"Kings" on the step chart, how are your knees?


  In the WeChat circle of friends, in addition to sunbathing, cooking food, and taking selfies, in recent years, the number of steps has become another fashion. The number of sports steps you catch up with, this not only stimulates motivation but also exercises the body. Sought after. Looking at the sports list, starting at 10,000 is standard, starting at 20,000 is likely to reach the top, and the proper "king" is more than 30,000. However, the more you walk, the better your health. The answer may not be the same as you think.

  With the improvement of the domestic epidemic situation, people spring out of the house to exercise in spring, and ask the group to take steps. Walking as a simple and easy way to exercise is loved by everyone. With the development of smart phones and the popularization of wearable devices such as sports bracelets, comparing each other's daily steps has gradually become a new fashion in the circle of friends. In the ranking of the number of steps in the circle of friends, we can also often see those friends who have 20,000 or 30,000 steps a day, constantly refreshing the "top" record.

  In life, I often hear the saying that "ten thousand steps per day protects health". Walking 10,000 steps seems to be a default indicator when people walk: whether you have completed your exercise goal today, open the pedometer to see the number of steps how many. So, is there a scientific basis for the widely circulated statement of "Daily health care"? It is reported that some people suffer from acute synovitis due to 20,000 steps per day, and their knees hurt when they are pressed normally. What problems should we pay attention to in daily walking exercises? What is the step counting principle of mobile phones and bracelets, is it really accurate? With a series of questions, a reporter from Science and Technology Daily interviewed relevant experts.

  Walking too much causes a variety of strained diseases

  Needless to say, the physical benefits of walking exercise. However, it should be noted that although walking is good, it is not necessary to pursue more steps. Judging from the existing research, it does not support the more steps, the healthier and longer life. On the contrary, excessive exercise can also lead to muscle, fascia and joint injuries and other strain diseases.

  During the clinical consultation, Lu Wei, director of the Department of Sports Medicine of the Second People's Hospital of Shenzhen, encountered many patients who developed anterior knee pain syndrome due to excessive exercise. The auxiliary examination results of these patients are basically normal, but the subjective symptoms are severe. They often do not exercise much at ordinary times, and suddenly increase exercise, resulting in repeated symptoms of knee pain and discomfort after the next day or a few days.

  "In fact, everyone's joints are different, and the gene type of cartilage is also different. Once the pain symptoms occur, you need to adjust the exercise mode in time." Lu Wei suggested that patients with anterior knee pain syndrome should change their lifestyle habits as much as possible. Reduce movements that cause knee pain. At the same time, cooperate with rehabilitation training, such as knee flexion and extension and quadriceps training under non-weight-bearing.

  This shows that walking seems simple, but walking for fitness purposes still has certain requirements for personal constitution. Every day should be based on their own physical conditions, as appropriate to determine the number of walking steps and speed. In addition, walking posture is also particularly important. Incorrect walking posture can not only play a health-care effect, but will adversely affect limbs, muscles, joints, and body posture.

  Shao Zengwu, director of the orthopedics department of Wuhan Union Medical College Hospital, made several suggestions for maintaining the correct walking posture. First, raise your head and chest, relax your back, and stretch your knees to straighten your shoulders. At the same time, in the process of the leg stepping, the toes should be as far forward as possible, not stepping in eight characters, swing the arm naturally, and try not to walk with your hands behind your back. In addition, pay attention to make preparations before exercise, fully stretch, increase joint flexibility.

  It is still controversial how many steps to take each day are most beneficial to health

  How many steps should I take every day to stay healthy?

  According to Shao Zengwu, when it comes to walking scientifically and reasonably, the two concepts that have to be mentioned are walking steps and walking intensity. Different researchers also have different views on how many steps to take each day and how fast they must be to be in good health.

  In 2019, researchers at Harvard Medical School measured the number of walking steps, walking intensity, and all-cause mortality per day for 16741 elderly women. 60% is relevant; but after more than 7,500 steps, there is little relationship between all-cause mortality and the number of steps.

  "All-cause mortality, which is the 'mortality rate of all deaths', refers to the ratio of the total number of deaths caused by various causes within a certain period of time to the average population of this group over the same period." Shao Zengwu explained.

  An analysis by the National Institutes of Health (NIH) of nearly 5,000 subjects this year showed that for middle-aged and elderly people, the number of walking steps reached 8,000 and 12,000 steps, compared with 4,000 steps a day. The all-cause mortality risk decreased by 51% and 65%.

  Although there are controversies on how many steps to take each day are most beneficial to health, it is very interesting that both studies considered that walking intensity was not related to the risk of all-cause death. When interpreting the “Dietary Guidelines for Chinese Residents” (2016 edition), experts suggest that everyone should maintain sufficient daily physical activities, equivalent to 6000 steps or more per day.

  "Daily Ten Thousand Steps" originates from the marketing concept

  "And for the saying of" walking every step to protect health ", there is no scientific research to support this conclusion. Walking exercise should be step by step, and it is enough." Lu Wei said bluntly in an interview with the Science and Technology Daily reporter.

  So, where does the concept of "every day and every step benefit the body" come from? The BBC documentary "The Truth about Fitness" explores this claim. In the 1960s, a Japanese pedometer manufacturer used the slogan "10,000 steps a day" to sell a mechanical pedometer.

  At that time, pedometer manufacturers made a rough statistics and came to the conclusion that "Japanese people walk on average 3500-5000 steps per day." In order to add the concept of assisting physical exercise to the pedometer, the manufacturer took the opportunity to multiply the upper limit of the average number of steps by 2 to associate the ten thousand steps per day with physical fitness. Gradually, the slogan "10,000 steps a day" was promoted.

  "But so far, there is no official recommendation of '10 thousand steps per day ', nor does it specifically support the relevant research on '10 thousand steps per day to be healthy'." Shao Zengwu said.

  Further reading

  This device in your phone is "secretly" counting your steps

  The earliest pedometers used by humans were mechanical pedometers. Its principle is based on a very common mechanical device in physics-the pendulum. When people walk, the "pendulum" structure in the pedometer will move with it. The movement of the "pendulum" structure is approximately the same as the pace of people walking, and this movement is recorded through the corresponding circuit sensor computing system to record the "step counting" process.

  Now people use mobile phones or sports bracelets for step counting. What is the step counting principle of mobile phones and bracelets? Yan Huaizhi, director of the Institute of Computer Network and Countermeasure Technology, Beijing Institute of Technology, introduced that mobile phones and bracelets use high-precision motion state sensor chips for human motion state perception, supplemented by software algorithms to correct and display steps.

  Specifically, the motion state sensor mainly senses the motion conditions such as acceleration or vibration of the three-dimensional rhythm through a high-precision accelerometer. Commonly used acceleration sensors are divided into three-axis and six-axis. The three-axis accelerometer generally senses and records sports data when the arm swings, while the high-end six-axis accelerometer further judges walking, running, cycling, and going upstairs to improve the accuracy of sports data recording.

  The software algorithm is based on the three-dimensional motion data captured by the accelerometer in real time, after digital filtering, scene recognition, model correction and other arithmetic processing, and finally converts the raw data obtained by the accelerometer into the number that can be displayed on the bracelet APP or bracelet. The user presents numerical information on steps, distance, and calorie consumption.

  "In fact, sports bracelet or mobile phone step counting is mainly based on the swinging arm and vibration of the human body to measure the number of steps or distance." Yan Huaizhi said, for example, even if you step on the spot, if the stride and arm movement are large enough , Will also be recorded. Different height, step length, movement habits, etc. will also affect the accuracy of step counting, so it must be corrected by software to be more accurate.

  As another example, the integral accelerometer and the environment perception algorithm are used to determine whether a spatial displacement has actually occurred to determine whether to count steps. In addition, the frequency can be used to determine whether the human body is actually walking or running, or swaying the wrist or swinging the body. In Yan Huaizhi's view, the current step counting functions of mobile phones and bracelets have fully considered various interference scenarios and interference factors. After correction by software algorithms, the results are more accurate.