Incident: Hiker diagnosed with knee problems
Zhang Fan, who just celebrated his 45th birthday, is a seasoned hiker with nearly 20 years of mountaineering experience. He has conquered all 72 valleys of the Qinling Mountains and scaled many high mountains in other provinces. In his own words, hiking has become a habit. Over the years, he has climbed mountains almost every week. He looks strong and healthy, and all his medical check-up results have been within normal ranges. But in recent weeks, he has clearly felt something wrong with his knees. “My kneecaps started hurting for no reason—I have no idea why. Walking normally has become difficult these days.” As a result, he had to stop hiking over the past few weekends.
On April 16, he got X-rays of his knees at Xi’an Red Cross Hospital. “The doctor said all the cartilage in my knee joints has been worn away, and I need artificial joint replacement surgery to fix it,” he said, adding that it gave him a terrible shock.
According to the doctor, frequent mountain climbing is the culprit behind his condition.
Doctor: Nearly 100 such patients treated annually
“We receive patients like Zhang Fan almost every day,” said Zhang Yumin, director of the Joint Surgery Department and chief physician of orthopedics at Xi’an Red Cross Hospital, on April 19. Many hikers and mountaineering enthusiasts believe that hiking is a very green outdoor activity that is entirely beneficial with no downsides. They never expect that frequent hiking is actually the main cause of knee diseases and can easily lead to the complete wearing away of knee cartilage.
Zhang Yumin said their hospital has been receiving nearly 100 patients like Zhang Fan every year since 2009. “Usually, I can tell the cause as soon as I see the X-ray and hear that the patient frequently hikes or jumps rope. Those with mild symptoms don’t need medication—just stopping those activities will allow gradual recovery. More serious cases require surgery.” It is understood that there are about 500,000 hikers in Xi’an who often go climbing on weekends.
Cause: Knee joint pressure is 3 to 6 times body weight when descending
Why does hiking wear out knee cartilage? Zhang Yumin used a knee joint model to analyze and explain it to reporters.
He said the knee joint is composed of the medial and lateral condyles of the femur and tibia, plus the patella. It is the largest, most complexly structured, and most injury-prone joint in the human body. When walking or exercising, the knee joint performs flexion and extension movements, during which friction occurs between various joints, and the patella and the medial and lateral condyles of the femur bear pressure. This pressure varies depending on the type of movement. When hiking, this pressure becomes even greater. This is because when the knee is bent, it has to support the full weight of the body, especially when descending, where the force on the cartilage surfaces can reach 3 to 6 times the body’s own weight. Once or twice may not be an issue, but doing this frequently will inevitably cause problems. The same logic applies to why frequent jump roping causes knee pain.
Physiology: Joint cavity lubricant decreases with age
“Cars and other machines need lubricating oil to operate, and so do human joints,” Zhang Yumin said. The human body naturally secretes lubricant in the joint cavity. This lubricant acts like oil, reducing wear between joint cartilages. But this lubricant isn’t continuously secreted—it decreases with age and varies with an individual’s physical constitution. “When there is enough lubricant, the knee can flex and extend normally. When there is insufficient lubricant, the cartilages rub directly against each other. Over time, the cartilage gets completely worn away. Then, when you move your knees, it becomes painful. Many hikers think of hiking as a full-body exercise, but they often overlook how descending puts extra strain on the joints.”
Zhang Yumin also said he has encountered other hiker patients in his clinic who suffered cartilage and ligament injuries in the knees due to increased joint movement. Severe cases involved cartilage wear and ligament degeneration.
Reminder
It’s best to land on the soles of your feet when descending
Elderly people should avoid squatting in horse stance too much
Besides hiking, jump roping and going downstairs or downhill can also lead to knee cartilage wear. Zhang Yumin said this is also due to the increased pressure on the knee joint during flexion and extension. “When going downhill, try to slow down your steps and avoid running. When descending, the body tends to lean forward, but it also instinctively tries to maintain balance by leaning backward. These two forces concentrated on the knee joint create a big impact, wearing down the cartilage,” Zhang Yumin explained. When going downhill or downstairs, landing on the soles of your feet first allows the foot arch to act as a cushion.
“Elderly people like practicing tai chi, which often involves horse stance. Like hiking and jump roping, this can also lead to joint damage. Due to aging, the elderly produce less lubricating fluid, making them more prone to knee pain. Therefore, elderly people practicing tai chi should minimize horse stance.”
Different age groups should choose different types of exercise
Zhang Yumin said, “Exercise one hour a day, live healthily for fifty years”—this is the relationship between exercise and life that is currently advocated. But in fact, to maximize the benefits of exercise while avoiding harm to the body, different age groups should choose different kinds of activities.
He suggests that men in their 20s should engage in more outdoor activities, such as playing ball games regularly to build muscle and enhance cardiopulmonary function. Girls in this age group can jog or cycle. Men in their 30s should avoid intense exercise and always warm up before working out to prevent strains. Women in their 30s, whose metabolism slows down, can opt for outdoor jogging or brisk walking, aiming for at least 30 minutes a day.
In your 40s, men should choose low-intensity exercises like jogging to strengthen joints and the cardiovascular system, while women should incorporate certain strength training to help slow down osteoporosis and weight gain.
Men over 50 can choose aerobic exercises such as brisk walking, swimming, and cycling. Women in this age group can opt for swimming and walking.
By our reporter Qing Rongbo
Author: Qing Rongbo (Source: Huashang Daily)