posted Apr-27-2006 11:00 AM               

The length of peoples' legs may vary, but the acceleration of gravity is a constant. This means that at 180 spm, you are in the air for .33sec/stride. To have a slower rate, you must spend longer in the air, so you must have a greater vertical component to your push-off (spending more energy) is necessary; this must be at the expense of forward velocity unless you use more energy per stride (thuus becoming less efficient!). I think it is clear that in running, where forward velocity is the key, increasing the % of energy in the vertical direction is bad.

This little bit of geometry and physics should indicate while leg length is more or less meaningless in determining proper stride frequency. Yes, there will be some personal variability, but nothing drastic. Maybe there will be a variation at the extremes (say, someone 6'5" vs 5'1") but I'd bet if you looked at a lot of efficient runners you'd see little difference.

Just for kicks I counted mine during an easy (6:30 pace) run the other day and it was 176-178.

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posted Apr-27-2006 11:46 AM               

I agree 100% with your heel arguement. it is breaking no matter how you look at it. Breaking at best is going to hurt efficiency and at worst add a ton of stress to your feet, legs, and entire body.

I never thought about your physics arguement - meaning that leg length does not really matter. It makes sense.

I used to have so much vertical motion in my stride. Stuff I wore (like a fuel belt, something in my pocket) would bounce around so much. And I made such noise with my feel - slapping down. You could hear me 100 yards away I bet.
With work on cadence I now land mid foot and have fast turnover. I am amazed nearly every run at how smooth I am now - almost no noise at all and my head does not bob up and down much at all. It now seems obvious that I was putting myself through much extra work and pounding that was not needed.

I was a major heel striker/very slow cadence. I think when I first tried a 160 metronome beat on my MP3 it felt like a big speed up. However, I see 'me' at every race I run now. People with their hands and feet way out in front of them and banging all over the place. I would never give unsolicited advice, so I just hope maybe they will read something somewhere.

180 is now natural for my short legs.

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posted Apr-27-2006 11:51 AM               

My easy/slow run cadence is just about the same - just shy of 180.

When I started running, someone made the comment that I should take quick and light steps. Without hearing anything about any magic or optimal number, through experimentation I determined I could run, by far, the fastest with least energy and less wear on the joints and just plain less effort, if I was around 179-185 spm. A year later I heard about this optimal 180 number.

Personally, I don't care where it comes from. It is empirical, I guess. My own proof is the only proof I need.

Nowadays, I do not control it, I simply observe it. The body seems to know what to do. When running a hard tempo run, I start at a rapid turnover, 184-186 spm, then after a mile or two, when I'm fully warm, it slows just shy of 180, but then goes back up to settle just at or just over 180.

I find that, in a marathon, I have two different gears. I don't think about it but while keeping the same pace, it seems to shift from slightly faster and shorter, to longer and slower. Maybe this alternation helps the body conserve energy.

There's a lot going on when you run. For the most part, we don't need to think about it. Put in enough miles and your own natural best economy will become apparent.

I know that when I run with any experienced runner - or in a race, that we run at nearly lock-step cadence. It has been argued by some that this cadence may be, "only for the elite" - but I don't think so. Look at the very experienced 50, 60, 70 yr old runners.

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posted Apr-27-2006 12:13 PM               

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posted Apr-27-2006 12:35 PM            

quote:

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Originally posted by AndyHass:
I don't think you can argue that hell striking is somehow better. In order to land on you heel, your foot MUST come down in front of your body...if it landed under you'd land midfoot, and behind would be forefoot. If you land in front of your body, the footfall acts as a brake and you waste energy...and that wasted energy is transferred into your legs and joints as shock. Explain to me ONE logical way in which landing heel can be neutral or beneficial and I'm willing to listen.

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(a) The leg sticking out rigidly like a pole vault pole, requiring the body to rise - not necessary as the leg can bend.

(b) The foot striking the ground with forward velocity so that the forward momentum of the leg is lost to the ground. - not necessary as the foot could be moving back (relative to the body) when the foot lands, even if the contact point is in front of the body.

(c) The foot hits in front of the CG somehow causing braking. Why? Four feet seem to work well to those that have them. The forefeet land well before the CG.

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posted Apr-27-2006 12:51 PM            

quote:

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Originally posted by runawayjesse:
From everything I gather, everything you said is 100% accurate. I have beat my head against a wall trying to make sense of this in the past. I have yet to find any proof or science to back back this 180 spm theory.

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In his book "Running Formula" Daniels reports on his studies of elite runners (he did quite a bit of research on this) and they appeared to all run at around 180 for a variety of paces. That's the only research I'm aware of, however as a mechanical engineer I'm aware of natural frequencies and how to effect them.

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posted Apr-27-2006 12:56 PM            

Within weeks my running changed competely. No more heel striking and I hit 180 automatically without thinking about it no matter how fast or slow I run.

I also have no problems with hips, knees or anything else and I'm averaging between 40 and 50 miles a week now.

This is of course just anecdotal evidence at best and it may not work for you.

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posted Apr-27-2006 01:15 PM            

Thanks...very educational thread!

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posted Apr-27-2006 01:30 PM               

It was a huge revelation to find out that, when I switched from heel striking to fore/mid-foot landings, it was also possible to maintain a 180 steps/minute cadence for the full distance my very slow marathons (from 5 - 7 hours in the last year). The seven-hour (16min/mile), hamstring-hampered marathon needed 68,000 short steps compared to about 46,500 for most of the five hour ones (11:27 pace). I average 10 - 12 mpw too.

I got used to a higher cadence with a clip-on metronome at 176 or 182 beats/min setting (no setting at exactly 180)

http://www.zzounds.com/item--KORMM2 - $24.95 + $5.99 shipping

[This message has been edited by Tetsujin30 (edited Apr-27-2006).]

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posted Apr-27-2006 01:31 PM            

quote:

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Originally posted by indygreg:
[B]80% or runners are heel strikers . . .

and I think evidence shows 70% of all runners get injured each year.

B]

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Do you have a source to relate the two stats? Where does the 70% number come from? Perhaps I'm lucky but I don't get injured very often. What are you calling an "injury"?

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posted Apr-27-2006 01:46 PM               

I have no backing for the 70% of runners getting hurt. I think that is listed in the ChiRunning or Pose book or some other book I recently read.
I also did not mean to specify that the two were related - I think they might be, but my post was meant in partial jest. That is why there is a

EDIT - I just did a quick search
http://familydoctor.org/147.xml
http://www.cayugamed.org/articles/read.dbm?ID=308
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1439399&dopt=Abstract
http://www.clevelandclinic.org/health/health-info/docs/2000/2031.asp?index=8765
http://www.findarticles.com/p/articles/mi_m3225/is_n7_v55/ai_19463579

Some say 70% a year. Some say 70% a lifetime. Some say 35-70% per year.

To the defense of heel striking . . . just to take on the one point - comparing the running motion of a human to a 4 legged animal is completely meaningless.

As far as if it is or not breaking . . . watch slow motion images of the heel of a heel striker - or just feel on youself. On an dominate heel strike, the shoe compresses greatly (and this is the most built up part of the shoe) with much of the compression going forward, or towards mid foot. This is breaking, period. On a mid foot landing, all compression is going down.

[This message has been edited by indygreg (edited Apr-27-2006).]

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posted Apr-27-2006 02:43 PM            

As an adult I've read a lot on my own and don't have a coach taking responsibility for my training ... I check my cadence frequently in the past year, since coming back from injury, and found that mine is usually 31-32 counts in 10 seconds ... that's 186-192 spm ... that also correlates with the spm the elliptical had me at for average when I was indoors a couple months ago ...

As I've heard more and more about mid/forefoot striking being better I've tried it some ... but it tires my legs out and doesn't feel 'right' ... I do pay attention more to whether I am braking and don't think that is the case ... I believe I actually land mid-foot and rock back very lightly to my heel before propelling forward with toe-off ... I hope to get a family member to videotape me soon ... for various reasons, this being one, hahaha ...

I know I'm not a mid/forefoot only runner ... and I know my cadence is quite quick ... and my pace is also decent for a person of my age and recent 'running years' ... there's always room for improvement but I question whether my footstrike is actually any impedence ...

btw ... I think that a slower cadence doesn't always mean more airtime ... I think it could equal more ground time ... I've seen MANY runners that let their leg fall almost into a single leg squat on each footfall ... that has to be tiring and slowing ... just an observation ... take however you want :0)

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posted Apr-27-2006 04:41 PM               

Learning to run correctly from the start is easier than breaking bad habits IMHO.

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posted Apr-27-2006 06:12 PM            

quote:

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Originally posted by indygreg:
to the point that beginners should not mess with their form . . . as doing so is wrong as it is agianst their natual gate. The thing is it is not. Run barfoot for 30 yards and you will not be a heel striker. That is your natural gate.

Learning to run correctly from the start is easier than breaking bad habits IMHO.

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Agreed. I learned how to run landing on my heels on purpose when I was younger because that was what I saw on TV commercials, and shoes seemed to be built that way. The amount and rate of improvement since 'messing' with my form has been incredible.

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posted Apr-27-2006 06:31 PM               

If your foot lands in front of you and bears ZERO weight, then no, you won't be braking. But if it is bearing any weight at all, that translates into tension in your leg ((which is at an angle to your body) which must have a horizontal (ie braking) component.

Comparisons to animals, with completely different running forms, is meaningless. Animals stretch their front legs out and pull forward with their whole body. Some people have tried to say that humans can pull back with their front leg, but I have yet to be able to duplicate it myself so I doubt it is a real component of human running (hammys would be a lot bigger if this were true).

As for the physics, I was not thinking of pendulums but of velocity vectors. Human legs bend at the knee and I don't think analogies to a pendulum are appropriate. You're right on the .33 sec thing, but that was just for illustration only and not important to the point I was making. WHY is 180 optimal? I would say that there is a maximally efficient value related to the acceleration of gravity that maximized the forward velocity derived and minimizing the amount lost to up-and-down movement. I'm sure this does in fact vary somewhat with leg length, but I'm sure this results in a few strides/min difference (say 175-185) and does not justify people with stride rates of 150, almost 20% off.

I have a suspicion that at outlying velocities 180 does not hold. If you're running 12 min/mile, I won't doubt your stride rate will be different than someone running 4min/mile. Clearly, sprinters are well over 180 on that end of the spectrum.

By and large, most beginning runners I've worked with use too large of strides. I disagree that this isn't an important factor to work on. Not only will greater efficiency speed them up and create motivation to continue, but it also reduces impact forces and reduces the chances of injury.

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posted Apr-27-2006 06:39 PM            

I shoulda wore my shoes, lol

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posted Apr-27-2006 09:05 PM            

quote:

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Originally posted by AndyHass:
I don't think you can argue that hell striking is somehow better. In order to land on you heel, your foot MUST come down in front of your body...if it landed under you'd land midfoot, and behind would be forefoot. If you land in front of your body, the footfall acts as a brake and you waste energy...and that wasted energy is transferred into your legs and joints as shock. Explain to me ONE logical way in which landing heel can be neutral or beneficial and I'm willing to listen.

The length of peoples' legs may vary, but the acceleration of gravity is a constant. This means that at 180 spm, you are in the air for .33sec/stride. To have a slower rate, you must spend longer in the air, so you must have a greater vertical component to your push-off (spending more energy) is necessary; this must be at the expense of forward velocity unless you use more energy per stride (thuus becoming less efficient!). I think it is clear that in running, where forward velocity is the key, increasing the % of energy in the vertical direction is bad.

This little bit of geometry and physics should indicate while leg length is more or less meaningless in determining proper stride frequency. Yes, there will be some personal variability, but nothing drastic. Maybe there will be a variation at the extremes (say, someone 6'5" vs 5'1") but I'd bet if you looked at a lot of efficient runners you'd see little difference.

Just for kicks I counted mine during an easy (6:30 pace) run the other day and it was 176-178.

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Was that a freudian slip to call it "hell" striking???

Here's what Dr Jack Younggren (biomechanics) says in "run Strong" - P 8

"Our discussion of the gait cycle begins with the moment the rubber meets the road - the footstrike. For about 80%of runners, this means a heel strike in which the heel or rear foot makes initial contact with the ground (see figure 1.1a). The other 20 percent of runners, the midfoot strikers, land on the outer portion of the middle section of the foot. While it's clear that there are definitely two distinct footstrike camps - the rear-footers and the midfooters - it's not clear that runners should spend much energy deciding where to pitch their tent. Much of this decision may have been made for you based on your particular architecture. So, if you are landing on your midfoot, for example, it is likely due to your skeletal structure and other inate factors. However, running speed can also influence a runner's footstrike, with increasing speeds and longer strides pushing the site of contact farther toward the fore-foot and sprinting speeds usually moving the contact to the toes or the balls of the feet. Also, despite the sonsequences of each "style" that a biomechanics expert could list (for example, heel-strikers spend more time in the stance phase), it's not clear that there are significant functional differences between landing fore versus landing aft."

What I take from this article is that foot strike is kind of like left vs right handedness. Neither is inately good or bad and one of the two is natural while the other is something that can be practiced for no useful purpose.

I think your physics could use a little touch-up. First of all, every moving object has a natural frequency at which it will resonate and provide optimal energy transfer to the surrounding environment. Recall the Tacoma Narrows Bridge failure from the mid '40's? That was a bridge subjected to wind forces that exactly hit the bridge harmonic and caused the bridge to self destruct. Humans also have a resonant running frequency based on their particular biomechanical and physical properties. These properties combine at an optimal turnover rate that matches the body's natural harmonic. For elite runners the optimum appears to be around 180 but it may not be so for everyone due to differences in body weight, center of mass, and yes, even leg length. Believe it or not it makes a difference. Try the old pendulum trick with a weight and string to see how. Simply shorten the string to see how the frequency changes.

Your example where the runner is in the air 100% of the time (0.33 seconds per step) and therefore never touches the ground. How then does he generate any pushoff?

Nevertheless, lets assume for a moment that this case is better than the case of your "bounder" who spends more time in the air. Assuming then that less time in the air is better, would not someone who never left the ground then be even better than your 0.33 runner? I fully agree that vertical movement provides absolutely no improvement to horizontal pushoff, and I only use this case to illustrate there are several reasons why runners may or may not spend time in the air. Youngren himself suggests another reason when he says that heel strikers tend to spend more time in the stance phase. The absolute extreme would be race walkers who must always have one foot on the ground.

Lastly, and unfortunately, even something as constant as the law of gravity has lately come under question by theoretical physicists. That leaves death and taxes as the only universal constants.

[This message has been edited by tigger (edited Apr-27-2006).]

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posted Apr-27-2006 09:50 PM               

I already stated the .33 sec was for comparison purposes, not running computations. I agreed with you pointing out that error yet you still harp on it. Give it a rest already. As for "hell" strike, I'm hoping you're smart enough to figure out how that happened?

As for harmonics and comparing to pendulums and a bridge (!!!), none of these rigid structures remotely resemble the human body and trying to draw analogies insults our intelligence. A pendulum is fixed to a pivot and while influenced by gravity does not rise and fall to meet the ground...basically, you are trying to oversimplify an incredibly complex action. It's pretty clear you have no education in engineering or science to try and make those comparisons, so please, unless you understand the concepts don't go there.

If you believe landing on your heel is spiffy, go ahead, I don't care. But quoting someone else who can't support their argument with any data is no more convincing than my argument. Go ahead an run at 140 steps per minute and land squarely on your heel, tell me how that works out for you. I learned many things in my progression from 27min 2-milers to 15min 5ks, and proper running form was one of the biggest ones.

As for indicating that believing in the laws of physics are wrong, if you are going to suggest that we managed to land on the moon and build the computer you're reading this on by some miraculous accident rather than understanding the science on which it is based...well, I'll be nice and say you've made it clear it's not worth trying to have a real discussion with you on this issue. I mean, first you attack my point by indicating the laws of physics are flawed but you base YOUR argument on harmonics and pendulums....which are based on the same laws? Huh?

[This message has been edited by AndyHass (edited Apr-27-2006).]

[This message has been edited by AndyHass (edited Apr-27-2006).]

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posted Apr-27-2006 10:48 PM            

quote:

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Originally posted by AndyHass:
First read and comprehend, THEN respond....

I already stated the .33 sec was for comparison purposes, not running computations. I agreed with you pointing out that error yet you still harp on it. Give it a rest already. As for "hell" strike, I'm hoping you're smart enough to figure out how that happened?

As for harmonics and comparing to pendulums and a bridge (!!!), none of these rigid structures remotely resemble the human body and trying to draw analogies insults our intelligence. A pendulum is fixed to a pivot and while influenced by gravity does not rise and fall to meet the ground...basically, you are trying to oversimplify an incredibly complex action. It's pretty clear you have no education in engineering or science to try and make those comparisons, so please, unless you understand the concepts don't go there.

If you believe landing on your heel is spiffy, go ahead, I don't care. But quoting someone else who can't support their argument with any data is no more convincing than my argument. Go ahead an run at 140 steps per minute and land squarely on your heel, tell me how that works out for you. I learned many things in my progression from 27min 2-milers to 15min 5ks, and proper running form was one of the biggest ones.

As for indicating that believing in the laws of physics are wrong, if you are going to suggest that we managed to land on the moon and build the computer you're reading this on by some miraculous accident rather than understanding the science on which it is based...well, I'll be nice and say you've made it clear it's not worth trying to have a real discussion with you on this issue. I mean, first you attack my point by indicating the laws of physics are flawed but you base YOUR argument on harmonics and pendulums....which are based on the same laws? Huh?

[This message has been edited by AndyHass (edited Apr-27-2006).]

[This message has been edited by AndyHass (edited Apr-27-2006).]

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I can see from your response that you prefer to wallow in ignorance. So be it. But a couple of comments....

Your suggestion that I was comparing bridges to the human body is wrong. I was using bridges to illustrate the principle of HARMONICS, which is obviously not taught in biology classes. Harmonics is very important in running as any biomechanics expert like Jack Youngren will attest.

I don't have a 140 cadence as you accuse. It's much higher than that. I guess in your frustration you overlooked the point that in this forum there are probably more important things to work on for improvement, such as aerobic capacity or proper weight. But I guess I shouldn't even mention those things to a runner of your stature for fear of being put in my place by the great Andy HAss (oops! another Freudian slip!)

Your attempt to link my point about gravity to accidental landing on the moon is even more feeble than my original attempt at humour. Let us overlook the gravity of this situation OK?

PS...when you grow up your humor index will begin to appear and you'll learn to ignore those things that annoy you. Oh! What the Hell!

Oh yes, one more thing....you said " It's pretty clear you have no education in engineering or science to try and make those comparisons, so please, unless you understand the concepts don't go there."

I'll put my math/physics background in this area up against yours any day (have a look at my bio....it's mechanical) and come out far ahead. So don't be so childishly foolish on an internet site.

...and lastly, I apologize for the repetition. I tried to post the first one earlier but I didn't think it got through. At least that's what my computer said. Now I see that it did. My bad! I'll take it out to sooth your feelings.

Have a good day!

[This message has been edited by tigger (edited Apr-28-2006).]

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posted Apr-27-2006 11:28 PM            

I often noticed that my legs ususally move much faster than the people I am running with, but I always figured it was because I was so much shorter. As a matter of fact, I often wondered if my injuries could be due to the fact that my legs seem to hit the ground so much more often than most other people. Now after reading this it seems maybe not such a curse after all.

What if you are faster than 180 bpm? Should you try to keep it right at 180?

------------------
My Profile

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posted Apr-28-2006 12:36 AM            

quote:

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Originally posted by tigger:
I can see from your response that you prefer to wallow in ignorance. So be it. But a couple of comments....

Your suggestion that I was comparing bridges to the human body is wrong. I was using bridges to illustrate the principle of HARMONICS, which is obviously not taught in biology classes. Harmonics is very important in running as any biomechanics expert like Jack Youngren will attest.

I don't have a 140 cadence as you accuse. It's much higher than that. I guess in your frustration you overlooked the point that in this forum there are probably more important things to work on for improvement, such as aerobic capacity or proper weight. But I guess I shouldn't even mention those things to a runner of your stature for fear of being put in my place by the great Andy HAss (oops! another Freudian slip!)

Your attempt to link my point about gravity to accidental landing on the moon is even more feeble than my original attempt at humour. Let us overlook the gravity of this situation OK?

PS...when you grow up your humor index will begin to appear and you'll learn to ignore those things that annoy you. Oh! What the Hell!

Oh yes, one more thing....you said " It's pretty clear you have no education in engineering or science to try and make those comparisons, so please, unless you understand the concepts don't go there."

I'll put my math/physics background in this area up against yours any day (have a look at my bio....it's mechanical) and come out far ahead. So don't be so childishly foolish on an internet site.

...and lastly, I apologize for the repetition. I tried to post the first one earlier but I didn't think it got through. At least that's what my computer said. Now I see that it did. My bad! I'll take it out to sooth your feelings.

Have a good day!

[This message has been edited by tigger (edited Apr-28-2006).]

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Alright you two, am I going to have to go find leon2 to come and weigh in? I hope this doesn't get too uncivil to the point of others abandoning ship along with their expertise like leon2 did. I'd hate to lose andyhass who has learned a lot over the years running and greatly improving his times, which is what most people are shooting for. While people can argue about the physics of it all they want, I liken it to scientific versus outcome studies in my field (medicine). While often something may work in the lab or with controlled fixed parameters, that may or may not translate to improved patient survival, fewer cardiac events, etc., etc. I think this is analagous to the cadence argument. You can try all day to argue the physics of it, but the real data is does it improve running times and decrease injury rates? Tigger, Daniels did research on elites (I realize this is a re-hash and has been mentioned), and the mean cadence was 180/min. Do you not think that the fastest distance runners would have naturally gravitated to the most efficient cadence? They would have to as the difference between winning and losing is so close and even the superbly trained and talented runner would be going up against a similarly equipped runner, and any running form efficiencies would likely not allow a person to compete at that same level. Now, I agree this is an assumption, but I will go ahead and assume then that the fastest runners would naturally be the most efficient, as it is part of the equation of speed and others would have equal VO2 max, desire, training, etc., and you would need every component of speed to be perfect to be the best. Now, Daniels doesn't specify how many people he studied, or their heights, but I think it's safe to again assume that they were of varying sizes. How about Alan Culpepper vs. some of the Kenyans, they have very different leg lengths, but still run around 180/min.-- the most efficient cadence for running.

Anecdotally, I read about this last year and specifically worked on increasing my cadence from a natural 172-74/min. up to 180-182. I went from a 3:15-3:20 marathoner to 2:55-57, and have had many fewer aches and pains and injuries. Coincidental? You be the judge.

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posted Apr-28-2006 01:11 AM            

quote:

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Originally posted by Johnny J:
Tigger, Daniels did research on elites (I realize this is a re-hash and has been mentioned), and the mean cadence was 180/min. Do you not think that the fastest distance runners would have naturally gravitated to the most efficient cadence?

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OK, I'll ignore Andy's insults from now on. I agree he often has good advice and because of that I would not want him to leave, but he can also get pompous and condescending. When he gets like that he needs to be put in his place just like any of us.

Yes, I agree with the quote. And I would not stop at the fastest distance runners. I'm beginning to believe we all naturally gravitate to our most efficient cadence, although we probably can and do get a little lazy from time to time. And yes, that's an largely an assumption on my part without supporting data other than my observations on myself. On a 10 mile track run today at about 9:40 pace I varied my cadence from about 165 to 175 without much effort. If I relaxed and ignored it I found it to be around 170. If I tried to go beyone 175 I found (as in the past) it difficult to sustain. However (on other occasions) I've found my cadence to be around 180 at 5k (8 minute) or faster pace.

I don't have my copy of "Running Formula" with me but I recall Daniels did his research at the Olympics back in the '60's or '70's.

In another book (XXX Miller - I forget his first name - Thomas?) he suggests heel striking is not normal and should be corrected. He uses Jim Ryun as an example, however Ryun was a very fast runner and he ran relatively short distances. Nevertheless I tried to convert from heel to midfoot and was successful, but I found my entire mechanics had to change as well, and I began to feel abnormal aches and pains in my knees and thighs. So I switched back and the problems disappeared. That (and Jack Youngren) is why I would not recommend beginners switch until they have developed a good running base and have optimized their weight. These are primary areas for improvement. Cadence is less so in my opinion.

Now I mainly heel strike but switch to midfoot when climbing hills, which I do a lot of around my place of work. When I focus on heel striking I find my cadence slows a bit but I can get a smoother landing. It requires a lot of ankle flex, both during landing and push off, which is why (I think) my cadence slows. It takes extra time for the ankle to flex. When I don't focus on it I land harder but maintain better cadence.

Lots of things to think about when running....including watching for black bears and grizzlies on the road. When I see them you can believe that's when my cadence is fastest!

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posted Apr-28-2006 08:35 AM               

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posted Apr-28-2006 09:56 AM               

quick background: I've been back into running about a year after 16 years off. I used to be pretty fast but I was never on track or CC. (About 6 min avg combat boots) Anyway, fast forward to today. I'm up to 26 miles per week and I'm still feeling out my old form and strengths coming back here and there. I've developed asthma since then so a lot of my running is curtailed by that. I feel like I can go faster, maybe a lot faster if I could get more oxygen. I figure I'll get better with a bigger base. I'm also 5'11" and 204 lbs and need to strengthen up a little more to this weight, as I was 180 way back when. I'm aiming for a 7:30 pace for a 5K tommorrow as a minimum goal. When I train I'm very conscious of my form. Breathing, head, neck, back, arms, legs, feet...overall efficiency. I'm not a heel striker and I have a pretty naturally quick turnover. I counted it at 170 yesterday at a pretty easy pace.

Anyway, more to the question. I haven't done any real speedwork the last year because I've been worried about the extra 20 lbs and injuries. (well..I have timed myself on a fast mile run every couple months but that's it....never done intervals in my life...) But I read something about tapering to a 5K and doing intervals leading up to it and nothing else with the day before off so I decided to give it a try. It said to do race pace but my legs were just there so I let it go to see what I could do and ran three quarter mile intervals in 1:14, 1:09 and 1:10. The thing that's bugging me is that I'm completely heel striking at this pace. It felt like a little of my form went out the window as well and I'd guess that my stride lengthened way out there, or it at least felt like it. It just felt like I was coming down abnormally hard and loud. Is this normal at that kind of pace? Is it my weight? Or is this something that will work itself out when I get used to the pace with some more intervals/speedwork/training and control my stride more? Sorry if this seems obvious, it's just been bugging the hell out of me the last couple days.

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posted Apr-28-2006 10:25 AM               

(Don't worry, I'm not going anywhere...then this type of behavior is encouraged).

No one ever said that working on cadence is THE MOST important thing for a runner to work on...that would be ridiculous. It is simply one of a basket of things to work on in an effort to become a better runner. It does not surprise me you got some aches from doing so; you probably got aches the first time you ran a 10-miler too. New runners' bodies have a lot of strengthening and adjusting to do in order to become more resilient to the activity, and any change will cause some aches.

As already discusses, there is probably some point on the slow end of the scale where, like with sprinting, there is deviation from the ideal cadence. 10min pace seems a little quick still but at 170 you were only 6% off of 180...hardly a disproving difference. I don't think even Daniels would argue that 180 is a firm number, and someone with a cadence reasonably close to that has a problem.

While we all might gravitate toward an efficient cadence (and I'd argue that some people of the people I see bouncing along need some help getting there), I think it's no coincidence that studies of elites, who vary widely in height, come up with the same number.

I wish I remember where I read it, but I remember an article on what it would be like to run the Olympics on the moon or Jupiter vs Earth. If you can imagine it conceptually, with the moon having only 1/6 the gravity of Earth, when you push off you won't be pulled down nearly as quickly and therefore you would spend longer in the air. Of course, in order to load your legs for the next stride you need a certain amount of downward force, which would require a more bounding stride to generate, decreasing cadence. Conversely, in Jupiter's crushing gravity, an Earthlike stride would be impossible since you wouldn't stay aloft long enough to complete the stride so cadence would increase dramatically (assuming you weren't crushed!). Hence the link between gravity and cadence. Yes, tigger, everyone knows you disagree with this, and that's fine.

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