With the aging of the population, the number of elderly patients in orthopedic clinics is increasing, and patients suffering from osteoporosis and osteoarthritis have gradually become the mainstream of outpatients. However, there are some patients whose cause is not due to bone degeneration, which seems to be a minor problem, but brings great pain to the patient, and the treatment is often more difficult. This is the sports injury caused by improper exercise. The most common type of sports injury is pain in the knee joint after running. The pain often lasts for a long time and is difficult to subside. It is really a small problem, big confusion. According to the data, currently in the United States, it is estimated that more than 35 million people use running as a daily exercise routine, and the annual occurrence of running-related sports injuries is 19-79%. 80% of sports injuries are due to overuse injuries. Chronic knee pain has forced some people to give up running for exercise. Patients often complain to me in the clinic: “If I don’t run, I can’t get my blood sugar and blood lipids down; if I don’t exercise, I can’t lose my obesity and weight! But the result of exercise is that my knees hurt so much that I can’t walk. What should I do?” What should I do? My answer is: if you want to stick to running exercise, you have to learn to protect your knee joint. The structure of the knee joint determines its “many hardships” First, let’s look at the structure of the knee joint. The knee joint is composed of the distal femur, the proximal tibia and the patella, which are the largest and most complex joints in the human body and are subject to high loads in various sports. The anterior and posterior cruciate ligaments, lateral collateral ligaments, joint capsule and meniscus are also attached to them and form the stable structure of the joint. The synovial layer of the joint capsule is extensive, except for the articular cartilage and meniscus, which are not covered by synovial membrane on the surface, the rest of the structures are covered with a layer of synovial tissue. This is also the most common site of painful sports injuries, and the inflammatory response of synovial tissue is called synovitis by orthopedic surgeons. The meniscus is a disc of fibrocartilage within the knee joint that absorbs impact, increases the adaptability of the joint surface, and helps to distribute joint fluid evenly. Improper motion can lead to damage to the anterior and posterior cruciate ligaments, lateral collateral ligaments, and the meniscus. The main movements of the knee joint The most important movements of the knee joint are: 1. Flexion and extension of the knee joint. The joint is most stable when the knee joint is fully extended. The active movement of the knee joint is 0 to 140°, while passive movement can be flexed up to 160°. 2. Rotational movement of the knee joint. The rotation of the knee joint is based on the femur of the thigh, and the internal and external rotation of the tibia of the lower leg occurs. When the knee joint is maximally extended, the tibia cannot do the movement of internal and external rotation. The main risk factors for knee injuries caused by running can be summarized as follows: 1. Self-factors. This includes the runner’s gender, age, height, weight, high BMI (Body Mass Index, Body Mass Index, or BMI) and genetic factors; 2, running training factors. This includes the length of the runner’s weekly running time, the running distance, whether the runner has received running training, etc.; 3, physical conditions and lifestyle factors. This includes whether the runner smokes, alcohol abuse, whether suffering from various chronic diseases, and whether also suffering from previous knee injury. In these risk factors that can lead to sports injuries, the current research shows that only the previous knee injury is certainly closely related to the new injury (or perhaps the previous knee injury is not healed), while other factors still exist in a great deal of uncertainty, need more research to confirm. In addition, biomechanical studies have shown that the coronal (anterior-posterior) and transverse (lateral) motion of the knee joint during running can cause knee injuries. How to run without running knee After understanding the basic structure of the knee joint, its main movement, and the various risk factors that lead to injury, we can target to avoid those undesirable factors, so that running becomes a more beneficial physical exercise method. Looking at the structure of the knee joint, the distal femur, proximal tibia and patella make up its bony structure. The femur provides the patella with a track of its own, and during running, the patella moves within this fixed track. Any external force perpendicular to the knee joint from the front can lead to increased pressure on the contact surface of the patella and femur and excessive wear on the contact surface, resulting in typical medial patellofemoral pain, which is clinically known as “patellofemoral pain syndrome”, also known as “running knee”! This is clinically known as “patellofemoral pain syndrome” or “running knee”! Current research has confirmed that abnormal movement of the tibia and femur in the coronal (anterior-posterior) and transverse (lateral) planes will affect the trajectory of the patella, thus increasing the chance of patellofemoral pain syndrome. Another study found that the decrease in muscle strength, especially the quadriceps muscle strength, will also increase the incidence of “running knee”. Therefore, in a sense, how to do a good job of knee joint protection measures in running exercise, should start from the following two aspects. First, minimize the load on the knee joint, so that the load is controlled below the threshold of injury; second, constantly improve the ability of the knee joint to withstand the load. The specific approach is: 1, choose the right running shoes. Choosing the right running shoes is very important, as the saying goes: the work is good, it must first be good! Running shoes are not necessarily expensive, but must be conducive to running exercise; 2, the warm-up exercise before running. This point is often ignored by people, think it is not necessary, in fact, the idea is wrong. The warm-up exercise before running, just like our winter morning “warm-up car”, can not start the car immediately after the start, need to let the car have a process of adaptation, so as to prolong the life of the car. Our knee joints in the human body before the activity also need to have a process of adaptation; 3, choose a plastic track or flat tarmac. The plastic track in the stadium can effectively reduce the stress on the knee joint when running, is the best place to run exercise. If conditions do not allow, you should choose the flatter tarmac, never in the uneven hills or gravel roads. The actual car, if exercised every day on the rugged mountain road, its shock absorption system will be damaged very early, life will be greatly shortened; 4, the time of exercise. The time of running exercise should be regular, not “three days to fish, two days to sunbathe”. The weather is good today, the sun is shining, the mood is good, go to run a circle. After a few days feel tired, no longer interesting, give up. According to the relevant research, the group of knee injury caused by running mainly occurs in the over-exercise and occasional running sports; 5, the distance of running. For the distance of running, should follow the principle of gradual and progressive, gradually increase the amount of exercise and running distance, so that the knee joint to the continuous stress has a gradual adaptation process, otherwise excessive knee injury will occur; 6, the control of running posture. This is really difficult for ordinary runners. Only those athletes with professional training can have the opportunity to receive professional coaching to improve their running posture. Running posture control, not only the pursuit of running speed, for ordinary runners, it is more important to good running posture can reduce the damage to the knee joint when running. As already mentioned, the coronal and transverse motion of the knee joint can lead to knee injury. If the runner’s running posture is poor, the body shakes left and right when running, the knee joint will certainly be subject to more stress, “running knee”; 7, the strengthening of muscle strength. This is mainly through the strengthening of the thigh quadriceps muscle strength and gluteus muscle strength to complete. The quadriceps non-weighted straight leg raise training: try to straighten the knee, contract the quadriceps in front of the thigh, dorsal extension of the ankle joint slowly lift the entire lower limb, adhere to 5 to 10 seconds and then slowly lower. The role of the gluteal muscles is to extend the hips and to control the position of the pelvis when standing on one leg. If the pelvis is not positioned correctly when running, it will increase the stress on the knee joint. To train the gluteals, lie on your side, then abduct the upper hip joint and extend the leg laterally. The point of this exercise is that the hip must not be flexed. In a scientific article published in 2014, the idea was presented that exercising the gluteus alone is not completely effective in reducing sports injuries in the knee. The rationale is that the exercise of the gluteus only strengthens the muscle strength of the proximal part of the lower limb, while the muscle strength of the distal part is not improved, thus not fully protecting the knee joint; secondly, the exercise of the gluteus is carried out in the non-sport state, and the effect on the sport state during running is not necessarily very satisfactory. Therefore, the article proposes the idea of strengthening the muscle strength training near the distal ankle joint of the lower limb. Of course, this idea is still in the initial stage of research; 8, to prevent the semi-flexion rotation movement of the knee joint during exercise. This knee movement can damage the meniscus, and special attention should be paid when running exercise. 9, appropriate use of active vitamin D. Active vitamin D has a synergistic effect on muscle strength, the elderly can do running exercise during the appropriate use of active vitamin D. This can prevent running falls and knee injuries; 10, oral glucosamine drugs to protect the knee joint. The joint knee is one of the joints that bear a large load in human activities, and there are many chances of injury in running sports. As long as we can pay attention to avoid those risk factors that lead to knee injury, running exercise should be a positive significance is the way of exercise. Recently, there is a kind of “squatting wall root” type of thigh quadriceps exercise method on the network. The actual wall is a half-squatting exercise. Is this method good for the knee joint? Let’s look at the changes in pressure between the patella and femur of the knee joint during the squatting process. With the gradual flexion of the knee joint, the pressure on the patellofemoral joint surface will gradually increase, peaking at half-squat. After a full squat, the pressure between the patellofemoral joint returns to a minimum. Therefore, it is naturally self-evident whether this type of exercise is feasible.