tailieunhanh - Báo cáo y học: " Research Skeletal muscle contraction. The thorough definition of the contractile event requires both load acceleration and load mass to be known"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học quốc tế cung cấp cho các bạn kiến thức về ngành y đề tài: Research Skeletal muscle contraction. The thorough definition of the contractile event requires both load acceleration and load mass to be known. | Grazi and Pozzati Theoretical Biology and Medical Modelling 2010 7 24 http content 7 1 24 THEORETICAL BIOLOGY AND MEDICAL MODELLING RESEARCH Open Access Skeletal muscle contraction. The thorough definition of the contractile event requires both load acceleration and load mass to be known Enrico Grazi and Sara Pozzati Correspondence 1 Dipartimento di Biochimica e Biologia Molecolare Università di Ferrara Via Borsari 46 44100 Ferrara Italy Full list of author information is available at the end of the article Abstract Background The scope of this work is to show that the correct and complete definition of the system of muscle contraction requires the knowledge of both the mass and the acceleration of the load. Results The aim is achieved by making use of a model of muscle contraction that operates into two phases. The first phase considers the effects of the power stroke in the absence of any hindrance. In the second phase viscous hindrance is introduced to match the experimental speed and yield of the contraction. It is shown that at constant force of the load changing load acceleration changes the time course of the pre-steady state of myofibril contraction. The decrease of the acceleration of the load from to 1 increases the time length of the pre-steady state of the contraction from a few microseconds to many hundreds of microseconds and decreases the stiffness of the active fibre. Conclusions We urge that in the study of muscle contraction both the mass and the acceleration of the load are specified. Background It is a general opinion that the load force cross-section determines the muscle response power output force and speed of contraction . Apparently it is not realized that 1. one of the components of the load the force is the product of the mass by the acceleration 2. the same force is generated by an infinite number of mass and acceleration couples 3. each one of these couples displays different .