

Fax: +44 (0) 116 230 1857

Motion analysis corporation

3617 Westwind Blvd

Santa Rosa, CA 95403

USA

Tel.: (707) 579-6500

Fax: (707) 526-0629

Peak performance

7388 S. Revere Parkway

Suite 603

Englewood, CO 80112

USA

Tel.: (303) 799 8686

Fax: (303) 799 8690Primas

Motion Studies Laboratory

Delft University of Technology

P.O. Box 5

2600 AA Delft

The Netherlands

Tel.: +31 (0) 15 278 9111

Fax: +31 (0) 15 278 6522

Qualisys Inc.

148 Eastern Blvd, Suite 110

Glastonbury, CT 06033

USA

Tel.: +1 860 627 5060

Fax: +1 860 627 4041

Qualisys AB

Drottninggatan 31

Goteborg 41114

Sweden

Tel.: +46 (u) 317743830

Fax: +46 (u) 317014145

Selspot, AB

Sallarangsgatan 3

S-431 37 Molndal, Sweden

Skill Technologies, Inc.

1202 E. Maryland Ave., Suite IG

Phoenix, AZ 85014

USA

Tel.: 602-277-7678

Fax: 602-277-2326

VICON motion systems

Oxford Metrics Limited

Unit 14, MINNS ESTATE

7 West Way

Oxford OX20JB




UK

Tel.: +44 (1865) 26 1800

Fax: +44 (1865) 24 05 27

Appendix B

B.1. Copy of letter to Raymon Linder, from Dr

David Sutherland, dated August 23, 1965.




B.2. Copy of letter to John Hagy, from Dr E. R.

Schottstaedt, dated November 29, 1965.




D e s c r i p t i o n o f o u r fi r s t u s e o f a d e d i c a t e d c o m p u t e r f o r ‘ D i a g n o s t i c G a i t A n a l y s i s ’ , b y E l e c t r o n i c P r

o c e s s o r s , I n c . ( t w o p a g e s ) .




tion —a statistical study based on TV data. J Biomech

1974;7(6):479 – 86 November.

[49] Winter DA, Yack HJ. EMG profiles during normal human

walking: stride-to-stride and inter-subject variability. Electroen-

cephalogr Clin Neurophysiol 1987;67(5):402 – 11.

[50] Winter DA. Biomechanics and motor control of human move-

ment, 2nd ed. New York: Wiley, 1990.[51] Simon SR, Knirk J, Mansour JM, Koskinen MF. A comprehen-

sive clinical system for four-dimensional motion analysis. Bull

Hosp Joint Dis 1977;38(1 April):41 – 4.

[52] Simon SR, Deutsch SD, Nuzzo RM, Mansur MJ, Jackson JL,

Koskinen M, Rosenthal RK. Genu-recurvatum in spastic cere-

bral palsy. J Bone Joint Surg 1978;60A:882 – 94.

[53] Simon SR, editor. Orthopaedic basic science. American

Academy of Orthopaedic Surgeons, 1994.

[54] Gage JR, Fabian D, Hicks R, Tashman S. Pre- and postopera-

tive gait analysis in patients with spastic diplegia: a preliminary

report. J Pediatr Orthop 1984;4:715 – 25.

[55] Gage JR, Perry J, Hicks RR, Koop S, Werntz JR. Rectus

femoris transfer to improve knee function in children with

cerebral palsy. Dev Med Child Neurol 1987;29:159 – 66.

[56] Gage JR. Surgical treatment of knee dysfunction in cerebralpalsy. Clin Orthop 1990;253:45 – 54.

[57] Gage JR. An overview of normal walking. Instr Course Lect

1990;39:291 – 303.

[58] Gage JR. Gait analysis. An essential tool in the treatment of

cerebral palsy. Clin Orthop 1993;288:126 – 34.

[59] Gage JR. The role of gait analysis in the treatment of cerebral

palsy. J Pediatr Orthop 1994;14(6):701 – 2.

[60] Gage JR. Gait analysis in cerebral palsy. New York: MacKeith

Press, 1991.

[61] Ounpuu S. The biomechanics of running: a kinematic and

kinetic analysis, Inst. Course Lect. 1990:305 – 318.

[62] Ounpuu S, Gage JR, Davis RB. Three-dimensional lower ex-

tremity joint kinetics in normal pediatric gait. J Pediatr Orthop

1991;11:341 – 9.

[63] DeLuca PA, Ounpuu S, Davis RB, Walsh JH. Effect of ham-string and psoas lengthening on pelvic tilt in patients with spastic

diplegic cerebral palsy. J Pediatr Orthop 1998;18(6):712 – 8.

[64] Ounpuu S, Muik E, Davis RB, Gage JR, DeLuca PA. Rectus

femoris surgery in children with cerebral palsy. Part II: a com-

parison between the effect of transfer and release of the distal

rectus femoris on knee mot ion. J Pediatr Orthop

1993;13(3):331 – 5.

[65] Ounpuu S, Muik E, Davis RB, Gage JR, DeLuca PA. Rectus

femoris surgery in children with cerebral palsy. Part I: the effect

of rectus femoris transfer location on knee motion. J Pediatr

Orthop 1993;13(3):325 – 30.

[66] DeLuca PA, Davis RB, Ounpuu S, Rose S, Sirkin R. Alterations

in surgical decision making in patients with cerebral palsy based

on three-dimensional gait analysis. J Pediatr Orthop

1997;17(5):608 – 14.[67] Davis RB, O 8 unpuu S, Tyburski DJ, Gage JR. A gait analysis

data collection and reduction technique. Hum Mov Sci

1991;10:575 – 87.

[68] Watts HG. Gait laboratory analysis for preoperative decision

making in spastic cerebral palsy: is it all it’s cracked up to be? J

Pediatr Orthop 1994;14:703 – 4.

[69] Bartlett J. In: Kaplan J, editor. Bartlett’s familiar quotations,

16th ed. Little, Brown and Co, London, UK 1992.

[70] Kadaba MP, Ramakrishnan HK, Wootten ME, Gainey J, Gor-

ton G, Cochran GV. Repeatability of kinematic, kinetic, and

electromyographic data in normal adult gait. J Orthop Res

1989;7(6):849 – 60.

[71] Kadaba MP, Ramakrishnan HK, Jacobs D, Chambers C, Scar-

borogh N, Goode B. Pattern recognition in spastic diplegia.

Biomecanica 1995;III(4):49 – 58.

[72] Kadaba MP, Wootten ME, Gainey J, Cochran GV. Repeatabil-

ity of phasic muscle activity: performance of surface and intra-

muscular wire electrodes in gait analysis. J Orthop Res

1985;3(3):350 – 9.

[73] Kadaba MP, Ramakrishnan HK, Wootten ME. Measurement of

lower extremity kinematics during level walking. J Orthop Res

1990;8(3):383 – 92.[74] Campbell KR. Expert vision, data acquisition and analysis, in:

ASME International Computers in Engineering Conference and

Exhibition, New York, NY, 1987.

[75] Craig JJ. Introduction to robotics. Addison-Wesley, Boston, MA

1989.

[76] Grood ES, Suntay WJ. A joint coordinate system for the clinical

description of three-dimensional motions: application to the

knee. J Biomech Eng 1983;105:136 – 44.

[77] http://guardian.curtin.edu.au /cga/faq/angles.html O, Methods

for representation of angular rotations.

[78] Sutherland DH, Kaufman KR, Moitoza JR. Kinematics of

normal human walking. In: Rose J, Gamble JG, editors. Human

walking. Baltimore: Williams and Wilkins, 1994:23 – 43.

[79] Oef finger DJ, Pectol RWJ, Tylkowski CM. Foot pressure and

radiographic outcome measures of lateral column lengthening

for pes planovalgus deformity. Gait and Posture 2000;12(3):189 –

95.

[80] Tylkowski CM, Simon SR, Mansour JM. The Frank Stinchfield

Award Paper. Internal rotation gait in spastic cerebral palsy, in

Hip, 1982:89 – 125.

[81] Tylkowski CM, Rosenthal RK, Simon SR. Proximal femoral

osteotomy in cerebral palsy. Clin Orthop

1980;151(September):183 – 92.

[82] Mazur JM, Sienko-Thomas S, Wright N, Cummings RJ. Swing-

through vs. reciprocating gait patterns in patients with thoracic-

level spina bifida. Z Kinderchir 1990;45(Suppl. 1):23 – 5.

[83] Buckon CE, Sienko-Thomas S, Aiona MD, Piatt JH. Assess-

ment of upper-extremity function in children with spastic diple-

gia before and after selective dorsal rhizotomy. Dev Med Child

Neurol 1996;38(11):967 – 75.

[84] Cooper RA, Quatrano LA, Stanhope SJ, Cavanagh PR, Miller

F, Kerrigan DC, Esquenazi A, Harris GF, Winters JM. Gait

analysis in rehabilitation medicine: a brief report. Am J Phys

Med Rehab 1999;78(3):278 – 80 May – June.

[85] O’Connell PG, Lohmann Siegel K, Kepple TM, Stanhope SJ,

Gerber LH. Forefoot deformity, pain, and mobility in rheuma-

toid and nonarthritic subjects. J Rheumatol 1998;25(9):1681 – 6

September.

[86] Siegel KL, Kepple TM, O’Connell PG, Gerber LH, Stanhope SJ.

A technique to evaluate foot function during the stance phase of

gait. Foot Ankle Int 1995;16(12):764 – 70 December.

[87] Kepple TM, Sommer H Jr., Lohmann Siegel K, Stanhope SJ. A

three-dimensional musculoskeletal database for the lower ex-

tremities. J Biomech 1998;31(1):77 – 80 January.

[88] Holden J, Orsini J, Siegel K, Kepple TM, Gerber L, Stanhope S.

Surface movement errors in shank kinematics and knee kinetics

during gait. Gait and Posture 1997;5:217 – 27.

[89] Reinschmidt C, van den Bogert AJ, Nigg BM, Lundberg A,

Murphy N. Effect of skin movement on the analysis of skeletal

knee joint motion during running. J Biomech 1997;30(7):729 – 32.

[90] Cappozzo A, Catani F, Leardini A. Skin movement artifacts in

human movement photogrammetry, in: Abstracts of the XIVth

Congress of the International Society of Biomechanics, Paris,

1993.

[91] Angeloni C, Cappozzo A, Catani F, Leardini A. Quantification

of relative displacement between bones and skin and plate

mounted markers, in: Eighth Meeting of the European Society of

Biomechanics, Rome, 1992.

[92] Perry J, Enwemeka CS, Gronley JK. The stability of surface

markers during knee flexion, in: 34th Annual Meeting of the

Orthopaedic Research Society, 1988.




[93] Lafortune MA, Cavanagh PR, Kalenak A, Skinner SM, Sommer

HJ. The use of intra-cortical pins to measure the kinematics of

the knee joint, in: Proceedings of the Second Biennial Conference

of the Canadian Society for Biomechanics, Kingston, 1982.

[94] Lucchetti L, Cappozzo A, Cappello A, Croce UD. Skin move-

ment artefact assessment adn compensation in the estimation of

knee-joint kinematics. J Biomech 1998;31:977 – 84.[95] Alexander EJ, Andriacchi TP. Correcting for deformation in

skin-based marker systems. J Biomech 2001;34:355 – 61.

[96] Biafore S, Cottrell G, Focht L, Kaufman K, Wyatt M, Suther-

land D. Neural network analysis of gait dynamics. Trans Orthop

Res Soc 1991;16(1):225.

[97] Weintraub MA, Bylander T, Simon SR. QUAWDS: a composite

diagnostic system for gait analysis. Comput Methods Programs

Biomed 1990;32(1):91 – 106.

[98] Kidder SM, Abuzzahab FS, Harris GF, Johnson JE. A system

for the analysis of foot and ankle kinematics during gait. IEEE

Trans Rehab Eng 1996;4(1):25 – 32.[99] Kaufman KR, Kitaoka HP, Hansen D, Shaughnessy WJ. Tech-

nique for measurement of foot and ankle kinematics in children,

in: IEEE/EMBS 19th International Conference, Chicago, IL,

1997.

Sutherland 2

Documents

Transcript of Sutherland 2