What limits running performance?

SlowRunner said:

VO2max? Muscle Contractility? Nerves?

Traditionally, VO2max has been considered the limitation(and it's counterparts anaerobic threshold
and running economy-whatever that is). I think Noaks argues for some combination of muscle and
nerve in the 4th edition of the Lore of running. Reading the www.runtexu.com forums I see someone
arguing for muscles and someone else for nerves. I think I've read someone else arguing it's a
neural thing.

runtexu.comforum topics.aspOpen ↗

Anyone have any thoughts on this? Has anyone tried long slow runs all the time vs. intervals all
the time?

Define what you mean by running performance? Is this sprinting, distance, hurdling (some of both),
jumping rope?

Intuition and experience tells me it is all three with no idea at what proportion.

--
Doug Freese [email hidden]

In article N3p9b.56183$nf3.46286@fed1read07 said:

VO2max? Muscle Contractility? Nerves?

Everything boils down to VO2Max and running economy.

Running economy = speed/VO2, so IOW if your VO2 max is high but you can't run quickly, it's because
of your running economy.

Having said that, there are several factors that affect both VO2 Max and running economy.

Among those that affect VO2 max include the rate at which your heart can pump blood, capillary
density, amount of mitochondria, and body weight.

Factors that can influence economy include your shape (hip width, leg length), type of muscle fiber
(slow/fast twitch), body composition, small scale nervous adaptions (neuromuscular), larger scale
(running form), and muscle conditioning.

Quoted message said:

Anyone have any thoughts on this? Has anyone tried long slow runs all the time vs. intervals all
the time?

Intervals all the time will almost certainly be better, because they improve VO2 max, and running
economy. Slow running will improve VO2 max, but not economy. The optimal protocol, which athletes
use, is a combination of both.

Cheers,
--
Donovan Rebbechi pegasus.rutgers.edu~elflordOpen ↗

SlowRunner said:

VO2max? Muscle Contractility? Nerves?

The mind.

I'm sorry, yes middle and long distance performance. And I tend to agree with you that all 3
probably play a limiting role.

"Doug Freese" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

SlowRunner said:

VO2max? Muscle Contractility? Nerves?

Traditionally, VO2max has been considered the limitation(and it's counterparts anaerobic
threshold and running economy-whatever that is).

I

Quoted message said:

Quoted message said:

think Noaks argues for some combination of muscle and nerve in the 4th edition of the Lore of
running. Reading the www.runtexu.com forums I

see

Quoted message said:

Quoted message said:

someone arguing for muscles and someone else for nerves. I think I've

read

Quoted message said:

Quoted message said:

someone else arguing it's a neural thing.

runtexu.comforum topics.aspOpen ↗

Anyone have any thoughts on this? Has anyone tried long slow runs all

the

Quoted message said:

Quoted message said:

time vs. intervals all the time?

Define what you mean by running performance? Is this sprinting, distance, hurdling (some of both),
jumping rope?

Intuition and experience tells me it is all three with no idea at what proportion.

--
Doug Freese [email hidden]

ethnicity. If you ain't Kenyan you ain't gonna win the big one.

VO2max, by itself, has proven a very poor indicator of long distance running ability. People with
higher VO2 tend to be better yes, but among a group of similar-ability runners the VO2 can vary
widely. Development of mitochondria and capillary density influence VO2, but are partially
separated factors that greatly influence runnign ability. Since I started increasing my mileage
(and hence capillaries and mitochondria), my running ability has greatly increased. I think one
factor commonly overlooked is recovery ability. People who bounce back quickly can handle higher
training loads. I think muscle fiber composition is a big factor, however nerves are not for
distance running. Andy Hass

And behind all that has been mentioned *genetics* is a huge factor though we still don't know much
about the spesifics. That has recently been dicussed here. Genetics might seem invisible, and is not
talked much about publicly (preserves the equalityperspective, "he trained harder than everyone
else, was more dedicated" etc) but it is vital.

<[email hidden]> skrev i melding "]news:[email hidden]...

Quoted message said:

VO2max, by itself, has proven a very poor indicator of long distance

running

Quoted message said:

ability. People with higher VO2 tend to be better yes, but among a group of similar-ability
runners the VO2 can vary widely. Development of mitochondria and capillary density influence
VO2, but

are

Quoted message said:

partially separated factors that greatly influence runnign ability. Since

I

Quoted message said:

started increasing my mileage (and hence capillaries and mitochondria), my running ability has
greatly increased. I think one factor commonly overlooked is recovery ability. People who bounce
back quickly can handle higher training loads. I think muscle fiber composition is a big factor,
however nerves are

not

Quoted message said:

for distance running. Andy Hass

ethnicity. If you ain't Kenyan you ain't gonna win the big one.
___

Newsflash! "Kenyan" is not an "ethnicity"...it's a nationality. Tanzanian runners also do
well....for example they swept 1,2, and 3 in the 2002 Sydney Marathon. Anglos & Asians also win
Marathons......(when the Africans don't show up)....

Quoted message said:

VO2max, by itself, has proven a very poor indicator of long distance running ability. People
with higher VO2 tend to be better yes, but among a group of similar-ability runners the VO2 can
vary widely. Development of mitochondria and capillary density influence VO2, but are partially
separated factors that greatly influence runnign ability. Since I started increasing my mileage
(and hence capillaries and mitochondria), my running ability has greatly increased. I think one
factor commonly overlooked is recovery ability. People who bounce back quickly can handle higher
training loads. I think muscle fiber composition is a big factor, however nerves are not for
distance running.

Why do you think nerves are not a factor? Even at a wlaking pace a well trained ultra runner
will eventually fatigue. It's very unlikely that it's a VO2 max limitation, probably not a
energy limitation issue as energy can be converted and consumed at a rate higher than burnt
at a slow walking pace. Seems to me that the the only other plausible explanations would be
muscle fatigue or neural fatigue.(Note I'm not an expert here so I'm probably missing
something) I'm not saying that it is definately neural fatigue but I'm curious as to how you
can rule it out?

~Matt

Quoted message said:

Andy Hass

MJuric said:

On Tue, 16 Sep 2003 02:12:42 GMT, [email hidden] wrote:

Quoted message said:

Quoted message said:

VO2max, by itself, has proven a very poor indicator of long distance running ability. People
with higher VO2 tend to be better yes, but among a group of similar-ability runners the VO2 can
vary widely. Development of mitochondria and capillary density influence VO2, but are partially
separated factors that greatly influence runnign ability. Since I started increasing my mileage
(and hence capillaries and mitochondria), my running ability has greatly increased. I think one
factor commonly overlooked is recovery ability. People who bounce back quickly can handle
higher training loads. I think muscle fiber composition is a big factor, however nerves are not
for distance running.

Quoted message said:

Why do you think nerves are not a factor? Even at a wlaking pace a well trained ultra runner
will eventually fatigue. It's very unlikely that it's a VO2 max limitation, probably not a
energy limitation issue as energy can be converted and consumed at a rate higher than burnt
at a slow walking pace. Seems to me that the the only other plausible explanations would be
muscle fatigue or neural fatigue.(Note I'm not an expert here so I'm probably missing
something) I'm not saying that it is definately neural fatigue but I'm curious as to how you
can rule it out?

Quoted message said:

~Matt

I'm not an ultra-runner or walker, but I am a biologist and nerves don't fatigue. The only way
your nerves will cause a problem is if you sweat out all your electrolytes and they can't fire
right anymore. Soon after that you go into seizures and probably die. Ultra-running, in my
bystander understanding, is in fact the most energy- limited of the distances. The marathon is
just short enough that you can run most of it off glycogen and actually push a hard pace. Much
longer, and you are energy-limited by the rate at which you burn fat and digest what you can stuff
down while you go. Tiring from walking is most certainly muscular. Whether from eventual muscle
breakdown or general fatigue, it's not neuronal. In sprints however, nerves that fire faster are
bound to make a difference as it's an explosive event. Andy Hass

I noticed Donovan's comments regarding speed as a relationship between economy and VO2 and would love to hear everyone's thoughts on my situation...

I've never been a serious runner, but was roped into it at school as a cross-country runner due to my (then) fitness from swimming. No matter how much I ran, I still couldn't do much better than 4mins/km, but I could hold that for any distance between 3km and 10km. Obviously 4mins/km is ridiculously slow, and I had to rely on the other guys not doing enough training so that I might outlast them.

I'm now starting to get into the whole triathlon idea and am reasonably comfortable with swimming and cycling but am well aware that 4min/km is just not going to cut it against people that train properly.

After a lay-off of almost ten years, I've been running again lately and once again, I can hold about 4min km for about 6km or so. What I find interesting is that running at that pace produces a heart rate of 170+ for the entire distance (MHR 185, RHR 42) which is scary in itself... I'm not sure what else to do, as obviously I don't have a lot more up my sleeve at that heart rate to up my cadence any further. I'm 28, 5'9", 73kg with a swimmer's build and relatively short legs (so I'm told). I think the inseam is about 30". Not a lot of fast twitch in my legs, at school could only just sneak under the minute for the 400m.

Any tips appreciated, as it is hampering my enthusiasm in pursuing tris any more seriously, because my other two legs are coming along nicely, but I can't afford to give away a minute per km on the run! Thanks in advance.

I would generally agree with Andy on VO2max. If you took the population as whole you could make good
guesses on where each person would finish in a 10K (or just about any distance race) based on VO2max
measurements.

In a homogenous group (say the finalists in the Olympics), VO2max would have less ability to
predict. Velocity at VO2max would be better; pave at lactate threshold is probably the best
predictor of performance for endurance types. Running economy also plays a role.

<[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

VO2max, by itself, has proven a very poor indicator of long distance

running

Quoted message said:

ability. People with higher VO2 tend to be better yes, but among a group of similar-ability
runners the VO2 can vary widely. Development of mitochondria and capillary density influence
VO2, but

are

Quoted message said:

partially separated factors that greatly influence runnign ability. Since

I

Quoted message said:

started increasing my mileage (and hence capillaries and mitochondria), my running ability has
greatly increased. I think one factor commonly overlooked is recovery ability. People who bounce
back quickly can handle higher training loads. I think muscle fiber composition is a big factor,
however nerves are

not

Quoted message said:

for distance running. Andy Hass

Quoted message said:

MJuric said:

On Tue, 16 Sep 2003 02:12:42 GMT, [email hidden] wrote:

Quoted message said:

Quoted message said:

VO2max, by itself, has proven a very poor indicator of long distance running ability. People
with higher VO2 tend to be better yes, but among a group of similar-ability runners the VO2
can vary widely. Development of mitochondria and capillary density influence VO2, but are
partially separated factors that greatly influence runnign ability. Since I started increasing
my mileage (and hence capillaries and mitochondria), my running ability has greatly increased.
I think one factor commonly overlooked is recovery ability. People who bounce back quickly can
handle higher training loads. I think muscle fiber composition is a big factor, however nerves
are not for distance running.

Quoted message said:

Why do you think nerves are not a factor? Even at a wlaking pace a well trained ultra runner
will eventually fatigue. It's very unlikely that it's a VO2 max limitation, probably not a
energy limitation issue as energy can be converted and consumed at a rate higher than burnt
at a slow walking pace. Seems to me that the the only other plausible explanations would be
muscle fatigue or neural fatigue.(Note I'm not an expert here so I'm probably missing
something) I'm not saying that it is definately neural fatigue but I'm curious as to how you
can rule it out?

Quoted message said:

~Matt

I'm not an ultra-runner or walker, but I am a biologist and nerves don't fatigue.

I'm very interested in the topic of "neural fatigue" do you have some literture,links etc
that you can point me too?

Quoted message said:

The only way your nerves will cause a problem is if you sweat out all your electrolytes and they
can't fire right anymore. Soon after that you go into seizures and probably die.

There was something in Noakes "Lore of running" I read that unless I misinterpreted it
stated otherwise. I'm pulling this from memory adn paraphrasing so it's probably incorrect
but I thought it said something to effect that Ultra runners are runing nearly all on fat at
some point at a rate that was below the fat conversion point. I thought he also stated that
muscle fatigue can be limited and that woudl leave only neural fatigue. Again I'm probbaly
hallucinating as reading that book was a bit like reading 600 pages if medical documents.

Quoted message said:

Ultra-running, in my bystander understanding, is in fact the most energy- limited of the
distances. The marathon is just short enough that you can run most of it off glycogen and
actually push a hard pace. Much longer, and you are energy-limited by the rate at which you burn
fat and digest what you can stuff down while you go. Tiring from walking is most certainly
muscular. Whether from eventual muscle breakdown or general fatigue, it's not neuronal. In
sprints however, nerves that fire faster are bound to make a difference as it's an explosive
event. Andy Hass

It just seems strange to me that nerves will not "fatigue". Even electrical wires have
limitations on load and eventually break down. How is a nerve that is more of a chemical
reaction rather than mechanical does not? Of course I'm approaching this from a complete
laymans perspective so I'm probably missing something.

~Matt

Cletus75 said:

After a lay-off of almost ten years, I've been running again lately and once again, I can hold
about 4min km for about 6km or so. What I find interesting is that running at that pace produces a
heart rate of 170+

That's a fairly high heart rate and would ignore pace and run slower, getting a better base(more
miles) then add some hills and THEN worry about speed. If you can't converse with someone running
next to you, you are running too fast. Building a foundation even slowly, will help you run faster
and not [censored] the injury gods.

Quoted message said:

Not a lot of fast twitch in my legs, at school could only just sneak under the minute for
the 400m.

You can thank you parents for the slow twitch. You take what you have and make the best out it.

Quoted message said:

Any tips appreciated, as it is hampering my enthusiasm in pursuing tris any more seriously,
because my other two legs are coming along nicely, but I can't afford to give away a minute per km
on the run!

I realize you're only 28 but you need to be patient. Build slowly and don't put undo pressure on
yourself to achieve unrealistic(too fast) goals.

--
Doug Freese [email hidden]

Quoted message said:

I'm not an ultra-runner or walker, but I am a biologist and nerves don't fatigue. The only way
your nerves will cause a problem is if you sweat

out

Quoted message said:

all your electrolytes and they can't fire right anymore. Soon after that

you

Quoted message said:

go into seizures and probably die. Ultra-running, in my bystander understanding, is in fact
the most

energy-

Quoted message said:

limited of the distances. The marathon is just short enough that you can run most of it off
glycogen and actually push a hard pace. Much longer, and you are energy-limited by the rate at
which you burn fat and digest

what

Quoted message said:

you can stuff down while you go. Tiring from walking is most certainly muscular. Whether from
eventual muscle breakdown or general fatigue, it's not neuronal. In sprints however, nerves that
fire faster are bound to make a

difference

Quoted message said:

as it's an explosive event. Andy Hass

So you would not agree with this then?:

What Is ATP Forï...In Nerves.....

Nerves conduct electrical signals from brain, to muscle, which causes the muscle to produce force.
The nerves conduct these electrical signals by causing sodium and potassium to move into and out
of the nerve fiber. At a microscopic level along the covering (membrane) of nerves, there are
small tunnels (called channels) that allow sodium and other particles to move into and out of the
nerve fiber. Following each electrical signal that travels down the nerve fiber, the sodium and
other particles must be moved back to their original positions, so that another signal can be
sent. There are some pumps (called sodium/ potassium pumps) that are responsible for this process.
The pumps are located in the membrane (covering) of the nerve. They grab the sodiumï¾.turnï¾.and
dump it outside the nerve. It does the opposite with potassium, dumping it inside the nerve.
Energy (ATP) is needed to cause the pumps turn. The frequency of which signals are able to travel
down a nerve fiber determines the amount and velocity of force production by the muscle. This
(power) is fairly important in track and field running events. The athleteï¾'s ability to provide
high levels of ATP for the pumps, allows the pumps to function at high levels, resulting in
maintaining high muscle force outputs. Researchers are now showing that fatigue in the nerve may
precede the fatigue in muscle. Generally speaking, the muscle will produce force, if the nerve
tells it to. Thus the nervous system may reduce itï¾'s activation of muscle, prior to the muscle
reaching a state of fatigue.

doitregistration.comq and a fetch msg.tclOpen ↗

Why do you say an optimal protocol is a combination of both if intervals all the time improves both?

I found it interesting reading this article from Gibbens because I am one of those people who have
had my VO2max tested and did not show a VO2max. In fact, as Noakes states, about 50% of people
tested don't show a VO2max. So, something limited my performance before I got to VO2max - if indeed
there is such a thing. In any case, Gibbens argues that it's muscle contractility:

runtexu.comforum posts.aspOpen ↗

Running Physiology - The State of the Art

Part 7 - Review

By Richard Gibbens

Through the first 6 parts of this series we have discussed in some detail the current
state of the art of running and endurance physiology. In this final part we will review
the major points covered and advance an alternate theory for the reader's consideration.

The theory currently dominating the exercise physiology world, at least from the
perspective of training recommended by leading authors, trainers, the popular press, and
coaches, is that of VO2max. The concept of VO2max holds that the limiting factor in
endurance performance is the body's ability to absorb, transport and utilize oxygen. Put
succinctly, the reason you can't run faster is that you can't get enough oxygen to your
running muscles. When you increase the amount of oxygen available to your muscles, you
will then be able to run faster.

Due to some significant challenges to the theory of VO2max, two additional factors have
been proposed by exercise physiologists. These two factors are lactate threshold and
running economy. They are as follows.

A runner produces lactate (or lactic acid) in greater and greater quantities as
running speed increases. This is believed to happen because of the body's inability to
provide enough oxygen to meet the increasing energy needs of the muscles. It is widely
believed that lactate is a prime cause of fatigue and hence limits performance. It is
further believed that lactate does not increase linearly, instead showing a threshold,
such that at some running speed the amount of lactate being produced by the body
increases significantly. The theory holds that if a runner can increase the pace at
which he can run before crossing this "lactate threshold" running performance will be
significantly improved.

Running economy is a measure of the amount of oxygen a runners uses at any running
speed. It has been observed that even though runners may have the same VO2max, the
amount of oxygen they use at any running speed can be very different. This difference or
"running economy" is used to explain why it is possible for a runner with a lower VO2max
to beat a runner with a higher VO2max.

Since VO2max, lactate threshold, and running economy dominate the beliefs of
physiologists, most (all?) running and endurance training programs are designed around
these beliefs and are crafted to improve one or more of the above variables. Workouts
such as tempo runs, aerobic runs, anaerobic runs, lactate threshold runs, and VO2max
runs have been promoted as methods to improve the above factors. Additionally, basing
workouts on some percentage of heart rate and using a heart rate monitor to stay in the
appropriate range has been an easy method to employ the workouts mentioned above without
the necessity of expensive laboratory equipment or trained technicians.

Do They Really Exist?

Significant challenges to the concepts of VO2max, lactate threshold and running economy
exist. The counter arguments are based on research, empirical evidence, and logic. The
most significant of these challenges concerns the assumption that VO2max limits
performance; this has been assumed, but has not been proven. A significant amount of
research has been done that really calls into question whether VO2max, lactate
threshold, or running economy are viable concepts.

Alternatively, I have advanced the idea that the true limiting factor in running
performance is the muscular system, not the body's ability to utilize oxygen.

I further contend that basing a training program on a flawed theory (VO2max) could very
well mean that the training program is equally flawed. In the least, the training
program would not be designed to optimally improve the factors that limit performance,
and hence training results would be sub-optimal.

Since muscles are the true limiting factor in running performance, training programs
must be based on improving muscular power. Numerous studies have shown that high force
production training is the best method for accomplishing this. Additionally, research
also shows that much less frequency is required than most running programs advocate. Two
days of running has been shown to be as effective as 5 days of running. I recommend 2 -
3 quality workouts per week. Also, there is no evidence that easy runs promote faster
recovery. Instead, as training volume increases so does the number of running injuries.

I hope that this review of the current state of the art in running physiology has proven
useful to you and I welcome questions or comments. You can reach me at
[email hidden].

Other articles: runtexu.comforum posts.aspOpen ↗

A study conducted at the KIHU Research Institute for Olympic Sports in Jyvaskyla, Finland on 17
endurance runners found that 5k race times could be accurately predicted from 20 meter sprint times.
Not only that, but 20 meter sprints were a better predictor of 5k performance than VO2max.1

A study conducted at the University of Nebraska found that the10k performance of trained runners
could be accurately predicted from the 50 meter sprint, the 300 meter sprint, and from plyometric
leaping distance (plyometric leaping distance is similar to the triple jump, except that it is
performed from a standing rather than a running start).2

The most interesting thing about this study was that plyometric leaping distance was the single best
predictor of 10k performance, accounting for a whopping 75% of the variation in 10k race times; it
was a much better predictor of performance than either VO2max or that exalted attribute, lactate
threshold.

The common factor that 20m, 50m, 300m, and plyometric leaping distance all have in common is
that they are all "anaerobic" events. They are strength events; they are not "aerobic" or
endurance events.

runtexu.comforum posts.aspOpen ↗
runtexu.comforum posts.aspOpen ↗
runtexu.comforum posts.aspOpen ↗
runtexu.comforum topics.aspOpen ↗

"Donovan Rebbechi" <[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

In article N3p9b.56183$nf3.46286@fed1read07 said:

VO2max? Muscle Contractility? Nerves?

Everything boils down to VO2Max and running economy.

Running economy = speed/VO2, so IOW if your VO2 max is high but you can't run quickly, it's
because of your running economy.

Having said that, there are several factors that affect both VO2 Max and running economy.

Among those that affect VO2 max include the rate at which your heart can pump blood, capillary
density, amount of mitochondria, and body weight.

Factors that can influence economy include your shape (hip width, leg

length),

Quoted message said:

type of muscle fiber (slow/fast twitch), body composition, small scale nervous adaptions
(neuromuscular), larger scale (running form), and muscle conditioning.

Quoted message said:

Anyone have any thoughts on this? Has anyone tried long slow runs all

the

Quoted message said:

Quoted message said:

time vs. intervals all the time?

Intervals all the time will almost certainly be better, because they

improve

Quoted message said:

VO2 max, and running economy. Slow running will improve VO2 max, but not economy. The optimal
protocol, which athletes use, is a combination of

both.

Quoted message said:

Cheers,
--
Donovan Rebbechi pegasus.rutgers.edu~elflordOpen ↗

In article zs2bb.2795$Rd4.784@fed1read07 said:

Why do you say an optimal protocol is a combination of both if intervals all the time
improves both?

VO2 max is complicated. There are a lot of different physiological changes that contribute to VO2
max. These include capillary density, mitochondria, stroke volume, and weight.

Intervals will do a lot to increase stroke volume, but have less impact on the other factors.

Quoted message said:

I found it interesting reading this article from Gibbens because I am one of those people who have
had my VO2max tested and did not show a VO2max. In

What do you mean by "don't show a VO2 max" ?

What conclusions do you draw from those two articles ? I don't think there's a whole lot in there
that refutes conventional training methodology.

Cheers,
--
Donovan Rebbechi pegasus.rutgers.edu~elflordOpen ↗

----Yes, I would disagree with that. ATP is a transient molecule in the body due to the instability
of its high-energy phosphate bonds. This means that it is produced and used in milliseconds, not
stored. Even under high exertion levels, the level of ATP does not appreciably change in cells
because its production is so quick and also tightly regulated. There is no conceivable way that a
distance runner could use energy fast enough to reduce inctracellular ATP levels (MAYBE a sprinter
but I doubt it). Besides that fact, there is the fact that the body has self-defense mechanisms to
prevent an individual from killing themselves. If you were so short of energy that your body was low
on ATP in its cells, your brain would shut down muscle function to protect itself and basic life
functions like breathing and heart action. I have seen no evidence that nerves tire before muscles,
if you have a reference to some good primary literature I might be convinced. From a physiological
stanpoint I cannot see how this could be a significant factor in distance running. ANdy Hass

Cletus75 said:

I've never been a serious runner, but was roped into it at school as a cross-country runner due to
my (then) fitness from swimming. No matter how much I ran, I still couldn't do much better than
4mins/km, but I could hold that for any distance between 3km and 10km. Obviously 4mins/km is
ridiculously slow, and I had to rely on the other guys not doing enough training so that I might
outlast them.

I'm now starting to get into the whole triathlon idea and am reasonably comfortable with swimming
and cycling but am well aware that 4min/km is just not going to cut it against people that train
properly.

After a lay-off of almost ten years, I've been running again lately and once again, I can hold
about 4min km for about 6km or so. What I find interesting is that running at that pace produces a
heart rate of 170+ for the entire distance (MHR 185, RHR 42) which is scary in itself... I'm not
sure what else to do, as obviously I don't have a lot more up my sleeve at that heart rate to up
my cadence any further. I'm 28, 5'9", 73kg with a swimmer's build and relatively short legs (so
I'm told). I think the inseam is about 30". Not a lot of fast twitch in my legs, at school could
only just sneak under the minute for the 400m.

Interesting. Your MHR and RHR are similar to mine (186/38), and your HR during a ~5k seems
perfectly within my experience - I average around 175. But you're talking about two things, and I
think it deserves some clarification.

If you race - full out - a mile, can you really not do it any faster than 6:25? But you can
maintain that pace for 3 miles as well? I'd be surprised. Even though your HR is near max during a
5k - about where it should be, since the distance is at a pace above lactate threshhold - most
people have more speed left in you from anaerobic metabolism for shorter periods of time. If you
really do run a mile flat out at the same pace at which you run a 5k...

There are two areas I'd probably look at in that case: neuromuscular and strength. Or, from the
training perspective, strides and hills. From swimming, you've probably got good central aerobic
capacity (mostly your heart here), but that says nothing about your running muscles. You have to
train your legs to move efficiently at high speed (strides) and ensure that they've got the base
strength to move your body as fast as you want them to. Hills, plyometrics, weight lifting, etc.,
will address the latter.

The other possibility is that, despite your training, you just don't seem to be able to the longer
distances any faster than 6:30. The answer is very possibly the same as the above, but could also
be more related to increasing your LT. I'd be curious what your training is like.

Quoted message said:

Any tips appreciated, as it is hampering my enthusiasm in pursuing tris any more seriously,
because my other two legs are coming along nicely, but I can't afford to give away a minute per km
on the run! Thanks in advance.

If you can keep up a 6:24 pace during the run of an olympic distance triathlon, you'll be doing
well. Even in a sprint that's a respectable pace for an hour-long event. It won't win the olympic
tri, but it'll put you in the top 5-10%.

-Dave

--
work: dga - at - lcs.mit.edu me: angio - at - pobox.com MIT Laboratory for Computer Science
angio.netangio.netOpen ↗ (note that my reply-to address is vaguely despammed...) bulk emailers: I do
not accept unsolicited email. Do not mail me.