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There is physics everywhere in life, and there is life everywhere in physics

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But there is a difference between running and walking, that is, if the landing point of the front leg is in front of the projection of the center of gravity during running, there will be a friction that will hinder the progress of the system, so in the correct running movement, the landing point of the front foot should be directly below the center of gravity

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If your feet fall behind your center of gravity, your center of gravity will be more forward each time you fall, resulting in a fall

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After that, let’s talk about inertia

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Because in the process of running, the relative position of each part of the human body will change, that is, the particles in the particle system will have relative displacement

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If the landing point of the front leg is too far forward, you will feel a backward friction when the foot touches the ground, which will produce a backward impulse to the mass system of the person, thus reducing the running speed

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The center of gravity fluctuation does not contribute to the running speed, but you will consume more energy

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The so-called inertia is the ability of an object to maintain its original state of motion, including translational inertia (measured by mass) and rotational inertia (moment of inertia)

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In the process of running, the movement of human body can be divided into four movements: vertical upward motion, straight-line motion in the forward direction, rotating motion along the vertical center line of the body, and left-right swing of the body

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And can effectively avoid unnecessary force, reduce running injury

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Many running tutorials emphasize hip sending, which can increase stride length and speed

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Alternating legs, the lower body makes an alternating rotation

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The ground gives people forward friction and produces forward impulse, while the upward force makes people jump in the air

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In order to make a correct running posture, muscles must control different parts to make corresponding movements under the coordination of nervous system

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When running, rely on the flexible rotation of the spine, swing the arm with the lower limbs to form a very coordinated movement, and run briskly

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The forces in the vertical direction include gravity and the supporting force of the ground

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But if you do a hip feed, you will find that your lower body rotates around the vertical axis of your body

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Let’s take a look at the forces that affect running

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There is a kind of in-situ stride frequency training in sprint, which is to make running movements in-situ

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In this way, for the whole human body, a resultant moment as small as possible can be generated without the friction between the foot and the ground

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The greater the resultant force, the higher the jump height

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Now that you’ve finished arm swinging, let’s talk about legs

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As we said earlier, in order to overcome the rotation inertia, rotation needs to give an external moment to the rotating part of the body, while the swing arm just makes the other part of the body rotate in the opposite direction

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We know that the upward force has no direct contribution to the speed of running, so if the vertical component is too large, it will cause too much fluctuation of the center of gravity during the whole running process

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When we analyze running, we should not regard people as a whole as a particle, but as a system of particles

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Of course, most of us runners don’t need complicated physical calculation, but if we understand these knowledge in running, we can better understand the requirements of running posture

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Without friction, you can’t walk or run

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That’s why running requires good coordination

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This displacement is generated by keeping the running action, and it is powered by the muscles, which is the internal force

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If you fix your arms, you will find it difficult to run

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When the body uses the internal force (muscle force) to make a pedal action under the control of the nerve, the resultant force of the support force and gravity of the ground will give the mass of the human body an upward acceleration

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After the forelegs fall to the ground, they begin to push upward and backward on the ground

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Because of this, arm swing is not only good for running, but also reduces the extra energy consumption

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Although it does not do work, it provides the impulse when changing the movement of the limbs inside the human body

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Its function is to balance hip delivery

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Internal and external forces

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Friction when the foot pedals on the ground, it will produce friction with the ground

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With the increase of the frequency of high fives, you will find that only by increasing the frequency of arm swing, can the frequency of legs keep up, so the stride frequency is actually controlled by arm swing

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But do you know why? Xiao Bian, today, I’d like to talk about the physics knowledge in running, which helps you improve your running level quickly

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As a system of particles, different parts of the human body move in different ways, so the effects of inertia and rotational inertia are different

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And these movements need to overcome the inertia of different parts to make, so the impact of inertia is very big, which is why the running posture is not right, will feel very tired, internal consumption is too big

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Running is a process of jumping forward

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What if the foot falls behind the center of gravity? I can only say that in this way, you will fall, because running is the same as walking

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I don’t know if you have such an impression that every running tutorial is about teaching you how to swing your arms, legs, land and breathe

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What is the right running posture: when people teach you to run, they may start with legs, but I want to start with arm swinging, because arm swinging is the real core of running posture, the controller of running, and the energy-saving system of running

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Another function of the swing arm is to balance and save energy

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Air resistance when walking, if not facing the strong wind, air resistance is very small, almost negligible, but when running, air resistance is a factor that can not be ignored, air resistance is always a force to hinder the running speed, the faster the speed, the greater the air resistance, its size is proportional to the square of the speed, so the air resistance in sprint is It’s several times as fast as the middle distance race

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Using scientific running posture, conforming to natural forces and using natural forces will make running easier

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As I mentioned in the previous article “popular science: the way you walk is very” physical “, friction is very important in walking

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We mentioned that the landing point of the front leg should be directly below the center of gravity

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Studies have shown that the change of vertical center of gravity of professional athletes will be controlled within 6 cm, while the average runner is inferior, with an average of about 10 cm

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When the foot falls to the ground, it is a rotation of the human body with the supporting leg as the axis

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For the whole system of particles, the external forces are the supporting force of the ground, gravity, ground friction and air resistance

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