Muscle Contraction
Muscle Contraction
复制标题
DOI：
10.1113/jphysiol.1996.sp021275
复制
发表时间：
1998-06
期刊：
影响因子：
--
通讯作者：
R. Greenwood;O. Scott;H. P.E.M.;Habets;-D.;Franco;J. A.;Sargeantt;J. Pereira;A. Moorman
中科院分区：
文献类型：
--
作者：
R. Greenwood;O. Scott;H. P.E.M.;Habets;-D.;Franco;J. A.;Sargeantt;J. Pereira;A. Moorman
背景：在等张收缩过程中，骨骼肌在负荷作用下缩短。肌肉缩短的速度与所施加的载荷有关，可以用Hill方程图形化地表示：（F + a）(V + b) = (F + a)b方程1其中F为载荷，V为缩短的速度，F为肌肉在等距收缩过程中所能产生的最大力，a和b为常数。这个方程得到一条双曲曲线。现在，如果我们画出[(F - F)/V]并加载，我们会得到一条斜率为b， y轴截距为- a的直线。这是一种有用的方程形式，它允许我们使用回归的力量来计算常数，并从测量参数预测某些变量。更具体地说，它允许我们计算肌肉在施加任何负荷时缩短的速度。在动物系统中，肌肉通过附着在骨骼系统上并以杠杆方式移动骨骼来提供运动能力。杠杆有三大类（第一类、第二类和第三类），大多数动物的杠杆系统都是第三类，肌肉收缩更靠近支点，与负载在同一侧。然而，动物系统中确实存在其他杠杆系统我们今天要关注的是腓肠肌的第二类杠杆。第二类杠杆在支点的同一侧也有负载和肌肉收缩，但在这种情况下，负载在支点和杠杆之间。我们可以使用扭矩（扭矩=力x力矩肌肉收缩臂）来测量杠杆系统的机械优势，并确定给定肌肉骨骼系统所需的收缩力。我们还可以看到动物的速度归因于腓肠肌的收缩。为了做到这一点，我们使用旋转物理，将支点作为枢轴点，将负载和肌肉收缩作为围绕枢轴旋转的点。在一个旋转体中，沿一条直线的所有点都有相同的角速度（ω），然而，不是…
Background During isotonic contraction, skeletal muscle shortens against a load. The velocity of muscle shortening is related to the load applied and can be graphically represented by the Hill equation: (F + a)(V + b) = (F o + a)b Equation 1 Where F is the load, V is the velocity of shortening, F o is the maximum force that can be developed by the muscle during an isometric contraction, and a and b are constants. This equation results in a hyperbolic curve. To make it more useful as a tool, this equation can be linearized to produce the following equation: F = b [(F o – F)/V] – a Equation 2 Now if we graph [(F o – F)/V] and load we get a straight line with a slope of b and a y-intercept of –a. This is a useful form of the equation that allows us to use the power of regression to calculate the constants and to predict certain variables from measured parameters. More specifically, it allows us to calculate the velocity of muscle shortening when applying any load. In animal systems, muscles provide locomotor capacity by attaching to the skeletal system and moving the bones in a lever fashion. There are three major classes of levers (1 st class, 2 nd class, and 3 rd class) and most of the lever systems in animals are 3 rd class with the muscle contraction closer to the fulcrum and on the same side as the load. However, other lever systems do exist in animal systems and the one we are going to focus on today is the 2 nd class lever of the gastrocnemius muscle. 2 nd class levers also have the load and muscle contraction on the same side of the fulcrum, but in this case the load is between the fulcrum and the lever. We can use torques (torque = force x moment Muscle Contraction 2 arm) to measure the mechanical advantage of a lever system and to determine the force of contraction necessary in a given musculoskeletal system. We can also look at the animal's velocity attributable to contraction of the gastrocnemius. To do this, we use rotational physics with the fulcrum as the pivot point and the load and muscle contractions as points rotating about the pivot. In a rotating body, all points along a line have the same angular speed (ω), however, not …