i usually go barefoot on grass (not lately...it's snowing like crazy outside right now), but i love a good sprint on a beach...you have to work a little harder and if there are dunes to run up, it's like getting 10 workouts in one.
Sprinting BF on tarmac is OK but I wouldn't start out like that. There's a road I run BF on regularly and I know it's characteristics really well so sprinting works fine for me there.
Here's a good video of Jason Robillard running on the road. You can see on the last clip he's really going some there.
YouTube - Jason Robillard barefoot running form 2009
i usually go barefoot on grass (not lately...it's snowing like crazy outside right now), but i love a good sprint on a beach...you have to work a little harder and if there are dunes to run up, it's like getting 10 workouts in one.
I had the greatest time sprinting on a sand volleyball court. It was winter, and it was a little waterlogged and a little frozen. It was like sprinting in ice cream or something. Super tough and very rewarding.
I try to stay off pavement as much as I can. Dirt/grass is great, rubberized tracks are good, beach is fantastic. The unevenness of the terrain is still smoother than most of what Grok faced.
I wouldn't be too concerned about concrete/pavement - you'll be running on your forefoot anyway, so unless you have flat feet / no arches (in which case you should not be barefoot running), hard ground is actually better because your foot is supposed to do the cushioning. If you want to reduce stress on the joints effectively, run uphill.
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