When it comes to knee pain while hiking- there is a process which will help about 80% of hikers...
Step 1: You need to loosen certain mucles.
-Often an underlying cause of knee pain for trekkers is a lack of mobility in the muscles both above and below the knee.
-When these muscles are tight, the body compensates by allowing more movement through the knee (which not a good thing...)
Muscles that should be loosened are:
*Hips (Front and back)
* Quadricepts
* Hamstrings
*This is best done through a combination of regular foam rolling and stretching.
Step 2: you need to strengthen the stabilising muscles of the knee
- When the stabilising muscles of the knee aren't strong enough, this again allows more movement in the knee joint, making it take a lot more strain then it should!
These muscles should be strengthened:
*Glutes
*Quads (particularly the Vastus Medialis)
*Hamstrings
Step 3: Use Poles (as everyone has said already)
They 100% work - some studies have shown they can take up to 30% of the pressure off your knees when going downhill.
Hope that helps!