Interesting article. Tyson gay has 0.07 ground contacts... GAHHHH!
In some ways it's a shame that the article chose to compare these three athletes from 60-80m because while they don't explicitly state it... A very misleading interpretation of the data is easy to come by.
That is:
Gay is 6'0, Powell is 6'3, Bolt is 6'5 and ground contacts are 0.07, 0.08, and 0.09 respectively. All three are clearly very fast so it seems taller athletes have greater ground contact time (less leg stiffness) but make up for it with their stride length.
However, what's important is that while Bolt and Gay ran roughly equal 20m splits (1.63 and 1.62), Powell has poor speed endurance and maxV (in comparison) and was slower (1.69) from 60-80m. Thus, Tyson's greater stride frequency is in affect the reason why he runs faster than Powell. If you watch the video you will notice that Powell is overstriding by 70m which really throws the analysis off. I would bet that between 40-50m Powell and Gay would have much more similar ground contacts and stride lengths (as well as almost equal splits). The point being that world class sprinters from 5'9 to 6'4 have what is really only a minor correlation between contact time/stride distance and height. Bolt is the aberration. Remember stride rate hardly differs between amateur and world class athletes (note that's stride rate not contact time), but world class athletes impulse is much greater per stride.
Essentially, everyone else is running and Bolt and practically bounding down the track each ground contact propelling him ridiculously far forward. It's like the guy never leaves drive phase. Really gotta appreciate him for what he is, the greatest athlete of all time.