Tried another run in the heat. Thought after a day off my calves might have loosened up. No such luck. They are tight and sore. To the point that I am worried, if I push it, I might end up with an injury. Cut the run short again today. I can say that the barefoot forefoot striking seems great for speed, but it is working my legs a lot. Will try again tomorrow. Haven't been able to ride the bike lately as an alternative. Had a flat on the last ride and used the 2 CO2 canisters I had. Living out in the country, this is not an item you can just go and pick up. Ordered replacements on Amazon, but will have to wait for them to come in. Bike is o.k., but not going out on a ride with the chance of being stranded out on the road.