Fabrice Megrot

Publications

• Evaluating walking dynamic stability: A spatiotemporal parameters based score

  A. Gouelle, F. Mégrot, A. Yelnik, G.-F. Penneçot

  Annals of Physical and Rehabilitation Medicine. 10/2011; 54(S1-54):139.

• Simulated cerebral palsy gait patterns: The effects on joint and muscle activities

  T. Rezgui, F. Megrot, F. Marin

  Annals of Physical and Rehabilitation Medicine. 10/2011; 54(S1-54):146.
• 2.07

  Impact points

  Rectus Femoris Distal Tendon Resection Improves Knee Motion in Patients With Spastic Diplegia.

  Ana Presedo, Fabrice Megrot, Brice Ilharreborde, Keyvan Mazda, Georges-François Penneçot

  Clinical orthopaedics and related research. 08/2011;

  BACKGROUND: Children with spastic diplegia frequently show excessive knee extension (stiff-knee gait) throughout swing phase, which may interfere with foot clearance. Abnormal rectus femoris activity is commonly associated with a stiff-knee gait. Rectus femoris transfer has been recommended to enhan... [more] BACKGROUND: Children with spastic diplegia frequently show excessive knee extension (stiff-knee gait) throughout swing phase, which may interfere with foot clearance. Abnormal rectus femoris activity is commonly associated with a stiff-knee gait. Rectus femoris transfer has been recommended to enhance knee flexion during swing. However, recent studies suggest the transfer does not generate a knee flexor moment but diminishes knee extension moment in swing and MRI studies show the transferred tendons can be constrained by scarring to underlying muscles. Thus, it is possible knee flexion would be improved by distal rectus release rather than transfer since it would not be adherent to the underlying muscles. QUESTIONS/PURPOSES: We therefore determined whether rectus femoris distal tendon resection improves knee ROM and kinematic characteristics of stiff-knee gait in patients with spastic diplegia. PATIENTS AND METHODS: We studied 45 patients who underwent rectus femoris distal tendon resection as a part of multilevel surgery. Rectus femoris procedures were indicated based on kinematic characteristics of stiff-knee gait. All patients were walkers and had a mean age at surgery of 13 years (range, 6-22 years). We obtained gait analyses before surgery and at mean 2-year followup. We based postoperative assessment on clinical evaluation and gait analysis data. RESULTS: At followup, rectus femoris distal tendon resection was associated with improved knee ROM and timing of peak knee flexion in swing, and the absolute values of peak knee flexion became normal for those patients who showed abnormal preoperative values. CONCLUSIONS: Kinematic parameters of stiff-knee gait improved after rectus femoris distal tendon resection. Given the preliminary nature of our report, we intend to study the same patients to assess outcomes at a longer followup. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
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  Validity of Functional Ambulation Performance Score for the evaluation of spatiotemporal parameters of children's gait.

  Arnaud Gouelle, Fabrice Megrot, Ana Presedo, Georges-Francois Pennecot, Alain Yelnik

  Journal of motor behavior. 02/2011; 43(2):95-100.

  Gait characteristics of a healthy adult population have been used to develop the Functional Ambulation Profile (FAP) score to evaluate gait in patients with neuromuscular or musculoskeletal involvement (A. J. Nelson, 1974). Further technological progress allowed a more precise recording of walk para... [more] Gait characteristics of a healthy adult population have been used to develop the Functional Ambulation Profile (FAP) score to evaluate gait in patients with neuromuscular or musculoskeletal involvement (A. J. Nelson, 1974). Further technological progress allowed a more precise recording of walk parameters and propitiated the development of the Functional Ambulation Performance Score (FAPS). The authors aimed to explore the evolution of the FAPS in healthy children to determine what the lower limit of age would be to ensure reliability of this score. Participants were 32 children with normal development. A GAITRite® walkway was used to log the spatiotemporal parameters. Compared with values obtained in adults, the average FAPS was significantly lower for children under 12 years old. The interparticipant variability was particularly high for the younger children and decreased with age. Similar trends were observed regarding the intraparticipant variability. In conclusion, the authors observed that the FAPS is not suitable to compare the gait of different children younger than 12 years old. At least, the adult standards used to calculate FAPS would need to be modified if the score has to be applied to a pediatric population.
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  Study of cerebral palsy jump gait with generic musculoskeletal modelling.

  T. Rezgui, F. Mégrot, F. Marin

  Computer Methods in Biomechanics and Biomedical Engineering. 09/2010; 13(4-1476-8259):125.

• Intégration des outils d’analyse de la marche dans la démarche thérapeutique lors du suivi longitudinal du patient PC

  A. Lucet, F. Mégrot, D. Gouraud

  Journal de Réadaptation Médicale Pratique et Formation en Médecine Physique et de Réadaptation. 09/2010; 30(3):115-123.
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  Movement-production strategy in tennis: a case study.

  Eric Gillet, David Leroy, Régis Thouvarecq, Fabrice Mégrot, Jean-François Stein

  Journal of strength and conditioning research / National Strength & Conditioning Association. 07/2010; 24(7):1942-7.

  The present case study fell within the framework of the "absolute approach of expertise" because it assesses a "truly exceptional individual" (Chi, MTH, Cambridge Handbook of Expertise and Expert Performance, London, United Kingdom: Cambridge University Press, 2006, pp. 121-130).... [more] The present case study fell within the framework of the "absolute approach of expertise" because it assesses a "truly exceptional individual" (Chi, MTH, Cambridge Handbook of Expertise and Expert Performance, London, United Kingdom: Cambridge University Press, 2006, pp. 121-130). This technique analysis examined the movement-production strategy used by a professional tennis player performing serve-return strokes. This research enabled us to establish the relation between tennis serve-return technique and successful performance. An optoelectronic system was used to capture and analyze the expert player's stroke production in a live situation to determine the temporal trajectory of the serve-return initiation movement. Some differences between the serve-return shots were observed concerning the occurrence time of the lateral racquet displacement, the amplitude of the racquet movement, and the average latency time. No difference was observed for the gravity center (GC) movements. Backhand, forehand, and reprogramming strokes were executed with a general constancy of occurrence and average times of the GC and racquet movements. This expert player used a predictive movement-production strategy specified by a high level of reproducibility of the movement with nevertheless adaptive skills during reprogramming strokes. This adaptation supported either the development of highly consistent motor programs or the use of a more flexible strategy based on the perception-action coupling.
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  Changes in phase space during learning an unstable balance.

  Fabrice Mégrot, Benoît G Bardy

  Neuroscience letters. 08/2006; 402(1-2):17-21.

  Six participants learned to maintain an unstable balance on a stabilometer, during 6 consecutive days of practice (total of 90 trials). Lateral and angular variations of body segments and body center of mass were analysed, and their evolution over the learning period was compared to the changes in d... [more] Six participants learned to maintain an unstable balance on a stabilometer, during 6 consecutive days of practice (total of 90 trials). Lateral and angular variations of body segments and body center of mass were analysed, and their evolution over the learning period was compared to the changes in dimensional variables capturing the structure of the movement itself (embedding and correlation dimension, largest Lyapunov exponent). Results indicated that (i) learning occurred, (ii) was accompanied by persistence in the dimension of the movement, and (iii) by a reduction in chaotic (or stochastic) components. Compared to other results in the learning literature, these results suggest that dimensional changes over learning are task-specific.

• Influence de l’expertise sportive sur le maintien de l’équilibre précaire : une étude dynamique

  Mégrot, Bardy

  Bulletin de psychologie. 09/2005; 58:475.
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  Modelling and simulation of face to face motoractivities: A preliminary study

  G. Dietrich, J. Bredin, S. Hanneton, F. Mégrot, Y. Kerlirzin

  Gait & Posture. 06/2005; 21:138.
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  Does the rhythm of walking influence time perception?

  A. Sainthuile, F. Mégrot, I. Israël

  Gait & Posture. 06/2005; 21(S1-21):56.
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  Dimensionality and the dynamics of human unstable equilibrium.

  Fabrice Mégrot, Benoît Bardy, Gilles Dietrich

  Journal of motor behavior. 01/2003; 34(4):323-8.

  Maintaining an unstable equilibrium requires that multiple joints be coordinated so that the center of mass is kept above the base of support. The authors' aim in the present study was to discover the underlying dynamics of local (foot, hip, or head) and global (center of mass) components involv... [more] Maintaining an unstable equilibrium requires that multiple joints be coordinated so that the center of mass is kept above the base of support. The authors' aim in the present study was to discover the underlying dynamics of local (foot, hip, or head) and global (center of mass) components involved in balance control and how those dynamics are affected by changes in the available information. Participants (N = 6) had to maintain their balance on an unstable platform. Using dimensional analyses (largest Lyapunov exponent and correlation dimension), the authors examined the active degrees of freedom involved in balance control. Results indicated a similarity in dimension between local (joints) and global (center of mass) components, between a fixed point and a limit cycle. The behavior of the center of mass was found to be more predictable than the behavior of its local constituents. In addition, the available visual information affected the predictability of the postural behavior, which suggests that vision is used in the stabilization of the low-dimensional dynamics underlying balance control.