:in a kneeling position:in the position of someone who is kneeling on one knee下跪；单膝下跪
He proposed to her on bended knee. = He got down on bended knee and proposed to her.他单膝跪下，向她求婚。
— sometimes used figuratively有时用作比喻
He was forced to ask for their help on bended knee. [=he was forced to beg for their help; he was forced to ask for their help in a very humble way]他被迫低三下四地乞求他们的帮助。