eurodonkey wrote:
Impact. I'm a miler so when I say "stride" it's near to a sprint - on the toes, minimal ground contact time and thus a hard/fast footstrike. This HURTS on asphalt - at the time, and the day after.
A couple of times this fall, a combination of time pressure and a cool new Garmin footpod led me to do my planned interval sessions late at night on road (with various reps between 75 and 68 sec per lap - 5k down to summer 1500 pace). Both times, I was sore as hell in ankles, knees, shins etc. Same pace on track or treadmill is no problem.
I have no problem doing road 5ks, or reps at 5k pace.
Then again, maybe I'd adapt, but I see no reason to try and find out. If I want to stride fast on roads (e.g. winter evenings), I find a gentle hill so there is no impact.
I have been doing this for years with no problem. Asphalt is a fast surface, it's the speed endurance that migh make you sore, but if you are adapted to it, it's not a problem.