|
1:
Acta
Otolaryngol 2000 Mar;120(2):168-72 |
|
Postural behaviour responses to
visual stimulation in patients with vestibular disorders.
Suarez H, Muse P, Suarez A, Arocena M.
Laboratory of Audiology and
Vestibular Pathophysiology,
Patients with different vestibular disorders exhibit changes in postural behaviour when they receive visual stimuli, reproducing
environmental stimulation. Postural control was studied using an AMTI Accusway platform, measuring the
confidential ellipse (CE) and sway velocity (SV). Postural responses were
recorded according to the following stimulation paradigm: i)
without specific stimuli; ii) smooth pursuit with pure sinusoids of 0.2 Hz (foveal stimulation); and iii) optokinetic
stimulation (retinal stimuli). Patients with central vestibular disorders
(CVD), cerebellar damage and unilateral peripheral
vestibular lesions (UPVL) in asymptomatic periods were studied. A group of
normal subjects was studied as control. Signal processing was done with a scalogram by wavelets in order to observe the relation
between time and frequency in postural control. While patients with CVD and cerebellar disease showed a significant increase in CE and
SV in the three conditions of the paradigm compared to the normal group, the
patients with UPVL showed no change. Wavelets processing showed that the main
sway occurs in the Y axis (antero-posterior) and
below at 0.4 Hz in normal subjects, while the CVD and cerebellar
patients showed sway frequencies in both the X and Y axes. The clinical
implications of these findings are discussed.
PMID: 11603765 [PubMed - indexed for MEDLINE]
|
2: IEEE
Trans Neural Syst Rehabil
Eng 2001 Sep;9(3):295-301 |
|
Setup and procedure for online identification of
electrically stimulated muscle with Matlab Simulink.
Ponikvar M, Munih M.
Faculty of Electrical
Engineering,
This paper first describes a laboratory setup for
biomechanical experiments that runs within the universal simulation environment
Matlab Simulink. The
overall system comprises a personal computer, two AMTI (Advanced Mechanical Technology, Inc., Watertown, MA 02472)
force plates, Parotec force-sensor shoe insoles, Optotrak system for noncontact
three-dimensional (3-D)-position measuring, and a computer-controlled
four-channel electrical stimulator. Conceptually, the most important
application is implementation of closed-loop electrical stimulation of intact
and paralyzed subjects in the laboratory. Second, the system was tested in
real-time muscle model identification procedure during a standing experiment.
The plantarflexors of three nonimpaired
subjects were excited with pseudorandom binary sequences (PRBSs)
with small deviations around selected operating points. Electrically stimulated
muscles were presented with a linear local dynamic block that was identified
with a recursive least-square method (RARX). RARX block was designed with
fundamental Matlab Simulink
blocks that support real-time operation. Introduced was online estimation of
model output, which offers a great manner of instant model validation. Two
modes of operation with online validation were tested. In the first mode, the
operating point for selected excitation level was identified online. In the
second mode, the operating point was measured in preceding experiments. Both
procedures resulted in satisfying second-order models that will be used in the
adaptive controller design.
PMID: 11561666 [PubMed - indexed for MEDLINE]
|
3: Clin Biomech ( |
|
Box tilt and knee motions in manual lifting: two differential factors in
expert and novice workers.
Gagnon
M.
Laboratoire de biomecanique, Departement
d'education physique, Universite
de Montreal, Montreal, Quebec, Canada.
OBJECTIVE: It was the objective of this study
to investigate the kinematic and kinetic effects of
two specific handling factors that differentiate expert and novice workers,
namely the level of knee flexion and box tilt. DESIGN: Seven inexperienced
subjects were required to lift a 12-kg box in the sagittal
plane using three different strategies: (1) reduced knee flexion and a backward
box tilt (more typical of experts); (2) large knee flexion and a backward box
tilt; (3) large knee flexion and no box tilt (more typical of novices).
BACKGROUND: The lifting techniques of highly skilled workers differ
substantially from those of novices but only limited information is available
to compare their biomechanical differences. METHODS: The methods included
dynamic segmental analyses to calculate the net moments at all body joints and
a planar single-muscle equivalent to estimate compression loadings at L5/S1;
total work and joint work distribution were calculated using the integration of
joint power. The 3-D kinematic data were acquired
with three video cameras and force data were obtained with one AMTI force platform which were synchronized
with the film data. RESULTS: Box tilt reduced the load trajectory and loadings
on the lower back and shoulders; a reduced knee flexion affected body posture
and reduced mechanical work and loadings on all body joints. The combination of
these two factors, box tilt and reduced knee flexion, showed added effects for
almost all variables. CONCLUSIONS: These two factors proper to experts were, in
this context, biomechanically more advantageous.
PMID: 11415751 [PubMed - as supplied by publisher]
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4: Surg Radiol Anat 2001;23(1):27-31 |
|
Influence of the mode of load carriage on the static posture of the pelvic
girdle and the thoracic and lumbar spine in vivo.
Filaire M, Vacheron
JJ, Vanneuville G, Poumarat
G, Garcier JM, Harouna Y, Guillot M, Terver S, Toumi H, Thierry C.
Laboratoire
d'Anatomie, Faculte de Medecine,
B.P. 38, F-63001 Clermont-Ferrand, France.
The influence of various modes of carrying a
load of 16 kg (15.69 DaN) on the static positioning
of the pelvic girdle and the thoracic and lumbar segments of the spine was
examined in seven male subjects. The displacement of cutaneous
markers attached to easily palpable skeletal landmarks was recorded using 4 CCD
cameras; the data acquired were analysed using an
optoelectronic technique (SAGA3). The subjects stood upright on an AMTI biomechanical force platform, from which the ground reaction
forces enabled displacements of the centre of gravity axis and thus the moment
of the mass carried to be determined. The modes of load carriage examined were:
1) in a case in the left hand; 2) in a case in the right hand; 3) equally in
two cases; 4) on the head; 5) in a rucksack; and 6) in an anterior bag. The
results showed displacements of the pelvic girdle, the caudal and cranial
lumbar segments, and the caudal and cranial thoracic segments in the three
orthogonal planes (sagittal, frontal and transverse).
The influence of the moment created by the load was seen in the statokinesigrams. The use of external markers using an
optoelectronic technique, in association with the ground reaction forces,
enables the mode of load carriage to be determined. The results show that the
influence of the moment exerted by the mode of load carriage on the gravity
axis has important ergonomic consequences.
PMID: 11370138 [PubMed - indexed for MEDLINE]
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5:
Acta
Otolaryngol 2001 Jan;121(2):220-4 |
|
Assessment of the risk of fall, related to visual stimulation, in patients
with central vestibular disorders.
Suarez H, Muse P, Suarez A, Arocena M.
Laboratory of Audiology and
Vestibular Pathophysiology,
In order to assess the influence of visual stimulation in the triggering of
imbalance and falls in the elderly population, the postural responses of 18
elderly patients with central vestibular disorders and clinical evidence of
instability and falls were studied while receiving different types of visual
stimuli. The stimulation conditions were: (i) no
specific stimuli; (ii) smooth pursuit with pure sinusoids of 0.2 Hz as foveal stimulation; and (iii) optokinetic
stimulation (OK) as retinal stimuli. Using a platform AMTI Accusway platform, the 95% confidence
ellipse (CE) and sway velocity (SV) were evaluated with a scalogram
using wavelets in order to assess the relationship between time and frequency
in postural control. Velocity histograms were also constructed in order to
observe the distribution of velocity values during the recording. A non-homogeneous
postural behavior after visual stimulation was found among this population. In
five of the patients the OK stimulation generated: (i)
significantly higher average values of CE ( > 3.4+/-0.69 cm2); (ii) a
significant increase in the average values of the SV ( > 3.89+/-1.15 cm/s)
and a velocity histogram with a homogeneous distribution between 0 and 18 cm/s;
and (iii) a scalogram with sway frequencies of up to
4 Hz distributed in both the X and Y directions (backwards and forwards and
lateral) during visual stimulation with arbitrary units of energy density >
5. These three qualitative and quantitative aspects could be
"markers" of visual dependence in the triggering of the mechanism of
lack of equilibrium and hence falls in some elderly patients and should be
considered in order to prevent falls and also to assist in the rehabilitation
program of these patients.
PMID: 11349783 [PubMed - indexed for MEDLINE]
|
6: Am J
Knee Surg 2000 Spring;13(2):103-8; discussion 108-9 |
|
Walking, chair rising, and stair climbing after total knee arthroplasty: patellar resurfacing versus nonresurfacing.
Pollo FE, Jackson RW, Koeter
S, Ansari S, Motley GS, Rathjen
KW.
Department of Orthopedic Surgery,
During the past decade, the technology and design of knee joint prostheses has
progressed considerably. However, there is still much controversy on whether
resurfacing the patella during routine total knee arthroplasty
(TKA) is necessary. This study compares the biomechanics of the lower limb in
patients after TKA with and without patellar resurfacing during level walking,
stair climbing, and chair rising. Eighteen patients who underwent TKA by two
different surgeons using the same prosthesis were studied after full
rehabilitation while walking, stair climbing, and chair rising. Patients were
divided between those who were resurfaced and those who were not resurfaced. An
aged-matched control population was recruited for comparison. The Hospital for
Special Surgery Knee Rating Scale was used to gather clinical information. Kinematic and kinetic parameters were collected using a
5-camera Motion Analysis System and an AMTI OR6-5 force platform. For level walking, patients were asked to
walk at a self-selected speed down an 8-m walkway. For stair climbing, patients
were asked to climb a 4-step staircase without handrail support and for chair
rising, patients were asked to rise from a chair that was positioned at the
height of their knee joint line. Five trials for each side were recorded for
averaging and statistical analysis. Temporal-spatial parameters and kinematic and kinetic variables at the knee joint were
tested for significance using the repeated measures analysis of variance
(ANOVA). There were no significant differences in the biomechanics of walking,
stair climbing, or chair rising between patients after TKA with and without a
resurfaced patella.
PMID: 11281331 [PubMed - indexed for MEDLINE]
|
7: Arch
Phys Med Rehabil 2001 Jan;82(1):80-5 |
|
Postural control in the elderly: an analysis of test-retest and interrater reliability of the COP-COM variable.
Corriveau H, Hebert R,
Prince F, Raiche M.
School of Rehabilitation Sciences,
Physiotherapy, University of Ottawa, Ottawa, Ont,
Canada. hcorrive@uottawa.ca
OBJECTIVES: To estimate the test-retest and interrater
reliability of the center of pressure-center of mass (COP-COM) variable of postural
control in the elderly. DESIGN: The biomechanic
variable COP-COM, which represents the distance between the COP and the COM,
was determined from 2 AMTI force
platforms and 3 OPTOTRAK position sensors. Measurements were taken in quiet
position, double leg stance, and eyes open and eyes closed conditions. SETTING:
Laboratory environment. PARTICIPANTS: Forty-five healthy subjects, 8 patients
with diabetes neuropathy, and 7 stroke survivors, all of whom were at least 60
years old. INTERVENTIONS: Subjects were evaluated on 2 separate occasions
within 7 days by the same evaluator to determine test-retest reliability. Interrater reliability was determined the same day. MAIN
OUTCOME MEASURES: The biomechanic variable COP-COM,
which represents the distance between the COP and the COM in terms of root mean
square. The mean of 4 trials of the COP-COM variable for each condition was
used for statistical analysis. Intraclass correlation
coefficients (ICCs) were used. RESULTS: The COP-COM
variable has good reliability for both the test-retest and interrater
studies, but its reliability varies according to the direction of the COP-COM.
For the test-retest and interrater studies, the ICC
ranged from.89 to.93 in the anteroposterior direction
and from.74 to.79 in the mediolateral direction.
CONCLUSION: The equivalence of the test-retest and interrater
coefficients obtained suggests that the measurement error of the COP-COM
variable is mainly linked to the biologic variability of this measure over a
short period of time. Using the mean of 4 trials stabilizes the COP-COM
variable enough to be potentially used to evaluate clinical change.
PMID: 11239290 [PubMed - indexed for MEDLINE]
|
8: Gait
Posture 2000 Oct;12(2):128-33 |
|
Comparison of an in-shoe pressure measurement device to a force plate:
concurrent validity of center of pressure measurements.
Chesnin
KJ, Selby-Silverstein L, Besser MP.
Human Performance
Laboratory, Department of Physical Therapy,
The purpose of this study was to assess the concurrent
validity of center of pressure (COP) measurements during walking, comparing the
Parotec System (an in-shoe pressure measurement
device) to an Advanced Mechanical Technology Inc. (AMTI) force plate. Pearson correlation
coefficients comparing COP displacement in the medial-lateral (ML) and
anterior-posterior (AP) direction calculated from the two systems were greater
than 0.70 for 52/67 trials (78%) in the ML direction and were greater than 0.90
for 67/67 trials (100%) in the AP direction. The mean root mean square (RMS)
error for COP displacement in the ML direction was 0.56+/-0.3 cm and in the AP
direction was 1.37+/-0.59 cm. Overall, the Parotec
System showed good correlation and small RMS errors when compared to the AMTI force plate. Additional analysis to investigate sources of
error pointed to the methods used for calculating the position and orientation
of the subject's foot on the force plate. Subsequent analysis to eliminate some
of these errors, compared force calculated from the Parotec
System and the AMTI plate and showed good to
excellent correlation (>0.70) for 62/67 trials (93%). Additional data were
collected that allowed for elimination of methodological errors. Again force
calculated from the two systems was compared using Pearsons.
These data showed excellent correlation (>0.90) for 20/20 trials (100%).
This study provides evidence of the validity of the Parotec
System for measuring COP during ambulation.
Publication Types:
· ·
Validation Studies
PMID: 10998609 [PubMed - indexed for MEDLINE]
|
9: Med Sci Sports Exerc 1999
Oct;31(10):1374-81 |
|
Etiologic factors associated with Achilles tendinitis
in runners.
McCrory JL, Martin DF, Lowery RB, Cannon
DW, Curl WW, Read HM Jr, Hunter DM, Craven T, Messier
SP.
Department of Health and Exercise Science,
PURPOSE: The purpose of this study was to determine whether relationships exist
between selected training, anthropometric, isokinetic
muscular strength, and endurance, ground reaction force, and rearfoot movement variables in runners afflicted with
Achilles tendinitis. METHODS: Specifically, we
examined differences in selected measures between a noninjured
cohort of runners (N = 58) and a cohort of injured runners with Achilles tendinitis (N = 31). Isokinetic,
kinetic, and kinematic measures were collected using
a Cybex II+ isokinetic
dynamometer (
PMID: 10527307 [PubMed - indexed for MEDLINE]
|
10: Rev Chir Orthop Reparatrice
Appar Mot 1999 Sep;85(5):466-74 |
|
[Influence of knee replacement arthroplasty on
modalities of weight transfer during the lateral step]
[Article in French]
Viton JM, Atlani
L, Mesure S, Rochwerger A, Franceschi JP, Delarque A, Massion J.
Departement Universitaire de Reeducation
et Readaptation, Universite
de la Mediterranee, Marseille.
INTRODUCTION: The aim of this work was to
study the relations between equilibrium and movement in patients after total
knee arthroplasty. A previous study, conducted in
patients with unilateral knee osteoarthritis, had shown that the timing of the
events occurring during a side-step was modified in an asymmetrical way
according to the supporting leg with respect to the affected one. METHOD: A
kinetic and kinematic analysis was performed in a
population of 9 patients before and after total knee arthroplasty
and in 11 control subjects, using an ELITE system and two AMTI force-plates. The different phases (i.e. postural, monopodal, landing and stabilization) of a side step were
studied. RESULTS AND DISCUSSION: Before surgery, the postural phase was longer
and the monopodal phase was shorter in knee arthritis
patients when the affected leg was the supporting one than when the sound leg
was supporting. Total step duration and landing-stabilization phase duration
were longer in patients no matter which leg was supporting than in control
subjects. After total knee arthroplasty, the postural
phase remained longer when the operated leg was supporting than when the sound
leg was supporting. Altered proprioception can
provide an explanation for this result. However, the duration of the postural
phase decreased significantly when the operated leg was supporting as compared
to when the affected leg was supporting before surgery. The duration of the monopodal phase was the same when the operated leg was
supporting than when the sound limb was supporting and increased significantly
as compared to when the affected leg was supporting before surgery. This result
can be related to the decrease of pain which was observed in all patients after
surgery. The duration of the landing-stabilization phase and the total movement
duration remained longer in patients after surgery no matter which leg was
supporting than in control subjects. CONCLUSION: This study shows that
relations between equilibrium and movement tend to become symmetrical with
respect to the leg used as supporting one in patients after undergoing total
knee arthroplasty but remain different from those of
control subjects. This movement analysis method enables to determine and to
quantify differences in patients before and after undergoing total knee arthroplasty and thus provides additional information for
the functional evaluation of patients with total knee prosthesis.
PMID: 10507108 [PubMed - indexed for MEDLINE]
|
11: Rev Chir Orthop Reparatrice
Appar Mot 1998 Nov;84(8):705-11 |
|
[Methods of shifting body weight in patients with knee arthroses]
[Article in French]
Viton JM, Atlani
L, Mesure S, Franceschi JP,
Massion J, Rochwerger A, Delarque A.
Departement Universitaire de Reeducation
et Readaptation, Universite
de la Mediterranee, Marseille.
INTRODUCTION: The aim of this work was to
study movement control strategies in patients with knee arthritis. These
strategies were expected to be different from healthy subjects because of
deficiencies due to knee arthritis (i.e. pain, altered proprioception).
METHOD: A kinetic and kinematic analysis was
performed in a population of 10 patients with unilateral knee arthritis and in
11 age-matched control subjects, using an ELITE system and two AMTI force-plates. The different phases of a side step were studied.
RESULTS: The timing of the movement was different in the two populations. The
postural phase was longer and the monopodal phase was
shorter in knee arthritis patients when the affected leg was the supporting one
than when the sound leg was supporting. Total step duration and
landing-stabilization phase duration were longer in knee arthritis patients
than in healthy subjects. CONCLUSION: This movement analysis method enables to
determine and to quantify differences between knee arthritis patients and
control subjects. Clinical examination cannot identify these differences.
Movement analysis methods bring up additional information to usual clinical
evaluation scales and could be used for evaluation of the results of total knee
arthroplasty.
PMID: 10192121 [PubMed - indexed for MEDLINE]
|
12: Biomed Sci Instrum 1997;33:360-5 |
|
Co-activation of the hamstrings and quadriceps during the
lunge exercise.
Hefzy MS, al Khazim
M, Harrison L.
Department of Biological & Medical Research,
The anterior lunge exercise is a closed chain kinetic exercise that has been
developed to improve the function of the lower limb and to strengthen the
hamstrings and quadriceps, simultaneously. In this study, a three-dimensional
biomechanical analysis of this exercise was conducted in order to understand
the mechanics of this rehabilitation activity. Experimental conditions were
recorded using an active optoelectronic kinematic
data capture system (OPTOTRAK), two force plates (AMTI) and electromyography (EMG). Data were collected from healthy
male subjects while performing several lunges. When the distance between the
toe of the rear leg and the heel of the front leg (lunging distance) was maximum, a large net flexion moment was predicted in the
front leg in the extented position. This moment was
reversed to a large net extension moment in the flexed position. A large
increase in the net extension moment in the rear leg was also predicted as the
front knee was bent from 5 degrees to 90 degrees of flexion. These data suggest
that quadriceps and hamstring muscles co-contraction occur during a maximum
lunge in the front leg when it is in the flexed position.
PMID: 9731386 [PubMed - indexed for MEDLINE]
|
13: Prosthet Orthot Int 1997
Aug;21(2):114-23 |
|
The effect of changing the inertia of a trans-tibial dynamic elastic response prosthesis on the
kinematics and ground reaction force patterns.
Hillery SC, Wallace ES, McIlhagger R, Watson
P.
Department of Leisure and Tourism,
The aim of this study was to assess, by means of gait analysis, the effect on
the gait of a trans-tibial amputee of altering the
mass and the moment of inertia of a dynamic elastic
response prosthesis. One male amputee was analysed
for four to five walking trials at normal and fast cadences, using the VICON
system of motion analysis and an AMTI
force plate. The kinematic variables of cadence,
swing time, single support time and joint angles for the knee and hip on the
affected and intact sides were analysed. The ground
reaction force was also analysed. The sample size was
limited to one as an example to indicate the changes which are possible through
simply changing the inertial characteristics. Descriptive statistics are used
to demonstrate these changes. Three mass conditions for the prosthesis were analysed m1: 1080g; m2: 1080 + 530g; m3: 1080 + 1460g. The
m1 condition is the mass of the prosthesis with no added weight while m2 and m3
were attachments of the same geometrical shape but were made from different
materials. It was felt that the large mass range would highlight biomechanical
adjustments as a result of its alteration. The effect on selected temporal
characteristics were that as the speed increased the cadence changed and the
affected side single support times as a percentage of the gait cycle were
altered. The effect on the joint angles was also apparent at the hip and knee
of both sides. The ground reaction force patterns were similar for all three
mass conditions, though the impact peak which was evident in the intact limb
was missing, indicating a shock absorbing property in the prosthesis. Clearly,
changing the mass and moment of inertia has an effect on the kinematic variables of gait and should be considered when
designing a prosthesis.
Publication Types:
· ·
Clinical Trial
PMID: 9285955 [PubMed - indexed for MEDLINE]
|
14: Can
J Neurol Sci 1997
Aug;24(3):230-4 |
|
Chronic stimulation of the left vagus nerve in
epilepsy: balance effects.
Clarke
BM, Upton AR, Griffin H, Fitzpatrick D, DeNardis M.
Division of Neurology,
BACKGROUND: Stimulation of the left vagus nerve (VNS)
has been shown to control seizures in double blinded crossover studies in man.
Animal studies have reported vagal afferent induced
depression of nociceptive and motor reflexes which
may be caused by an effect on the descending reticular system controlling
spinal cord function. Anticonvulsant drug therapy may cause postural
instability. The effects of VNS are assessed not only from the perspective of
seizure control but also from the view of potential harm to other bodily
systems. Long term (2 1/4 years) effects of VNS were compared to postural
stability analyses. METHODS: 8 subjects, 2 were females, mean age 34.5 +/- 8.23
SD years, with intractable complex partial seizures, taking 3 anticonvulsant
drugs were assessed for postural stability in quiet standing and while moving
forwards, backwards and sideways with eyes open (EO) and eyes closed (EC). Data
were collected and collated using an AMTI
Biomechanics immovable forceplate, Newton M.A.
Publication Types:
· ·
Clinical Trial
PMID: 9276109 [PubMed - indexed for MEDLINE]
|
15: Spinal
Cord 1997 Apr;35(4):217-22 |
|
Assisted reach and transfers in individuals with tetraplegia:
towards a solution.
Allison
GT, Singer KP.
The purpose of this study was to investigate the influence of a prototype trunk
orthosis to assist an individual with tetraplegia. A single case study (26 year old male, C5
motor complete) using an interrupted time series analysis was conducted to
investigate the individual's ability to reach, forward and laterally, and
transfer with and without the orthosis. All tasks
were performed on an AMTI force
platform in the long sitting position, with landmarks of the trunk and limbs
recorded using Peak Performances Technologies motion analysis system. After a familiarisation period ten trials were attempted for each
phase of the analysis. With the orthosis the subject
altered the sitting posture and significantly (F = 9.55, P = 0.003) increased
the distance the subject was able to reach. The median frequency of the centre
of pressure (COP) displacement during the reaching task was not significantly
altered. The ability to displace the COP when attempting to transfer increased
from 16.0 (+/-3.4 cm) to 19.6 (+/-2.5 cm), however,
this was not statistically significant. The likely user population, the overall
functional benefits, the compliance of the users and possible modifications to
the device to facilitate use with functional electrical stimulation are all
possible directions for future research.
PMID: 9143083 [PubMed - indexed for MEDLINE]
|
16: Prosthet Orthot Int 1997 Apr;21(1):17-27 |
|
Energy storage and release of prosthetic feet.
Part 1: Biomechanical analysis related to user benefits.
Postema
K, Hermens HJ, de Vries J, Koopman HF, Eisma WH.
St. Maartenskliniek,
The energy storing and releasing behaviour of 2
energy storing feet (ESF) and 2 conventional prosthetic feet (CF) were compared
(ESF: Otto Bock Dynamic Pro and Hanger Quantum; CF: Otto Bock Multi Axial and
Otto Bock Lager). Ten trans-tibial amputees were
selected. The study was designed as a double-blind, randomised
trial. For gait analysis a VICON motion analysis system was used with 2 AMTI force platforms. A special measuring device was used for
measuring energy storage and release of the foot during a simulated step. The
impulses of the anteroposterior component of the
ground force showed small, statistically non-significant differences
(deceleration phase: 22.7-23.4 Ns; acceleration phase: 17.0-18.4 Ns). The power
storage and release phases as well as the net results also showed small
differences (maximum difference in net result is 0.03 J kg-1).
It was estimated that these differences lead to a maximum saving of 3% of
metabolic energy during walking. It was considered unlikely that the subjects
would notice this difference. It was concluded that during walking differences
in mechanical energy expenditure of this magnitude are probably not of clinical
relevance. Ankle power, as an indicator for energy storage and release gave
different results to the energy storage and release as measured with the special
test device, especially during landing response. In the biomechanical model
(based on inverse dynamics) used in the gait analysis the deformation of the
material is not taken into consideration and hence this method of gait analysis
is probably not suitable for calculation of shock absorption.
Publication Types:
· ·
Clinical Trial
· ·
Randomized Controlled Trial
PMID: 9141122 [PubMed - indexed for MEDLINE]
|
17: Percept
Mot Skills 1997 Feb;84(1):287-90 |
|
Basic
Shih J.
Department of Health, Wellness and Exercise Science/274,
To examine the effect of 16 weeks of T'ai Chi exercise on the average velocity of sway 11
subjects were pre- and posttested by using the AMTI force platform. Analysis indicated that T'ai
Chi exercise was associated with substantial changes in the sway velocities in
anterior and posterior directions for the group but was not assessed against
any control groups performance. That remains to be evaluated.
PMID: 9132721 [PubMed - indexed for MEDLINE]
|
18: J Biomech 1996 Nov;29(11):1445-53 |
|
Knee movement strategies differentiate expert from novice workers in
asymmetrical manual materials handling.
Gagnon
M, Plamondon A, Gravel D, Lortie M.
Departement d'Education Physique, Universite
de Montreal, Quebec,
Canada.
One way to generate hypotheses on appropriate
handling principles is to compare the strategies of highly skilled workers
(experts) with those of novice workers (novices). This study was conducted to
determine whether experts differ from novices in their handling strategies and
to determine the effects of these differences in joint motions and net reaction
moments at the trunk (L5/S1) and knees. Six experts and five novices were
compared transferring two loads (12 and 22 kg) from four different initial low
positions to a standardized low position on a trolley. The external forces were
obtained from two AMTI force platforms, and two
16 mm Locam cameras coupled with two mirrors were
used to obtain the three-dimensional kinematic data.
An inverse dynamic analysis was performed on each segment and the net reaction
moments were evaluated at L5/S1 and the knees; trunk posture, knee flexion
angles and feet spacings were also calculated.
Results showed that both groups minimized trunk asymmetries of posture and
efforts; however, the experts were characterized by reduced knee flexion (31
degrees vs 53 degrees) and total knee excursion (20
degrees vs 38 degrees), increased flexion moments (72
vs 58 Nm) but reduced extension moments (4 vs 26 Nm) and valgus moments (30 vs 54 Nm). The experts' strategies appear safer overall
because they reduce trunk asymmetry, asymmetrical efforts on the knee and
stress on the femoropatellar joint. Moreover, these
strategies present a potential for reduced mechanical energy expenditure due to
lower knee excursions and increased knee stability due to reduced knee flexion.
PMID: 8894925 [PubMed - indexed for MEDLINE]
|
19: Ergonomics
1995 Jun;38(6):1156-71 |
|
Effects of symmetry and load absorption of a falling load on 3D trunk
muscular moments.
Gagnon
M, Plamondon A, Gravel D.
Departement d'education
physique, Universite de Montreal,
Quebec, Canada.
Some epidemiological data have suggested that
many physical causes of low back pain such as bending and twisting were, in
fact, sudden maximal efforts incidentally carried out at the moment of
accident. Sudden loading conditions may be encountered in several
circumstances, one of them being the recuperation of a falling load. Such
conditions are more likely to occur in conditions of trunk asymmetry. The
objective of this study was to determine spinal loadings associated with the
reception of a falling box symmetrically and asymmetrically for two mechanisms
of load absorption, one limited to the elbows and the other including full
absorption with the elbows and lower limbs. It was hypothesized that
asymmetrical receptions would be more strenuous for the spine; it was further
hypothesized that the full absorption to decelerate the load might be more
efficient in reducing the strain in the trunk muscular moments. Nine students
in physical education with limited experience in manual materials handling were
the subjects of the study. The tasks consisted of receiving a 6.6 kg load
falling from a height of 50 cm above the flexed forearms when in a standing
position. The subjects were tested with two AMTI force plates and two Locam cameras
coupled with two mirrors; dynamic 3D multi-segment models were constructed and
the net muscular moments as well as the angular velocities of the trunk
relative to pelvis were determined about the three orthogonal axes of the trunk
at L5/S1, in twisting, lateral bending, and flexion/extension. The dependent
variables included maximal moments, maximal rates of loading for these moments,
and the integration of these moments. Statistical analyses were performed to
test the main effects of symmetry and absorption and their interaction. The
results showed that asymmetrical conditions impose supplementary muscular
exertions for trunk muscles, especially the trunk extensors and lateral
flexors. Contrary to the proposed hypothesis, full absorption as used in the
present study was a condition leading to considerably larger muscular
exertions, especially for the loading rates. Thus it was concluded that the
process of training for load absorption is essential to effectively decrease
the risks of injuries. This factor would merit full consideration in future
studies.
PMID: 7758444 [PubMed - indexed for MEDLINE]
|
20: Handchir Mikrochir
Plast Chir 1994 Mar;26(2):84-90 |
|
Comment on:
·
· Handchir Mikrochir
Plast Chir. 1989 Nov;21(6):315-7.
[Functional follow-up of combined musculocutaneous
tensor fasciae latae and rectus
femoris flap repair. Supplementary
information on the Handchir. Mikrochir. Plast.
Chir. 21 (1989) 315-317 contribution]
[Article in German]
Bochdansky TL, Zauner-Dungl A, Kollmitzer J, Piza-Katzer H.
Universitatsklinik fur Physikalische Medizin und Rehabilitation, Universitat
Wien.
As a supplement to our publication in the
Journal Handchirurgie, Mikrochirurgie,
Plastische Chirurgie 21
(1989) 315-317, we would like to report a five-year follow up of a patient with
recurrent sigmoid carcinoma, infiltrating all layers of the abdominal wall.
Treatment was by radical tumor excision and reconstruction with a combined
tensor fasciae latae and rectus
femoris flap. Abdominal wall, hip, and knee functions
were evaluated by gait-analysis (Motion Analysis Corporation AMTI) and dynamometry (Cybex 6000). The
dynamometry of knee motion showed a slight deficit of the operated side
regarding the parameters of strength-endurance as well as work-recovery. All
other parameters (peak-torque) were equal for both sides corresponding to the
activities of daily living of the patient. Gait-analysis showed a reduced
rotation of the pelvis as well as a functional deficit of extension of the knee
during stance and swing phase. We can document a good functional result in all
motions without major impairment of every-day activities.
Publication Types:
· ·
Comment
PMID: 8020853 [PubMed - indexed for MEDLINE]
|
21: J
Sports Med Phys Fitness 1993 Dec;33(4):359-66 |
|
Ground reaction forces in high impact and low impact aerobic dance.
Michaud TJ, Rodriguez-Zayas J,
Armstrong C, Hartnig M.
Department of Health Promotion and Human Performance,
The purpose of this study was to compare ground reaction forces (vertical and
lateral) produced during commonly used high and low impact aerobic dance
maneuvers. Eight experienced aerobic dance instructors were the volunteer
subjects. During the first session, three subjects were videotaped performing
10 high and 10 low impact maneuvers that they commonly used in their own class
routines. Seven of the high and nine of the low impact maneuvers were then
selected and used in sessions 2 and 3. During the second session, all subjects
became proficient in performing the chosen maneuvers to music while striking an
AMTI force platform with the
right foot. During the third session, ground reaction force data generated
during footstrike were recorded for each movement. Of
the maneuvers examined, 5 high and four low impact maneuvers were used in the
data analysis. It was found that maximum vertical active peak and vertical
impact peak forces were lower for the low impact maneuvers. Maximum lateral
active peak and lateral impact peak forces were similar and highly variable in
magnitude for the 2 types of dance. The lower vertical loads produced in low
impact dancing may make this type of dance better for minimizing lower
extremity overuse injuries in aerobic dance. However, there does not seem to be
any advantage in emphasizing the use of low impact dance for minimizing lower
extremity injuries that evolve from lateral shear forces.
PMID: 8035584 [PubMed - indexed for MEDLINE]
|
22: Orthopedics
1993 Aug;16(8):875-9 |
|
Gait analysis of dysvascular below-knee and contralateral through-knee bilateral amputees: a
preliminary report.
Pinzur MS, Smith D, Tornow D, Meade K, Patwardhan A.
STAMP (Special Team for Amputations, Mobility, Prosthetics/Orthotics),
Four elderly peripheral vascular insufficiency below-knee amputees, average age
58, underwent contralateral through-knee amputation
for gangrene. All four became household ambulators
with end-weight bearing designed prosthetic sockets and four-bar linkage knees.
Gait analysis was performed with two AMTI
(
PMID: 8415271 [PubMed - indexed for MEDLINE]
|
23: Scand
J Rheumatol 1992;21(6):297-301 |
|
Postural control, muscle function and psychological factors in rheumatoid
arthritis. Are there any relations?
Ekdahl C.
Department of Physical Therapy,
The aim of the present study was to relate postural control, as measured on a quantitative
test battery as standing balance on an AMTI force platform, to results of muscle function of the lower
extremities, aerobic capacity, disease characteristics, attitudes revealing
anxiety, and demographic variables in patients with rheumatoid arthritis (RA).
A group of 61 patients with RA was investigated. Multiple regression analyses,
using both the stepwise and the backward elimination method, were employed for
length of sway path in two-leg standing looking straight ahead and blindfolded
as dependent variables. The results revealed postural control in two-leg
standing looking straight ahead to be highly related to age and sex but also to
isokinetic endurance and to anxiety. In the model,
55% of the variance was explained by these variables at a significance level of
p = 0.05. Characteristics of the RA disease, such as c-reactive
protein and joint-mobility did not play any major role in explaining postural
control.
PMID: 1475640 [PubMed - indexed for MEDLINE]
|
24: J Formos Med Assoc 1991 Feb;90(2):160-6 |
|
Gait analysis after total knee replacement for
degenerative arthritis.
Chen
PQ, Cheng CK, Shang HC, Wu JJ.
Department of Orthopedic
Surgery and Biomedical Engineering,
Using quantitative gait analysis and clinical evaluation, the functional
results of 18 total knee replacement (TKR) in 13
patients who had o