Hi, You have been told you have patellofemoral syndrome from marching. This is is typically anterior knee pain where there is pressure on the patellar cartilage. Hope you have been xrayed with standing knee and special patellar views. You need to reduce weight if overweight. Specific physical therapy will be short arc quadriceps exercises where the knee exercise is done with a short range of movement, hydrotherapy, and pain relieving measures with medications and TENs. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. George Verghese, Orthopedic Surgeon