THE KNEE KINEMATICAL COORDINATION INVESTIGATION OF AN IMC CHILD DURING GAIT

International audienceCerebral palsy patients (cerebral infirm motor or IMC in French) present kinematical and kinetic differences with normal subjects and between their own left/right sides. These kinematical differences can be in relation with segmental coordination differences. The aim of this study is to characterize such segmental organization between the shank and the thigh for a cerebral palsy child in order to compare this coordination between left/right sides with the method of relative phase. A population of healthy subject let to validate our method with Byrne et al.'s results [1]. A young cerebral palsy child constitutes our clinical population for this study. A motion capture system (Vicon250) was used in order to capture movements of shank and thigh in sagittal plane. All the subjects walk at their self-selected speed along a horizontal walkway (9m). The angular position and angular velocity (calculated from position) of the shank and the thigh are computed as Byrne et al. After validation of our healthy results with Byrne et al's ones, we can describe the patient's curves. For him, the same path is observed between left and right sides. However, right side globally leads the left side. An important part of the stance phase presents the same temporal organization between these two sides

Muscle activation during gait in children with Duchenne muscular dystrophy

The aim of this prospective study was to investigate changes in muscle activity during gait in children with Duchenne muscular Dystrophy (DMD). Dynamic surface electromyography recordings (EMGs) of 16 children with DMD and pathological gait were compared with those of 15 control children. The activity of the rectus femoris (RF), vastus lateralis (VL), medial hamstrings (HS), tibialis anterior (TA) and gastrocnemius soleus (GAS) muscles was recorded and analysed quantitatively and qualitatively. The overall muscle activity in the children with DMD was significantly different from that of the control group. Percentage activation amplitudes of RF, HS and TA were greater throughout the gait cycle in the children with DMD and the timing of GAS activity differed from the control children. Significantly greater muscle coactivation was found in the children with DMD. There were no significant differences between sides. Since the motor command is normal in DMD, the hyper-activity and co-contractions likely compensate for gait instability and muscle weakness, however may have negative consequences on the muscles and may increase the energy cost of gait. Simple rehabilitative strategies such as targeted physical therapies may improve stability and thus the pattern of muscle activity

Étude des adaptations locomotrices lors d'un portage dorsal chez l'adolescent

Load carriage corresponds to a courant practice, especially for adolescents who use to carry a schoolbag. This load carriage entails several adaptations (kinematical, physiological...). The aim of this work is to quantify adaptations during adolescents schoolbag carrying. First part of this study is based on sociological analysis (type of schoolbag, method of carriage, weight of schoolbag...). This lets to establish the principal particularities of schoolbag carrying and a classification of population with these sociological parameters. In second part, the movement analysis has been focused on coordination and electromygraphy on lower limbs. The studied conditions are: unload, 10% bodyweight and 20% bodyweight. The biomechanical results show two important results. On one hand, the results show an adaptation with same amplitude for both the load carriage conditions. On other hand, according to individuals, this adaptation can be more or less important: this result shows different classes that depend on gait clusters, movements of bag, anthropology of subject. The study is completed with a muscular activity analysis on the main muscles of ankle. The muscular contraction pattern is studied with several approaches: characteristic instants, envelope of signal and co-contraction. The heavier the bag is, the longer the contractions are, without inducing co-contraction of the muscles studiedLe portage d'une charge est une pratique courante notamment pour les adolescents amenés à porter dorsalement un sac scolaire. Le portage est susceptible d'induire plusieurs adaptations (cinématiques, physiologiques...). L'objectif de ce travail est de rechercher des indices d'adaptation lors d'un portage de sac scolaire chez l'adolescent. Une première partie de la thèse est basée sur une analyse sociologique. Elle vise à établir les principales particularités du portage d'un sac scolaire au quotidien (poids porté, habitudes de portage...), et à établir des classes d'individus à partir de ces paramètres sociologiques. La seconde partie de la thèse s'intéresse aux conséquences du portage sur la coordination des membres inférieurs par une approche biomécanique et physiologique. Les conditions de portage sont : aucune charge, 10% et 20% de la masse corporelle du sujet. Les résultats de l'étude biomécanique témoignent, d'une part, d'une adaptation de la coordination du même ordre pour les deux charges. D'autre part, selon l'individu, cette adaptation varie en fonction de la charge : il existe donc des classes d'adaptations. Ces classes sont en relation avec le type de marche du sujet, les mouvements du sac lors de l'étude, la morphologie du sujet. L'étude est complétée par une analyse des activités musculaires des principaux muscles agissant sur la cheville. Le " pattern " musculaire est étudié sous plusieurs approches : les instants de début et fin de contraction, l'enveloppe du signal, la co-contraction. Plus la charge portée est élevée, plus les contractions ont une durée importante, sans favoriser la co-contraction des muscles antagonistes étudiés

Can external work during walking in scoliosis patients be estimated from spatiotemporal parameters?

Background: Patients with scoliosis present gait impairments compared to healthy subjects. Clinically, spine deformity is evaluated with Cobb angle, a standard measurement to determine and track the progression of scoliosis. Scoliosis is a biomechanical trouble, dependant of external forces and muscular activity. External work is currently analyzed in patients with scoliosis because this work sums up consequences and evolutions of spine deformity. Habitually, biomechanics approach is used to compute this work. For asymptomatic subjects, a regression model let to compute external work. So, considering the area of research to facilitate the follow-up at lower cost, this regression function could be applied to patients with scoliosis but need to be validated. Research question: can external work during walking in scoliosis patients be estimated from spatiotemporal parameters with a regression model? Method: This retrospective study included twenty untreated patients with idiopathic scoliosis and sixteen asymptomatic participants. We used a regression model defined in case of asymptomatic subjects in literature and proposed a new specific model in case of patients with scoliosis. Findings: The external work in patients with scoliosis calculated with the Wirta's regression eq. (0.23 ± 0.04 J.kg-1.m-1) was underestimated compared to the external work calculated using a biomechanical method (0.33 ± 0.06 J.kg-1.m-1). A new regression model including Cobb angle and spatio-temporal parameter presents a high coefficient of determination. Interpretation: In opposition to biomechanical method, our new model let to compute external work without expensive gait laboratory. This specific model is more reliable than the model developed from asymptomatic subjects.</p

Adaptations segmentaires lors du port de charge chez l'adolescent

Conséquences du port d'une charge dorsale (sac à dos) chez l'adolescent : adaptations biomécaniques, d'ordre cinématique et affectant la coordination au niveau des membres inférieurs lors de la marche

Is lower motor control on the trunk in patients with non-specific chronic low back pain linked to difficulties in working despite functional restoration programs?

International audienceIntroductionIn the case of patients with Chronic Low Back Pain (cLBP), Functional Restoration Programs (FRP) can improve their condition. Chronicity may reoccur and lead to difficulties in the ability to work related to Fear-Avoidance Beliefs, which may depend on lower motor control. Rationale of the study: Whereas a limited clinical scale evaluates these beliefs, our study is justified by the search to define motor control parameters that can be used as quantified indicators of fear-avoidance beliefs associated with work activityAimThe aim of this study is to explore whether difficulty in working one year after participating in the FRP was related to low motor control in patients with cLBP.MethodsTwo groups were defined as: “the patients who could work one year after FRP” (called W-Group) and “the patients who could not work one year after FRP because of cLBP” (called NW-Group). The clinical analysis is based on the assessment of pain intensity and the Fear-Avoidance Belief Questionnaire (or FABQ). Gait stability and coefficients of attenuation on four back levels were considered.ResultsThe NW-Group had a significantly higher FABQ score than the W-Group one year after FRP (p = 0.02) without any difference regarding pain intensity (p = 0.31). The NW-Group (0.11 ± 0.02) presented significantly higher RMS values for the low back in the anteroposterior axis than the W-group (0.09 ± 0.01), showing lower gait stability in the NW-group.DiscussionMotor control parameters reveal significant differences between these groups.ConclusionsMotor control and fear-avoidance beliefs are associated with work

Alpha-phase synchrony EEG training for multi-resistant chronic low back pain patients: an open-label pilot study

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Correlations between muscle activation, kinematics and functional status in children with DMD.

<p>Correlations between muscle activation, kinematics and functional status in children with DMD.</p

Values of selected variables.

<p>Values of selected variables.</p

Illustration of co-activation index (CI) calculation.

<p>The percentage of the gait cycle is presented on the X-axis (0: heel strike, 100: the following ipsilateral heel strike) and the normalized amplitude of EMG activity on the Y-axis (0–1). Lines represent the mean linear envelope of muscle 1 activation. Dashed lines represent the mean linear envelope of muscle 2 activation. Black color represent muscle activation in the control group. Blue color represent muscle activation in one child with DMD. The calculation index involved overlapping the linear envelopes of muscle 1 and muscle 2, calculating the area of overlap and dividing by the number of data points. Areas of coactivation are represented in grey (control group) and in blue (DMD patient).</p