faster at running, more inflexible?

[everything]

http://running.competitor.com/2013/11/t ... ible_38726

A gymnast wants looser fibers so he or she can do the splits. A runner wants tighter muscle fibers. Why? Because when a runner’s foot hits the ground, muscle fibers on the back of the lower leg and the front of the thigh stretch as the ankle and knee bend. As these muscle fibers stretch, they capture and store energy from ground impact forces, much as a rubber band stores elastic energy when you stretch it. As the runner extends the ankle and knee to push off the ground, this stored energy is released back into the ground, helping to “spring” the runner forward. This “free energy” enables the runner to maintain any given pace with a lower energy cost. In other words, it improves running economy, hence running performance.

This kind of sounds like bullshit, but there is a part where a certain gene is correlated with both faster runners/inflexible runners. Doesn't seem like that necessarily means anything. Still, some food for thought.

[David Boxen]

Seems perfectly logical to me. I've heard a story about Deion Sanders - when he went to college he was very inflexible and his coaches had him work on his flexibility a lot in his first year. The result was that his sprint time got worse.

I believe that runners should be much more concerned with strength training than flexibility - both to be faster and to avoid injury

[wayne hansen]

I worked with a guy who was the fastest man in rugby union and the beach sprint champion
The two things I remember he couldn't get his hands past his knees,he was the thinnest guy I knew with the biggest attitude
If he had stretched a bit who knows he might have been faster

[Steve James]

It's an interesting question that also poses a dilemma. Researchers have identified a gene present in fast runners; however, those with the gene also tend to be less flexible than those who do not. (As measured by the ability to touch one's toes, for example). However, does that mean that tighter muscles equate to faster running? I don't know. Would Bolt be faster if he were less flexible? Iow, would an inflexible person run faster by tightening his muscles? I tend to think it's much more complicated than that, and very much related to the specific activity. For ex., I know that hurdler's can all stretch (ahem, the stretch is named after them). And, a world class 110 meter hurdler does it in about 13+ seconds. I'm not sure that being less flexible would help. So, perhaps more flexibility will help some and harm others.

[everything]

They said there was a group of fast and flexible runners but didn't say which group was faster.

So it's probably not valid to provide practical advice about get or not get flexible.

But the idea of elasticity in less flexible muscle is still interesting. When running you don't need/want to go through the full range of motion (if this isn't sprinting), It seems, compare to, say, a ballerina or gymnast or hurdler. So maybe you just optimize for that range of motion? Is it the same principle for powerlifters (who can squat low) vs some other kind of athlete who shouldn't squat so low? Fencers maybe?

[windwalker]

Statistical analysis suggests the faster runners tend to have stiffer knee extensors and less stiff plantar flexors – the opposite of what some previous studies have suggested, in the latter case. This is by far the biggest data set looking at this question, so the results are worth taking seriously, although there's plenty of scatter in the data.

So is there any clear conclusion we can draw from this? Personally, I don't see one—except that the results are a reminder that simple stories like "greater flexibility means your springs store less energy" should be taken with a grain of salt. Instead, take your cues from performance-based studies like this new one, which found that dynamic stretching before running improved performance.

The vertical axis shows how much force it took to elongate the muscle a given distance. For the runners, shown with the open squares, it took much more force to stretch the muscles: i.e. their calf muscles had greater stiffness. This is presumably a response to years of training, but there's also some evidence that genetic factors predispose some people to having stiffer muscles, and these people may self-select to become runners.

https://www.runnersworld.com/sweat-scie ... e-or-stiff

Lots of studies look into this question

https://www.ncbi.nlm.nih.gov/pubmed/25813019
Relationship between elastic properties of tendon structures and performance in long distance runners.

Interesting reading a little dry.
Used to run cross country as a teen ager,,,,,
also practiced gymnastics along with CMA
in high school

Might take a little time to find what works
for oneself according to a coach or study.

[everything]

fascinating (but dry) stuff. thanks for this better info.

I was never a runner, but my build seems like it was better for sprints and cuts (long achilles tendons, short legs, long torso) many years ago. my calves are pretty stiff but no idea what that means.

[yeniseri]

"Fast twitch" muscle fibers or "slow twitch" muscle fibers develops according to the physical fitness endeavours that one participates but elements of discipline, ability, motivation, nutrition, mentorship in specific sports activity, etc all are part of a total process

Fast twitch vs slow twitch background
https://www.verywell.com/fast-and-slow- ... rs-3120094

[Patrick]

That´s normal. It´s an adaption. The body - figurativley speaking - records the tension for the activity that is done regularly. It is similar for example when you do a drop jump, the muscle spindles and receptors in the tendons already prepare the muscles by adjusting the correct tension even before you land and start jumping again.

[Dmitri]

I believe that runners should be much more concerned with strength training than flexibility - both to be faster and to avoid injury

I can see how being more flexible would prevent one from sprinting as fast, but I can't imagine how it would possibly promote injury, or be worse for one's health in any way at all -- aside from hurting oneself by overstretching, of course.
Unless you're a professional runner trying to hit some winning times, IME you (general "you") are much better off maintaining a good range of motion - which implies/goes hand-in-hand with flexibility.

[David Boxen]

Not saying that stretching promotes injury. However, for anyone who has ever injured themselves from running... do you imagine it was lack of flexibility that was the problem?