<human>: Can you summarize the given text in a few sentences?

A few years ago I had a motorcycle crash that involved hitting my left knee quite hard. After the crash my left kneecap was all bruised and felt weird for a month or so. 

I started using the cross trainer (Elliptical trainer for Americans) everyday to keep mobile. I swim almost every day as well to excise my knee in a non impact way. Since the crash I've not really had any bad effects apart from the fact my left foot gets cold easier (suggesting some mild circulation issue)

I've started running twice a week back from work (2.4 miles in central London up a hill) and recently I've been getting mild pins and needles in my left foot after running and the outside edge of my foot is a little sore. My knee feels fine, but I think it's probably connected to the problem. I've got some reasonably good specialist running trainers that have a bit more support to make me run with my feet flatter.

* Are there some stretches I should be doing to stop this happening?
* Or other knee focused excises?
* Can I do something to increase my knee strength if it is the source of the problems? 

I've only recently started running and it's one of my favourite things to do but I'm concerned I might be doing myself damage.
<bot>: Had a bike accident and clonked knee. Knee isfine but now seem to be walking/running more on the edge of my foot. How do I stop?