Pathetic, Ahmad. You didn't read the article you cite at all!
The new study, however, debunks that theory. Richmond's team examined the wrist bones of two Australopithecus species: anamensis and afarensis. They found that the wrist joints of these ancestors were stable and resembled the wrist joints of modern chimpanzees and gorillas, the only living mammals that walk on their knuckles.
While they had wrist joints that would have been ideal for knuckle walking, these species, however, walked upright. Some of the best evidence for this came from the famous fossil named Lucy. She had relatively long lower legs compared to chimps, a big toe that did not stick out such as it does in chimps, and she had a curvature in her spine that strongly suggests she walked upright. So the knuckle-walking-type wrist joints were left over from an early ancestor, one that came down from the trees and was adapted to walking on the ground like modern-day chimpanzees.
The second article says exactly the same thing. Lucy was
BIPEDAL but retained knuckle walking features from her ancestry. So do we, I understand.
You're going to have to do better than that. Like read and find out whether the articles you are citing actually say what you want them to say.