Knees are one of the most often injured part of the runner. There are tons of the reasons which can lead knee pain/injuries, such as shoes, running terrain, posture, technique, etc. I’m always recommending take any abnormal feelings and pain seriously, denying it or lack of treatment (prevention) may cause long symptom and/or recovery period. Here are some most common “muscles” related pain producers.

Patellofemoral pain syndore- also known as runner’s knee

Runner’s knee is a repetitive stress injury, where the pain located in the under the kneecap (patella) or front of the knee. It occurs when pressure between patella and femur increases, as the knee flexes and extents patella glides trochlear groove, end of the femur. Normally the bursitis which are the lateral side of the knee reduce the friction, but if tendons tightened too much tissues irritated, and running even walking start to hurt. Weak leg muscles, sudden increase of training load, gender, body weight are some of the reason which increases the injury risk.
Treatment
Rest is the best medicine, if there is inflammation regimen of anti-inflammatory drugs can help. Massage can help release tight muscles avoid running until the knee is fully recovery, you may do other exercise such as, water running, swimming or cycling.
Prevention
Strength training and stretching.

Iliotibial band syndrome (ITBS)

This is often mixed with runner’s knee, but in ITBS the pain is lateral side of knee. It occurs when Iliotibial band/tract tightening and cause friction against the thigh bone, femur. Pronation, weak muscles, lack of stretching, especially outer side of thigh may cause ITBS. Iliotibial tract (IT tract) is deep fascia, which is attached to tensor fascia latae muscle, which origin is; anterior iliac crest outer lip, anterior border of the ilium, outer surface of anterior superior iliac spine and it insert on lateral condyle of the tibia. When IT tract end up continuous stretch it rubs bone surface and get irritated.
Treatment
Treatment are the same as runner’s knee; rest, massage and cold.
Prevention
Stretching, avoiding fast increases in training load.

Patellar tendinopathy – also known as Jumper’s knee

Jumper’s knee is not as common for runner as two previous knee injuries. In jumper’s knee, pain normally appear medial side or above the knee. Its treatments and prevention are still same as runner’s knee pain.