Papers by Keyword: Skeletal Muscle

Abstract: The objective of this study was to investigate the protective role of polysaccharide from Gynostemma pentaphyllum Makino (PGP) supplementation against exhaustive swimming exercise-induced oxidative stress. A total of 48 mice were randomly divided into four groups: control, low-dose, medium-dose, and high-dose PGP supplementation groups. The control group received distilled water and the supplementation groups received different doses of PGP (50, 100 and 200 mg/kg body weight) by gavage once a day for 28 consecutive days. After 28 days, the mice performed an exhaustive swimming exercise, and some biochemical parameters related to oxidative stress, including superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT) and malondialdehyde (MDA), were measured. The results showed that PGP supplementation could increase SOD, GPx and CAT contents, as well as decrease MDA contents in the liver and skeletal muscle of mice, which suggests that PGP supplementation has a protective role against exhaustive swimming exercise-induced oxidative stress.

Abstract: To research ultrastructure changes of rat skeletal muscle in the process of repetition eccentric exercise, Wistar rats were divided into normal control group, one eccentric exercise group, repeated eccentric exercise group. The ultrastructure and proteome changes made by downhill run and repetitive downhill run after a week in rats were observed in instant, 24h, 48h, 72h and 168h after one and repeated bout of exercise rats. The results showed that the most serious injuries of sarcomere in 48 hours after exercise, sarcomere disordered or disappeared, Z-line fractured and myofilament decomposed. From 24h to 48h, mitochondria was severely damaged, which structure gradually restored within 72 hours, the muscle fiber reconstructed, but mitochondrial number, structure and function had not yet been fully restored, the muscle cells in aerobic capacity have not yet fully been restored. At the same time, the injury severity of repeated exercise group was palliative compared to that of the first exercise, which may be related to recovery rate of mitochondrial damage. Therefore, repetitive motion can change the mitochondria's own repair speed, stimulate muscle to adapt the density of exercise, and reduce the extent of skeletal muscle micro-injury. Repeated eccentric exercise may promote key enzyme expression of energy metabolism and energy supply for damage cell, accelerate skeletal muscle contraction protein degradation and cell swallow, and scavenge free radicals and slow inflammatory reaction during 24-48h to speed up the skeletal muscle damage repair. Keywords: Eccentric Exercise, Repetitive Exercise, Skeletal Muscle, Ultrastructure, Peoteome

Abstract: In this paper, we propose a fast approach to simulate the dynamic behavior of skeletal muscles based on bio-mechanical and anatomical properties. In contrast to physically accurate deformation, this simulation achieves faster and better simulation of skeletal muscles, with the cost of unnoticeable visual accuracy. Internal constrains are generated to conserve linear and angular momentum which is essential for cloth self-collision. Deformation constraints are defined by using the muscle force-length relationship serve as Control Axial Curve, which constrainedly generates the active and passive force of the muscles to drive skeletal motion during the deformation process. This approach generates realistic visual effect, and manages the deformation of muscles on the basis of the bio-mechanical properties with fast speed. We have demonstrated the simulation by creating a musculoskeletal model of the upper limb.

Abstract: In this paper, we proposed a new approach to simulate the deformation of skeletal muscles based on bio-mechanical considerations. The musculo-tendon unit, which generates the active and passive force of the muscles to drive skeletal motion, is established according to the tension-length curve. Muscular deformation is achieved by embedding a musculo-tendon unit in the volume-preserving B-spline solid. The model provides suitable visual effect and manages the deformation of muscles on the basis of the bio-mechanical properties. We demonstrated the simulation by creating a musculoskeletal model of the upper limb.This document explains and demonstrates how to prepare your camera-ready manuscript for Trans Tech Publications. The best is to read these instructions and follow the outline of this text. The text area for your manuscript must be 17 cm wide and 25 cm high (6.7 and 9.8 inches, resp.). Do not place any text outside this area. Use good quality, white paper of approximately 21 x 29 cm or 8 x 11 inches (please do not change the document setting from A4 to letter). Your manuscript will be reduced by approximately 20% by the publisher. Please keep this in mind when designing your figures and tables etc.

Abstract: In order to evaluate the mechanical properties of the human skeletal muscles, the elasticity and viscosity of the human calf muscles were measured with Magnetic Resonance Elastography (MRE). MRE is a novel method to measure the mechanical properties of living soft tissues in vivo quantitatively by observing the strain waves propagated in the object. In this study, the shear modulus and viscosity coefficient were measured with MRE. The shear modulus was 3.7 kPa in relaxed state, and increased with increasing the muscle forces. Interestingly, the viscosity was changed with the vibration frequency applied to the muscles, that was 4.5 Pa·s at 100Hz vibration and 2.4 Pa·s at 200Hz vibration. This shows clearly the visco-elastic property.

Abstract: A three-dimensional finite element analysis was conducted to simulate the effects of the varying material parameters on the contraction behaviors of a muscle-tendon complex using an active finite element method. The material behavior of the skeletal muscle was assumed to be orthotropic and the muscle model consists of two parts: the active and the passive parts. An active finite element method was then used for accommodating both the active and passive behaviors of the muscle into the muscle model. In this active-passive muscle model, the active component is governed by an activation level, a time period, a muscle sensitivity parameter and a strain rate. The material property of the passive component was assumed to be viscoelastic and the tendon is assumed to be linear elastic. The effects of activation amplitude and viscoelastic material parameters on the active, passive and total force-length relationship of the cat muscle under isometric contraction were predicted. The predicted results were found to be close to the experimental data reported in the available literature. Hence, the active-passive muscle model was extended to simulate the stress distribution of the cat muscle subject to shortening contraction and different activation amplitude. By varying the magnitude of the material parameters, different muscle behaviors could be generated. The proposed active finite element method lays a good foundation for simulation of human musculoskeletal motion.