My achillies' heel, and my MD



[email protected] wrote:
> [email protected] wrote:
> >>
> > Brian:
> > I think that the Tim Noakes book is great, but it does not discuss
> all
> > the possible causes of Achilles tendon injury. Like you, I had a
lot
> > of trouble with my Achilles tendons, so did a ton of research:
> > articles, books, web. If you haven't seen it already, I recommend
> > checking the causes of Achilles injury page of
www.AchillesTendon.com
> > (http://www.achillestendon.com/CausesofInjury.html). It includes a
> few
> > things not covered by Noakes. Figuring out the real cause is often
> > harder than figuring the treatment. It helped me, it might help
you.
> > Good luck,
> > Murph
>
>
> Thank for the link, Murph. So did you recover, and can you run? Is
> there hope for me even though I have had this condition for a year?
> How long did your recover take? Were there relapses? Do you still
> have to be careful? What is your current running situation? If I
> don't start running again soon (one month as of 2-20) I will be as
big
> as a barn.
>
> Brian Jones

Brian:
Yes I did recover and do run. I had Achilles tendon problems for years
before I figured out what was going on and how to handle it, so I think
that there is hope for everyone.

It took me 2-3 months of physical therapy (mostly strengthening of the
calves), new running shoes, and cushioning in my non-running shoes. I
also threw out a pair of my favorite shoes because they had zero arch
support and zero cushioning.

The hardest part for me was "slow but steady". When I feel good I want
to run for a long time. I love to run. However, when I started
running again after the calf strengthening, I did so in excruciatingly
slow increments: 5 minutes "runs" 3 times a week for two weeks, 10
minutes runs the next two weeks, 15 minutes the next two weeks, etc. I
am now doing 50 minute runs 3 times a week and my Achilles tendons feel
fine.

I did have an Achilles tendon relapse, which I blame on my not
following the "slow but steady" principal. I didn't run for a bit
because I had the flu, and instead of starting with short time frames
and building up, I started running for the same 50 minute time frame.
This caused a lot of stiffness and soreness in both my Achilles
tendons. To get past it, I went back to what worked for me: calf
strengthening for a while without running, then slowwwwww but steady
increased in my running time (while always continuing to do calf
strengthening). It took much more time than I would have liked, but it
worked.

I have also been doing the message, stretching, and iceing that the
site recommends.
Good luck,
Murph
 
"Dot" <dot.h@#duh?att.net> wrote in message
news:[email protected]...
> pmb wrote:
> > <[email protected]> wrote in message
> >
> >>Recent years I have shortened my stride and have become thereby a more
> >>efficient runner(though I am the one with the bad achillies heel!).
> >
> >
> > I'd be more interested to know whether you've become a *faster* runner.
I'm
> > doubtful about this shorter-means-more-efficient theory. Whose theory is
it,
> > and what is the logic behind it?
>
> Just adding my perceptions to the pot. A general concept (really more of
> a symptom) behind it is that shorter strides usually involve quicker
> foot motion and less vertical time, resulting in "gentler" (relatively
> speaking) footfall. Also usually involves more of a mid- to fore-foot
> landing. Not sure where it originated, but many (not all) people here
> support the idea. It's helped many people here when they were starting.
> (also injured a few)


The question I'm always asking is, shorter than what? Shorter than the
stride you would pick instinctively? Because that is bound to be a flexible
thing. You would instinctively adopt a shorter stride when going uphill.
It's a lower gear. You would also adapt it on the level to your forward
speed, picking a longer stride when you wanted to go faster, and so on.


> I changed my stride almost 4 yrs ago when I was first starting
> "structured" (loosely used) running, and that's helped immensely,
> although I'm still very low volume. The shorter stride works better in
> snow, ice, steep hills, trails, etc. and provides a lot more stability.
> Shorter strides are more nimble for negotiating twisty, single-track
trails.


But have your times improved as a result of making the change?


> Admittedly, I haven't paid that much attention to whether my feet are
> directly under my cog or slightly ahead.


I don't think you need to. Your instincts would ensure that your foot comes
down forward of the c.o.g. To bring it down directly under would mean
contradicting your instincts.


> >>But I know that some advocates of Pose running and Oz as well, seem to
> >>want to argue that you really get something for nothing in this method.
> >> It always seems to me that some folks do not want to admit the physics
> >>of the situation.
> >
> >
> > Yes, the inventor of this Pose technique talks about using gravity to
propel
> > yourself horizontally. It's the modern equivalent of the 18th century
> > "perpetual-motion" machine. Another free lunch.
>
> FWIW, if I lean forward at ankles, I do go faster, but requires more
energy.


So - no free lunch, then.


> > Good idea. I haven't been on this ng long enough to judge properly but
there
> > doesn't seem to be much interest here in running technique or in
> > biomechanics generally.
>
> Actually, it's one of several topics that comes up periodically. Yep, it
> hasn't come up recently so I guess it's time for it again, esp. with
> some new perspectives ;)
>
> I'm interested in biomechanics because I've had some foot / ankle issues
> that my PT diagnosed and think I've got largely straightened out. Hill
> running form (like for 10-30% slopes both up and down) is also really
> interesting.

10-30% - that's pretty steep. I think I'll stick to sprinting.

Pat B
 
pmb wrote:
> "Dot" <dot.h@#duh?att.net> wrote in message
> news:[email protected]...
> > pmb wrote:
> > > <[email protected]> wrote in message
> > >
> > >>Recent years I have shortened my stride and have become thereby a
more
> > >>efficient runner(though I am the one with the bad achillies
heel!).
> > >
> > >
> > > I'd be more interested to know whether you've become a *faster*
runner.
> I'm
> > > doubtful about this shorter-means-more-efficient theory. Whose
theory is
> it,
> > > and what is the logic behind it?
> >
> > Just adding my perceptions to the pot. A general concept (really
more of
> > a symptom) behind it is that shorter strides usually involve
quicker
> > foot motion and less vertical time, resulting in "gentler"
(relatively
> > speaking) footfall. Also usually involves more of a mid- to
fore-foot
> > landing. Not sure where it originated, but many (not all) people
here
> > support the idea. It's helped many people here when they were
starting.
> > (also injured a few)
>
>
> The question I'm always asking is, shorter than what? Shorter than
the
> stride you would pick instinctively? Because that is bound to be a
flexible
> thing. You would instinctively adopt a shorter stride when going
uphill.
> It's a lower gear. You would also adapt it on the level to your
forward
> speed, picking a longer stride when you wanted to go faster, and so
on.
>
>
> > I changed my stride almost 4 yrs ago when I was first starting
> > "structured" (loosely used) running, and that's helped immensely,
> > although I'm still very low volume. The shorter stride works better
in
> > snow, ice, steep hills, trails, etc. and provides a lot more
stability.
> > Shorter strides are more nimble for negotiating twisty,
single-track
> trails.
>
>
> But have your times improved as a result of making the change?

Pat, here's my experience. When I intentionally shortened my stride
(from what it would have been under the same conditions) a couple of
years ago, I increased the rate at which my feet turn over. The most I
can say for this change is that it *seems* to provide for more
effortless running. I feel like I can cover the same course in the
same time with less apparent effort. I realize this is all entirely
subjective. I have heard/read the arguments for shortening one's
stride, and I find them unpersuasive, for a number of reasons.

So while I cannot show any proofs (I even have my own doubts) I do have
to give my experience some weight here. So far, my assumption is that
I was simply overstriding before, and now I have a more managable
stride.

Wouldn't you admit that at some point a longer stride would become
difficult to manage and be quite inefficient? And are you sure that
the stride one chooses instinctively will always be the correct-length
stride?

Brian Jones
 
"Brian j" <[email protected]> wrote in message
news:[email protected]...
>
> pmb wrote:
> > "Dot" <dot.h@#duh?att.net> wrote in message
> > news:[email protected]...
> > > pmb wrote:
> > > > <[email protected]> wrote in message
> > > >
> > > >>Recent years I have shortened my stride and have become thereby a
> more
> > > >>efficient runner(though I am the one with the bad achillies
> heel!).
> > > >
> > > >
> > > > I'd be more interested to know whether you've become a *faster*
> runner.
> > I'm
> > > > doubtful about this shorter-means-more-efficient theory. Whose
> theory is
> > it,
> > > > and what is the logic behind it?
> > >
> > > Just adding my perceptions to the pot. A general concept (really
> more of
> > > a symptom) behind it is that shorter strides usually involve
> quicker
> > > foot motion and less vertical time, resulting in "gentler"
> (relatively
> > > speaking) footfall. Also usually involves more of a mid- to
> fore-foot
> > > landing. Not sure where it originated, but many (not all) people
> here
> > > support the idea. It's helped many people here when they were
> starting.
> > > (also injured a few)
> >
> >
> > The question I'm always asking is, shorter than what? Shorter than
> the
> > stride you would pick instinctively? Because that is bound to be a
> flexible
> > thing. You would instinctively adopt a shorter stride when going
> uphill.
> > It's a lower gear. You would also adapt it on the level to your
> forward
> > speed, picking a longer stride when you wanted to go faster, and so
> on.
> >
> >
> > > I changed my stride almost 4 yrs ago when I was first starting
> > > "structured" (loosely used) running, and that's helped immensely,
> > > although I'm still very low volume. The shorter stride works better
> in
> > > snow, ice, steep hills, trails, etc. and provides a lot more
> stability.
> > > Shorter strides are more nimble for negotiating twisty,
> single-track
> > trails.
> >
> >
> > But have your times improved as a result of making the change?
>
> Pat, here's my experience. When I intentionally shortened my stride
> (from what it would have been under the same conditions) a couple of
> years ago, I increased the rate at which my feet turn over. The most I
> can say for this change is that it *seems* to provide for more
> effortless running. I feel like I can cover the same course in the
> same time with less apparent effort. I realize this is all entirely
> subjective. I have heard/read the arguments for shortening one's
> stride, and I find them unpersuasive, for a number of reasons.
>
> So while I cannot show any proofs (I even have my own doubts) I do have
> to give my experience some weight here. So far, my assumption is that
> I was simply overstriding before, and now I have a more managable
> stride.
>
> Wouldn't you admit that at some point a longer stride would become
> difficult to manage and be quite inefficient? And are you sure that
> the stride one chooses instinctively will always be the correct-length
> stride?

Well, I'm at a bit of a disadvantage here, Brian. Sprinting is my game. It's
just that when you talk of longer or shorter, it's difficult to know what it
means without having some standard to measure it against. Everyone's
physiology is different, and we all naturally, or instinctively, fall into a
striding pattern that fits the context - i.e. our forward speed, whether
we're going uphill or on the level, whether the going is rough or smooth, or
whether we're tired or not tired. But in the end I can't see any other way
of deciding whether we've hit the right mode except by noting whether a
deliberate change in our stride length has made us faster or slower over the
chosen distance.

I certainly agree that for one stride, a shorter one is more efficient.
There is less vertical force, less stress on the muscles and joints. But the
problem is that if you choose a shorter stride, you have to do more of them
to cover the same distance, and the grand total of energy expended might not
actually be less. In the end the proof of the pudding is a matter of what we
see on the clock, surely?

Pat B
 
pmb wrote:

> Well, I'm at a bit of a disadvantage here, Brian. Sprinting is my
game. It's
> just that when you talk of longer or shorter, it's difficult to know
what it
> means without having some standard to measure it against. Everyone's
> physiology is different, and we all naturally, or instinctively, fall
into a
> striding pattern that fits the context - i.e. our forward speed,
whether
> we're going uphill or on the level, whether the going is rough or
smooth, or
> whether we're tired or not tired. But in the end I can't see any
other way
> of deciding whether we've hit the right mode except by noting whether
a
> deliberate change in our stride length has made us faster or slower
over the
> chosen distance.
>
> I certainly agree that for one stride, a shorter one is more
efficient.
> There is less vertical force, less stress on the muscles and joints.
But the
> problem is that if you choose a shorter stride, you have to do more
of them
> to cover the same distance, and the grand total of energy expended
might not
> actually be less. In the end the proof of the pudding is a matter of
what we
> see on the clock, surely?
>
> Pat B

I can't say whether my times have improved as a result of shortening my
stride, and given our different running aims, maybe we will just never
see this matter in the same way. I don't know if I got faster as a
result. I know I got to be a much better runner at that time, but I
can't say why, exactly. It took probably 9 months to really change my
stride so that it began to feel natural. Over the course of that year,
my running improved much. My 5k time was better, and I began to run
much longer distances. My concern now is not speed, it is endurance
(though speed would be great!). In a half marathon or marathon, I
really don't worry nearly as much about the speed as I do the distance.

And that may be where you and I are on different wavelengths (if, in
fact, we are). I couldn't sprint to save my soul. I am not, and have
never been, fast. So, you know what they say, if you can't go fast, go
long. It was shortly after shortening my stride that I began to train
for my first long distances. The feeling of expending less energy is
really helpful on a 22 mile training run. So I may be wrong, but
self-deceived enough to have helped myself. I don't know.

But I do have this nagging thought that I maybe could have avoided the
achillies problems if I had just stuck with my original stride.

Brian Jones
 
pmb wrote:
> "Dot" <dot.h@#duh?att.net> wrote in message
> news:[email protected]...
>
>>pmb wrote:
>
> I'm
>
>>>doubtful about this shorter-means-more-efficient theory. Whose theory is
>
> it,
>
>>>and what is the logic behind it?
>>
>>Just adding my perceptions to the pot. A general concept (really more of
>>a symptom) behind it is that shorter strides usually involve quicker
>>foot motion and less vertical time, resulting in "gentler" (relatively
>>speaking) footfall. Also usually involves more of a mid- to fore-foot
>>landing. Not sure where it originated, but many (not all) people here
>>support the idea. It's helped many people here when they were starting.
>>(also injured a few)
>
>
>
> The question I'm always asking is, shorter than what? Shorter than the
> stride you would pick instinctively?

Yes. My experience is that one of two things commonly precede the switch
in form. (1) Person overstrides with heel strike. (2) What also happens
a fair amt when a newbie, like myself, starts training at "easy" level,
trying to keep hr low. A fairly common response is to take longer
duration strides, which usually results in almost a leaping-like motion
(obviously exaggerated a little).

Then one hears of the shorter steps, quicker cadence, landing on mid- to
forefoot, try it, and it makes running so much more pleasant, that we
never look back. How my current stride compares to earlier one, I'm not
sure. But keep in mind a large part of my running has been winter on
snow or ice - which are conditions where you would want to shorten
stride. (I'm in Alaska - field ecologist in past summers but can run in
winter - and future summers)

Another thing I'll throw in here that may affect my concept of short /
long is that I had been dealing with a sore groin and some other things
(result of overstretching in a cross-training class) for probably over a
year. Shortening stride reduced pain. I still run with what I think may
be a shorter stride than "normal" (whatever that is) about half the
time, but that's also on snow. Sooo, what my true stride may be while
running on easy trail on firm footing, I'm not sure. But I suspect with
time, my normal stride will lengthen as I get more experience running
under what most people consider normal conditions.


> Because that is bound to be a flexible
> thing. You would instinctively adopt a shorter stride when going uphill.
> It's a lower gear.

Right. But depending on length of run (that is, not a long run), etc, on
short steep hills, there may also a tendency to take longer stride to
get up the hill in few strides - say a dozen longer ones rather than
25-30 short ones. Just get it over with. (Other times these are walked
or run with short stride, just depending on an assortment of variables).
Same way as on mtn bike on hills, it's sometimes just easier to mash a
few rpm's than it is to sit there peddling feverishingly at high cadence
and not going anywhere (I've done it both ways). Depends on training and
conditions in both cases.

>
>>I changed my stride almost 4 yrs ago when I was first starting
>>"structured" (loosely used) running, and that's helped immensely,
>>although I'm still very low volume. The shorter stride works better in
>>snow, ice, steep hills, trails, etc. and provides a lot more stability.
>>Shorter strides are more nimble for negotiating twisty, single-track
>
> trails.
>
>
> But have your times improved as a result of making the change?

But the more relevant questions for me and my running goals are:
Can I run farther? yes
Does it hurt less? yes
Can I run more frequently? yes
Am I progressing toward long-term goals? yes

Short-term speed isn't a goal for me. For others, it may be.

One of the key things I've seen in long-term elites' training is that
they can handle volume over long periods of time - years. Being able to
train consistently is a major factor in how they got to be fast. So
anything that would allow more consistent running would be good, I
think. Trailrunner made a comment to this extent the other day, I think.
For many (not all), it's long-term goals of running, not an issue of a
few seconds or minutes on the clock in one race out of a lifetime of
opportunites.

For me, whether that form change alone resulted in faster times
directly, I certainly can't say from my experience because I was too
new. I changed so early in my running training (within first few
months), that any change in speed is likely confounded with beginners'
gains. Also speeds on trails are confounded substantially with terrain,
weather, snow, mud, etc that comparisons are almost useless. I'm a
stronger runner (run same distances, more elevation change, longer
durations, relatively painless) now partly because I changed but more
importantly because I have a little more experience, although still low
volume.

>
>
>>Admittedly, I haven't paid that much attention to whether my feet are
>>directly under my cog or slightly ahead.
>
>
> I don't think you need to. Your instincts would ensure that your foot comes
> down forward of the c.o.g. To bring it down directly under would mean
> contradicting your instincts.

I went back and re-read one of your earlier posts. I think what you're
saying is that where the foot first touches ground is probably forward
of cog. However, we may not perceive where the foot touches until it's
weighted, which actually happens a short time later as the body passes
over the point of contact. For snowshoe running, I know I'm clueless as
to what hits first but suspect the tail never clears the snow in many
cases :)


I haven't found any pictures in my collection of what I'm trying to say,
but let's look at downhill running. Someone else already mentioned the
resolution of force vectors. If running down a steep, say 20-30%
downhill, I find I'm more in control of the situation if I lean forward
so my cog may be in front of feet, at least if they have any amount of
weight on them. I need to keep the normal force (that
perpendicular to the slope) sufficient that my feet don't slide out from
underneath me. I know for a fact if I run downhill or even stand with my
cog over my feet on that one muddy slope on a local trail, I *will* end
up on my butt (been there, done that) since there isn't enough friction
against the ground that way. Also happens when walking to my mailbox on
ice. In the hill running situation, I can choose to fight gravity by
landing with my feet in front of cog, but risk falling on my butt - a
lot depends on slope and footing. I'm assuming I'm not trying to
glissade down, where I want to minimize normal force. (sorry, I don't
sprint on flat ground, which I know is what you do. These are just my
perceptions / experiences from a different background.)

At least that's my perception of foot placement with downhill running,
and it is consistent with my somewhat rusty understanding of physics.

I haven't thought as much about uphill, but I'm having trouble
convincing myself that I want to touchdown in front of my cog -
certainly not with any weight on the lead foot.


I think what may be happening, is there's a visual model that people
suggest - land with foot under cog. Whether it was intended to mean 1st
touchdown or when you're aware your foot touches the ground or when it's
weight bearing, I don't really know. But that visual model has helped
numerous people enjoy running more since it gets away from a lot of
clunkiness and heavy-duty braking (breaking also ;) ) that sometimes
accompanies heel strike. (don't confuse heel strike with heel landing,
which may be a mid-foot landing that ended a little farther back than
intended, which happens on uneven terrain)


>>FWIW, if I lean forward at ankles, I do go faster, but requires more
>
> energy.
>
>
> So - no free lunch, then.
>
right, but it could also be my inexperience - doing something new always
takes more energy. I seldom do this.
>
>
>
> 10-30% - that's pretty steep. I think I'll stick to sprinting.

That's what our topography offers us and most trail races have slopes at
least 10-20%. Mountain races may have up to 50% slopes (I don't run
mountain races, I'm a wimp).

I'm probably not the best person to discuss flat running with.

Dot

--
"You try to slow down and enjoy it. You try to look at the scenery. But
your brain can kind of go blank. All you want to do is tell your feet to
keep working."
-Cedar Petrosius, women's winner 2004 Matanuska Peak Challenge (14mi,
9000ft up and down)
 
Hi Brian,
My background is Sports Med dealing mostly with biomechanical injuries.

Most Docs are not trained in running mechanics, so that explains your
frustration. From what you have described, you may have an excessive
lower leg rotation injury which is common with pronators or supinators
with a leg length discrepancy.
The right evaluation, shoe change, and a pair of inserts to align your
posture should be enough to get you back on track.
Please let me know if I can be of any assistance.
Cheers,
Adrian Rosa
Biocorrect LLC
Grand Rapids, MI
616-356-5030
[email protected] wrote:
> I thought this might be of interest to any of you who have had
nagging
> injuries and unsympathetic doctors.
>
> I have been bothered by achillies pain for almost a year. Last
spring
> I took a month off, and then cranked up the mileage so that I could
run
> a marathon in October. By October, the heel was feeling pretty bad,
so
> after the marathon I reduced my mileage to about 20 mpw. It got no
> better, so I stopped running altogether in mid December, starting
again
> after the first of the year. I had pain almost immediately.
>
> I have read more than anybody would ever want to know about this
> injury, and have learned that some (see Noakes et. al) are now saying
> that it isn't tendonitis per say, but really tedonosis, a
degenerative
> (but often reversible) condition of the tendon.
>
> I have done heat and ice. I have done ice alone. I have done calf
> strengtheing exercises til the cows came home. I have stretched, and
I
> have refrained from stretching.
>
> So 3 weeks ago, I stopped running again, thinking that a month off
> might be just what I need. By yesterday, the problem was still bad
so
> I went to see an MD (I spent much of last summer in the office of a
> sports therapist in the office of a chiro).
>
> The MD (a GP and close acquaintence of mine) looks at the heel, rubs
> it, and piches it in just the right (wrong!) place, and diagnoses
> achillies tendonitis. He says take 3 ibuprophens 3X daily for 7-10
> days, use ice and heat, stretch. He says: "You know, this running is
> not a good long-term methond of maintaining cardiovascular fitness."
> He reminded me that Jim Fixx died.
>
> Now if, at the beginning of our visit, he had told me what he
thought
> about running, I would have known I had come to the wrong place and
> saved us both some time.
>
> I only write to say that I have much respect for the medical
community,
> but we cannot let that respect turn into blind obedience. He is a
good
> MD, but he, I believe, is just really, really uninformed about
running,
> running injuries, the cardio benefits of running and probably some
> other things, too. And if I didn't already know a good deal about my
> injury, I would not have known that, and would have probably quit
> running--on the advice of my doctor!
>
> So what am I doing? Three ibuprophens 3X daily for 7-10 days, ice
and
> heat (maybe no heat) and I am off running until this feels better. I
> really want to run another fall marathon.
>
> May you all avoid achillies hell.
>
> Brian Jones
 
"Dot" <dot.h@#duh?att.net> wrote in message
news:[email protected]...
> pmb wrote:
> > "Dot" <dot.h@#duh?att.net> wrote in message
> > news:[email protected]...
> >
>
> Another thing I'll throw in here that may affect my concept of short /
> long is that I had been dealing with a sore groin and some other things
> (result of overstretching in a cross-training class) for probably over a
> year. Shortening stride reduced pain. I still run with what I think may
> be a shorter stride than "normal" (whatever that is) about half the
> time, but that's also on snow. Sooo, what my true stride may be while
> running on easy trail on firm footing, I'm not sure. But I suspect with
> time, my normal stride will lengthen as I get more experience running
> under what most people consider normal conditions.
>
>
> > Because that is bound to be a flexible
> > thing. You would instinctively adopt a shorter stride when going uphill.
> > It's a lower gear.
>
> Right. But depending on length of run (that is, not a long run), etc, on
> short steep hills, there may also a tendency to take longer stride to
> get up the hill in few strides - say a dozen longer ones rather than
> 25-30 short ones. Just get it over with. (Other times these are walked
> or run with short stride, just depending on an assortment of variables).
> Same way as on mtn bike on hills, it's sometimes just easier to mash a
> few rpm's than it is to sit there peddling feverishingly at high cadence
> and not going anywhere (I've done it both ways). Depends on training and
> conditions in both cases.

Yup. I can see the point there. On a short hill the "disturbance" cost of
changing your current striding pattern (and then having to revert to it
again at the top), might be as big as the energy cost of being briefly in
the "wrong" gear. But there would always be the temptation to do that on
longer hills - as you say, "just to get it over with". You could easily get
it wrong there, as your marathon runner might get it wrong by not bothering
to take on water in the early stages. It's bound to catch up with you later.
It would be a fine judgement you'd have to make whether a slope was short
enough to be worth "mashing".


> >>Admittedly, I haven't paid that much attention to whether my feet are
> >>directly under my cog or slightly ahead.
> >
> >
> > I don't think you need to. Your instincts would ensure that your foot
comes
> > down forward of the c.o.g. To bring it down directly under would mean
> > contradicting your instincts.
>
> I went back and re-read one of your earlier posts. I think what you're
> saying is that where the foot first touches ground is probably forward
> of cog. However, we may not perceive where the foot touches until it's
> weighted, which actually happens a short time later as the body passes
> over the point of contact.

Well, that's only because it's happening too fast for the perceptions to
follow. But forces are operating as soon as the foot lands, whether the
perceptions notice them or not. You will, of course, notice them when the
foot passes under the body, because of their magnitude - but they've been
building up since the foot first touched down.

> I haven't found any pictures in my collection of what I'm trying to say,
> but let's look at downhill running. Someone else already mentioned the
> resolution of force vectors. If running down a steep, say 20-30%
> downhill, I find I'm more in control of the situation if I lean forward
> so my cog may be in front of feet, at least if they have any amount of
> weight on them. I need to keep the normal force (that
> perpendicular to the slope) sufficient that my feet don't slide out from
> underneath me. I know for a fact if I run downhill or even stand with my
> cog over my feet on that one muddy slope on a local trail, I *will* end
> up on my butt (been there, done that) since there isn't enough friction
> against the ground that way. Also happens when walking to my mailbox on
> ice. In the hill running situation, I can choose to fight gravity by
> landing with my feet in front of cog, but risk falling on my butt - a
> lot depends on slope and footing. I'm assuming I'm not trying to
> glissade down, where I want to minimize normal force. (sorry, I don't
> sprint on flat ground, which I know is what you do. These are just my
> perceptions / experiences from a different background.)
>
> At least that's my perception of foot placement with downhill running,
> and it is consistent with my somewhat rusty understanding of physics.

It's just about feasible to have your foot landing behind your c.o.g going
down a steep slope, provided you're prepared to go on accelerating
indefinitely. Because in that configuration you'd have no braking force, and
gravity would accelerate you up to unmanageable speeds. But, in practice,
long before that point you'd have to start applying braking forces, which
would mean bringing your foot down in front of your c.g. There's no other
way of braking without overbalancing.

> I haven't thought as much about uphill, but I'm having trouble
> convincing myself that I want to touchdown in front of my cog -
> certainly not with any weight on the lead foot.

This is the one case where touching down under or behind the cg is
desirable. You can't run with the stride rate that you do on the level, so
things happen much more slowly. It's a comparatively long drive off the rear
leg, and there's plenty of time to build up the propulsive force, which in
level running there wouldn't be. Also, in level running we need the ankle
drive, because it's such a fast muscle. And we do it by lowering the heel to
the ground between the time the foot lands (in front of the c.g) and the
time it passes under the body. We roll down onto the heel, as it were. (In
sprinting the heel might actually touch the ground briefly, though at lower
speeds it probably doesn't.) But basically, level running takes advantage of
this heel-down position to provide propulsion by raising it again behind the
body. But going up a steep slope there isn't much ankle movement. Unless you
are very flexible, you couldn't get the heel-down position in the first
place, and you'd need to be very strong to use the anke as a driver against
gravity. I'm not saying it isn't possible, but it would murder the calf
muscles. So essentially the ankle is just used as a brace. We land heel-up
and stay heel-up. It's the leg that does all the driving.

Good points you raised here, though. I hadn't really thought about the how
the mechanics of running is modified on slopes before. Hope I got it right.

Pat B
 
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