| 1. |
|
|
| 2. |
- Bartonek, Asa, et al.
(författare)
-
A new carbon fibre spring orthosis for children with plantarflexor weakness
- 2007
-
Ingår i: Gait & Posture. - : Elsevier BV. - 0966-6362 .- 1879-2219. ; 25:4, s. 652-656
-
Tidskriftsartikel (refereegranskat)abstract
- We tested a new orthosis with a carbon fiber spring constructed to enable energy storing during increasing dorsiflexion in mid-stance, and to use the energy at the end of stance phase to aid push-off. The orthosis was tested on children with plantarflexor weakness due to motor disorders. All subjects were tested with 3D gait analysis with both the new orthosis and with their regularly used orthosis. In this technical note, the results of three individuals are reported. The preliminary findings show increased dorsiflexion, altered knee kinematics and improved kinetic and temporo-spatial parameters. Although the carbon spring orthosis influenced the subjects' gait in different ways, we conclude that the tested subjects with plantarflexion weakness benefit from the carbon fiber spring orthoses during walking. The parents' and children's subjective impressions as acquired from a questionnaire were also positive.
|
|
| 3. |
- Bartonek, A., et al.
(författare)
-
The influence of spasticity in the lower limb muscles on gait pattern in children with sacral to mid-lumbar myelomeningocele : a gait analysis study
- 2005
-
Ingår i: Gait & Posture. - : Elsevier BV. - 0966-6362 .- 1879-2219. ; 22:1, s. 10-25
-
Tidskriftsartikel (refereegranskat)abstract
- Gait analysis and recording of standing position were performed in 38 ambulatory children with myelomeningocele. Thirty-four were independent ambulators and four required a walking aid. All subjects were assigned one of four muscle function groups based on muscle strength. They were also divided into subgroups based on the distinction between flaccid and spastic paresis in the lower limb joints. A comparison was made between the gait pattern of the children with spasticity and that of the children with flaccid paresis in each muscle function group. Spasticity in only the ankle joint muscles influenced the subject's gait and standing position compared to the subgroups with a flaccid paresis. Even larger deviations in gait and standing position were observed when spasticity occurred in muscles at the knee and hip joints. When setting ambulatory goals the presence of additional neurological symptoms such as spasticity and inadequate balance should be taken into consideration.
|
|
| 4. |
- Benoit, Daniel L, et al.
(författare)
-
Effect of skin movement artifact on knee kinematics during gait and cutting motions measured in vivo
- 2006
-
Ingår i: Gait & Posture. - : Elsevier. - 0966-6362 .- 1879-2219. ; 24:2, s. 152-164
-
Tidskriftsartikel (refereegranskat)abstract
- Eight healthy male subjects had intra-cortical bone-pins inserted into the proximal tibia and distal femur. Three reflective markers were attached to each bone-pin and four reflective markers were mounted on the skin of the tibia and thigh, respectively. Roentgen-stereophotogrammetric analysis (RSA) was used to determine the anatomical reference frame of the tibia and femur. Knee joint motion was recorded during walking and cutting using infrared cameras sampling at 120Hz. The kinematics derived from the bone-pin markers were compared with that of the skin-markers. Average rotational errors of up to 4.4 degrees and 13.1 degrees and translational errors of up to 13.0 and 16.1mm were noted for the walk and cut, respectively. Although skin-marker derived kinematics could provide repeatable results this was not representative of the motion of the underlying bones. A standard error of measurement is proposed for the reporting of 3D knee joint kinematics.
|
|
| 5. |
- Coury, H. J. C. G., et al.
(författare)
-
Change in knee kinematics during gait after eccentric isokinetic training for quadriceps in subjects submitted to anterior cruciate ligament reconstruction
- 2006
-
Ingår i: Gait & Posture. - : Elsevier BV. - 1879-2219 .- 0966-6362. ; 24:3, s. 370-374
-
Tidskriftsartikel (refereegranskat)abstract
- Knee kinematics after anterior cruciate ligament (ACL) reconstruction is of interest in studies evaluating the effect of training programs. Many studies have addressed knee flexion/extension but not valgus/varus movements. Considering that joint stability is a major concern in ACL reconstruction surgery, movements occurring in the frontal plane of the knee also deserve attention. Knee extensor torque was analyzed by an isokinetic dynamometer and the angular amplitudes and velocities of flexion/extension and valgus/varus movements were analyzed by goniometry during gait 9 months after ACL reconstruction. The analysis was repeated after 3 months of eccentric isokinefic training of the quadriceps in five patients. The gait pattern was also recorded for 10 healthy controls. The knee extensor torque and flexion/extension range of movement during gait increased significantly after training. However, an unexpectedly increased valgus, most pronounced during the swing phase, which may imply adverse effects on the knee, was also observed in the ACL reconstructed knee. The recorded valgus angles may however be overestimated due to crosstalk. Thus, the extent of the increased valgus, as well as the mechanisms involved and the functional and clinical implications, need clarification before eccentric training after ACL reconstruction can be generally recommended. (C) 2005 Elsevier B.V. All rights reserved.
|
|
| 6. |
- Gomez, S., et al.
(författare)
-
Differences between body movement adaptation to calf and neck muscle vibratory proprioceptive stimulation
- 2009
-
Ingår i: Gait & Posture. - : Elsevier BV. - 1879-2219 .- 0966-6362. ; 30:1, s. 93-99
-
Tidskriftsartikel (refereegranskat)abstract
- Adaptation is essential in maintaining stability during balance-challenging situations. We studied, ill standing subjects with eyes open and closed, adaptive responses of the anteroposterior head, shoulder, hip and knee movements: gastrocnemius and tibialis anterior EMG activity and anteroposterior body Posture when proprioceptive information from the neck or calf muscles underwent vibratory perturbations. After 30 s of quiet stance, vibratory stimuli were applied repeatedly for 200 s, and adaption to stimulation was analyzed in four successive 50 s periods. Repeated neck and calf vibration significantly increased linear body movement variance at all recorded sites (p < 0.001, except neck stimulation with eyes closed, EC-neck), increased tibialis anterior (p < 0.001, except EC-neck) and gastrocnemious muscle activity (p < 0.001). Most body movement variances and tibialis anterior EMG activity decreased significantly over time (most p-values < 0.01 or lower) and overall, the body leaning forward increased from 5.5 degrees to 6.5 degrees (p < 0.01). The characteristics of the responses were influenced by vision and site of vibration, e.g., neck vibration affected body Posture more rapidly than calf vibration. Our findings support the notion that proprioceptive perturbations have different effects in terms of nature, degree and adaptive response depending on site of vibratory proprioceptive stimulation, a factor that needs consideration in clinical investigations and design of rehabilitation programs. (C) 2009 Elsevier B.V. All rights reserved.
|
|
| 7. |
- Gullstrand, Lennart, et al.
(författare)
-
Measurements of vertical displacement in running, a methodological comparison
- 2009
-
Ingår i: Gait & Posture. - : Elsevier BV. - 0966-6362 .- 1879-2219. ; 30:1, s. 71-75
-
Tidskriftsartikel (refereegranskat)abstract
- The aim was (1) to evaluate measurements of vertical displacements (V-disp) of a single point on sacrum as an estimate of the whole body centre of mass (CoM) V-disp during treadmill running and (2) to compare three methods for measuring this single point. These methods were based on a position transducer(PT), accelerometers (AMs) and an optoelectronic motion capture system. Criterion method was V-disp of the whole body CoM measured with the motion capture system. Thirteen subjects ran at 10, 12, 14, 16. 18, 20 and 22 km h(-1) with synchronous recordings with the three methods. Four measurements of the (V-disp) were derived: (1) V-disp of CoM calculated from a segment model consisting of 13 segments tracked with 36 reflective markets, (2) V-disp of the sacrum recorded with the PT, (3) V-disp of the sacrum Calculated from the AM, and (4) V-disp of the sacrum calculated as the mid point of two reflective markets (sacrum marker, SM) attached at the level of the sacral bone. The systematic discrepancy between the Measurements of sacrum V-disp and CoM V-disp varied between 0 and 1.5 mm and decreased with increasing running velocity and decreasing step duration. PT and SM measurements showed strong correlation, whereas the AM showed a variability increasing with velocity. The random discrepancy within each Subject was 7 mm for all three methods. In conclusion single-point recordings of the sacrum V-disp may be used to monitor changes in V-disp of CoM during treadmill running.
|
|
| 8. |
- Gutierrez, Elena M, 1973-, et al.
(författare)
-
Kinetics of compensatory gait in persons with myelomeningocele
- 2005
-
Ingår i: Gait & Posture. - : Elsevier BV. - 0966-6362 .- 1879-2219. ; 21:1, s. 12-23
-
Tidskriftsartikel (refereegranskat)abstract
- This study investigated the kinetic strategy and compensatory mechanisms during self-ambulatory gait in children with lumbo-sacral myelomeningocele. Thirty-one children with mid-lumbar to low-sacral myelomeningocele who walked without aids and 21 control children were evaluated by three-dimensional gait analysis. Joint moments in all planes at the hip and knee and sagittal moments at the ankle, as well as joint power and work done at all three joints, were analyzed. Joint moment capacity lost due to plantarflexor and dorsiflexor weakness was provided instead by orthotic support, but other joints were loaded more to compensate for the weakness at the ankles and restricted ankle motion. Subjects with total plantarflexor and dorsiflexor paresis and strength in the hip abductors had more knee extensor loading due to plantarflexor weakness and dorsiflexion angle of the orthotic, ankle joint. The subjects with orthoses also generated more power at the hip to supplement the power generation lost to plantarflexor weakness and fixed ankles. The most determinant muscle whose paresis changes gait kinetics was the hip abductor. Hip abductor weakness resulted in a characteristic pattern where the hips displayed an eccentric adduction moment, mediating energy transfer into the lower limbs, and the hips replaced the knees as power absorbers in early stance. Joint moment, power and work analyses complement a kinematic analysis to provide a complete picture of how children who have muscle paresis recruit stronger muscle groups to compensate for weaker ones.
|
|
| 9. |
- Halvorsen, Kjartan, et al.
(författare)
-
Minimal marker set for center of mass estimation in running
- 2009
-
Ingår i: Gait & Posture. - : Elsevier BV. - 0966-6362 .- 1879-2219. ; 30:4, s. 552-555
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose was to study the validity of a recently proposed method [Forsell C, Halvorsen K. A method for determining minimal sets of markers for the estimation of center of mass, linear and angular momentum. journal of Biomechanics 2009;42(3):361-5] for estimating the trajectory of the whole-body center of mass (CoM) in the case of running at: velocities ranging from 10 to 22 km h(-1). The method gives an approximation to the CoM using the position of fewer markers on the body than the standard method of tracking each segment of the body. Fourteen male athletes participated. A standard method for determining the CoM from a model of 13 segments and using the position of 36 markers was used as reference method. Leave-one-out cross-validation revealed errors that decreased with increasing number of markers used in the approximative method. Starting from four markers, the error in absolute position of the CoM decreased from 15 mm to 3 mm in each direction. For the velocity of the CoM the estimation bias was neglectable, and the random error decreased from 0.15 to 0.05 m s(-1). The inter-subject and intra-subject variability in the estimated model parameters increased with increasing number of markers. The method worked well also when applied to running at velocities outside the range of velocities in the data used to determine the model parameters. The results indicate that a model using 10 markers represents a good trade-off between simplicity and accuracy, but users must take into account requirements of their specific applications.
|
|
| 10. |
- Harringe, M L, et al.
(författare)
-
Postural control measured as the center of pressure excursion in young female gymnasts with low back pain or lower extremity injury.
- 2008
-
Ingår i: Gait & Posture. - : Elsevier BV. - 0966-6362 .- 1879-2219. ; 28:1, s. 38-45
-
Tidskriftsartikel (refereegranskat)abstract
- Gymnasts are known to practice and compete although suffering from injuries and pain. Pain may change strategies for postural control. The primary aim of the present study was to investigate how center of pressure (COP) measurements are influenced by low back pain and lower extremity injury in top-level female gymnasts. A secondary aim was to study the reliability of these measurements using a test-retest design, and how this depends on the duration of the test. Fifty-seven top-level gymnasts were included in four groups: non-injured (NI, n=18), low back pain (LBP, n=11), lower extremity injury (LEI, n=17) and a multiple injury group (MI, n=11). COP excursion during quiet stance was measured on a force platform, during 120s: (1) hard surface/eyes open, (2) hard surface/eyes closed, (3) foam surface/eyes open and (4) foam surface/eyes closed. The COP excursion increased, for all groups, during the foam surface/eyes closed measurement compared to the other three tests. Furthermore, the LBP group showed a 49% (p=0.01) larger COP area compared to the LEI group in the foam surface/eyes closed condition. Measurements on foam surface were in general more reliable than tests on hard surface and tests with eyes closed were more reliable than tests with eyes open. Tests during 120s were in most cases more reliable than tests during 60s. In conclusion the COP excursion is influenced by injury location. Quiet stance measurements on foam surface with eyes closed seems to be reliable and sensitive in young female gymnasts.
|
|
| 11. |
|
|
| 12. |
|
|
| 13. |
- Heintz, Sofia, et al.
(författare)
-
Static optimization of muscle forces during gait in comparison to EMG-to-force processing approach
- 2007
-
Ingår i: Gait & Posture. - : Elsevier BV. - 0966-6362 .- 1879-2219. ; 26:2, s. 279-288
-
Tidskriftsartikel (refereegranskat)abstract
- Individual muscle forces evaluated from experimental motion analysis may be useful in mathematical simulation, but require additional musculoskeletal and mathematical modelling. A numerical method of static optimization was used in this study to evaluate muscular forces during gait. The numerical algorithm used was built on the basis of traditional optimization techniques, i.e., constrained minimization technique using the Lagrange multiplier method to solve for constraints. Measuring exact muscle forces during gait analysis is not currently possible. The developed optimization method calculates optimal forces during gait, given a specific performance criterion, using kinematics and kinetics from gait analysis together with muscle architectural data. Experimental methods to validate mathematical methods to calculate forces are limited. Electromyography (EMG) is frequently used as a tool to determine muscle activation in experimental studies on human motion. A method of estimating force from the EMG signal, the EMG-to-force approach, was recently developed by Bogey et al. [Bogey RA, Perry J, Gitter AJ. An EMG-to-force processing approach for determining ankle muscle forcs during normal human gait. IEEE Trans Neural Syst Rehabil Eng 2005;13:302-10] and is based on normalization of activation during a maximum voluntary contraction to documented maximal muscle strength. This method was adapted in this study as a tool with which to compare static optimization during a gait cycle. Muscle forces from static optimization and from EMG-to-force muscle forces show reasonably good correlation in the plantarflexor and dorsiflexor muscles, but less correlation in the knee flexor and extensor muscles. Additional comparison of the mathematical muscle forces from static optimization to documented averaged EMG data reveals good overall correlation to patterns of evaluated muscular activation. This indicates that on an individual level, muscular force patterns from mathematical models can arguably be more accurate than from those obtained from surface EMG during gait, though magnitude must still be validated.
|
|
| 14. |
- Höglund, Anette, et al.
(författare)
-
Influence of dual tasks on sitting postural sway in children and adolescents with myelomeningocele
- 2009
-
Ingår i: Gait & Posture. - : Elsevier BV. - 0966-6362 .- 1879-2219. ; 30:4, s. 424-430
-
Tidskriftsartikel (refereegranskat)abstract
- Performing dual tasks, e.g. cognitive and motor tasks simultaneously, may be especially challenging to children with motor disorders. Changes in postural sway have been used to evaluate the effect of dual tasks. Increases in postural sway frequency and concurrent decrease in sway amplitude have been interpreted as tighter control of postural sway. The purpose of this study was to analyze postural sway under single and dual task conditions, while sitting. Thirteen children and adolescents with myelomeningocele and a matched control group were included in the study. The participants performed two single and two dual tasks each. The single task was a sitting still task. The dual tasks were one visual-spatial task and one executive task while simultaneously sitting still. Amplitude, velocity and frequency of center of pressure displacement of postural sway were analyzed between tasks and between groups. The results of the cognitive tasks were analyzed as well. The results revealed different patterns in the groups. During single tasks, the MMC group displayed significantly lower frequencies and velocities of center of pressure displacement compared to the control group. Adding the visual-spatial task influenced postural sway significantly in the control group, while adding the executive task influence the postural sway significantly in the MMC group. The myelomeningocele group confirmed our clinical experience by performing the cognitive tasks slowly but accurately. Further studies are needed to evaluate whether motor function, sensory function, structural anomalies in the brain or any other causes, separately or together, may explain the observed differences in the groups.
|
|
| 15. |
- Kangas, Maarit, et al.
(författare)
-
Comparison of low-complexity fall detection algorithms for body attached accelerometers
- 2008
-
Ingår i: Gait & Posture. - : Elsevier BV. - 0966-6362 .- 1879-2219. ; 28:3, s. 285-291
-
Tidskriftsartikel (refereegranskat)abstract
- The elderly population is growing rapidly. Fall related injuries are a central problem for this population. Elderly people desire to live at home, and thus, new technologies, such as automated fall detectors, are needed to support their independence and security. The aim of this study was to evaluate different low-complexity fall detection algorithms, using triaxial accelerometers attached at the waist, wrist, and head. The fall data were obtained from standardized types of intentional falls (forward, backward, and lateral) in three middle-aged subjects. Data from activities of daily living were used as reference. Three different detection algorithms with increasing complexity were investigated using two or more of the following phases of a fall event: beginning of the fall, falling velocity, fall impact, and posture after the fall. The results indicated that fall detection using a triaxial accelerometer worn at the waist or head is efficient, even with quite simple threshold-based algorithms, with a sensitivity of 97-98% and specificity of 100%. The most sensitive acceleration parameters in these algorithms appeared to be the resultant signal with no high-pass filtering, and the calculated vertical acceleration. In this study, the wrist did not appear to be an applicable site for fall detection. Since a head worn device includes limitations concerning usability and acceptance, a waist worn accelerometer, using an algorithm that recognizes the impact and the posture after the fall, might be optimal for fall detection.
|
|
| 16. |
- Kangas, Maarit, et al.
(författare)
-
Sensitivity and specificity of fall detection in people aged 40 years and over
- 2009
-
Ingår i: Gait & Posture. - : Elsevier BV. - 0966-6362 .- 1879-2219. ; 29:4, s. 571-574
-
Tidskriftsartikel (refereegranskat)abstract
- About one third of home-dwelling people over 65 years of age fall each year. Falling, and the fear of falling, is one of the major health risks that affects the quality of life among older people, threatening their independent living. In our pilot study, we found that fall detection with a waist-worn triaxial accelerometer is reliable with quite simple detection algorithms. The aim of this study was to validate the data collection of a new fall detector prototype and to define the sensitivity and specificity of different fall detection algorithms with simulated falls from 20 middle-aged (40-65 years old) test subjects. Activities of daily living (ADL) performed by the middle-aged subjects, and also by 21 older people (aged 58-98 years) from a residential care unit, were used as a reference. The results showed that the hardware platform and algorithms used can discriminate various types of falls from ADL with a sensitivity of 97.5% and a specificity of 100%. This suggests that the present concept provides an effective method for automatic fall detection.
|
|
| 17. |
- Nilsson, Kjell-Åke, 1956-
(författare)
-
Detecting post-operative change in gait function using principal component analysis in subjects with cerebral palsy
- 2006
-
Ingår i: Gait & Posture. - : Elsevier. - 0966-6362 .- 1879-2219. ; 24, s. 152-153
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Principal components analysis is a multivariate statistical method that has been used in gait analysis. One example of use of the method is the production of The Gillette Gait Index. This index, indicating normality in gait function, has been presented and validated by previous authors. According to suggestions made by these authors, the index could potentially be used to evaluate change in gait function after surgical intervention in subjects with cerebral palsy. The Gillette Gait Index was calculated using principal components analysis for nineteen individuals with cerebral palsy (5 hemiplegics, 13 diplegics and 1 quadriplegic; mean age 16 years, range 10-31 years) in a retrospective study. The change in index value per individual from the pre- to the postoperative situations was compared to the evaluation of change made by an experienced clinician. Agreement was evaluated using Cohen´s kappa ( k ), resulting in a value of k=0.406, which is usually considered to be a fair to moderate level of agreement.
|
|
| 18. |
- Patel, Mitesh, et al.
(författare)
-
The effect of foam surface properties on postural stability assessment while standing.
- 2008
-
Ingår i: Gait & Posture. - : Elsevier BV. - 1879-2219 .- 0966-6362. ; 28, s. 649-656
-
Tidskriftsartikel (refereegranskat)abstract
- A common assessment of postural control often involves subjects standing on a compliant surface, such as a foam block, to make balance tests more challenging. However, the physical properties of the foam block used by different researchers can vary considerably. The objective of this study was to provide an initial approach for investigating whether two of the foam properties, i.e. density and elastic modulus, influenced recorded anteroposterior and lateral torque variance with eyes open and eyes closed. Thirty healthy adults (mean age 22.5 years) were assessed with posturography using three different types of foam block placed on a force platform. These blocks were categorised: firm foam, medium foam and soft foam by their elastic modulus. To investigate the spectral characteristics of recorded body movements, variance values were calculated for total movements, movements <0.1Hz and movements >0.1Hz. Results showed that anteroposterior and lateral torque variances >0.1Hz were larger when standing on the firm foam compared with medium and soft foam and in turn were larger on the medium foam compared with the soft foam with eyes closed. Moreover, GLM and correlation analysis demonstrated that the properties of the foam blocks affected anteroposterior torque variance >0.1Hz and lateral torque variance in all frequency ranges. In addition, the stabilising effect of vision in the anteroposterior direction had a greater influence when the subjects' stability was increasingly challenged by the support surface, as illustrated by the higher torque variance values. In conclusion, caution should be taken when analysing balance deficits with foam test setups, because the foam properties may influence the recorded body movements.
|
|
| 19. |
|
|
| 20. |
- Weiss, Rüdiger J., et al.
(författare)
-
Gait pattern in rheumatoid arthritis
- 2008
-
Ingår i: Gait & Posture. - Clare, Ireland : Elsevier. - 0966-6362 .- 1879-2219. ; 28:2, s. 229-234
-
Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to analyse kinematic and kinetic gait changes in rheumatoid arthritis (RA) patients in comparison to healthy controls and to examine whether levels of functional disability (Health Assessment Questionnaire (HAQ)-scores) were associated with gait parameters. Using a three-dimensional motion analysis system, kinematic and kinetic gait parameters were measured in 50 RA patients and 37 healthy controls. There was a significant reduction in joint motions, joint moments and work in the RA cohort compared with healthy controls. The following joint motions were decreased: hip flexion-extension range (Delta6 degrees ), hip abduction (Delta4 degrees ), knee flexion-extension range (Delta8 degrees ) and ankle plantarflexion (Delta10 degrees ). The following joint moments were reduced: hip extensor (Delta0.30Nm/kg) and flexor (Delta0.20Nm/kg), knee extensor (Delta0.11Nm/kg) and flexor (Delta0.13Nm/kg), and ankle plantarflexor (Delta0.44Nm/kg). Work was lower in hip positive work (Delta0.07J/kg), knee negative work (Delta0.08J/kg) and ankle positive work (Delta0.15J/kg). Correlations were fair although significant between HAQ and hip flexion-extension range, hip abduction, knee flexion-extension range, hip abductor moment, stride length, step length and single support (r=-0.30 to -0.38, p<0.05). Our findings suggest that RA patients have overall less joint movement and specifically restricted joint moments and work across the large joints of the lower limbs during walking than healthy controls. There were only fair associations between levels of functional disability and gait parameters. The findings of this study help to improve the understanding how RA affects gait changes in the lower limbs.
|
|
| 21. |
- Johansen, Kerstin, et al.
(författare)
-
Coordination in collaborative manufacturing mega-networks : a case study
- 2005
-
Ingår i: Journal of engineering and technology management. - : Elsevier BV. - 0923-4748 .- 1879-1719. ; 22:3, s. 226-244
-
Tidskriftsartikel (refereegranskat)abstract
- Collaborative manufacturing networks are becoming popular. Today, the scale of these networks can be enormous, and include a complex myriad of partners from numerous companies and organizations spanning several countries and even continents. This paper explores how these partners successfully coordinate projects through an investigation of one such “collaborative manufacturing mega-network” or CMMN in the commercial aerospace industry. The case is analyzed with the aid of the literary state-of-the-art, and a number of organizational, structural, and cultural issues are discussed including mass customization. Finally, some of the most important factors for the successful CMMN are presented.
|
|
