Sitting here (on my day off) watching the World Championship 50km on TV. The men hit the 20km mark in 88 mins. That is approximately 45 mins for a 10k. If I ran a 10k in that time, i'd be estatic. I was also thinking that as one foot needs to be on the ground at all times, it's a low impact exercise and therefore no knee injuries. All the injuries I've had are knee related. Any thoughts?