When a boxer repeatedly punches with his fist and kicks with his legs and feet, his legs and feet are more stressed. After long-term exercise, the bone density of this part will be higher than that of other parts that are not stressed. This is also the reason why fierce fighters such as Muay Thai are tough, because practicing Muay Thai from an early age requires hitting their main hitting parts with wooden sticks.

National Geographic magazine mentioned that "practicing hard skills will change the bones themselves, which is called Wolf's Law, and it was a great discovery made by surgeon Julius Wolf in the19th century". "Bone trabecular, its name comes from the Latin word trabecular. If the bones are repeatedly damaged, the calcareous structure will increase, that is, there will be more trabeculae, and the bones will become denser, harder and more tolerant. Ancient kung fu masters have long known the mystery of Wolff's law. For hundreds of years, they practiced with boards, sand, iron or stones. As the saying goes, everything turns into steel! "

(2) Slimming clothes and abdominal belts

Since ancient times, the waist has always been one of the key parts for women to highlight their exquisite curves and aesthetic feelings, regardless of Chinese and western cultures. /kloc-in the 0/9th century, a "thin waist" wind swept across Europe. At that time, European women thought that only when the waist was thin could they sway when walking, so as to better show the beauty of the chest and buttocks. Therefore, "the thinner the waist, the better" became the supreme aesthetic standard of women at that time.

According to the Daily Express, a 68-year-old woman in the United States has been wearing tights every day for the past 22 years, setting a Guinness World Record for "the world's thinnest waist lady" (pictured). According to reports, the old woman who loves beauty is Kathy Gann, who is 68 years old this year. Kathy is nearly 1.7 meters tall and weighs 58 kilograms, but her waist circumference is only the thickness of a large beer glass. Her "waist-to-hip ratio" is as low as 0.48 (the average woman can only be slim if she reaches 0.7), even more outrageous than Barbie's 0.54.

According to Kathy, "one day I looked at myself in the mirror and my body was seriously deformed because I had a baby. I made up my mind to change all this." Therefore, Kathy, then 46, has been wearing "tights" for 23 hours every day for 22 years since 1983, and her waist will only relax when she takes a shower. Kathy recently set a Guinness World Record for "the thinnest waist lady in the world". According to the data of authoritative verification organization, Kathy's waist circumference is only 50 cm even when she is full of gas, and when she is wearing a tight skirt, her waist circumference is as low as 38 cm.

(3) Sports

Various movements have a great influence on the shape of bones. Due to different sports events, the stress points and exercise intensity will have different forces on bones in different parts of the body, so the stress state of bones will be different. The body will automatically adjust the structure and shape of bones to cope with this external stimulus, and grow, absorb and rebuild with time, so that the body can complete daily training more efficiently. For example: weightlifting, basketball, marathon, etc. The picture shows the little-known side of Ai Dongmei, Guo Ping and Ma Jiajun.