1. The proportion of slow muscle fibers of endurance athletes such as marathon is much higher than that of ordinary people, and the proportion of fast muscle fibers of sprinters and bodybuilders is much higher than that of ordinary people.

2. Slow muscle fibers are not easy to get tired.

3. In intensive exercise, fast muscle fibers are mobilized first; Low-intensity slow muscle fibers are mobilized first.

4. The diameter of fast muscle fiber is larger than that of slow muscle fiber. So sprinters who account for 80% of fast muscle fibers look strong.

It is difficult for us to see a person's slow muscle mobilization ability and cardiopulmonary endurance through the naked eye.

1. Why are marathoners thin and sprinters strong?

If you often look at children's shoes in track and field competitions, you will find that athletes who participate in long-distance track and field events such as marathon are generally thin, while athletes who participate in 100 meters and 200 meters sprints are much stronger than the average person.

For example, the following picture shows Samuel Kamau, the marathon world champion, on the left, and Bolt, the 100m world champion, on the right. Look at the ratio of arm circumference and head circumference of two people, and you can probably see the figure of two people. The former is obviously an endurance athlete.

Why is this?

There are two reasons: First, the fast muscle ratio of endurance athletes is relatively small, while the fast muscle ratio of sprinters is relatively high, which requires explosive force. The second reason is that the muscle fiber diameter of fast muscle fiber is larger than that of slow muscle fiber. Therefore, sprinters with a large proportion of fast muscle fibers look strong.

(Source: Exercise Physiology, edited by Wang Ruiyuan, People's Sports Publishing House, 20 12 edition)

As can be seen from the above figure, the proportion of fast muscle fibers of sprinters is much larger than that of ordinary people (reaching an astonishing 80%), while the proportion of fast muscle fibers of endurance athletes such as race walking, cross-country running and long-distance running is smaller than that of ordinary people (only 465, 438+0% and 33%), and the proportion of slow muscle fibers is even larger.

2. Muscle characteristics: slow muscle has strong endurance and fast muscle strength ~

(Source: Exercise Physiology, edited by Wang Ruiyuan, People's Sports Publishing House, 20 12 edition)

The above picture shows the experimental conclusion of testing subjects with different muscle fiber ratios to "repeatedly complete the maximum knee extension exercise". The experiment was divided into two groups, the experimental group was the subjects with high proportion of fast muscle fibers in thigh, and the control group was the subjects with high proportion of slow muscle fibers in thigh.

At the beginning of the experiment, the strength of the subjects with high proportion of fast muscle fibers in the thigh is much greater than that of the subjects with high proportion of slow muscle fibers. However, with the passage of time, the strength of fast muscle fibers decreased rapidly compared with the subjects with significant fibers, and was soon lower than that of the subjects with large slow muscle fibers. However, the strength of subjects with large slow muscle fibers decreased slowly.

So we can know two things from the above picture: first, the anti-fatigue performance of slow muscle fiber is stronger than that of fast muscle fiber, and second, the explosive force and absolute strength of fast muscle fiber are stronger than that of slow muscle fiber.

Physiologically speaking. Fast muscle fiber is rich in contractile protein and sarcoplasmic reticulum, so it is fast and contractile, but it is easier to get tired. Slow muscle fiber contracts slowly, but because of its richer capillary network (so it looks redder than fast muscle fiber visually), slow muscle fiber is not mainly powered by phosphoric acid system and glycolysis system like fast muscle fiber, and slow muscle fiber can also be mainly powered by aerobic energy supply system, and all three energy supply systems can act on slow muscle fiber (see Chen Bailing's "Three Energy Supply Systems of Human Body" for details).

Having said that, it is not difficult for us to understand why the proportion of fast muscle fibers of sprinters is larger than that of long-distance runners: because sprinting needs explosive power, while long-distance running needs endurance. The former is the strength of fast muscle fibers, and the latter is the strength of slow muscle fibers.

Third, do muscular men have poor endurance? -Fast and slow muscle and energy supply systems

Gollnick and other scholars have done research to let subjects exercise at 64%VO2max (maximum oxygen uptake), and found that the sugar in slow muscle fibers was originally consumed, and then turned to fast muscle fibers. Even when glycogen in slow muscle fibers is completely exhausted, glycogen remains in fast muscle fibers. However, during the intensity exercise of 150%VO2max, the glycogen of fast muscle fiber is first mobilized. This shows that in high intensity exercise, fast muscle fibers are mobilized first, and in low intensity exercise, slow muscle fibers are mobilized first.

Different intensity of exercise and different training methods exercise different muscle fibers, and finally show different body shapes and physical qualities. On the level of professional athletes, it is easy for us to tell whether an athlete is an endurance athlete, but it is difficult for us to tell whether an ordinary person has strong endurance from his body shape.

Boxer Roy Jones. Image source: boxrec.com)

Many people say that muscular men have poor endurance. This is a kind of prejudice.

In fact, it is difficult for you to estimate a person's endurance according to his figure. Because you can't infer each other's training methods and training purposes according to your figure. If the opponent is not a professional player, you can't determine whether he has done endurance training according to his figure, and it is difficult for your naked eye to distinguish the proportion of fast and slow muscle fibers in ordinary people's bodies.

A thin man claims to be an athlete, so he is probably an endurance athlete. But if the other person is just a thin ordinary person, it is difficult to know whether he has received systematic training. Like a muscular man, you can't infer from a muscular figure whether he has regular endurance training.

The so-called "muscle man" in people's eyes must have a high proportion of fast muscle fibers. So his strength level and explosive power will be stronger than the average person. But his endurance depends on whether he has endurance training at ordinary times.

(Muhammad Ali)

Take boxing as an example, there are four rounds, eight rounds and 12 rounds, among which 12 rounds often exceed 1 hour, which is a great test for athletes' physical fitness (especially endurance).

For boxers, they also need a high level of speed and strength (explosive power), a certain level of absolute strength, sufficient reaction ability and sensitivity, and excellent cardiopulmonary endurance and anaerobic endurance.

Boxers of different grades and sizes. Image source: Baidu and Google search boxing)

Again: it is difficult for us to see a person's slow muscle mobilization ability and cardiopulmonary endurance through the naked eye.

Only through high-intensity, short-time and low-frequency exercise can a person build good muscles. Muscle man has poor endurance, but muscle man is not a sufficient condition for poor endurance.

Let me share my experience, and you can also be your own fitness instructor-WeChat official account "Chen Bailing's soy sauce table" ID: soychen 0 1.