Inclusion Criteria:  Clinical diagnosis of degenerative knee arthritis. Must be able to stand up and sit down.  Exclusion Criteria:  surgery on the knee or hip joint. rheumatoid arthritis and uarthritis in past six years. lower limb fractures neurological diseases,e.g.,stroke、parkinson's disease injected hyaluronic acid into the knee joint in the past two months severe cardiovascular and heart failure.