Ersha Island's technical analysis room.
The group of people were watching the Bolt video being played, nodding from time to time.
This is the latest data analysis established by Randy and Ralph Mann after analyzing the Champion Model.
Some fixed data are typed above:
The conversion speed of excitation and inhibition of the motor center of the cerebral cortex, that is, the flexibility of the neural process. According to data, the fastest exchange frequency of the two legs during running is 3.1 to 4.85 times/second. This can be said to be very rare given his height.
Because athletes of such height usually have long strides, and Bolt is obviously a "special case".
He actually has a cadence type. The key is...his stride length is basically both due to physiological reasons.
①The formula of kicking force: F=mv/t(∵F=ma;a=(v-v0)/t and ∵v0=0 ∴a=v/t), since m here represents the mass of the human body and is a constant , so the greater the back-pedaling force (F) in unit time, the greater the forward speed (v) of the human body.
②Kicking speed: If the force of kicking (F) is constant, the speed (v) is inversely proportional to the time of kicking off the ground (t). That is to say, the shorter the time of kicking off the ground, the faster the speed obtained. big.
③The degree of straightening of the legs: mainly manifested in the alignment of the three joints of the hips, knees, and ankles, so that the reaction force from the ground to the human body can fully push the body forward through the human body's center of gravity.
④Kicking angle: Due to the characteristics of the human body structure, the back kicking angle is limited. Reducing the back kicking angle will not only increase the horizontal component of force, but also reduce the ups and downs of the body's center of gravity. In addition, reducing the back pedaling angle is also an important factor in speeding up the frequency of legs exchange.
⑤ Direction of back pedaling force: The direction of back pedaling force should be consistent with the forward direction. If the direction of back pedaling force is to the left or right, it will produce a component force, reduce the forward speed, and affect the linearity of the movement of the body's center of gravity.
Then we brought in Bolt's physical data and competitive data one by one.
Under the "Championship Model" display, Bolt's various data changes in the Beijing Olympic finals:
The applied force F/N is 804.7, which is significantly improved compared to the previous one in 2007.
The maximum speed is 12.04s, which is also significantly improved compared to the previous year.
The starting acceleration is 9.36, which is still a significant improvement.
The peak output power is 2554.35, which is nearly a hundred points higher than last year.
The overall work done is 80.465, compared to 2007↑.
The efficiency work is 6.235, which is still a significant increase in unit efficiency compared with 2007.
The front swing angle of the leg when starting to send the hip forward/°: 62.3.
The front swing angle of the swing leg at the end of the hip movement/°: 77.
Swing leg swing angle/° from the beginning to the end of hip delivery: 14.7.
When starting to move the hip, swing the leg forward and the fan angle of the knee joint/°: 50.8.
At the end of the hip movement, the fan angle of the front knee joint of the leg swing/°: 78.3.
The difference in fan angle of the knee joint between the beginning of the hip thrust and the end of the hip thrust: 27.5.
…
Seeing this dense data displayed on the big screen, even these "battle-hardened" veterans and coaches felt that these data were too... detailed.
Compared with this, previous competition summaries are at the level of a primary school student.
"41.25 steps were used in the Olympics." Randy looked at the video above and moved the progress bar bit by bit: "It is 2-6 steps less than other athletes, which shows Bolt's super step length ability. Step length Frequency + step length, he is currently the most perfect one.”
"The knee angles of Bolt's supporting leg at the moment of landing and in the vertical phase in the Olympic Games are 157.1° and 146.8° respectively."
"The path to start has very little deviation and is pretty straight."
"As the knee moves forward, his hips are internally rotating and there's a lot of lateral weight transfer."
"His starting posture was obviously not compact enough. Instead, he was unconventional and a little relaxed."
"I think this is a compensatory strategy he adopted to maximize the initial velocity of force production at the beginning."
"Look at Bolt's kick again." Randy clicked on the video, played it for a while, and paused again: "Look at his kick, the mass point change in the center of gravity. He doesn't seem to have put his foot on the center of gravity. Under this, I think the only time he might lower his center of gravity is during the starting stage. This means that because the closer the feet are to the body's center of gravity, the person can complete the running cycle faster, so the results will naturally be faster."
"There is also the problem of Bolt's hip lifting." Randy said: "I think this is the key."
"Many of our athletes place too much emphasis on step frequency and ignore the full movement of the hips. In this way, power will be lost in the process of gradually reducing step length, thus affecting performance."
"There is also Bolt's vertical oscillation, which is very small." Randy tapped the corner of the screen with a small wooden stick, just facing Bolt's running posture and said: "Because the smallest vertical oscillation usually reduces the pressure on the joints. , and improve efficiency during operation.”
"These are some of the points that we neglect in training."
…
"Okay, let's take a look at the data comparison of our athletes in this Olympics." Randy typed a photo of Lao Yi and said: "First of all, there are not many problems with Lao's future positioning from a physiological point of view. Although Lao is taller than Bolt is 25cm shorter in height, but we can see that even so, Law's stride length index is still 1.249, which exceeds Bolt's 1.245. This shows that Law should indeed follow the stride length trend. , with cadence as an aid. It also reveals a major reason why Law’s rear range is so strong.”
Can Yi Yi beat Bolt in stride index? It really is.
But in the past, no one dared to say anything in China.
I am afraid that if I make a wrong judgment, I will face a huge public attack.
"But while Law has an excellent stride length index, his stride frequency index is quite bad." Randy carefully analyzed the data model and gave it to all Ersha Island coaches and athletes: " The difference is 0.554.”
"Lao, in the future you not only need to strengthen your future, but your entire cadence must also be strengthened so that you can run faster."
Although Lao Yi is a little unclear, when it comes to himself, he still listens more carefully than ever.
Otherwise, the fourth 100-meter spot in Ersha Island, which he had managed to get through with great difficulty, would just give up to him.
"When running on the road, 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 there is still a lot of potential in Lao's 'ground-grabbing technique'." An analysis was displayed on the screen, which read: A small landing angle means that the vertical projection point of the person's center of gravity is further away from the landing point, which will inevitably produce a greater support reaction force opposite to the running direction, resulting in a horizontal speed loss and impact. running speed.
The knee angle of the supporting leg becomes 140.4 from 148.3.
As a result, the change range of the two movements of work and rest is too small, only 7.9.
The knee angle changes in these two technical movements are most obvious for Usain Bolt. His data is directly more than double that of work and rest. This shows that Bolt's supporting leg muscles give way more actively, and because of this, the active muscles of the supporting leg are passively stretched during the buffer period, the initial length of the muscle increases, and the contact area between the cross bridge and the site increases, which increases the muscle tension. As a result, the direction can be changed to preserve Bolt's muscles during the back pedaling phase, allowing greater contraction force and speed.
How to operate it specifically? Randy looked at Su Shen below and asked him to come up and explain together.
Su Shen was not polite. He walked up and faced Lai Yi in the audience and said, "The next thing you have to do is to speed up the swinging speed of your swinging leg. This can effectively improve the cushioning and kicking speed, and also shorten the competition time. , and finally got a strategy to improve cadence.”
"Big cow, the minimum knee angle of your swing leg is 25.5. It can be seen that your swing leg folding degree is not enough, which will affect your forwardness. This year until the end of winter training, your swing leg folding technology will also need to be reworked. Practice it carefully, and remember to use pendulum to promote pedaling and combine pedaling with pendulum.”
"Okay, I understand, Brother Tim." Hearing this, Lao Yi silently took notes.
Although he may not be that good in theoretical knowledge, Randy's method of replacing data with videos and then pairing it with text analysis allows many players who are not so good at digesting theoretical knowledge to get into the zone quickly.
Understand where you went wrong and where you still need to improve.
"Brother Kai, these are the data from your Olympic shots. Especially in the vertical phase at the moment of landing, Bolt's knee angle changes by nearly 20 degrees. And you, Brother Kai, are only in your early 10s. This shows that the supporting leg shrinks from eccentric to axial. The heart is contracting, Brother Kai, you haven’t done enough. There is still room for improvement.”
"Looking at the distribution of your cadence and stride length over the entire 100 meters, it's still a little too fast in the front." Su Shen said: "This will prevent your back from reaching its true peak, and the overall performance will be less optimized. It's a bit slow. Especially between the eleventh and fifteenth steps, the instability is more obvious. If you can stabilize it, your results may improve in the future."
Hu Kai also pushed up his glasses.
Looking at his various running data on the large projection screen, he patiently read it and nodded silently.
There has never been such a detailed data analysis system before.
Therefore, even coaches can mostly only rely on feeling.
But now Randy has brought scientificity and systematization, which has greatly improved the team's observability.
Under the championship system model, Hu Kai has a clearer and more visible understanding of his own shortcomings.
It's so clear.
It doesn't matter if it's a new player, he doesn't know enough about this system and doesn't have deep feelings about it.
But for the veteran players, they can clearly feel the earth-shaking "change" in the post-match review.
The previous "post-game reviews" were not so detailed, but now... everyone has a lot of things to remember.
This is the benefit of being systematic and scientific.
It's clear, clear, where the athletes want to improve, sometimes even looking at the data gap, that's enough.
…
"Hao Huan, let's take a look at your data. You are about five centimeters shorter than Bolt, but as a big man who is also over 1.9 meters tall, the angle between your legs and the angle of your swinging legs are both good. There is an obvious difference with Bolt. Bolt's leg angle and swing leg angle in this final were 96.8 and 12.1 respectively, while yours was 100 and 11.1, which illustrates one point." Su Shen nodded. The continue play button shows another line of analysis, saying: "Your back kick, back kick knee angle, and your support time are too long, which will cause the angle between your legs and the angle of your swinging leg to be different." Weaker than Bolt.”
"Even considering the physiological segmentation curve, we think if you correct this aspect, it should be faster."
"The specific method is to strengthen the scissors of your legs, appropriately reduce the back pedaling angle, and shorten your support time. This is the championship model analysis we calculated based on your four shots and 100 meters in this Olympics."
Zhao Haohuan looked at it and touched his chin with his hand. By visual comparison, he and Bolt could indeed see a lot of problems under the high-definition close-up lens. And compared to before, the current adjustments are more detailed and more high-end.
This is an adjustment after the athlete has progressed to a higher level.
It is no longer just a simple adjustment of a certain technical action.
Each of these physical data may have to be turned out to be compared and viewed one by one.
As for why Bolt is used.
Needless to say.
Because Bolt is the fastest.
Not only now, but also in the original timeline, Bolt was pulled out for analysis and comparison countless times.
If a person is the fastest runner, any set of his running data will be useful for scientific data models to absorb, analyze, and learn from. This is why Su Shen must introduce the "champion model theory" to the country.
Otherwise, there is no theoretical guidance from a scientific data model, and we just rely on the so-called experience summary of coaches.
It's just too old.
To use Randy's original words in later generations -
"I often tell some coaches, don't argue with me about science. What I'm telling you now is something that is already recognized by scientists all over the world, and you just have to follow it. If there is no training in psychology and biochemistry, human mechanics, etc. By integrating this scientific knowledge, you cannot create a new training system, this is basic common sense.”
“Education is not meant to encourage florist coaches to study in the United States, because a lot of knowledge is available there, and it’s all in Chinese. Coaches only need to study carefully and systematically in class... I think florists should allow all coaches to participate in scientific training. , If they have not gone through classroom training, they will not be given a diploma. The coaches must understand that this is my major, and all our coaches must be professional."
Referring to Randy's words, to make training truly scientific and get rid of the "experience training doctrine" that has dominated the track and field training system for decades or even longer, you must have real scientific reserves. And it is not just one person, it requires many smart minds to work together.
After all, a person's mind always has its limits.
Even Su Shen himself wouldn't have been able to accomplish so many things by himself if it hadn't been for reopening.
And in the later stages, even he will need a strong and stable team and laboratory to constantly innovate.
In sports science, the most taboo thing is to be complacent.
If you think something is the best and then stop trying to surpass and break through, then you will lose the meaning of the scientific movement.
"In the end, it's me." Su Shen asked Randy and the others to come over again, but Randy waved his hand and refused.
Because Randy and Ralph Mann hope that Su Shen can do it by himself.
For them, bringing out a few outstanding athletes brings a high sense of accomplishment, but... the highest sense of accomplishment is helping a country create an overall scientific sports system. And these, in the end, still need to be operated by local people.
Seeing the two people expressing this, Su Shen had nothing to say. He nodded and continued to talk to the video playing: "These are my four 100-meter shots this time."
"As you can see, from the preliminaries to the finals, within four shots, my number of steps actually increased slightly, my average cadence also increased, but my average step length decreased. In other words, my cadence index is increasing with time. As the game progresses, the step length index decreases."
"The following shows the step frequency changes during my 100-meter run with the North Olympic 4-gun. It can be divided into two situations: one is the three stages of increasing frequency - maintaining - decreasing after starting, showing an inverted "V "Character". Another situation is the increase in frequency after starting - maintain - decrease - increase frequency - then decrease again. The change trend of step frequency in the entire process shows an "M" shape."
"Considering the relationship between excitement and inhibition of the nervous system, high-step frequency running methods often cannot appear and maintain extremely high step frequencies multiple times during the entire fast running process. Also, considering that the former type mainly appears in preliminaries and semi-finals, The subsequent semi-finals and finals are all M-shaped, so I think the latter type may be more meaningful for research under current physiological conditions in high-intensity confrontations.”
"And now we are also comparing Bolt." Su Shen pressed the pause button, and a running diagram of himself and Bolt appeared on the big screen, saying: "We can see that Bolt won the Olympic Games in Beijing. From steps 6 to 35, the cadence for a long period of time or distance during this 100-meter run is unchanged. And other runners, including myself, have larger differences in these segments. It fluctuates up and down. Especially after 60 meters, the fluctuation becomes more obvious."
"Then what does the smaller fluctuation mean? Look at this set of data. When Bailey broke the world record, the change in cadence was very small. The difference between the maximum and minimum cadence in the whole process was only 0.1 step/second. In the first 10 meters, the change was very small. Reaching 4.63, he maintained it until 30 meters. From 30 to 60 meters, his cadence increased to 4. 72 steps/second, and in the last 60 to 100 meters, his cadence returned to 4. 63 steps/second. Su Shen looked at the big screen seriously and said, "So his entire stride frequency change line is almost a horizontal line."
"Then we have to put forward a hypothesis. Compared with other players, Bolt's cadence is lower throughout the whole process. Can a lower cadence be maintained for a longer time and not easy to fatigue?" Clicked the mouse, Su Shendao: "Although Bolt has a cadence type, due to physiological conditions, his stride length is naturally very large. For example, when running 100 meters, 40.5 steps, while others run 49 steps. From the perspective of energy distribution, you only need He ran about 80% of his distance. According to the data, we can find that whether it is Chinese athletes or foreign athletes, as long as the six-second rule is correctly activated, then basically most athletes will start in steps 30-34. Decrease speed. If your stride is long and it takes 27 steps to reach 60 meters, then you may have to go 80 meters away to enter the physiological natural deceleration stage mentioned above. If your stride is small and it takes 32 steps to reach 60 meters, then You will naturally start to slow down around 65 meters. Due to the excitation and inhibition mechanisms of the nervous system, it is impossible for people to maintain a very high frequency for a long time, and the 100-meter run can only be completed by increasing or decreasing the frequency throughout the entire process, so How to stabilize it has become a key point."
"But is it true that bigger strides are better?" Su Shen looked down and said, "That's definitely not the case."
"Because even in terms of stride length, it is not impossible to surpass Bolt, such as Bloomfield (39 and a half steps in the 100 meters). If you consider the physiological proportions of the human body and look at the stride index, Gatlin, Bailey Coe Paul, Mike Rogers, etc. are all better than Usain Bolt. Therefore, the domestic idea of simply extending stride length is not suitable for everyone. Reduce and eliminate redundant "enlargement of stride length", and the combination of cadence + stride length is the best Good. After all, the essence of modern sprinting is relaxation technology in high-speed displacement based on pedaling. Therefore, we must determine that creating a different golden stride length and frequency ratio for each person according to the individual physiological conditions of the human body is the future trend."
"Our country has fallen into a trap where people usually regard step length and cadence as "causes" and running speed as "effect", that is, people usually think that "what kind of step length and cadence will lead to what kind of running results." "Speed." Su Shendao: "Most people start from the perspective of optimizing cadence and step length to study the improvement of special speed. But in fact, there is no direct causal relationship between cadence, step length and special speed. Running Speed is a kinematic parameter of the horizontal displacement of the body's center of gravity when the athlete is running, but step length and stride frequency are spatio-temporal structural parameters. Both sides describe the kinematic indicators of athletes' running from different angles."
"Then what is the most reasonable way to do it? There has been a similar saying for a long time, for example, reasonable speed = athlete's maximum stride length 94.12.9% × maximum stride frequency 95.1±3.5%. Therefore, we will also work hard on mathematical model research in the future. . If you want to consciously promote the increase of step length and the reduction of single step time, it will actually destroy the continuity of running force and the systematic and coordinated force of each link, which will have adverse effects on the running speed of the human body. In fact, for sprinters, their running speed is mainly affected by the relaxation ability and high-speed swing ability of high-speed running. Therefore, in future related research, attention should be paid to the kinematic parameters that reflect the human body's high-speed swing ability, and around Only through in-depth exploration will it become more scientific and systematic.”
Randy was listening below, nodded and said: "Do you treat the whole person as a whole machine? This is an interesting point of view. Right, old man."
As he was talking, he saw Ralph Mann lost in thought.
He paid no attention to Randy next to him.
Because Su Shen's statement provided him with a new idea. It is true that everyone now pays too much attention to the study of simple stride length and stride speed. In fact, they have forgotten that the body is a whole and is the most sophisticated body in the world. instrument. If we study it as a whole, will we be able to discover more paths and methods in the future?
"Looking at my own side, the knee angle of Bolt's supporting leg at the moment of landing and the vertical stage in the Olympics. In fact, we can clearly see that due to physical fitness and performance reasons, my shot in the final was 40-50 during the running stage. Mi's data is obviously more deviated than the semi-final data. Compared with my own data currently collected by the championship system, it is even more offset by 10 to 5 points."
"This shows that the stability of my ground-breaking skills is still lacking."
"And this problem can actually be optimized using a new technological concept."
new technology?
Upon hearing this, everyone became excited and looked at Su Shen one after another, with little stars almost popping out of their eyes.
Even Randy was stunned.
It was obviously a summary analysis meeting, but why did it turn into directly giving conclusions and launching new technologies?
You do this.
When we coach the team in the future, we will be under a lot of pressure and it will be difficult to handle it.
Su Shen inserted the PPT he had made, and after the computer started reading the USB flash drive, he said: "This is it."
"In the future winter training, we will allow a group of people who have the conditions to start training to enhance their ability to run on the road."
At this time, on the big screen, there were a few big words written clearly————
Optimized version of "credit card" landing technology.
PS: This type of chapter is difficult to write, hahahaha, it’s so slow, but I believe that this way, the realism will explode. And it is logical to take advantage of the opportunity to improve and launch new technologies~~~~
I hope everyone will support me and help Xiaozi get excited while reading papers late at night~~~o(╥﹏╥)o~~~
