I did my first off road run today, round the local woods. The trails are varied and much is simply mud. It was great fun!
I found this today, an article which encourages running on different surfaces to minimise damage. Interesting stuff. I run on concrete, and grass usually but now I will be using the woods too.
Thanks barrygarlow that's really interesting. So if we carry that argument on, treadmill running is also less good for the body than trail running, because again it's the same stress all the time.
I'll be out in the woods again asap, but at the moment I'd be up to my ears in mud and there's more snow forecast for next week so I'm not holding my breath. 
I suppose though if we varied our pace-length during every session too that would make for a slightly different stress on the muscles and joints as well. I'll give it a go tomorrow! 
Very interesting article, thanks. Doing a muddy parkrun is definitely quite different to running along a pavement - I could feel it was different pretty quickly! Just lifting my feet out of the mud (and avoiding going flying) was hard work, and my thighs were aching after just a couple of minutes - usually i don't notice that much until near the end of a run!
All the information about muscles, bones and ligaments is fascinating. I'd no idea that 'shin splints' can be three completely different problems.
The article author seems to assume all runners are heel-striking, I think, which was curious (or maybe I misread it).
Likewise don't just train off road in the woods then think you can run safely on road. I haven't been able to run for the past 4 months after entering a road race after only ever doing trail running. The change in surface is a great way to give youself plantar facitiis as I found out to the cost of my new found fitness!
The difference between trail and pavement running
Tough on the pavement
Sparkly pavements
The dangers of sponteneity
Frosty pavements
