Sore knees can be a disaster for your exercise- such a small joint can be SOOO debilitating.
There’s a lot that can go wrong with the knees, and obviously, correct diagnosis from a professional is always your ideal option.
If you haven’t had a direct injury and your knees bother you going downstairs one cause could be incorrect tracking of the patella.
This is preventable and often fixable.
Keep your quads and hamstrings strong and flexible. Very tight quads can really interfere with proper knee function. Think about it- you’ve effectively got this huge rubber band exerting an upward pulling force on the kneecap- no wonder it hurts.
We are seeing a lot of this since lockdown- things are seizing up everywhere as people working from home are moving less.
The other thing that stops your knees tracking properly is weak glutes. Glute medius is an external rotator of the femur (upper leg bone). So, if that is rotating in, your knee will turn in and then the result will be a painful knee.
So, the moral here is- stretch, strengthen and keep your butt strong! Even the smallest improvement makes a difference.