By way of coincidence, I went out for a run this morning and decided to try a slightly different route, which included the first portion on The Gallops which run behind where I live. It's probably the first time I've run for running's sake, on grass, since I was at school. Other than the undulations, I didn't notice much difference...
...until I reached the road and returned to tarmac. Blimey - the difference in impact and jarring was significant. I think I'm going to make an effort to include more off-road whenever I can now.
Don't think people realise just how much difference it makes.....really is quite remarkable. Ironically, I decided to do a road run this morning, not super-long and very slow paced but did 19 miles. Definitely noticed the impact more and had a slightly sore knee going downhill after about 15m. Hit 500 miles for the year this morning and that's the first time I have felt anything there.