On Sept. 9, 2007, Asafa Powell broke his own 100-meter sprint/dash world record, his new record is now 9.74 sec. This race and his record can be a source for interesting calculations:
1. how many steps it takes the runners to cover 100 m?
2. what is the average step size?
3. What is their speed in terms of mph?
4. How much time during the race they spend in the air (as oppose to touching the ground)?
This can be evaluated/estimated by viewing the video frame by frame.
I believe it is more than half the time.
Look at it another way, with respect to distance, not time:
Most of the 100-meter distance he covers while he is airborne. If so, in a sense, with respect to distance, he is flying. But this is a misrepresentation because he must touch the ground every step in order to propel his airborne self for the next segment of his flight.
5. Assuming that Asafa Powell’s weight is still 88 kg (per Wikipedia’s older article), then:
5.1. What is his acceleration?
5.2. How much force he spent?
5.3. How much energy?