Dr Scott's weight training has many advantages, but Bailey always has one disadvantage. Sports injury is the most common and annoying side effect. Knee is one of the most common joints in human body. Some famous orthopedic surgeons say that climbing stairs is the stupidest exercise, because the knee will bear four times the weight. This sentence embodies the concept that "the knee is a machine". The more times it is used or the greater the force, it will wear out. Then, if we do squats and hard lifts in the gym, will it also cause knee cartilage wear and early degeneration? Does retraining or other sports hurt your knee? Is there any way to avoid reporting to the rehabilitation department prematurely? This article will introduce in detail. What is degenerative arthritis of knee joint? The knee consists of femur (femur), patella (kneecap) and tibia (calf bone), and there is a layer of cartilage between the bones as a buffer and to reduce friction. The biggest feature of degenerative arthritis of the knee joint is the absence of this layer of cartilage (note 1). The picture on the right shows a normal knee joint. It can be seen that there is enough space between bones, and this space is occupied by cartilage. However, the internal space of the left knee joint is obviously narrowed, which means that the cartilage thickness is reduced (Note 2). This disease usually occurs over 40 years old, which will bring pain, stiffness and mobility inconvenience to patients. Degenerative arthritis is also one of the important causes of disability in middle-aged and elderly people. Imagine if you walk for ten minutes, your knee will swell up and it will hurt you to go nowhere. How much impact will this have on your quality of life? (Note 1: Although cartilage loss and thinning are important features of degenerative arthritis, the degree of wear is often inconsistent with the degree of pain. Some patients have thin cartilage, but it doesn't hurt at all, and the opposite is not uncommon. (Note 2: Degenerative arthritis is not only the loss of cartilage, but also the pathological changes around it, including bones, ligaments, tendons, muscles and synovium. ) Dr. Scott's weight training has many advantages, but Bailey always has one disadvantage. Sports injury is the most common and annoying side effect. Knee is one of the most common joints in human body. Some famous orthopedic surgeons say that climbing stairs is the stupidest exercise, because the knee will bear four times the weight. This sentence embodies the concept that "the knee is a machine". The more times it is used or the greater the force, it will wear out. Then, if we do squats and hard lifts in the gym, will it also cause knee cartilage wear and early degeneration? Does retraining or other sports hurt your knee? Is there any way to avoid reporting to the rehabilitation department too early? This article will introduce in detail. What is degenerative arthritis of knee joint? The knee consists of femur (femur), patella (kneecap) and tibia (calf bone), and there is a layer of cartilage between the bones as a buffer and to reduce friction. The biggest feature of degenerative arthritis of the knee joint is the absence of this layer of cartilage (note 1). The picture on the right shows a normal knee joint. It can be seen that there is enough space between bones, and this space is occupied by cartilage. However, the internal space of the left knee joint is obviously narrowed, which means that the cartilage thickness is reduced (Note 2). This disease usually occurs over 40 years old, which will bring pain, stiffness and mobility inconvenience to patients. Degenerative arthritis is also one of the important causes of disability in middle-aged and elderly people. Imagine if you walk for ten minutes, your knee will swell up and it will hurt you to go nowhere. How much impact will this have on your quality of life? (Note 1: Although cartilage loss and thinning are important features of degenerative arthritis, the degree of wear is often inconsistent with the degree of pain. Some patients have thin cartilage, but it doesn't hurt at all, and the opposite is not uncommon. (Note 2: Degenerative arthritis is not only the loss of cartilage, but also the pathological changes around it, including bones, ligaments, tendons, muscles and synovium. How is degenerative arthritis produced? Detective Conan said: "There is always only one truth", but in the medical field, there is often more than one truth. At present, scientists do not fully understand how degenerative arthritis comes from. The previous concept that mechanical wear caused cartilage loss sounds reasonable, but recent research has found that the truth is actually much more complicated. Age, obesity, occupation (often squatting or kneeling), old injuries, impact sports and heredity are all risk factors for degenerative arthritis. At present, it is considered that simple pressure is not enough to damage cartilage, but the ability of tissue repair decreases (such as aging), coupled with joint structure problems (such as O-leg) and complex interaction with environmental factors, which eventually leads to knee joint degeneration. Recently, some scholars put forward a new point of view: muscle is an important contributor to stabilizing joints and absorbing shocks, so muscle disability and weakness are the main reasons for knee degeneration, which Scott will discuss in detail in the following chapters. Can exercise lead to degenerative arthritis? If you think of human joints as mechanical gears, the way to maintain your knees is simple: use them as little as possible and lubricate them often. For adults, it is best not to exercise as much as possible, squat, run and climb mountains, as long as it will bear the weight on the knees. Scott can tell you directly that this idea is wrong. If the above-mentioned "mechanical viewpoint" is true, then all people who exercise should have degraded their knees long ago, but this inference has long been denied by science. From 2065438 to 2007, the American Journal of Sports Medicine published a comprehensive study and analyzed the accumulated literature so far. Scholars have found that runners are less likely to undergo knee replacement surgery than non-runners. Comparing 70-year-old runners with ordinary people of the same age who don't exercise, it is found that running does not increase the risk of knee degeneration. Not only running, according to the current scientific research, moderate-intensity exercise will not cause degenerative arthritis. Please pay attention to the key point of this sentence: "moderate intensity", because some exercises do accelerate knee degeneration. The study found that once special sports such as long-distance running, weightlifting and football reach the elite level, for example, if you are a member of the national team and have played abroad on behalf of your country, the probability of developing degenerative arthritis in old age will be higher. In addition, contact and high-impact sports, such as fighting, hockey, American football, skydiving, etc., are generally worse with age. So should professional and amateur athletes, or readers who like weight training, worry about knee problems? Here is Scott's opinion: A healthy knee is very tough and can absorb high-intensity impact. But why are professional sports or contact sports particularly prone to knee degeneration? 1. Contact sports are easy to cause knee injuries: non-contact sports, such as squats, are carried out in a controlled environment, so players only need to pay attention to their posture. However, in martial arts, American football and other sports, it is impossible to avoid injuries when opponents scurry around on the court and want to catch you at any time. Once the knee is injured, the self-repair ability of cartilage and meniscus is limited, or ligament injury and muscle disability lead to further instability and accelerated wear of the knee, and contact exercise especially hurts the knee. Professional players are born to win the game, so physical performance often gives priority to health factors. With the improvement of sports performance, the higher the training intensity, the greater the training intensity and the higher the risk. It is not difficult to imagine that the risk of injury is much higher than lifting 300 kilograms. But professional athletes rarely stop training even if they are injured. In the case of injury, the knee joint is more unstable, coupled with the pressure of training, the knee will of course deteriorate ahead of time. 3. In professional high-level competitions, players often need to continue to bear joint impact under the condition of muscle fatigue. Muscle fatigue will reduce its ability to absorb impact and stabilize joints, and may also cause knee joint wear. Simply put, knee joint injury combined with continuous exercise under long-term high pressure or muscle fatigue is the main reason for degenerative arthritis in professional and contact athletes. On the premise of no injury or excess, the knee joint has a good ability to withstand increasing pressure. For example, the study of nuclear magnetic resonance found that the knee joint of professional marathon did not change well after the race, while beginners produced joint effusion and various structural abnormalities after the race. Running the same distance, the old bird's joints are fine, and the rookie is miserable. This is because professional athletes' knee joints have accumulated enough compressive strength after long-term training to withstand marathon races, while beginners' cartilage is still "tender", so suddenly running a whole horse is not training for them, but destruction. For the retrained ethnic groups, step by step, keep the correct posture, pay attention to physical recovery, and don't exercise to exhaustion every time (Note 3), so that the bones, muscles and soft tissues of the knees have time to gradually adapt to the increased pressure. If you are lucky enough not to get hurt all your life, then I personally guess that weight-bearing training will not degrade your knees, but it may protect them. (Note 3: This is my personal guess. Since exhaustion is absolute muscle fatigue, if each group of squats is exhausted, it should have a bad influence on the stability of the knee joint. I don't think it's impossible to use it up, but we should "save some for use" ) Can patients with degenerative arthritis exercise? So far, there are many scientific hypotheses and Scott's inferences, but "can patients with knee joint degeneration exercise?" The answer to this question is almost indisputable: "Yes, and it is recommended to do so. Whether it is aerobic in water (reducing joint load), aerobic on land, weight-bearing training, physical therapy, walking and quadriceps strengthening, it can relieve pain and improve the function of daily activities. These effects are supported by a lot of scientific evidence. Even for very old people, weight training has its effect. At present, scientific research does not think that exercise will aggravate the symptoms of degenerative arthritis, and non-drug exercise therapy has the same effect as medicine. This echoes what we mentioned earlier. If degenerative arthritis is caused by simple wear and tear, then exercise should only aggravate the symptoms, not improve the pain. Regarding the exercise prescription for patients with knee degenerative arthritis, the American Geriatrics Association recommends one week:? Do moderate stretching exercises every day to improve the activity. ? Weight training 2-3 times a week, the intensity is 40-60% 1RM 8- 10. ? Aerobic exercise 2-5 times a week, 20-30 minutes each time, and the intensity is 40-60% of the maximum heart rate (or oxygen intake). The actual implementation is still recommended under the guidance of doctors, physiotherapists, or specialized physical fitness coaches. Conclusion: At present, it is scientifically believed that even patients with knee joint degeneration should not stop exercising. On the contrary, exercise can relieve pain and improve function, which is an important part of treating degenerative arthritis. The operation of human body is much more complicated than machinery. Tissue will repair itself, joint function will change with muscle function, and pain will be dominated by nervous system. We should abandon the old thinking that "all stress will lead to joint degeneration" or "joint degeneration should be rested more" Dr. Scott, his real name is Wang Siheng. I have been fascinated by fitness since medical school. In his spare time, he is either exercising/cooking/eating or studying scientific knowledge of exercise/diet/health. He is a fitness fan. Dr. Scott's one-minute fitness classroom