The knee joint is the largest joint in the body and particularly vulnerable to damage and pain, because it takes the full weight of your body! It is the most frequently injured joint in athletics, with most injuries being caused by extreme stresses, such as twisting and turning.
There can be structural deviations to knees, commonly known as ‘knocked knees’ (bent inwards), ‘bow legged ‘(bent outwards), hyper-extension of the knee (bent backwards)and Pes Planus (commonly known as flat-footed).
Jumper’s knee caused by overuse
Achilles tendon, overuse, excessive training, change in training and sub optimal footwear.
Knee sprains, joint injuries
Runner’s Knee (IT band friction syndrome) is caused by overuse (repetitive knee flexion and extension) and excessive or sudden increase in training. but crucially poor biomechanics when running. In addition, weak hip flexors and glutes can compound the issue.

How do you go about fixing your knee pain? As per your other pages for uniformity?
Acknowledge ( e.g adapt training/rest)
Assessment (and special orthopaedic testing)
Application (treatment and/or invention
Active Rehab program including home exercise)