Running on asphalt is almost certainly easier than running on anything in the past. Try running on a rocky beach someday. :D. Running cross country through trails, you should expect that you will be going far slower than you could comfortably do on asphalt.
The shoes things is an odd one. Current thinking is that a lot of the effort people went through to dampen the shock to knees oddly resulted in people accepting longer periods of stress on their knees than they would have had they learned a different gait. That said, building up callouses on your feet, as was the norm before shoes, by definition hurts?
I hate that I put "running" as my example. Standing and walking would also make my point. Physically using your body is more difficult than not. And if you aren't used to it, it is a type of hurting.
Heck, learning to play a musical instrument is the same way. Guitars hurt your fingers as you build up the ability to play. Piano doesn't have the same pain, but expect a sore hand after a few sessions.
The shoes things is an odd one. Current thinking is that a lot of the effort people went through to dampen the shock to knees oddly resulted in people accepting longer periods of stress on their knees than they would have had they learned a different gait. That said, building up callouses on your feet, as was the norm before shoes, by definition hurts?
I hate that I put "running" as my example. Standing and walking would also make my point. Physically using your body is more difficult than not. And if you aren't used to it, it is a type of hurting.
Heck, learning to play a musical instrument is the same way. Guitars hurt your fingers as you build up the ability to play. Piano doesn't have the same pain, but expect a sore hand after a few sessions.