6 results on '"Navallas, Javier"'
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2. Effects of muscle shortening on single-fiber, motor unit, and compound muscle action potentials
- Author
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Rodriguez-Falces, Javier, Malanda, Armando, and Navallas, Javier
- Subjects
Muscle shortening ,End-of-fiber components ,Motor Neurons ,Non-propagating components ,Electromyography ,Muscles ,Muscle Fibers, Skeletal ,EMG modeling ,Biomedical Engineering ,Action Potentials ,Isometric contraction ,Computer Science Applications ,Muscle Fatigue ,Muscle architecture ,Original Article ,Surface motor unit potential ,Muscle, Skeletal ,Muscle Contraction - Abstract
Even under isometric conditions, muscle contractions are associated with some degree of fiber shortening. The effects of muscle shortening on extracellular electromyographic potentials have not been characterized in detail. Moreover, the anatomical, biophysical, and detection factors influencing the muscle-shortening effects have been neither identified nor understood completely. Herein, we investigated the effects of muscle shortening on the amplitude and duration characteristics of single-fiber, motor unit, and compound muscle action potentials. We found that, at the single-fiber level, two main factors influenced the muscle-shortening effects: (1) the electrode position and distance relative to the myotendinous zone and (2) the electrode distance to the maxima of the dipole field arising from the stationary dipole created at the fiber-tendon junction. Besides, at the motor unit and muscle level, two additional factors were involved: (3) the overlapping between the propagating component of some fibers with the non-propagating component of other fibers and (4) the spatial spreading of the fiber-tendon junctions. The muscle-shortening effects depend critically on the electrode longitudinal distance to the myotendinous zone. When the electrode was placed far from the myotendinous zone, muscle shortening resulted in an enlargement and narrowing of the final (negative) phase of the potential, and this enlargement became less pronounced as the electrode approached the fiber endings. For electrode locations close to the myotendinous zone, muscle shortening caused a depression of both the main (positive) and final (negative) phases of the potential. Beyond the myotendinous zone, muscle shortening led to a decrease of the final (positive) phase. The present results provide reference information that will help to identify changes in MUPs and M waves due to muscle shortening, and thus to differentiate these changes from those caused by muscle fatigue. Graphical abstract
- Published
- 2021
3. A muscle architecture model offering control over motor unit fiber density distributions
- Author
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Navallas, Javier, Malanda, Armando, Gila, Luis, Rodríguez, Javier, and Rodríguez, Ignacio
- Published
- 2010
- Full Text
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4. Comparative evaluation of motor unit architecture models
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Navallas, Javier, Malanda, Armando, Gila, Luis, Rodriguez, Javier, and Rodriguez, Ignacio
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- 2009
- Full Text
- View/download PDF
5. A new muscle architecture model with non-uniform distribution of muscle fiber types
- Author
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Navallas, Javier, Malanda, Armando, Gila, Luis, Rodriguez, Javier, Rodriguez, Ignacio, Universidad Pública de Navarra. Departamento de Ingeniería Eléctrica y Electrónica, and Nafarroako Unibertsitate Publikoa. Ingeniaritza Elektriko eta Elektronikoa Saila
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Motor unit ,EMG simulation ,Muscle architecture ,Muscle model - Abstract
According to previous studies, some muscles present a non-homogeneous spatial distribution of its muscle fiber types and motor unit types. However, available muscle models only deal with muscles with homogeneous distributions. In this paper, a new architecture muscle model is proposed to permit the construction of non-uniform distributions of muscle fibers within the muscle cross section. The idea behind is the use of a motor unit placement algorithm that controls the spatial overlapping of the motor unit territories of each motor unit type. Results show the capabilities of the new algorithm to reproduce arbitrary muscle fiber type distributions., {"references":["D. W. Stashuk, \"Simulation of electromyographic signals,\" J. Electromyogr.\nKinesiol., vol. 3, pp. 157-173, 1993.","M. A. Schnetzer, D. G. Ruegg, R. Baltensperger, and J. P. Gabriel,\n\"Three-dimensional model of a muscle and simulation of its surface\nEMG,\" Engineering in Medicine and Biology Society, 2001. Proceedings\nof the 23rd Annual International Conference of the IEEE, vol. 2, pp.\n1038-1043, 2001.","A. Hamilton-Wright and D. W. Stashuk, \"Physiologically based simulation\nof clinical EMG signals,\" IEEE Trans. Biomed. Eng., vol. 52, pp.\n171-183, 2005.","J. Navallas, A. Malanda, L. Gila, J. Rodriguez, and I. Rodriguez,\n\"Mathematical analysis of a muscle architecture model,\" IEEE Trans.\nBiomed. Eng., submitted for publication.","ÔÇöÔÇö, \"New muscle architecture model with uniform motor unit fiber\ndensity,\" IEEE Trans. Biomed. Eng., submitted for publication.","E. Henneman, G. Somjen, and D. O. Carpenter, \"Functional significance\nof cell size in spinal motorneurons,\" J. Neurophysiol., vol. 28, pp. 560-\n580, 1965.","E. Henneman and C. B. Olson, \"Relations between structure and\nfunction in the design of skeletal muscles,\" J. Neurophysiol., vol. 28,\npp. 581-598, 1965.","H. S. Milner-Brown, R. B. Stein, and R. Yemm, \"The orderly recruitment\nof human motor units during voluntary isometric contractions,\" J.\nPhysiol., vol. 230, pp. 359-370, 1973.","A. J. Fuglevand, D. A. Winter, and A. E. Patla, \"Models of recruitment\nand rate coding organization in motor-unit pools,\" J. Neurophysiol.,\nvol. 70, pp. 2470-2488, 1993.\n[10] S. C. Bodine, R. R. Roy, E. Eldred, and V. R. Edgerton, \"Maximal force\nas a function of anatomical features of motor unit in the cat tibialis\nanterior,\" J. Neurophysiol., vol. 57, pp. 1730-1745, 1987.\n[11] S. Chamberlain and D. M. Lewis, \"Contractile characteristics and\ninnervation ratio of rat soleus motor units,\" J. Physiol., vol. 412, pp.\n1-21, 1989.\n[12] S. Bodine-Fowler, A. Garfinkel, R. R. Roy, and V. R. Edgerton, \"Spatial\ndistribution of muscle fibers within the territory of a motor unit,\" Muscle\nNerve, vol. 13, pp. 1133-1145, 1990.\n[13] K. Kanda and K. Hashizume, \"Factors causing differences in force\noutput among motor units in the cat medialis gastrocnemius muscle,\" J.\nPhysiol., vol. 448, pp. 677-695, 1992.\n[14] S. C. Bodine, A. Garfinkel, R. R. Roy, and V. R. Edgerton, \"Spatial\ndistribution of motor unit fibers in the cat soleus and tibialis anterior\nmuscles: local interactions,\" J. Neurosci., vol. 8, pp. 2142-2152, 1988.\n[15] R. R. Roy, A. Garfinkel, M. Ounjian, J. Payne, A. Hirahara, E. Hsu,\nand V. R. Edgerton, \"Three-dimensional structure of cat tibialis anterior\nmotor units,\" Muscle Nerve, vol. 18, pp. 1187-1195, 1995.\n[16] R. L. Lieber and J. Friden, \"Functional and clinical significance of\nskeletal muscle architecture,\" Muscle Nerve, vol. 23, pp. 1647-1666,\n2000.\n[17] R. M. Enoka and A. J. Fuglevand, \"Motor unit physiology: some\nunresolved issues,\" Muscle Nerve, vol. 24, pp. 4-17, 2001.\n[18] B. Feinstein, B. Lindegard, E. Nyman, and G. Wohlfart, \"Morphologic\nstudies of motor units in normal human muscles,\" Acta Anat, vol. 23,\npp. 127-142, 1955.\n[19] X. Dennett and H. J. H. Fry, \"Overuse syndrome: a muscle biopsy study,\"\nLancet, pp. 905-908, 1988.\n[20] G. C. Elder, K. Bradbury, and R. Roberts, \"Variability of fiber type\ndistributions within human muscles,\" J. Appl. Physiol., vol. 53, pp.\n1473-1480, 1982.\n[21] S. Grotmol, G. K. Totland, H. Kryvi, A. Breistol, B. Essen-Gustavsson,\nand A. Lindholm, \"Spatial distribution of fiber types within skeletal\nmuscle fascicles from standardbred horses,\" Anat. Rec., vol. 268, pp.\n131-136, 2002.\n[22] J. Lexell, K. Henriksson-Larsen, and M. Sjostrom, \"Distribution of\ndifferent fiber types in human skeletal muscles. 2. a study of crosssections\nof the whole m. vastus lateralis,\" Acta Physiol. Scand., vol.\n117, pp. 115-122, 1983.\n[23] F. J. R. Richmond, K. Singh, and B. D. Corneil, \"Marked non-uniformity\nof fiber-type composition in the primate suboccipital muscle obliquus\ncapitis inferior,\" Exp. Brain Res., vol. 125, pp. 14-18, 1999.\n[24] C. A. Knight and G. Kamen, \"Superficial motor units are larger than\ndeeper motor units in human vastus lateralis muscle,\" Muscle Nerve,\nvol. 31, pp. 475-480, 2005.\n[25] R. D. Adams and J. D. Reuck, \"Metrics of muscle,\" in Basic Research in\nMiology. Proceedings of the Second International Congress on Muscle\nDiseases, B. A. Kakulas, Ed., 1971, pp. 3-11."]}
- Published
- 2007
6. Mathematical analysis of a muscle architecture model
- Author
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Navallas, Javier, Malanda, Armando, Gila, Luis, Rodríguez, Javier, and Rodríguez, Ignacio
- Subjects
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MATHEMATICAL analysis , *UNITS of measurement , *PLANT products , *FIBERS - Abstract
Abstract: Modeling of muscle architecture, which aims to recreate mathematically the physiological structure of the muscle fibers and motor units, is a powerful tool for understanding and modeling the mechanical and electrical behavior of the muscle. Most of the published models are presented in the form of algorithms, without mathematical analysis of mechanisms or outcomes of the model. Through the study of the muscle architecture model proposed by Stashuk, we present the analytical tools needed to better understand these models. We provide a statistical description for the spatial relations between motor units and muscle fibers. We are particularly concerned with two physiological quantities: the motor unit fiber number, which we expect to be proportional to the motor unit territory area; and the motor unit fiber density, which we expect to be constant for all motor units. Our results indicate that the Stashuk model is in good agreement with the physiological evidence in terms of the expectations outlined above. However, the resulting variance is very high. In addition, a considerable ‘edge effect’ is present in the outer zone of the muscle cross-section, making the properties of the motor units dependent on their location. This effect is relevant when motor unit territories and muscle cross-section are of similar size. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
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