O-shaped legs can't be corrected quickly, except for surgery, which is too painful, and it's not recommended to stretch the legs. I'm not a prisoner, and I can't stand the time and energy. You should know that the O-shaped legs formed the day after tomorrow are caused by the unbalanced development of the lateral muscles stronger than the medial ones due to the improper standing posture and less development of the medial thigh muscles. It's more difficult if it's congenital.

A simple and effective method to correct the O-shaped leg requires some perseverance. It will take longer if you are older, but it will certainly be useful. It is what I use to correct the athlete's O-shaped leg.

1 Stand upright, chest out and back out (it is best to stand against the wall), forcibly clamp a slightly thicker book (half less than the O-shape) at the knees of both legs (clamp the dictionary if the O-shape is very harmful), keep your legs straight, and don't bow your head, and stand for 1-15 minutes (if you really can't hold on, 5 minutes is ok), 2-3 times, and you can stand several times a day.

2 the same posture, but gradually change the book into thinner and thinner, and finally ask to be able to hold the newspaper.

3 keep it up for a while.

4 When standing, pay attention to your hips and knees touching when walking.

5 try it! I wish you success.