A training ground for a group of sprinters. Pen | fun | pavilion www. ｂｉｑｕｇｅ。 ｉｎｆｏ

Xue Li looked at the arena with his eyes, but asked on his lips: "I have read your resume, you just graduated three years ago, majoring in sports training, you should have been exposed to the training content of sprinting in school, right?" ”

Li Dai nodded: "I've learned some, but it's all a little fur." ”

"I know that I personally participated in compiling many of the sprinting-related textbooks that are commonly used in universities. Truth be told, those things are outdated. Now is the information age, in all walks of life, all kinds of new technologies emerge in an endless stream, the same is true for sports, the so-called records, the main use is to be refreshed, athletes are really higher, faster, stronger. Xue Li said.

Li Dai didn't know what Xue Li was going to say, so he could only nod his head silently and listen carefully.

Xue Li then asked, "What you learned in school, sprinting emphasizes the technique of kicking, right?" ”

"Yes, the textbook requires athletes to push the ground, hip, knee and ankle joints as straight as possible to obtain higher pushing force and achieve faster speed." Li Dai replied.

"Well, more than a decade ago, I thought the same thing, we thought that the best way for athletes to kick their knees was 180 degrees, so that's how the textbook was written. However, with the latest technology, we don't require athletes to push their legs too straight, what we pursue is a 'flexion' technique. Xue Li opened his mouth to explain.

"Flex technique? Does it mean that the back leg is not fully extended? Li Dai asked.

"Yes, we used to think that the back pedal was the only source of power for sprinting, but this conclusion was too one-sided on front support and resistance, and even more one-sided on rear support power. Until the appearance of Gittel, it changed our cognition. Xue Li said.

The Gitter mentioned by Xue Li is from Jamaica, which is a sprinting capital, and there have been many world-class flyers, and among these flyers, the best is undoubtedly Gittel, including the relay race, he won nine gold medals in three Olympic Games, he has broken the 100m and 200m world records many times, and the world record he has set is unshakable. Although Li Dai has never seen Gittel's real person, he has already determined in his heart that Gittel's talent has definitely reached the top S+, and in fact, he does rule this era!

I only heard Xue Li continue: "What Gittel uses is the flexion technique, the knee angle of his support leg is from vertical to backward kicking off the ground, the change is very small, and his center of gravity level is very stable, which is a bit beyond our cognition, in the case of pushing the ground violently, it can still maintain a stable center of gravity, which is almost impossible to do." ”

"It was only later that we found out that we were overemphasizing a certain link, and that sprinting technology was actually an organic whole. Our one-sided emphasis on the resistance of the front support and the power of the back support has led to the imbalance of the athlete's thigh front and back cluster strength, and the strength of the posterior muscle group seriously lags behind the strength of the front muscle group, resulting in the focus point must be close to the center of gravity projection point, so as to ensure that the center of gravity of the body moves quickly to the support point, but this makes the title time prolonged and the cadence decreased! ”

Xue Li's explanation, if it sounds to a layman, it is definitely in the clouds, but in Li Dai's ears, there is a feeling of sudden enlightenment, just these few words make Li Dai feel that his understanding of sprinting technology has improved by a whole level.

Xue Li continued: "At the same time, our research also found that Gittel's motivation is not only based on the ground, but also on the forward swing of the legs. In our previous cognition, kicking is the power to create speed, and the cushioning is the resistance, the loss of speed, so we have been emphasizing increasing the back kick force, emphasizing the kick extension, the direction of the kick and the speed of the kick. ”

"But when the pedal technique is applied to sprinting, the previous theory of emphasizing the straight pedal does not exist, and at this time, focusing on the front swing technique and strengthening the combination of the front swing and the pedaling becomes the only way to improve the speed. Therefore, the latest sprinting technique used by our national team is based on the pendulum, the pendulum promotes the pedaling, and the technical theory of combining the pendulum and the pedal. ”

"You must know that when an athlete is standing, he only pushes the ground, and the thrust is vertically upward, which cannot promote the migration of the human body. At this time, if you want to maintain the balance of the body, you need to support the leg to achieve, and the original support leg will produce a downward direction of the ground at the same time, which will prompt the center of gravity of the human body to move forward again, so as to complete a repetition, which is the basic principle of promoting pedaling with pendulum. ”

Li Dai nodded: "I understand, to put it simply, in our previous training philosophy, kicking the ground is the source of power, and the forward swing is just to grasp the direction of progress; But in the current training philosophy, the front swing is the power, and the push is also the power, and the two are combined. It seems to be the difference between rear-wheel drive and four-wheel drive in a car. ”

"Well said! This example of a car is aptly given. Xue Li looked at Li Dai with an appreciative face, and he secretly said in his heart that he was really not mistaken, Li Dai was indeed very talented.

Li Dai is not only a plug-in of the coaching system, he is talented, he is also good at learning, he usually works hard, and after several years of work experience, he has learned to think actively, instead of copying the content of textbooks as he did when he just graduated.

Before Xue Li finished speaking, he continued to introduce in a teacher's tone: "Sprinting is a complex biomechanical activity involving the action of multiple forces. Since humans are erect animals, it is easier to push a relatively stationary object with a strong push than to push a relatively moving object with a leg, so it is easier for a sprinter to accelerate at the start, but when the athlete's speed increases, it becomes more difficult for the human body to continue to increase the effect of the back pedal because the acceleration time becomes shorter. At the same time, when the speed increases, it also faces greater air resistance and braking resistance. ”

"It's impossible for a person to grow into a streamline, so air resistance is very difficult to solve. The Americans used high-tech means to make a fuss about athletes' competition uniforms to reduce air resistance, such as those one-piece tight-fitting sportswear made of nanomaterials, which was once sought after and imitated by the whole world. ”

But since Jamaica's Gittel was born, they have discovered that the small action of tight sportswear is not worth mentioning in the face of absolute strength. Gittel, dressed in a plain tank top and shorts, still ran faster than the Americans. Therefore, a strong body and better technique are the most important things to improve performance. ”

"As for braking resistance, the essence of reducing braking resistance is to reduce the speed of the landing foot relative to the ground, the closer the landing foot is to 'zero' at the moment of landing, the better, the instantaneous speed of my athlete's foot landing is about 1.35 m/s, which is 17% more than that of American athletes, which is also where we need to continue to improve."

After Xue Li finished speaking, he pointed to an athlete galloping in front of him, and asked: "Look at him, in terms of foot landing movements, what is he doing well, and what is not good enough?" ”

Li Dai knew that this was an on-site exam question that Xue Li had given him, so he immediately observed it carefully.