Why do my thighs hurt the day after running?

Running can be said to be the most economical and cost-effective way of exercise, and it is not restricted by time and place. Whether it is on city streets or on country roads, you can run freely as long as you wear a pair of running shoes. However, you should also pay attention to protecting your health when running to avoid muscle strain. So, what is the reason for thigh pain the day after running?

Reasons for thigh muscle soreness after running:

The muscle soreness we often talk about mainly refers to the latter type, namely delayed onset muscle soreness. There is a clear difference between muscle soreness and a strain. In fact, muscle soreness is a normal and positive physiological phenomenon. People often experience obvious muscle soreness and discomfort after strength training or an exercise that they are not used to (such as high intensity of exercise or a new sport). These symptoms will disappear naturally after a period of rest, and when the same exercise is performed again, the muscle soreness symptoms will be significantly reduced or will not occur.

However, muscle strain caused by exercise is different. Muscle or ligament strain can cause large-area pathological changes in skeletal muscle, such as cell degeneration, cell necrosis, etc., which not only affects continued exercise or training, but may also bring more serious consequences. Self-identification of strains and muscle soreness Muscle and ligament strains occur suddenly due to an damaging movement, while muscle soreness gradually worsens. There is a way to distinguish between the two: muscle soreness can be relieved by stretching, but if it is a sports injury, stretching will make the pain worse. In short, muscle soreness after exercise and muscle (or ligament) damage are completely different in nature. Muscle soreness can be relieved by rest, stretching, massage, etc. Muscle (or ligament) injuries must be solved by medical means.

Why do muscles ache? The mechanism of muscle soreness is relatively complex, mainly including the following aspects:

① Lactic acid accumulation.

②Muscle spasm.

③ Damage to muscle fibers or connective tissue.

④Other factors. Changes in interstitial osmotic pressure or acute inflammation can also cause muscle soreness. How is lactic acid produced? Human exercise requires energy. If the energy comes from aerobic metabolism in the cells, it is aerobic exercise; but if the energy comes from anaerobic glycolysis, it is anaerobic exercise. During aerobic exercise, glucose is metabolized into water and carbon dioxide, which can be easily excreted from the body through breathing and are harmless to the human body. During anaerobic exercise, glucose is fermented into a large amount of intermediate metabolites such as lactic acid, which cannot be eliminated through breathing, resulting in lactic acid accumulation.

Self-treatment of muscle soreness: Rest can relieve muscle soreness, slowly promote blood circulation, accelerate the elimination of metabolic products, and eliminate the supply and repair of nutrients to the muscle sore area, resting it back to normal. Static stretching of muscles can accelerate muscle relaxation and relieve antagonist muscles, which helps the recovery of spastic muscles. Perform static stretching exercises on the sore area, maintain the stretch for 2 minutes, then rest for 1 minute, and repeat. Doing this stretching exercise several times a day can help relieve spasms. Patting massage is used to massage the sore areas to relax the muscles, promote muscle blood circulation, and help repair injuries and relieve spasms.