Last Updated on March 10, 2013 by Jimson Lee
Two years ago, I wrote about how the Women’s world records were almost impossible to break with the exception of the recent additions of the Pole Vault, Triple Jump and Hammer Throw.
The reason was possibly the “looser” drug testing policies from the 1980’s.
I never thought I would see the 12.21 WR of Yordonka Donkova 100 meter hurdles broken anytime soon.
Sally Pearson from Australia came ever-so-close with her 12.28 last year.
Some people think she will break it because “Speed Wins”. Just ask USA’s Gail Devers. Thus Sally also competes in the 100 meter with a PR of 11.14.
But hold on…
Flight Time vs Stride Length
If you ever watch Dayron Robles 110mH, one thing is clear: his hurdle clearance is exceptionally smooth, efficient, & quick, and that he “shuffle steps” between hurdles.
Sprinters analyze stride length and stride frequency, and for some the holy grail is reducing ground contact time.
The 100m sprint can be summarized as ~45 synchronized large leaps and bounds.
But the high hurdles has those darn sticks in the way. Thus coaches love to measure the flight time.
Yes, the high hurdles is a sprint, but instead of being obsessed with stride length, stride frequency, & ground contact time, it’s about clearance (i.e. flight time) as well.
To get a 0.27 second flight time for ALL 10 hurdles is like asking for an Eagle for every Par 5, and a Birdie for every Par 3 & 4 on a golf course. In a perfect day, you would shoot 50 in golf for 18 holes!
When you consider 8.5m between hurdles, and a 3.2m total flight clearance, that leaves 5.3m for 3 strides (1.77m) instead of the usual 2.17 in normal sprinting. Hence, the stutter steps between hurdles.
More on this topic from www.dailytelegraph.com.au:
While Pearson’s great improvement from 2010 to 2011 is substantially down to enhancing her endurance over the last four hurdles – and work will continue in that area - Hannan says they are also looking at skimming time off her hurdle clearance.
"We have to work on her flight time which was 0.28sec for five of the 10 hurdles (Hurdles 2,3,4,5,6), four at 0.29sec (H1,7,8,9) and one of 0.30sec (H10) in Daegu. If we could get that down to 0.27 it would be awesome. That would be 0.08sec which would be the world record, all else being equal.
"I want her taking off closer to the hurdle. It has more to do with sighting the hurdle at the speed she’s running. Sally sees the hurdle coming at her fast and so she automatically chops her step.
"But I don’t want her to chop. In races she’s taking off a little too far from the hurdle. She can do it perfectly in training.
"The solution is over-riding the survival instinct and attacking it more, yep. It’s the chicken and the egg though. You can’t work on that until you get your speed up in training."
If Pearson gets the world record she will follow a very different course to Donkova, who, at 179cm, would tower over the 166cm tall Gold Coast athlete. Donkova’s accumulated flight time for the 10 hurdles is 2.72sec as against Sally’s much slower 2.86sec (in her semi and final in Daegu, heat was 2.88). But Pearson is a couple of metres faster on the flat than Donkova was.
French sprints and hurdles coach Pierre-Jean Vazel, a biomechanics lecturer at a Paris university, told The Telegraph: "The trick is that at full speed Sally’s stride length is 2.17m long (during the Daegu 4x100m relay) while the 8.50m interval, excluding the hurdle clearance, between the barriers leaves only 5.30m for the three strides between the hurdles. This works out at 1.77m per stride.