Iliotibial (IT) band syndrome: A common injury for runners. The IT band is the connective tissue that stretches from your hip to your knee and can become irritated and painful (on the outside of the knee) when it becomes overstretched. Building up time/distance over time and avoiding too much downhill running can ease IT band syndrome.
Bursitis or "preacher’s knee": Occurs when a small sac at the top of your knee (Bursa) ruptures due to irritation and excessive impact. This type of injury is more common if you’re often on your knees for work (e.g. carpenters or mechanics) but can occur through excessive bending or a fall too.
Loose or broken cartilage: Often caused by overuse or as part of another knee injury. Small pieces of cartilage can break loose and then become stuck within the knee joint causing an uncomfortable sensation, rather than knee pain.
Patellar tendonitis or “jumper’s knee”: The tendon that connects your kneecap to your shin bone can become inflamed from excessive exercising or jumping.