The Force of a Runner's Foot Against the Floor
This page is the CodyCross answer for the clue below from Health and Fitness, Group 2124, Puzzle 1 (Treadmills).
Question is: The Force of a Runner's Foot Against the Floor
and the answer is: IMPACT
Word Meaning:
IMPACT — The striking of one body against another; collision.
Definitions from Wiktionary.