scholarly journals Cross-bridge mechanics estimated from skeletal muscles’ work-loop responses to impacts in legged locomotion

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kasper B. Christensen ◽  
Michael Günther ◽  
Syn Schmitt ◽  
Tobias Siebert
Keyword(s):  
Skeletal Muscles ◽  
Legged Locomotion ◽  
Maximum Activity ◽  
The Body ◽  
Dissipated Energy ◽  
Terrestrial Locomotion ◽  
Cross Bridge ◽  
Custom Made ◽  
Passive Muscle ◽  
Work Loop

AbstractLegged locomotion has evolved as the most common form of terrestrial locomotion. When the leg makes contact with a solid surface, muscles absorb some of the shock-wave accelerations (impacts) that propagate through the body. We built a custom-made frame to which we fixated a rat (Rattus norvegicus, Wistar) muscle (m. gastrocnemius medialis and lateralis: GAS) for emulating an impact. We found that the fibre material of the muscle dissipates between 3.5 and $$23\,\upmu \hbox {J}$$ 23 μ J ranging from fresh, fully active to passive muscle material, respectively. Accordingly, the corresponding dissipated energy in a half-sarcomere ranges between 10.4 and $$68\,z\hbox {J}$$ 68 z J , respectively. At maximum activity, a single cross-bridge would, thus, dissipate 0.6% of the mechanical work available per ATP split per impact, and up to 16% energy in common, submaximal, activities. We also found the cross-bridge stiffness as low as $$2.2\,\hbox {pN}\,\hbox {nm}^{-1}$$ 2.2 pN nm - 1 , which can be explained by the Coulomb-actuating cross-bridge part dominating the sarcomere stiffness. Results of the study provide a deeper understanding of contractile dynamics during early ground contact in bouncy gait.

Movement on Land

2018 ◽  
Keyword(s):  
Large Body ◽  
Legged Locomotion ◽  
The Body ◽  
Body Axis ◽  
Legged Robots ◽  
Body Movements ◽  
Irregular Terrain ◽  
Terrestrial Locomotion ◽  
New Generation

Animals must support their weight when moving over land, while also accommodating changes in terrain and substrate conditions. Most terrestrial animals accomplish this by using limbs to exert forces on the ground. Some groups have lost their limbs (snakes) or never evolved them in the first place (worms), relying instead on contractions of body muscles to transmit force between their body axis and the ground. Undulatory modes of terrestrial locomotion are frequently associated with a burrowing existence. In other animals, some combination of body undulation and limb propulsion moves the body forward. In this chapter we focus on the mechanisms and strategies for legged locomotion on land. Recent studies have examined how animals maneuver and accelerate, and how they stabilize body movements when running. A large body of work on terrestrial locomotion has also yielded inspiration for a new generation of legged robots that can move nimbly over irregular terrain than previous robot designs.

scholarly journals Contemporary image-based methods for measuring passive mechanical properties of skeletal muscles in vivo

2019 ◽  
Vol 126 (5) ◽  
pp. 1454-1464 ◽  
Author(s):  
Lynne E. Bilston ◽  
Bart Bolsterlee ◽  
Antoine Nordez ◽  
Shantanu Sinha
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behavior ◽  
Skeletal Muscles ◽  
Diffusion Tensor ◽  
Imaging Techniques ◽  
Muscle Mechanics ◽  
Muscle Architecture ◽  
The Body ◽  
Passive Muscle

Skeletal muscles’ primary function in the body is mechanical: to move and stabilize the skeleton. As such, their mechanical behavior is a key aspect of their physiology. Recent developments in medical imaging technology have enabled quantitative studies of passive muscle mechanics, ranging from measurements of intrinsic muscle mechanical properties, such as elasticity and viscosity, to three-dimensional muscle architecture and dynamic muscle deformation and kinematics. In this review we summarize the principles and applications of contemporary imaging methods that have been used to study the passive mechanical behavior of skeletal muscles. Elastography measurements can provide in vivo maps of passive muscle mechanical parameters, and both MRI and ultrasound methods are available (magnetic resonance elastography and ultrasound shear wave elastography, respectively). Both have been shown to differentiate between healthy muscle and muscles affected by a broad range of clinical conditions. Detailed muscle architecture can now be depicted using diffusion tensor imaging, which not only is particularly useful for computational modeling of muscle but also has potential in assessing architectural changes in muscle disorders. More dynamic information about muscle mechanics can be obtained using a range of dynamic MRI methods, which characterize the detailed internal muscle deformations during motion. There are several MRI techniques available (e.g., phase-contrast MRI, displacement-encoded MRI, and “tagged” MRI), each of which can be collected in synchrony with muscle motion and postprocessed to quantify muscle deformation. Together, these modern imaging techniques can characterize muscle motion, deformation, mechanical properties, and architecture, providing complementary insights into skeletal muscle function.

Change in skeletal muscle index and its prognostic significance in conversion therapy for initially unresectable colorectal cancer.

2021 ◽  
Vol 39 (3_suppl) ◽  
pp. 56-56
Author(s):  
Hiroaki Nozawa ◽  
Shigenobu Emoto ◽  
Koji Murono ◽  
Yasutaka Shuno ◽  
Soichiro Ishihara
Keyword(s):  
Colorectal Cancer ◽  
Skeletal Muscle ◽  
Muscle Mass ◽  
Skeletal Muscles ◽  
Systemic Chemotherapy ◽  
Stage Iv ◽  
The Body ◽  
Pharmacological Intervention ◽  
Conversion Therapy ◽  
Skeletal Muscle Index

56 Background: Systemic chemotherapy can cause loss of skeletal muscle mass in colorectal cancer (CRC) patients in the neoadjuvant and palliative settings. However, it is largely unknown how the body composition is changed by chemotherapy rendering unresectable CRC to resectable disease or how it affects the prognosis. This study aimed at elucidating the effects of systemic chemotherapy on skeletal muscles and survival in stage IV CRC patients who underwent conversion therapy. Methods: We reviewed 98 stage IV CRC patients who received systemic chemotherapy in our hospital. According to the treatment setting, patients were divided into the ‘Conversion’, ‘Neoadjuvant chemotherapy (NAC)’, and ‘Palliation’ groups. The cross-sectional area of skeletal muscles at the third lumbar level and changes in the skeletal muscle index (SMI), defined as the area divided by height squared, during chemotherapy were compared among patient groups. The effects of these parameters on prognosis were analyzed in the Conversion group. Results: The mean SMI increased by 8.0% during chemotherapy in the Conversion group (n = 38), whereas it decreased by 6.2% in the NAC group (n = 18) and 3.7% in the Palliation group (n = 42, p < 0.0001). Moreover, patients with increased SMI during chemotherapy had a better overall survival (OS) than those whose SMI decreased in the Conversion group (p = 0.021). The increase in SMI was an independent predictor of favorable OS on multivariate analysis (hazard ratio: 0.26). Conclusions: Stage IV CRC patients who underwent conversion to resection often had an increased SMI. As such an increase in SMI further conveys a survival benefit in conversion therapy, it may be important to make efforts to preserve muscle mass by meticulous approaches, such as nutritional support, muscle exercise programs, and pharmacological intervention even during chemotherapy in patients with metastatic CRC.

Cinematographic and electromyographic analysis of vertical standing jump in the dog

1979 ◽  
Vol 83 (1) ◽  
pp. 271-282
Author(s):  
M. Tokuriki
Keyword(s):  
Skeletal Muscles ◽  
Lower Extremities ◽  
Axial Skeleton ◽  
The Body ◽  
Wire Electrode ◽  
Centre Of Gravity ◽  
Electrode Method ◽  
Electromyographic Analysis ◽  
Floating Phase

The electromyograms of 37 skeletal muscles were obtained using the bipolar wire electrode method in the vertical standing jump of a dog. Their electromyographic patterns were analyzed in conjunction with cinematographic films. Co-contraction of muscles of the extremities was observed during take-off and landing. Electromyograms also revealed that the forelimbs were accelerated against the body just after take-off and that the fore quarters transferred the centre of gravity of the body in a much more complicated movement than the hind quarters. In the floating phase, the muscles of the lower extremities had no activity, apart from some proximal ones. That the muscles of the four extremities exhibited their activity just before landing indicates that the activity may have been controlled by a central programme. In the vertical standing jump, the dog brings the centre of gravity of the body near to the kicking or landing paws by skillful movement of the axial skeleton. Cinematography revealed that, in the leaping gallop gait, the dog makes a similar movement of its axial skeleton.

The Role of the ‘Walking Legs’ in Aquatic and Terrestrial Locomotion of the Crayfish Austropotamobius Pallipes (Lereboullet)

1975 ◽  
Vol 62 (2) ◽  
pp. 447-454 ◽  
Author(s):  
CAROLINE M. POND
Keyword(s):  
The Body ◽  
Hydrodynamic Drag ◽  
Terrestrial Locomotion ◽  
Austropotamobius Pallipes ◽  
The Third ◽  
Fourth Pair

1. The hydrodynamic drag acting on the crayfish Austropotamobius pallipes is measured and it is concluded that, in the range of velocities used in walking, the drag is independent of the posture of the limbs and the direction of motion of the body. At swimming velocities the streamlining caused by promotion of the legs reduces the drag losses to half that of a crayfish moving in the forwards walking posture at the same speed. 2. The forwards walking of intact crayfish is compared with that of the same animal after amputation of one or more pairs of legs. It is concluded that the third and fourth pair of legs provide most of the propulsion under water and the second pair is not essential to locomotion under any of the conditions tried.

Mediolateral somitic origin of ribs and dermis determined by quail-chick chimeras

Development ◽  
2000 ◽  
Vol 127 (21) ◽  
pp. 4611-4617 ◽  
Author(s):  
I. Olivera-Martinez ◽  
M. Coltey ◽  
D. Dhouailly ◽  
O. Pourquie
Keyword(s):  
Skeletal Muscles ◽  
Body Wall ◽  
Primitive Streak ◽  
Axial Skeleton ◽  
Lateral Compartment ◽  
The Body ◽  
The Other ◽  
Lateral Part ◽  
Respective Contribution ◽  
Epaxial Muscles

Somites are transient mesodermal structures giving rise to all skeletal muscles of the body, the axial skeleton and the dermis of the back. Somites arise from successive segmentation of the presomitic mesoderm (PSM). They appear first as epithelial spheres that rapidly differentiate into a ventral mesenchyme, the sclerotome, and a dorsal epithelial dermomyotome. The sclerotome gives rise to vertebrae and ribs while the dermomyotome is the source of all skeletal muscles and the dorsal dermis. Quail-chick fate mapping and diI-labeling experiments have demonstrated that the epithelial somite can be further subdivided into a medial and a lateral moiety. These two subdomains are derived from different regions of the primitive streak and give rise to different sets of muscles. The lateral somitic cells migrate to form the musculature of the limbs and body wall, known as the hypaxial muscles, while the medial somite gives rise to the vertebrae and the associated epaxial muscles. The respective contribution of the medial and lateral somitic compartments to the other somitic derivatives, namely the dermis and the ribs has not been addressed and therefore remains unknown. We have created quail-chick chimeras of either the medial or lateral part of the PSM to examine the origin of the dorsal dermis and the ribs. We demonstrate that the whole dorsal dermis and the proximal ribs exclusively originates from the medial somitic compartment, whereas the distal ribs derive from the lateral compartment.

scholarly journals A Systematic Review of Continuum Modeling of Skeletal Muscles: Current Trends, Limitations, and Recommendations

2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Tien Tuan Dao ◽  
Marie-Christine Ho Ba Tho
Keyword(s):  
Systematic Review ◽  
Skeletal Muscle ◽  
Parameter Identification ◽  
Skeletal Muscles ◽  
Finite Elasticity ◽  
Data Uncertainty ◽  
Continuum Models ◽  
Holistic View ◽  
Muscle Modeling ◽  
Passive Muscle

Finite elasticity theory has been commonly used to model skeletal muscle. A very large range of heterogeneous constitutive laws has been proposed. In this review, the most widely used continuum models of skeletal muscles were synthetized and discussed. Trends and limitations of these laws were highlighted to propose new recommendations for future researches. A systematic review process was performed using two reliable search engines as PubMed and ScienceDirect. 40 representative studies (13 passive muscle materials and 27 active muscle materials) were included into this review. Note that exclusion criteria include tendon models, analytical models, 1D geometrical models, supplement papers, and indexed conference papers. Trends of current skeletal muscle modeling relate to 3D accurate muscle representation, parameter identification in passive muscle modeling, and the integration of coupled biophysical phenomena. Parameter identification for active materials, assumed fiber distribution, data assumption, and model validation are current drawbacks. New recommendations deal with the incorporation of multimodal data derived from medical imaging, the integration of more biophysical phenomena, and model reproducibility. Accounting for data uncertainty in skeletal muscle modeling will be also a challenging issue. This review provides, for the first time, a holistic view of current continuum models of skeletal muscles to identify potential gaps of current models according to the physiology of skeletal muscle. This opens new avenues for improving skeletal muscle modeling in the framework of in silico medicine.

scholarly journals Reciprocal innervation and symmetrical muscles

1913 ◽  
Vol 86 (587) ◽  
pp. 219-232 ◽  
Keyword(s):  
Skeletal Muscles ◽  
Knee Extensor ◽  
General Rule ◽  
The Body ◽  
Ordinary Sense ◽  
Excitatory Effect ◽  
Biological Meaning ◽  
Vasomotor Reflexes ◽  
The One ◽  
The Right

If we attempt to decipher the biological meaning of reciprocal innervation its various instances when marshalled together say plainly that one of the functional problems which it meets and solves is mechanical antagonism. Where two muscles have directly opposed effect on the same lever, “reciprocal innervation” is the general rule observed by the nervous system in dealing with them, and this holds whether the reciprocal innervation is peripheral as with the antagonists of the arthropod claw, or is central as with vertebrate skeletal muscles. Also where one and the same muscle is governed by two nerves influencing it oppositely, reciprocal innervation seems again the principle followed in the co-ordination of the two opponent centres, as has been shown by Bayliss in his observations on vasomotor reflexes. But the distribution and occurrence of reciprocal innervation extend beyond cases of mere mechanical antagonism. The reflex influence exerted by the limb-afferents on symmetrical muscle-pairs such as right knee-extensor and left is reciprocal. Thus right peroneal nerve excites the motoneurones of left vastocrureus, and concomitantly inhibits those of the right. The reflex inhibition of the one is concurrent with, increases with increase, and decreases with decrease of, the excitatory effect on the other. Here the muscles are not in any ordinary sense antagonistic; not only do they not operate on the same lever, but they are not even members of the same limb, nor do they belong even to the same half of the body. They are, however, actuated conversely in the most usual modes of progression—the walking and the running step—though not always in galloping.

scholarly journals Assessment of Knowledge about Lefort I Fracture Among Dental Students

2020 ◽  
Vol 11 (SPL3) ◽  
pp. 736-739
Author(s):  
Pravinya ◽  
Dhanraj Ganapathy ◽  
Subhashree Rohinikumar
Keyword(s):  
Traffic Accidents ◽  
Clinical Presentation ◽  
Cerebrospinal Fluid Leak ◽  
Dental Students ◽  
The Body ◽  
Intermaxillary Fixation ◽  
Custom Made ◽  
Maxillofacial Fractures ◽  
The Face ◽  
Facial Area

Fractures of the middle third of the face have increased in number over the past two decades. Trauma to the facial area results in injuries not only to dental structures but also maxillomandibular fractures. In addition, these injuries frequently occur in combination with injuries of other parts of the body. The etiology of these fractures have various causes, such as traffic accidents, falls, assaults, sports, and others. The aim of the study was to assess the knowledge and awareness about LeFort I fracture among undergraduate dental students. A custom made questionnaire comprising of 10 questions to assess the knowledge about LeFort I fracture was formulated and circulated among 100 undergraduate dental students. The responses were then subjected to statistical analysis. Among 100 undergraduate dental students, 52% of them were aware of the types of maxillofacial fractures, and LeFort I fracture is a maxillary fracture, 34% of them have reported that Le Fort I fracture causes disruption of the cribriform plate of the ethmoid bone,35% of them reported that LeFort I fracture might be associated with cerebrospinal fluid leak and 25% of them were still unaware that floating palate is the typical clinical presentation of LeFort I fracture. Also, only 30% were aware that intermaxillary fixation is the management of LeFort I fracture. The present study suggests that among undergraduate dental students, the knowledge about the clinical presentation and the management of LeFort I fracture is inadequate.

Fermentative extraction of Amylase using waste Biomaterials as Substrate

2021 ◽  
pp. 4580-4582
Author(s):  
Sharmila S. ◽  
Preetha S. ◽  
Kowsalya E. ◽  
Kamalambigeswari R. ◽  
L. Jeyanthi Rebecca
Keyword(s):  
Specific Activity ◽  
Raw Materials ◽  
Maximum Activity ◽  
The Body ◽  
Biological Molecules ◽  
Treated Sample ◽  
Wide Range ◽  
Speed Up ◽  
Crude Sample ◽  
Groundnut Shell

Enzymes are biological molecules that significantly speed up the rate of virtually all of the chemical reactions that takes place within the cells. They are vital for life and serve as a wide range of important functions in the body. Solid state fermentation holds a high potential for the production of enzyme amylase using Aspergillus niger. In this work, different solid substrates such as groundnut shells, coconut coir and Palmyra sprout peels were used for the production of amylase as they are very cheap and also easily available raw materials. Then the maximum enzyme activities were analysed. Results showed that the enzyme activity of for which palmyra sprout peel was used as substrate had maximum activity in both crude sample (0.63µmol/ml.min) and in partially purified sample (1.42µmol/ml.min) and activity was found to be less for groundnut shell as substrate (crude sample 0.36µmol/ml.min) and in (treated sample 0.26µmol/ml.min) and also the specific activity was found to be maximum in palmyra sprout peel (29.2U/mg of protein) and less in groundnut shell (8.6U/mg of protein).

Sign in / Sign up

Export Citation Format

Share Document