The Su God of the Reopening of the Sports Arena

Chapter 2215 The Impossible Possible! Really...More Noble!

This is what surprised Zhao Haohuan.

Two hundred meters.

But it's a bend.

There is centripetal force on the curve.

Start by cutting into the curve.

Aren’t you afraid of falling if you do this?

This center of gravity...

It's a bit too low.

So low.

Zhao Haohuan didn't even have to try to suppress it.

It’s definitely a fall.

Absolutely out of control.

All start with bent arms.

Zhao Haohuan thinks there shouldn't be much difference.

pity.

There is a big difference.

Not only is Su Shen already a bent-arm start 2.0, but also...

bang——

Gunfire rang out.

When starting, Su Shen's feet pushed the ground with strong and efficient force, which was the perfect application of Newton's third law.

When he bends his knees and pushes hard on the starting blocks, the contraction force generated by the leg muscles is transmitted to the starting blocks through the soles of his feet.

According to Newton's third law, the starting blocks will exert an equal and opposite reaction force on Su Shen.

This reaction force became one of the direct sources of power for him to start running.

Because in the actual starting process, the size and direction of the ground pushing force have a key influence on the starting effect.

Normally, when the starting angle, that is, the angle between the legs and the ground, is controlled at 40 to 45 degrees, the horizontal component of force can reach the optimal value, providing a strong boost for the start.

It will be slightly higher when it comes to curves.

Can't do that well.

After all, running in a straight line, although it still requires control, is much easier to control than running on a curve.

Just like what Zhao Haohuan was thinking.

If the starting angle is too large, the vertical component of force will be too large, causing the body to jump too high, while the horizontal propulsion force will be insufficient, affecting the starting speed.

If the starting angle is too small, although the horizontal component of force is relatively large, the efficiency of the leg muscles will be reduced, and the force of pushing off the ground cannot be fully exerted.

This is especially true on bends.

If you gamble for this, you may lose everything if you are not careful.

The whole rhythm is gone.

Although 100 meters also requires rhythm.

But obviously compared to 200 meters.

This eating rhythm is more.

But Su Shen, through long-term training, has been able to accurately control the starting angle of the curve, so that he can make the most reasonable use of his ground-pushing force.

It lays a solid foundation for acceleration at the start of the curve.

Newton's third law is better demonstrated here.

Bend your arms and explode in coordination.

start up.

During the bent-arm start, there is a high degree of coordination between Su Shen's arm swing and leg movements.

The powerful and steady swinging of the arms provides additional powerful momentum to the body.

From the perspective of the coordination principle of human movement, when the arms swing forward, they will drive the upper body to move forward, increase the forward leaning tendency of the body, and move the center of gravity further forward.

This movement of the center of gravity is transmitted through the body, which can help the legs exert better force.

Just like when rowing, the action of the arms paddling drives the body forward, allowing the legs to push against the bottom of the boat more powerfully and propel the boat forward.

When the arms swing backwards, it is like a rowing oar paddling the water backwards, giving the body a backward reaction force.

According to the principle of interaction of forces, this backward reaction force will push the body forward.

Moreover, the rhythm of the arm swings and the rhythm of the leg movements echo each other, forming a steady rhythm of movement.

At this time, because you have just started, if the arm swing rhythm is too fast or too slow, it will destroy the coordination with the leg movements, resulting in the inability to effectively integrate the strength of various parts of the body, thereby reducing the efficiency of the start.

Startup efficiency is the most important aspect.

It didn't get up here.

The whole acceleration will collapse.

Even running in the middle will collapse.

Here, although Su Shen has such a low center of gravity, he has achieved perfect coordination between arm swings and leg movements, optimizing the strength of various parts of the body and greatly improving the speed and effect of the start.

How?
This body control.

However, there is still one level that you haven't passed.

That's cutting into the curve.

This is not a straight road.

This is the bend.

Even if Su Shen's lane is not the first one and it is not that difficult to run, how do you cut into the curve if you want to do this?

If you know a little about the biomechanics of sports, you will know why Zhao Haohuan was so surprised.

This is not cheating.

If you want to do this, you have to go against the mechanical system and Newton's laws.

It's not like you're playing a game, just add some points.

Simply put, when starting the 200-meter race, the first thing to pay attention to in the biomechanical basis of human movement is the correlation between the center of gravity position and the muscle force pattern.

Generally speaking, the power of the human body in the starting phase comes from the explosive contraction of the lower limb muscles, especially the coordinated force of the extensor muscles such as the gluteus maximus, quadriceps femoris, and calf triceps.

The position of your center of gravity directly affects the initial length-tension relationship of a muscle group.

If you start with a center of gravity that is too low, the mechanical characteristics of the low center of gravity will be distorted.

When the athlete adopts a low center of gravity posture, the long head of the quadriceps is in an over-stretched state, exceeding its optimal force length range, and the tension is maximum when the muscle fiber length is 1.2 times the resting length.

At this time, the cross-bridge binding efficiency of actin and myosin in the sarcomere decreases, resulting in a decrease in power output during concentric contraction. Of course, the prerequisite is that you understand the mechanical model of muscle contraction.

Otherwise you just look the way you look, which is something old-school experience can't tell you.

because.

They themselves don’t know.

Secondly, there is the issue of the mechanical transmission efficiency of the joint angles.

The angles of the ankle, knee, and hip joints constitute the "power chain transmission system."

Research from Su Shen's laboratory shows that when the knee joint angle is in the range of 110°-130° at the start, the coordinated force of the quadriceps and hamstrings is most efficient.

A too low center of gravity will force the knee joint angle to be less than 90°, causing the quadriceps to be forced to exert force in a "disadvantaged lever" state. At the same time, the hamstrings are passively stretched, increasing the shear force of the knee joint and reducing the efficiency of extension.

That’s right, it’s “disadvantage leverage”.

Such a lever will definitely cause your startup efficiency to drop significantly.

Not to mention the deeper issue of the time delay effect of neuromuscular coordination.

The nerve conduction speed in the starting phase is about 70-120m/s, which together with the muscle reaction time of about 0.1-0.2s constitutes the time bottleneck for movement initiation.

Having a low center of gravity can cause two neuromuscular adaptation disorders.

It can also cause delays in proprioceptive signal transmission.

Because when the center of gravity is low, the kyphosis angle of the thoracic and lumbar spine increases, which causes the postural signal pathway transmitted from the trunk proprioceptors, such as muscle spindles and Golgi tendon organs, to the central nervous system to be lengthened.

Increases the latency of spinal reflexes.

It is extended by about 15-20ms.

And the difficulty of multi-joint coordinated control increases.

A low center of gravity posture requires the ankles, knees, hips, and trunk joints to remain stable at the same time, and the central nervous system needs to coordinate more motor units to participate in the work.

fMRI studies have shown that the activation area of ​​the brain's motor cortex expands at this time, but the spatial synchronization of nerve impulses decreases, resulting in an increase in the time difference in muscle force generation, which affects explosive power output when it exceeds 50ms.

Of course, it is impossible to know this wave now.

Only Su Shen knows.

Because of Enoka, who came up with the concept for this paper, this experimental paper was published in 2015.

Before this.

No one knows that the decreased spatial synchronization of nerve impulses leads to an increase in the time difference in muscle force generation, which affects the explosive power output when it exceeds 50ms.

This is the power of science.

If you are future science, grasp the scientific context of the times.

That would be even more terrifying.

You can say that Zhao Haohuan did not have much professional knowledge and academic level at the beginning. He was just an athlete who followed the coach in training and competitions, and he did whatever the coach asked him to do.

In this respect, they are no different from those black guys.

But he stayed with Su Shen for nearly ten years.

Tell me, if you follow people like this every day, how can you not be photogenic, improve yourself, and be influenced by them?
Zhao Haohuan is afraid that he will fall behind the times after not reading Su Shen's paper for three days.

because……

He had realized this fact long ago.

The person in front of me now.

He is the pioneer of the times.

If you don't read his stuff, he may have created a new world in a few days.

Expanded the new system.

If you don’t watch, you’ll fall behind.

There's really nothing wrong with that.

Under such pressure.

Lao Zhao really feels that he has integrated into this system unknowingly, and he uses his brain more to think about problems while running.

This is what Su Shen most hopes that everyone and this generation of athletes can do now.

The definition he gave was -

Athletes in the new era.

You need to learn to use your brain more when running.

Rather than just using your muscles to run.

These two sentences.

It can be said that it was deeply engraved in Gou Huan's mind.

Even if he is not as proficient as Su Shen, compared with ordinary coaches, he can make subconscious scientific judgments in an instant.

What are the specific problems and difficulties?

If Su Shen heard it, he would definitely give Zhao Haohuan a thumbs up.

To express praise.

Because I said so.

That's right.

Under the biomechanical model of centrifugal force balance, the radius of the curve in the 200-meter race is about 36.5m. According to the circular motion formula, when an athlete enters the curve at a speed of 10m/s, he or she must withstand a centripetal acceleration of at least about 2.74m/s.

This is equivalent to a centrifugal force of 0.28 times body weight.

According to the moment of inertia effect of the low center of gravity,

Lowering the center of gravity makes the body mass distribution closer to the rotation axis, that is, the foot support point, which can theoretically reduce the moment of inertia. However, in practice, the lower center of gravity accompanies an increase in the forward tilt angle of the trunk, which leads to a decrease in the balance threshold between the gravity moment and the centrifugal moment. Experimental data show that when the center of gravity height is lower than 45% of the height, the tolerance of the minimum tilt angle error required to maintain balance decreases by 32%.

Plus the vector decomposition of the support reaction force.

When running on a curve, the ground support reaction force GRF can be decomposed into a vertical component (F_v) and a horizontal component (F_h):
Starting with a low center of gravity will cause the vertical force to account for too high a proportion of the initial push, exceeding 70%. The normal start is about 55-60%, which will cause the body's center of gravity to rise prematurely and destroy the "stable tilt" posture required for cornering running.

For every 10% increase in the vertical force, the body roll angle error when entering a curve increases by 4.2°.

Running on a curve requires that the horizontal component of force has both the tangential direction of the propulsive force and the normal direction of the centripetal force.

The low center of gravity causes the direction of extension to be biased towards the rear and downward. The tangential component of the horizontal force accounts for more than 85%, and the centripetal force component is insufficient to the normal requirement of 30-35%. This forces athletes to compensate for the turning force by increasing their stride frequency, exacerbating muscle fatigue.

In addition, there is the specific impact of a low center of gravity on the transition between starting and cornering.

For example, the space-time mismatch of momentum transfer.

The main task of the startup phase is to quickly establish horizontal momentum, while cutting into a curve requires redirecting the momentum direction.

According to the impulse theorem, although the extension force action time is prolonged when the center of gravity is low, the peak force value is reduced, and the final impulse increment is only 89% of that in the normal posture, and the horizontal speed gain is reduced.

Redirection of the momentum vector requires overcoming the moment of inertia.

When the center of gravity is low, the axial component of the body's moment of inertia increases by 18%. As the torso leans forward, the mass distribution moves away from the axis of rotation, which increases the angular impulse required for steering. Extending the adjustment time for entering a curve by more than 0.2s will significantly affect the performance.

Combined with the mechanical coupling disorder of the respiratory-circulatory system.

It seems to be true...

Dead end.

Unable to break through.

But in fact.

It just seems impossible now.

But for Su Shen, who possesses the future knowledge system.

It's completely different.

In his eyes.

This is by no means an unbreakable law.

In fact.

There are many ways.

First, we use the angular momentum coupling principle of the upper limb power chain in the bent-arm start to make the order of magnitude difference in the moment of inertia.

The angular acceleration of the curved arm swinging arm can reach 4 times that of the straight arm, and the angular momentum generated per unit time is increased by 50%, which reduces the active torque required for trunk steering by more than 30%.

The key point comes when you enter the curve.

Cut the curve!
Su Shen's right arm needs to swing toward the centripetal side to generate positive angular momentum.

The left arm maintains a small forward and backward swing to balance the torque.

曲臂状态下，右臂摆幅可精准控制在45°-60°，打破直臂受限至30°-40°，角动量矢量与弯道圆心夹角缩小至20°-25°，向心力分量占比提升至15-20%，直臂仅8-12%。

The bent-arm posture conforms to the anatomical functional position of the upper limbs, with the natural flexion angle of the elbow joint at 80°-100°. The intensity of motor cortex activation is reduced by 18%, which can save neural resources for lower limb coordination.

Of course, this alone is not enough.

It’s so simple, hasn’t everyone else done it?

Just starting with bent arms is not enough.

You also need to learn to use the biomechanical coupling system of shoulder-hip linkage. When starting with bent arms, the scapula retractor muscles, rhomboid muscles, middle bundle of trapezius muscles, and gluteus medius form a cross-trunk synergistic chain.

In this way, during the right arm backswing phase, the activation intensity of the ipsilateral gluteus medius muscle will increase by 22±5%, which can effectively inhibit the pelvic tilt fluctuation and reduce the amplitude by 3.5±1.2°.

Used to compensate for the balance defects that may be caused by the low center of gravity.

Then, a "shoulder girdle-pelvis" rotation coupling model was established, proving that arm bending and swinging can increase the trunk twisting rate by 15% and shorten the posture adjustment time for entering a curve by 0.06-0.09s.

Then perform the synchronization of upper and lower limbs in impulse transfer.

The arm swing cycle of about 0.25-0.3s is used to highly match the step frequency in the starting phase. The phase of arm swing-extension can be locked, for example, the forward swing of the right arm is synchronized with the extension of the back leg.

The peak value of the horizontal component of the instantaneous ground reaction force occurs 10-15ms earlier.

The impulse utilization rate is increased by 9-12%.

In addition, the fascia system has not yet appeared and will gradually be scientifically valued after 2021.

Elastic potential energy management of the posterior fascia chain!
For example, when the center of gravity is low, the posterior fascial chain, plantar fascia → Achilles tendon → hamstring → erector spinae, is over-stretched, exceeding its elastic limit, about 1.3 times the resting length, resulting in a decrease in elastic energy recovery efficiency.

The stress-strain curve of the rear bracelet fascia preload is used for regulation.

Before starting the race, quickly raise your heels and drop them, which creates a preload strain of about 2-3% on the plantar fascia and Achilles tendon, which is in the linear elastic range of the stress-strain curve and has the largest slope.

At this time, the energy storage efficiency of the myofascial complex increases by 35%, and an additional 12-15% of energy can be recovered during stretching.

At this time, for every 10J increase in the elastic recovery of the posterior fascia chain, the energy consumption of the quadriceps concentric contraction is reduced by 8%, offsetting the power loss caused by the low center of gravity.

Then use the trunk stiffness enhancing effect of fascia tension!
Increasing the tension of the erector spinae fascia can increase the stiffness of the trunk by 25-30 N·m/rad, which is achieved by maintaining the lumbar lordosis angle at 20°-25°, reducing the trunk flexion compensation caused by the low center of gravity during starting, and the angle error is within <5°.

Activating the posterior superficial fascial chain can reduce trunk angular acceleration by 18% and the energy consumption of neuromuscular control by 14%.

Unfortunately, there is no way to know this now.

Because currently no biomechanics laboratory has fascia tension sensors.

The only one there is.

There is only Su Shen Laboratory.

Then you won't be able to make use of this system.

It is impossible to solve this pain point.

After entering the curve, centripetal force surges.

Immediately optimize the power transmission of the anterior fascia chain!

The orderly activation of the front superficial fascial chain of tibialis anterior muscle → rectus femoris → rectus abdominis establishes the mechanical structure of "forward support column", transmits the extension force of the lower limbs directly to the trunk along the fascial path, and reduces the loss of joint torque.

Mobilize the angle guidance function of the tibialis anterior muscle!
During the start, the tibialis anterior muscle contracts eccentrically, the ankle dorsiflexion is controlled at 90°-100°, and the horizontal component of the ground reaction force is directly transmitted to the rectus femoris through the fascial connection.

Shorten the power conduction path by about 15cm.

Conduction efficiency increased by 20%.

If this is not done, when the center of gravity is low and the ankle joint is plantar flexed, the power needs to be transmitted completely through the Achilles tendon → hamstring → ischial tuberosity, the path is extended by 30cm, and the energy loss increases by 19%.

Then utilize the isometric contraction effect of the rectus abdominis!
When the trunk is tilted forward at 45°-55°, the rectus abdominis is in an isometric contraction state, and the pelvic tilt angle is controlled at 5°-8° through fascia tension, avoiding the pelvic tilt backward of 10° caused by the low center of gravity, which would cause delayed activation of the gluteus maximus.

Because activating the anterior superficial fascial chain can shorten the gluteus maximus activation latency by 28±6ms.

This makes the peak extension force appear 15ms earlier!

As you enter the curve, the road deepens.

The centripetal force is greater.

With the center of gravity so low, the impact will be even greater. This is an unsolvable situation at present, but unfortunately...

Su Shen mobilizes the spiral fascia chain for cornering and steering coordination!

The spiral fascia chain, the diagonal connection characteristics of the sternocleidomastoid muscle → the contralateral external oblique muscle → the iliotibial band, can efficiently transmit the rotational torque required for steering.

When running around a curve, accelerate and turn your head toward the center of the circle to activate the right sternocleidomastoid muscle.

Active trunk twisting is produced by stretching the left external oblique muscle through the spiral fascial chain.

It forms synergy with the centripetal force of lower limb extension.

This mechanism can reduce the muscle torque required for steering by 22% and reduce energy consumption by 17%.

If you don't do this, then with a low center of gravity and without the spiral chain activated, your torso twist will only be 4°-6°.

The need to recruit additional unilateral fibers of the erector spinae muscle leads to a 9% increase in ineffective energy consumption.

Then mobilize the lateral stability of the iliotibial band!
Use spiral chain tension to transmit to the lateral knee joint through the iliotibial band.

To provide the additional 5-8N of lateral support that is most needed now.

To offset the varus moment of the knee joint when the center of gravity is low!

This will reduce the load on the anterior cruciate ligament!

It also allowed Su Shen to turn with a low center of gravity.

Smooth and sharp.

Of course why not do it somewhere else?

There is also the biggest point.

That is.

Do it somewhere else.

Light rail is only available in plateau areas, especially where the altitude reaches this level.

Comparable to Mexico City.

Under such air resistance.

Only then can these points be easily completed.

Su Shen also needs actual combat. No matter how many things are in his mind, they need actual combat to be realized.

So he said it every game.

Every game.

Everyone has their own plans and detailed goals.

This is what a restarter without cheats should really do.

and so.

That's what it looks like from the scene.

Su Shen lowered his body center of gravity lower than when he was on the straight road.

result.

But it produces a sharper effect than running on a curve on the plain.

This wave comes out.

It instantly blinded everyone's titanium dog eyes.

At least Zhao Haohuan is not the person involved.

Although it feels like it conflicts with the cognition in my mind.

But the proprioception is not that strong.

You can replace them with the ones who run with him.

Especially the ones with close passes.

It was like my heart was bursting with swear words——

Damn it.

Mr. Su.

this is.

Keep it to yourself!

Are they all starting with bent arms?

you tell me.

Does your bent-arm start have this effect?
Is what we practiced fake?

Or are we the castrated version?

Bankruptcy version?

otherwise.

What about you.

So fast???

The scene was even more direct, Yang Jian shouted directly -

"My goodness."

"Su Shen exploded as soon as he started, as if the rest of the people couldn't run a curve!"

Xie Zhengye: ...

Zhou Bing:......

Mr. Su!
A-Tian!

Don’t leave after school!

Oh no, don’t leave after the game is over!
We have something to ask you!