http://sports.espn.go.com/nfl/trainingcamp10/news/story?id=5449113

Snippets below. Full article HERE.

“The study, just published in the International Journal of Design and Nature and Ecodynamics, starts with a puzzle about racing sports: “More and more, the winning runners are black athletes, particularly of West African origin, and the winning swimmers are white. More and more, the world finalists in sprint are black and in swimming are white.”

The authors—Edward Jones of Howard University and Adrian Bejan and Jordan Charles of Duke University—attribute the two trends to a common factor: center of gravity. They explain:

Anthropometric measurements of large populations show that systematic differences exist among blacks, whites and Asians. The published evidence is massive: blacks have longer limbs than whites, and because blacks have longer legs and smaller circumferences (e.g. calves and arms), their center of mass is higher than that in other individuals of the same height. Asians and whites have longer torsos, therefore their centers of mass are lower.

These structural differences, they argue, generate differences in performance. Using equations about the physics of locomotion, they analyze racing as a process of falling forward. Based on this analysis, they conclude that having a higher center of body mass in a standing position is advantageous in running but disadvantageous in swimming.

Drawing on data from 17 groups of soldiers around the world, the authors note that in terms of upper body length, “the measurements of the group of blacks fall well below those of the other groups. Their average sitting height (87.5 cm) is 3 cm shorter than the average sitting height of the group of men with the same average height (172 cm).” From this, they calculate that “the dimension that dictates the speed in running (L1) is 3.7 percent greater in blacks than in whites. At the same time, the dimension that governs speed in swimming is 3.5 percent greater in whites than in blacks.”

“Upper- and lower-extremity bone lengths are significantly longer in adult black females than in white females. For the lower-extremity bone lengths, the difference is between 80.3 ± 10.4 cm (black females) and 78.1 ± 6.2 cm (white females). This difference of 2.2 cm represents 2.7 percent of the lower-extremity length, and it is of the same order as the 3.7 percent difference between the sitting heights of whites and blacks.”

“a 1.5 percent increase in the winning speed for the 100 [meter] dash. This represents a 1.5 percent decrease in the winning time, for example, a drop from 10 to 9.85 [seconds]. This change is enormous in comparison with the incremental decreases that differentiate between world records from year to year. In fact, the 0.15[-second] decrease corresponds to the evolution of the speed records ... from 1960 (Armin Hary) to 1991 (Carl Lewis). The 3 percent difference in L1 between groups represents an enormous advantage for black athletes.
For swimming, the conclusion is quantitatively the same, but in favor of white athletes. The 3 percent increase in [lower-body length] means a 1.5 percent increase in winning speed, and a 1.5 percent decrease in winning time. Because the winning times for 100[-meter] freestyle are of the order of 50 [seconds], this represents a decrease of the order of 0.75 [seconds] in the winning time. This is a significant advantage for white swimmers, because it corresponds to evolution of the records over 10 years, for example, from 1976 (James Montgomery) to 1985 (Matt Biondi).”

http://www.livescience.com/animals/human-speed-limit-running-100122.html

Been tralling various online journals and am struggling to find research on Exercise Induced Bronchospasm (EIB), particularly it’s affect on endurance athlete’s performance.
Any help or a point in the right direction would be much appreciated. I need as much scientifically based research as possible for use as references.

Cheers
Rob

How does Usain Bolt do it?

Jamaican sprinter Usain Bolt hardly fits the physical profile of most of his peers. At 6-feet-5, he towers over most other shorter, stockier runners. This seems to work for the 23-year-old Bolt, who recently set world records in the 100 meter and 200 meter races at the 12th World Track and Field Championships in Berlin.

Why he’s faster than his cohorts, despite being significantly taller, is the subject of much speculation among coaches, exercise physiologists and geneticists.

“Most sprinters are pretty small people,” says Carl Foster, a professor in the department of exercise and sports science at the University of Wisconsin-La Crosse. “It’s a mechanical thing—runners have got to be able to generate the power to accelerate a body, and a bigger body is harder to accelerate than a smaller one.”

It’s a simple law of physics—it takes more energy to move a larger mass than a smaller one. But somehow Bolt manages to make his larger, longer legs move as fast as those of his shorter competitors.

Foster and other experts say that various factors (none of which seem to involve an affinity for chicken nuggets) could contribute to Bolt’s success. It goes to show, they add, that sprinting is much more complex a sport than simply running as fast as you can.

One thing Bolt has going for him, besides his longer stride length, is that he doesn’t lose energy toward the end of a race.

Corey Hart, an exercise physiologist with the Physio Performance Lab in Boise, Idaho, chalks that up to Bolt’s dorsiflexion, the way the foot flexes toward the shin, while walking or running. This may predispose him not to put his heel too close to the ground, which would make him lose energy.

“Sprinters run on their forefeet,” he says. “When you think about sprinting, you resist the force that goes into the ground by not putting the heel down.”

Dan Cipriani, a professor of exercise science at San Diego State University, thinks one of the keys to Bolt’s success may lie in what he does specifically during push-off, when his foot is in plantar flexion, or the movement of the foot away from the shin—the opposite of dorsiflexion. “The way he’s able to propel himself forward, I would assume he has very good plantar flexion strength and speed.”

Bolt also might be doing something more efficient with his upper body, which is extremely important for sprinters and helps maintain efficiency in the forward movement, Cipriani says. “If you’re not using your upper body correctly, it could force the pelvis to rotate sideways more than straight ahead.”

Still, Cipriani wonders how Bolt is able to move his joints fast enough to be on a par with his peers. Legs are like levers, and shorter levers are going to move more quickly than longer ones. Bolt’s long legs should also be a disadvantage in starting, he adds, since they may make it more difficult to gain speed quickly.

How much of Bolt’s speed can be credited to genetics and how much to training may never be known. Some speculate that Bolt may have the ACTN3 gene, also known as the speed gene. Studies have shown that many power athletes have this gene, which allows the body to produce a specific muscle protein that aids in activities such as sprinting. “There’s no question in my mind that he’s going to have a convergence of certain genetics that contribute to his success,” says Martin Munzer, president and chief executive of CyGene Laboratories Inc., a Florida-based biotechnology company offering genetic testing for consumers. “But that’s not the only reason he’s successful. There are all kinds of factors that play into that, by either coincidence or purpose.”

Besides, Munzer adds, genes don’t tell the whole story. “Just because you have a certain genetic profile it doesn’t predestine you to anything. You can affect the existing genes by switching them on and off through dietary or environmental effects, like smoking.”

While analyzing Bolt’s running gait or gazing into his gene pool might ultimately help us understand what makes a runner fast, there may be something else to learn from Bolt’s accomplishments: Body type doesn’t always dictate who will do well in a certain sport. Some coaches tend to look for specific body types to be good fits with certain sports—and maybe they shouldn’t be pigeon-holing young athletes that way, Foster says. “This probably argues that you should have children do as many activities as they can.”

Thoughts?

In the book there is a chapter focused on the footwear that this tribe in Mexico (Tarrahumarra) wears when they run.  It’s pretty much a tire tread with some leather lacing made into a sandal.  In this chapter the author goes on about how the foot was “designed” and how this tribe doesn’t get hurt in part due to their footwear.  Lannana at Stanford is also cited, explaining that they do a lot of running barefoot and that his athletes are better for it.  This ended up being one of the reasons Nike researched and created the Free.

The author then goes into how before Bowerman created the first “modern” running shoes (the Cortez), there were very little injuries in terms of plantar facisitis, Achilles injuries, etc.  The extra cushioning, support, heel, etc, created an “unnatural” stride that caused more injuries.  I could cite more, but I think you get the idea.

I’ve read several articles about minimalist shoes and the reasoning and results behind them.  A lot of it makes sense and gets me wondering why more people haven’t jumped on to this theory.  I know that Lannana does it, as does the coach at Kansas State; I even incorporate a little into my team’s training in terms of barefoot exercises.  Every now and then I’ll do a running on the infield barefoot and I immediately feel faster and run better.

If minimalist shoes like the Free and Vibram 5 Fingers are the way “to get back to our beginnings,” why don’t we see more people using these shoes?  Is there something to the modern running shoe that still allows us to perform better?  Is it something in between?  Are we too afraid to try something “new” and make changes?

This theory has perplexed me…I’d love to hear more of what you guys think about this.

EDIT: I should add, most of this refers to distance running, but I don’t see how it can’t apply to sprinting also.  Most speed work is done in spikes anyways, which is a pretty minimalist shoe.

Watching the head on and top down views of the 100 and 200, Bolt has slightly more side to side head swaying than everyone else when at top speed.

Is this just his personal running style and I’m looking too far into it? Or does it possibly have to do with him have greater hip oscillation/projection resulting in a more powerful step down and stiffer toe off, and the head sway is just the result of that… or possibly its a cue he uses in order to create greater oscillation?

In the HPC MaxV DVD, Mike talks about hip projection and how the hip has to roll up and over the support side hip. Would this slight head sway be a sign of him achieving this, either through actively using his non-support side oblique muscle to raise and roll the hip (which would cause the head to sway in that direction) or through some other cue?

I Haven’t posted in awhile, but had to share these videos with you guys!
[youtube]http://www.youtube.com/watch?v=tXkXHX6NoRY[/youtube]
[youtube]http://www.youtube.com/watch?v=7ZjGWtI6FqA[/youtube]

This is exactly what I had in mind in the discussion of the Sport Science series Mike did a few months ago. I dreamt it and these guys made it a reality!

I’ve only been able to find 2 references in the web about these tests in Barcelona:
El Mundo Deportivo
FCBarcelona

Here are some numbers:
- Reactime system
- 12 timing gates
- 18 Casio F1 cameras
- 30 meters of Optojump cells
- “Stalker” radar
- MusceLab system
- Chronojump system(eheh! I have one of these!)
- Total investment 60,000 euros ~ US$ 85,300

Could anyone run through a list of potential problems this would cause for a sprinter?

I often have problems with the tendons behind my knee. Through seeing physiotherapists the prescribed treatment has always been core stability work, neural stretches and hamstring stretches, with no mention of my pelvic allignment. Am I correct in thinking that I should be doing more to correct this, such as stretching the hip flexors and spinal erectors, along with a lot more glute and hamstring work in the gym? And possibly even laying off the hamstring stretching?

And possibly rather than stretching a tight nerve I should be more concerned with freeing it up? I’m thinking all the core stability work and stretching, while still beneficial, isn’t enough alone to correct the condition.

There are a few of reasons why I believe anterior pelvic tilt to be the cause of my constant hamstring tendon problems. Firstly, APT causes an inward rotation of the femur, the evidence of this can be seen by my arches which are very flat. Both of these symptoms have their own implications on how the knee is alligned, this could be putting certain tendons under unnecesary strain?

The next reason I am not completely sure on, I believe that APT will cause my foot to plant IN FRONT (?) of my center of mass, which will result in a braking force? This can’t be good for…well anything at all.

And finally, APT would mean my glutes are pretty much turned off. Constantly. How long do I have in every stride to transfer energy into the ground? 0.1 seconds? Lazy glutes don’t fire quickly, so my hamstrings are left having to pick up the slack, they don’t like being overworked and I eventually strain a tendon again.

So before I let my consultant send me off for another costly MRI scan of my knee which will undoubtedly show no abnormalities whatsoever again, could somebody please take a look at the attached photograph and tell me whether or not this is likely to be the cause of my injuries?