Technical analysis room in Ersha Island.

The group was watching the Bolt video played and nodded from time to time.

This is the latest data analysis established by Randy and Ralph Mann after the championship model analysis.

Some freeze-framed data are shown above:

The speed of excitation and inhibition in the movement center of the cerebral cortex, that is, the flexibility of the neural process. According to data, the fastest exchange frequency of the legs when running along the way is 3.1~4.85 times/second. This can be said to be very rare in his height.

Because athletes of such high height generally have stride types, and Bolt is obviously a "special case".

He is actually of the type of stride frequency, the key is... his stride is basically both due to physiological reasons.

1. The formula of stomping force: F=mv/t(∵F=ma;a=(v-v0)/t and ∵v0=0 ∴a=v/t ) is a constant, since m represents the mass of the human body here, the greater the force (F) of the rear stomping within unit time, the greater the speed of the human body moving forward (v).

2 The speed of pushing the ground: If the force of pushing the ground (F) is constant, the speed (v) is inversely proportional to the time of pushing off the ground (t), that is, the shorter the time of pushing off the ground, the greater the speed obtained.

The degree of straightening of 3 legs: it is mainly reflected in the three joints of the hip, knee and ankle, so that the reaction force on the ground can fully push the body forward through the center of gravity of the human body.

4. The angle of pedaling: Due to the characteristics of the human body structure, the angle of the rear pedaling is limited. Reducing the angle of the rear pedaling is not only conducive to increasing the horizontal component force, but also reduces the degree of ups and downs of the body's center of gravity. In addition, reducing the angle of the rear pedaling is also an important factor in accelerating the frequency of exchange between the two legs.

5. The direction of force of the rear pedal: The direction of force of the rear pedal should be consistent with the direction of progress. If the direction of force of the rear pedal is to the left or right, the force will be generated, reducing the speed of progress and affecting the linearity of the movement of the body's center of gravity.

Then he brought Bolt's physical and competitive data one by one.

Under the "Champion Model" display, Bolt's data changes in the Beijing Olympic finals:

The applied force F/N, 804.7 is significantly improved compared with the previous 2007.

The maximum speed is 12.04s, which is also significantly higher than the previous year.

The startup acceleration is 9.36, which is still significantly improved.

The peak output power is 2554.35, an increase of nearly 100 points compared to last year.

Overall work is 80.465, compared with ↑ in 2007.

The efficiency of work is 6.235, which is still a significant increase in unit efficiency compared to 2007.

When the hip is sent, the front swing angle of the leg body is swinged/°: 62.3.

When the hip is sent, the front swing angle of the leg body is swinged/°: 77.

Swing the legs at the beginning to end of the hip delivery/°: 14.7.

When the hip is sent, the front knee joint fan angle of the leg body is swung at the beginning/°: 50.8.

The fan angle of the front knee joint of the front of the leg is swung at the end of the hip delivery/°: 78.3.

The difference between the fan angle of the knee joint at the beginning and the end of the hip delivery: 27.5.

...

Seeing the dense data displayed on the big screen, even these "battle-standing" veterans and coaches felt that the data was too...a bit detailed.

Compared with this, the previous competition summary is at the level of elementary school students.

"The Olympics used 41.25 steps." Randy watched the video above and moved the progress bar bit by bit and said: "There are 2-6 steps less than the other players, showing Bolt's super step size ability. The step frequency step size is the most perfect one at present."

"The knee angles of Bolt's support legs are 157.1° and 146.8° at the moment of the Olympic landing and vertical stages, respectively."

“The path deviation of the startup is small and quite straight.”

"When the knee moves forward, his hips will rotate inward and there will be a lot of transverse center of gravity."

"His starting posture is obviously not compact enough, but it is unconventional and a little relaxed."

“I think it was his compensation strategy to maximize the initial speed of force production in the initial stage.”

"Look at Bolt's ground again." Randy clicked the video, played for a while, and paused again: "Look at his ground foot, the changes in the center of gravity, he did not seem to put his feet under the center of gravity. I think the only thing he could put down his center of gravity should be in the starting stage. This means that the closer the center of gravity of the body, the faster the person can complete the running cycle, so the results will naturally be faster."

"There is also the problem of Bolt's hip lifting back," Randy said. "I think this is the key."

"Many of our athletes emphasize pace frequency too much and ignore full hip movement, so that motivation will be lost during the gradual reduction of step length, which will affect performance."

"There is also Bolt's vertical oscillation, very small." Randy pointed a corner of the screen with a small wooden stick, just in front of Bolt's running position: "Because the smallest vertical swing usually reduces the pressure on the joints and increases efficiency during operation."

“These are some of the key points we overlook in our training.”

...

"Okay, look at the data comparison of our athletes this Olympic Games." Randy put out the photo of Lao's rest and said: "First of all, we don't have much physiological problems with Lao's future positioning. Although Lao's height is 25cm shorter than Bolt's height, we can see that even so, Lao's step length index still surpassed Bolt's 1.245 at 1.249. This shows that Lao should indeed mainly move the stride flow and the step frequency is auxiliary. It also reveals a major reason why Lao's future success is so strong."

Can work and rest actually beat Bolt in the stride index? It's true.

But in the past, I am afraid no one dares to say this.

For fear of making a wrong judgment, he ushered in huge public opinion attacks.

"But while Lao has an excellent step length index, his step frequency index is quite bad." Randy carefully analyzed the data model to all Ersha Island coaches and athletes in-depth: "It's 0.554."

"Law, your future needs not only to strengthen your future, but also to strengthen your entire pace frequency, so that you can run faster."

Although he was a little less clear about work and rest, when he talked about himself, he still listened carefully to the teachings more seriously than ever.

In order to avoid the fourth 100-meter chair in Ersha Island that I finally got into, I will give in.

"On the way, your landing angle ratio is 65.3, which is five or six percentage points less than Bolt. The smaller the landing angle, it actually means that Lao's "ground-picking technology" still has a lot of potential to dig." An analysis was displayed on the screen, which reads: A small landing angle means that the vertical projection point of a person's center of gravity is farther away from the landing point, which will inevitably produce a larger support reaction force opposite to the direction of running, causing a horizontal speed loss and affecting the running speed.

The angle of the knee angle of the support leg becomes 148.3 to 140.4.

In this way, the change in the two actions of work and rest is too small, only 7.9.

The knee angle changes of these two technical movements are the most obvious. His data is directly doubled than work and rest. This shows that Bolt's support leg muscles are more active in retreating. Because of this, the active muscles of the support leg during the buffer period are passively lengthened, the initial length of the muscle increases, and the contact area between the crossbridge and the site increases, which increases the muscle tone. Therefore, the direction can be changed to preserve Bolt's muscles in the rear kick stage and exert greater contraction force and speed.

How to do it specifically? Randy looked at Su Shen below and asked him to come up and explain together.

Su Shen was not polite, and walked up to the work and rest in the audience and spoke: "The next thing you have to do is to speed up the swinging speed of the swing legs, which can effectively increase the buffering and pedaling speed, and shorten the competition time, and finally get a strategy to increase the pace frequency."

"Big bull, the minimum knee angle of the doting swing legs is 25.5. It can be seen that your swing legs are not folded enough, which will affect your forwardness. This year until the end of winter training, your swing legs folding technique should be reconciled. Remember to try to promote pedals with swing and combine pedals with swing."

"Okay, I know Brother Xiaotian." After hearing this, Lao Yi silently took notes.

Although he may not be so excellent in theoretical knowledge, Randy's method of changing data into video and then adding text analysis allows many team members who are not as good as digestion of theoretical knowledge and can quickly get into the state.

Understand where you are wrong and where you need to continue to improve.

"Brother Kai, this is your Olympics data, especially the vertical stage at the moment of landing. Bolt's knee angle changes to nearly 20. But Brother Kai, you are only in your early 10s. This shows that the support legs are shrinking from centrifugal to centripetal contraction. Brother Kai, you are not doing enough. There is still room for strengthening."

"Look at the distribution of your stride frequency and stride width of the entire 100 meters, it is still a little too fast in the front." Su Shen said: "This will prevent your back from playing the real extreme, and your overall score will be less optimized, and it will be slower. Especially between the 11th and 15th steps, the instability will be more obvious. If you can stabilize, your score may be improved later."

Hu Kai also pushed his glasses.

Looking at his running data on the entire projection screen, he also nodded silently after reading it patiently.

There was no such detailed data analysis system before.

Therefore, even coaches can only see the feeling.

But now Randy has brought scientific and systematicity, which has greatly improved the observability of the team at once.

Under the championship system model, Hu Kai has a clearer understanding of his shortcomings.

It's really clear at a glance.

It doesn’t matter to the new team members, and they don’t have enough understanding of this system and are not deeply touched.

But for the old players, they can clearly feel the earth-shaking "change" of post-match review.

The previous "post-match review" was not so detailed, but now... everyone has a lot of things to remember.

This is the benefit of systematization and scientificity.

Clear, clear, what the athletes want to improve, and sometimes even look at the data gap, that is enough.

...

"Haohuan, let's look at your set of data. Your height is about five centimeters shorter than Bolt, but as a big man who is over 1.9 meters tall, your legs and swing legs are significantly different from Bolt. Bolt's two legs and swing legs in this final were 96.8 and 12.1, respectively, while you are 100 and 11.1, which shows a little bit." Su Shen clicked on the continue play button, and another line of analysis was shown above, saying: "Your rear kicking foot, rear kicking knee angle and your support time are too long, so your legs and swing legs are weaker than Bolt."

"Even if you consider the physiological segmentation curve, we think you can correct this aspect more quickly."

"The specific method is to strengthen your legs, reduce the rear pedal angle appropriately, and shorten your support time. This is our analysis of the championship model calculated based on your four shots and 100 meters in this Olympics."

Zhao Haohuan looked at it, touched his chin with his hand, and in an intuitive comparison, he could indeed see many problems in the high-definition close-up shot. And compared with the past, the adjustments now are more detailed and more high-end.

This is the adjustment after athletes have improved to a higher level.

It's no longer just a simple adjustment of a certain technical action.

Each of these physical data may be translated out to compare and view one by one.

As for why Bolt is used.

That's all.

Because Bolt is the fastest.

Not only now, but also Bolt has been pulled out countless times to analyze and compare.

If a person runs the fastest, any set of running data of his will have the meaning of absorption, analysis and reference for scientific data models. This is also the reason why Su Shen must introduce the "champion model theory" to China.

Otherwise, there is no scientific data model theoretical guidance, and it only depends on the so-called coach experience summary.

It's really too old.
To be continued...