HuffNPuff wrote:
No, it simply meant that frozen asphalt is much harder than warm asphalt. If it is freezing out there is virtually no difference between running on concrete or tar. Sort of how most people would rather get hit in the face
with a cup of water versus an ice cube of similar volume. :)
A particularly poor example. One is solid, and the other is not. Further, both are making direct contact with the face without any cushioning. Thus making it a complete non-sequitor.
"Much harder" is completely dependant upon the instrument used to measure it. A hammer striking both surfaces may be able to detect the difference in hardness. A hammer striking 1/2" of soft foam on top of the asphalt may not be able to discern the difference. Why?
Well, because shock absorbtion is about distributing the strike impulse over time. Mostly what that means is that the surface between the strike implement and the center of the earth compresses, and allows the implement to decelerate over a longer period of time. So, when the hammer strikes the frozen asphalt, maybe it decelerates to 0 in 1ms. Hot summer asphalt, 2ms. That's a pretty big difference for the hammer.
However, when you insert the soft foam...frozen asphalt deceleration time is maybe 50ms. Hot summer asphalt+foam, 50.5ms. So, 99% of the change in deceleration rate is due to the FOAM, and the change in hardness of the asphalt is practically irrelevant (1/100th of the total).
The science backs this up. Your anecdote does not refute anything. You believe it, because you've been told its true. If you run on a concrete surface that's been treated to look like asphalt, you will likely tell us how much better it feels. Conversely, if you run on an asphalt surface that has been treated to look like concrete you will complain about how "painful and hard" that surface is. That's psychology, not physics.