The Experts below are selected from a list of 135 Experts worldwide ranked by ideXlab platform
Yasuo Kawakami - One of the best experts on this subject based on the ideXlab platform.
-
Increase in vastus lateralis aponeurosis width induced by resistance training: implications for a hypertrophic model of Pennate Muscle
European Journal of Applied Physiology, 2015Co-Authors: Taku Wakahara, Naokazu Miyamoto, Ryoichi Ema, Yasuo KawakamiAbstract:Purpose This study aimed to ascertain whether training-induced Muscle hypertrophy is accompanied by an increase in the aponeurosis width, and to infer its impact on the training-induced increase in the pennation angle. Methods Eleven young men completed a resistance training program of unilateral knee extensions for 12 weeks. Before and after training, anatomical cross-sectional area (ACSA) of the vastus lateralis and its distal aponeurosis width in the transverse plane were measured with magnetic resonance imaging. The pennation angle and fascicle length were also determined with ultrasonography at the midbelly of the Muscle. The effect of change in aponeurosis width on the magnitude of training-induced increase in pennation angle was estimated by using a parallelepipedon model. Results After the training, there were significant increases in ACSA (10.7 ± 7.6 %), pennation angle (10.8 ± 7.3 %) and aponeurosis width (1.9 ± 3.1 %), whereas no significant change was found in the fascicle length. The model simulation shows that the increase in aponeurosis width by 1.9 % reduces the magnitude of increase in pennation angle by only 0.4°. Conclusions These results indicate that (1) the aponeurosis width of the vastus lateralis increases after 12 weeks of resistance training and (2) the increase in the aponeurosis width accompanying Muscle hypertrophy by the amount of ~10 % does not substantially affect the increase in pennation angle.
-
increase in vastus lateralis aponeurosis width induced by resistance training implications for a hypertrophic model of Pennate Muscle
European Journal of Applied Physiology, 2015Co-Authors: Taku Wakahara, Naokazu Miyamoto, Yasuo KawakamiAbstract:Purpose This study aimed to ascertain whether training-induced Muscle hypertrophy is accompanied by an increase in the aponeurosis width, and to infer its impact on the training-induced increase in the pennation angle.
-
superficial aponeurosis of human gastrocnemius is elongated during contraction implications for modeling Muscle tendon unit
Journal of Biomechanics, 2002Co-Authors: Tadashi Muramatsu, Yasuo Kawakami, Tetsuro Muraoka, Tetsuo FukunagaAbstract:Abstract Two questions were addressed in this study: (1) how much strain of the superficial aponeurosis of the human medial gastrocnemius Muscle (MG) was obtained during voluntary isometric contractions in vivo, (2) whether there existed inhomogeneity of the strain along the superficial aponeurosis. Seven male subjects, whose knees were extended and ankles were flexed at right angle, performed isometric plantar flexion while elongation of superficial aponeurosis of MG was determined from the movements of the intersections made by the superficial aponeurosis and fascicles using ultrasonography. The strain of the superficial aponeurosis at the maximum voluntary contraction, estimated from the elongation and length data, was 5.6±1.2%. There was no significant difference in strain between the proximal and distal parts of the superficial aponeurosis. Based on the present result and that of our previous study for the same subjects (J. Appl. Physiol 90 (2001) 1671), a model was formulated for a contracting uni-Pennate Muscle-tendon unit. This model, which could be applied to isometric contractions at other angles and therefore of wide use, showed that similar strain between superficial and deep aponeuroses of MG contributed to homogeneous fascicle length change within MG during contractions. These findings would contribute to clarifying the functions of the superficial aponeurosis and the effects of the superficial aponeurosis elongation on the whole Muscle behavior.
Naokazu Miyamoto - One of the best experts on this subject based on the ideXlab platform.
-
Validity of Measurement of Shear Modulus by Ultrasound Shear Wave Elastography in Human Pennate Muscle
PloS one, 2015Co-Authors: Naokazu Miyamoto, Hiroaki Kanehisa, Kosuke Hirata, Yasuhide YoshitakeAbstract:Ultrasound shear wave elastography is becoming a valuable tool for measuring mechanical properties of individual Muscles. Since ultrasound shear wave elastography measures shear modulus along the principal axis of the probe (i.e., along the transverse axis of the imaging plane), the measured shear modulus most accurately represents the mechanical property of the Muscle along the fascicle direction when the probe's principal axis is parallel to the fascicle direction in the plane of the ultrasound image. However, it is unclear how the measured shear modulus is affected by the probe angle relative to the fascicle direction in the same plane. The purpose of the present study was therefore to examine whether the angle between the principal axis of the probe and the fascicle direction in the same plane affects the measured shear modulus. Shear modulus in seven specially-designed tissue-mimicking phantoms, and in eleven human in-vivo biceps brachii and medial gastrocnemius were determined by using ultrasound shear wave elastography. The probe was positioned parallel or 20° obliquely to the fascicle across the B-mode images. The reproducibility of shear modulus measurements was high for both parallel and oblique conditions. Although there was a significant effect of the probe angle relative to the fascicle on the shear modulus in human experiment, the magnitude was negligibly small. These findings indicate that the ultrasound shear wave elastography is a valid tool for evaluating the mechanical property of Pennate Muscles along the fascicle direction.
-
Increase in vastus lateralis aponeurosis width induced by resistance training: implications for a hypertrophic model of Pennate Muscle
European Journal of Applied Physiology, 2015Co-Authors: Taku Wakahara, Naokazu Miyamoto, Ryoichi Ema, Yasuo KawakamiAbstract:Purpose This study aimed to ascertain whether training-induced Muscle hypertrophy is accompanied by an increase in the aponeurosis width, and to infer its impact on the training-induced increase in the pennation angle. Methods Eleven young men completed a resistance training program of unilateral knee extensions for 12 weeks. Before and after training, anatomical cross-sectional area (ACSA) of the vastus lateralis and its distal aponeurosis width in the transverse plane were measured with magnetic resonance imaging. The pennation angle and fascicle length were also determined with ultrasonography at the midbelly of the Muscle. The effect of change in aponeurosis width on the magnitude of training-induced increase in pennation angle was estimated by using a parallelepipedon model. Results After the training, there were significant increases in ACSA (10.7 ± 7.6 %), pennation angle (10.8 ± 7.3 %) and aponeurosis width (1.9 ± 3.1 %), whereas no significant change was found in the fascicle length. The model simulation shows that the increase in aponeurosis width by 1.9 % reduces the magnitude of increase in pennation angle by only 0.4°. Conclusions These results indicate that (1) the aponeurosis width of the vastus lateralis increases after 12 weeks of resistance training and (2) the increase in the aponeurosis width accompanying Muscle hypertrophy by the amount of ~10 % does not substantially affect the increase in pennation angle.
-
increase in vastus lateralis aponeurosis width induced by resistance training implications for a hypertrophic model of Pennate Muscle
European Journal of Applied Physiology, 2015Co-Authors: Taku Wakahara, Naokazu Miyamoto, Yasuo KawakamiAbstract:Purpose This study aimed to ascertain whether training-induced Muscle hypertrophy is accompanied by an increase in the aponeurosis width, and to infer its impact on the training-induced increase in the pennation angle.
Taku Wakahara - One of the best experts on this subject based on the ideXlab platform.
-
Increase in vastus lateralis aponeurosis width induced by resistance training: implications for a hypertrophic model of Pennate Muscle
European Journal of Applied Physiology, 2015Co-Authors: Taku Wakahara, Naokazu Miyamoto, Ryoichi Ema, Yasuo KawakamiAbstract:Purpose This study aimed to ascertain whether training-induced Muscle hypertrophy is accompanied by an increase in the aponeurosis width, and to infer its impact on the training-induced increase in the pennation angle. Methods Eleven young men completed a resistance training program of unilateral knee extensions for 12 weeks. Before and after training, anatomical cross-sectional area (ACSA) of the vastus lateralis and its distal aponeurosis width in the transverse plane were measured with magnetic resonance imaging. The pennation angle and fascicle length were also determined with ultrasonography at the midbelly of the Muscle. The effect of change in aponeurosis width on the magnitude of training-induced increase in pennation angle was estimated by using a parallelepipedon model. Results After the training, there were significant increases in ACSA (10.7 ± 7.6 %), pennation angle (10.8 ± 7.3 %) and aponeurosis width (1.9 ± 3.1 %), whereas no significant change was found in the fascicle length. The model simulation shows that the increase in aponeurosis width by 1.9 % reduces the magnitude of increase in pennation angle by only 0.4°. Conclusions These results indicate that (1) the aponeurosis width of the vastus lateralis increases after 12 weeks of resistance training and (2) the increase in the aponeurosis width accompanying Muscle hypertrophy by the amount of ~10 % does not substantially affect the increase in pennation angle.
-
increase in vastus lateralis aponeurosis width induced by resistance training implications for a hypertrophic model of Pennate Muscle
European Journal of Applied Physiology, 2015Co-Authors: Taku Wakahara, Naokazu Miyamoto, Yasuo KawakamiAbstract:Purpose This study aimed to ascertain whether training-induced Muscle hypertrophy is accompanied by an increase in the aponeurosis width, and to infer its impact on the training-induced increase in the pennation angle.
James M. Wakeling - One of the best experts on this subject based on the ideXlab platform.
-
The Energy of Muscle Contraction. II. Transverse Compression and Work
Frontiers in physiology, 2020Co-Authors: David S. Ryan, Sebastián Domínguez, Stephanie A. Ross, Nilima Nigam, James M. WakelingAbstract:In this study we examined how the strain energies within a Muscle are related to changes in longitudinal force when the Muscle is exposed to an external transverse load. We implemented a three-dimensional (3D) finite element model of contracting Muscle using the principle of minimum total energy and allowing the redistribution of energy through different strain energy-densities. This allowed us to determine the importance of the strain energy-densities to the transverse forces developed by the Muscle. We ran a series of in silica experiments on Muscle blocks varying in initial pennation angle, Muscle length, and external transverse load. As Muscle contracts it maintains a near constant volume. As such, any changes in Muscle length are balanced by deformations in the transverse directions such as Muscle thickness or Muscle width. Muscle develops transverse forces as it expands. In many situations external forces act to counteract these transverse forces and the Muscle responds to external transverse loads while both passive and active. The Muscle blocks used in our simulations decreased in thickness and pennation angle when passively compressed and pushed back on the load when they were activated. Activation of the compressed Muscle blocks led either to an increase or decrease in Muscle thickness depending on whether the initial pennation angle was less than or greater than 15°, respectively. Furthermore, the strain energy increased and redistributed across the different strain-energy potentials during contraction. The volumetric strain energy-density varied with Muscle length and pennation angle and was reduced with greater transverse load for most initial Muscle lengths and pennation angles. External transverse load reduced the longitudinal Muscle force for initial pennation angles of β0 = 0°. Whereas for Pennate Muscle (β0 > 0°) longitudinal force changed (increase or decrease) depending on the Muscle length, pennation angle and the direction of the external load relative to the Muscle fibres. For Muscle blocks with initial pennation angles β0 ≤ 20° the reduction in longitudinal Muscle force coincided with a reduction in volumetric strain energy-density.
-
Transverse anisotropy in the deformation of the Muscle during dynamic contractions
The Journal of Experimental Biology, 2018Co-Authors: Avleen Randhawa, James M. WakelingAbstract:ABSTRACT When Pennate Muscle fibres shorten, the transverse deformation of fibres results in an increase in pennation angle of fascicles (bundles of fibres) and transverse deformation of Muscle belly. Transverse shape changes of a Muscle can influence force generation. Recent modelling studies predicted asymmetrical transverse deformations in the Muscle fascicles in the gastrocnemii. However, these predictions have not been tested experimentally. As Muscle is a 3D entity, it is important to explore the structural changes in a 3D perspective to enhance our understanding of the underlying structural mechanisms that have functional implications. The medial and lateral gastrocnemius Muscles from 12 subjects were imaged during plantarflexion movements on a dynamometer. The Muscle belly was simultaneously scanned from two orthogonal directions using two ultrasound probes. Fascicle deformations were measured from the two orthogonal ultrasound scans to provide 3D information of Muscle geometry. Whilst transverse deformations in the medial gastrocnemius were similar from the two directions, the data for the lateral gastrocnemius confirm that transverse anisotropy can occur in the Muscle fascicles. As the lateral gastrocnemius fascicle length shortened, the pennation angle increased and the fascicles bulged transversally in one direction (closest to the typical 2D scanning plane) while thinning in the other orthogonal direction. We suggest that the transverse deformation of the Muscle fascicles depends on the stiffness of the aponeuroses, properties of connective tissue structures surrounding Muscle, and compressive forces both internal and external to the Muscle. These results highlight that Muscle fascicles do not bulge uniformly and the implications for this behaviour on Muscle function remain largely unexplored.
-
Multidimensional models for predicting Muscle structure and fascicle pennation
Journal of theoretical biology, 2015Co-Authors: Avleen Randhawa, James M. WakelingAbstract:Pennation angles change during Muscle contraction and must be tracked by Muscle models. When Muscles contract they can change in depth (distance between the bounding sheets of aponeurosis) or width, and this is related to pennation angle and Muscle fascicle length. As a simplification to these relationships, many models of Pennate Muscle assume a constant distance between aponeuroses during contraction (constant depth). It is possible that these 1D models do not recreate the internal structure of Muscles adequately, whereas 2D panel models that assume a constant panel area, or 3D models that assume a constant Muscle volume may better predict the structural changes that occur within Muscle during contraction. However, these ideas have never been validated in man. The purpose of this study was to test the accuracy with which 1D, 2D or 3D structural models of Muscle could predict the pennation and Muscle depth within the medial gastrocnemius (MG) and lateral gastrocnemius (LG) in man during ankle plantarflexions. The 1D model, by definition, was unable to account for changes in Muscle depth. The 2D model predicted change in depth as the aponeurosis was loaded, but could only allow a decrease in depth as the aponeurosis is stretched. This was not sufficient to predict the increases in depth that occur in the LG during plantarflexion. The 3D model had the ability to predict either increases or decreases in depth during the ankle plantarflexions and predicted opposing changes in depth that occurred between the MG and LG, whilst simultaneously predicting the pennation more accurately than the 1D or 2D models. However, when using mean parameters, the 3D model performed no better than the more simple 1D model, and so if the intent of a model is purely to establish a good relation between fascicle length and pennation then the 1D model is a suitable choice for these Muscles.
-
Transverse strains in Muscle fascicles during voluntary contraction: a 2D frequency decomposition of b-mode ultrasound images
International journal of biomedical imaging, 2014Co-Authors: James M. Wakeling, Avleen RandhawaAbstract:When skeletal Muscle fibres shorten, they must increase in their transverse dimensions in order to maintain a constant volume. In Pennate Muscle, this transverse expansion results in the fibres rotating to greater pennation angle, with a consequent reduction in their contractile velocity in a process known as gearing. Understanding the nature and extent of this transverse expansion is necessary to understand the mechanisms driving the changes in internal geometry of whole Muscles during contraction. Current methodologies allow the fascicle lengths, orientations, and curvatures to be quantified, but not the transverse expansion. The purpose of this study was to develop and validate techniques for quantifying transverse strain in skeletal Muscle fascicles during contraction from B-mode ultrasound images. Images were acquired from the medial and lateral gastrocnemii during cyclic contractions, enhanced using multiscale vessel enhancement filtering and the spatial frequencies resolved using 2D discrete Fourier transforms. The frequency information was resolved into the fascicle orientations that were validated against manually digitized values. The transverse fascicle strains were calculated from their wavelengths within the images. These methods showed that the transverse strain increases while the longitudinal fascicle length decreases; however, the extent of these strains was smaller than expected.
-
Research Article Transverse Strains in Muscle Fascicles during Voluntary Contraction: A 2D Frequency Decomposition of B-Mode Ultrasound Images
2014Co-Authors: James M. Wakeling, Avleen RAbstract:Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. When skeletal Muscle fibres shorten, they must increase in their transverse dimensions in order to maintain a constant volume. In Pennate Muscle, this transverse expansion results in the fibres rotating to greater pennation angle, with a consequent reduction in their contractile velocity in a process known as gearing. Understanding the nature and extent of this transverse expansion is necessary to understand the mechanisms driving the changes in internal geometry of whole Muscles during contraction. Current methodologies allow the fascicle lengths, orientations, and curvatures to be quantified, but not the transverse expansion. The pur-pose of this studywas to develop and validate techniques for quantifying transverse strain in skeletalMuscle fascicles during contrac-tion from B-mode ultrasound images. Images were acquired from the medial and lateral gastrocnemii during cyclic contractions, enhanced using multiscale vessel enhancement filtering and the spatial frequencies resolved using 2D discrete Fourier transforms. The frequency information was resolved into the fascicle orientations that were validated against manually digitized values. The transverse fascicle strains were calculated from their wavelengths within the images. These methods showed that the transverse strain increases while the longitudinal fascicle length decreases; however, the extent of these strains was smaller than expected. 1
Yasuhide Yoshitake - One of the best experts on this subject based on the ideXlab platform.
-
Validity of Measurement of Shear Modulus by Ultrasound Shear Wave Elastography in Human Pennate Muscle
PloS one, 2015Co-Authors: Naokazu Miyamoto, Hiroaki Kanehisa, Kosuke Hirata, Yasuhide YoshitakeAbstract:Ultrasound shear wave elastography is becoming a valuable tool for measuring mechanical properties of individual Muscles. Since ultrasound shear wave elastography measures shear modulus along the principal axis of the probe (i.e., along the transverse axis of the imaging plane), the measured shear modulus most accurately represents the mechanical property of the Muscle along the fascicle direction when the probe's principal axis is parallel to the fascicle direction in the plane of the ultrasound image. However, it is unclear how the measured shear modulus is affected by the probe angle relative to the fascicle direction in the same plane. The purpose of the present study was therefore to examine whether the angle between the principal axis of the probe and the fascicle direction in the same plane affects the measured shear modulus. Shear modulus in seven specially-designed tissue-mimicking phantoms, and in eleven human in-vivo biceps brachii and medial gastrocnemius were determined by using ultrasound shear wave elastography. The probe was positioned parallel or 20° obliquely to the fascicle across the B-mode images. The reproducibility of shear modulus measurements was high for both parallel and oblique conditions. Although there was a significant effect of the probe angle relative to the fascicle on the shear modulus in human experiment, the magnitude was negligibly small. These findings indicate that the ultrasound shear wave elastography is a valid tool for evaluating the mechanical property of Pennate Muscles along the fascicle direction.