Why do my legs always feel weak when I go up and down the stairs?

(the picture comes from the Internet)

Many friends, Especially old friends who are a certain age, usually don’t feel any special feeling when walking, but when they go up and down the stairs or walk with things, they will feel their legs and feet become weak. This may be a sign of osteoarthritis. Today, let’s get to know this osteoarthritis, which seems to be a disease but not a disease.