Re: The aerobic mechanism in the 400 metres

[Guest guest]

This sentence caught my attention:

" They also look at oxygen consumption and suggest an increase in pH level in

the first 150-200m

inhibits Type II muscle fibres from using the aerobic mechanism in the later

stages of the race. "

What would cause an increase in pH level during the phospho-creatine first

20 seconds of intense exercise? I thought the reaction was creating an

increase in protons (H+) in the cells and this in turn the body to remove

this H+ with lactates, carbonates etc. an increase in H+ concentration would

lower the pH not increase it, have I missed something - I am willing to

admit I have.

Regards

Nick Tatalias

Johannesburg

South Africa

> Members may find the following to be of interest:

>

> Thursday, 28 August 2008 The aerobic mechanism in the 400 metres

>

> New Studies in Athletics

>

> The 400m is generally considered to be a highly anaerobic race, but the

> findings of various researchers on the percentage contributions of

> anaerobic and aerobic energy mechanisms are not consistent. Drawing on

> a selection of publications, this article looks at how the energetic

> characteristics of the event are studied and explains the reasons

> behind the variation in findings. It considers 1) differences between

> men and women athletes, 2) differences between sprinter and endurance

> type athletes, 3) the influence of different methodologies and 4)

> differences caused by the performance level of the athletes studied.

> The authors find that performance capacity represents the most

> important quantitative factor for explaining the different percentages

> of intervention of the energy mechanisms. They also look at oxygen

> consumption and suggest an increase in pH level in the first 150-200m

> inhibits Type II muscle fibres from using the aerobic mechanism in the

> later stages of the race.

>

> ========================

> The relative contributions of anaerobic and aerobic energy supply during

> track 100-, 400- and 800-m perform

>

> Nevill A. M., Ramsbottom R., Nevill M. E., Newport S., C.

>

> The Journal of Sport Medicine and Physical Fitness

> Year 2008 - Vol. 48 - N. 02 - June - pag. 138

>

> Aim. The present study set out to identify the relative contribution of the

> laboratory determined physiological measures, (maximal) accumulated oxygen

> deficit (AOD) and maximal oxygen uptake (.VO2max), when predicting track

> performance.

>

> Methods. Fourteen volunteers (men: n=10; women: n=4); mean (± standard

> deviation [sD]) height 1.76±0.1 (men) vs 1.62±0.08 m (women); body mass:

> 67.9±7.1 (men) vs 50.6±8.2 kg (women), ran track races at distances of 100,

> 400 and 800 m. The individually determined (maximal) AOD and .VO2max were

> measured under controlled laboratory conditions (68.3±10.2 vs 60.7±16.1; men

> vs women, mL.O2.Eq.kg-1) and (68.7±7.3 vs 55.6±4.3; men vs women,

> mL.kg-1.min-1), respectively.

>

> Results. Track performance could be predicted using both laboratory

> measures, AOD and , with a high degree of accuracy: R2=76.9%, 84.8% and

> 89.1% for 100, 400 and 800 m, respectively. Data analysis confirmed the

> dominant energy supply during 100-m sprinting was the anaerobic energy

> supply processes, reflected as AOD. In contrast, oxidative metabolism

> (reflected as .VO2max) was the dominant source of energy supply during 800-m

> performance.

>

> Conclusion. The results support earlier research, rather than present

> textbook dogma, namely that aerobic and anaerobic processes contribute

> equally to maximal exercise lasting approximately 60 s.

>

> ====================

> Med Sci Sports Exerc. 2001 Jan;33(1):157-62. Links

> Energy system contribution during 200- to 1500-m running in highly trained

> athletes.Spencer MR, Gastin PB.

>

> PURPOSE: The purpose of the present study was to profile the aerobic and

> anaerobic energy system contribution during high-speed treadmill exercise

> that simulated 200-, 400-, 800-, and 1500-m track running events.

>

> METHODS: Twenty highly trained athletes (Australian National Standard)

> participated in the study, specializing in either the 200-m (N = 3), 400-m

> (N = 6), 800-m (N = 5), or 1500-m (N = 6) event (mean VO2 peak [mL x

> kg(-1)-min(-1)] +/- SD = 56+/-2, 59+/-1, 67+/-1, and 72+/-2, respectively).

> The relative aerobic and anaerobic energy system contribution was calculated

> using the accumulated oxygen deficit (AOD) method.

>

> RESULTS: The relative contribution of the aerobic energy system to the

> 200-, 400-, 800-, and 1500-m events was 29+/-4, 43+/-1, 66+/-2, and

> 84+/-1%+/-SD, respectively. The size of the AOD increased with event

> duration during the 200-, 400-, and 800-m events (30.4+/-2.3, 41.3+/-1.0,

> and 48.1+/-4.5 mL x kg(-1), respectively), but no further increase was seen

> in the 1500-m event (47.1+/-3.8 mL x kg(-1)). The crossover to predominantly

> aerobic energy system supply occurred between 15 and 30 s for the 400-,

> 800-, and 1500-m events.

>

> CONCLUSIONS: These results suggest that the relative contribution of the

> aerobic energy system during track running events is considerable and

> greater than traditionally thought.

>

> ==================

> Energy system contribution to 400-metre and 800-metre track running.

>

> J Sports Sci. 2005 Mar;23(3):299-307.Links

> Duffield R, Dawson B, Goodman C.

>

> As a wide range of values has been reported for the relative energetics of

> 400-m and 800-m track running events, this study aimed to quantify the

> respective aerobic and anaerobic energy contributions to these events during

> track running. Sixteen trained 400-m (11 males, 5 females) and 11 trained

> 800-m (9 males, 2 females) athletes participated in this study. The

> participants performed (on separate days) a laboratory graded exercsie test

> and multiple race time-trials. The relative energy system contribution was

> calculated by multiple methods based upon measures of race VO2, accumulated

> oxygen deficit (AOD), blood lactate and estimated phosphocreatine

> degradation (lactate/PCr).

>

> The aerobic/anaerobic energy system contribution (AOD method) to the 400-m

> event was calculated as 41/59% (male) and 45/55% (female). For the 800-m

> event, an increased aerobic involvement was noted with a 60/40% (male) and

> 70/30% (female) respective contribution. Significant (P < 0.05) negative

> correlations were noted between race performance and anaerobic energy system

> involvement (lactate/PCr) for the male 800-m and female 400-m events (r = -

> 0.77 and - 0.87 respectively).

>

> These track running data compare well with previous estimates of the

> relative energy system contributions to the 400-m and 800-m events.

> Additionally, the relative importance and speed of interaction of the

> respective metabolic pathways has implications to training for these events.

>

> =====================

[Guest guest]

The accepted normal for blood pH is 7.35 to 7.45. It is most directly(quickly)

affected by CO2 (carbon dioxide) levels. CO2 levels are most " controlled " by

respiration. The more air one moves the more CO2 is expelled (if the lungs are

functioning properly) and if CO2 is expelled faster than it is " produced " the

more the pH is pushed upward (hyperventilation). In a healthy person as soon as

respiration is normalized pH should also be normalized since blood pH is what

primarily drives respiration.

In other words if blood pH is other than normal (during exercise in a healthy

person)(and, I am unsure if it would go outside of normal during exercise in a

healthy person) it will return to normal very quickly (as in minutes not days).

Sorry so wordy.

Jim Storch

Elmira, NY USA

From: Nick Tatalias <nick.tatalias@ gmail.com>

Subject: Re: The aerobic mechanism in the 400 metres

To: Supertraining@ yahoogroups. com

Date: Friday, September 19, 2008, 12:47

This sentence caught my attention:

" They also look at oxygen consumption and suggest an increase in pH level in

the first 150-200m

inhibits Type II muscle fibres from using the aerobic mechanism in the later

stages of the race. "

What would cause an increase in pH level during the phospho-creatine first

20 seconds of intense exercise? I thought the reaction was creating an

increase in protons (H+) in the cells and this in turn the body to remove

this H+ with lactates, carbonates etc. an increase in H+ concentration would

lower the pH not increase it, have I missed something - I am willing to

admit I have.

============ ========= =========

[Guest guest]

Jim, what you have written is fundamentally correct and there is no need to

apologize for being " wordy " . All too often short answers convey little if any

useful information and sometimes lead to misinformation or misunderstandings.

Just a minor clarification. The prime buffer for maintaining a proper pH is

bicabonate HCO3. An acidic pH occurs when there are too many H ions. HCO3

combines the H ion to form H2O and CO2. The as you stated correctly the rise in

CO2 stimulates the respiratory system which in turns gets rid of the CO2. Most

people think that increased respiration is caused by a drop in oxygen. In

exercise, as you correctly stated, it is the rise in CO2 that drives the

respiratory system.

Ralph Giarnella MD

Southington Ct USA

> From: Nick Tatalias <nick.tatalias@ gmail.com>

> Subject: Re: The aerobic mechanism in the

> 400 metres

> To: Supertraining@ yahoogroups. com

> Date: Friday, September 19, 2008, 12:47

>

> This sentence caught my attention:

>

> " They also look at oxygen consumption and suggest an

> increase in pH level in

>

> the first 150-200m

>

> inhibits Type II muscle fibres from using the aerobic

> mechanism in the later

>

> stages of the race. "

>

> What would cause an increase in pH level during the

> phospho-creatine first

>

> 20 seconds of intense exercise? I thought the reaction was

> creating an

>

> increase in protons (H+) in the cells and this in turn the

> body to remove

>

> this H+ with lactates, carbonates etc. an increase in H+

> concentration would

>

> lower the pH not increase it, have I missed something - I

> am willing to

>

> admit I have.

>

> ============ ========= =========

[Guest guest]

If the blood pH returns to normal in minutes, then the claim that interval work

reduces pH and therefore endurance seems to make no sense, but it is one that is

frequently repeated.  It would appear, that the loss of endurance when switching

to interval work is merely the function of having stopped doing endurance

work.  

That gets us back in a very round about way to the original post about the

aerobic/anaerobic contributions to various distance events and the Weyand study

that showed that a 30% reduction in oxygen did not effect race times in events

lasting less 60 seconds.  It seems to me that the only way the different studies

can be reconciled is to conclude that while a 60 second race may be

approximately 40% aerobic, the anaerobic system can make up for up to a 30% loss

in oxygen. This brings into question how much time should be spent developing

the aerobic system in certain events.

Jon Haddan

Irvine, CA

> From: Nick Tatalias <nick.tatalias@ gmail.com>

> Subject: Re: The aerobic mechanism in the

> 400 metres

> To: Supertraining@ yahoogroups. com

> Date: Friday, September 19, 2008, 12:47

>

> This sentence caught my attention:

>

> " They also look at oxygen consumption and suggest an

> increase in pH level in

>

> the first 150-200m

>

> inhibits Type II muscle fibres from using the aerobic

> mechanism in the later

>

> stages of the race. "

>

> What would cause an increase in pH level during the

> phospho-creatine first

>

> 20 seconds of intense exercise? I thought the reaction was

> creating an

>

> increase in protons (H+) in the cells and this in turn the

> body to remove

>

> this H+ with lactates, carbonates etc. an increase in H+

> concentration would

>

> lower the pH not increase it, have I missed something - I

> am willing to

>

> admit I have.

>

> ============ ========= =========

[Guest guest]

I have a question- is there going to be a difference in aerobic system

contribution for runners running closer to 50s than 60s?  Certainly the shorter

the race and the faster speed will change anaeorobic/ aerobic system ratios. 

The goal for my HS boys is to break 50- which is where national class women

are.  Better men are running somewhere between 43 and 48 sec- was the research

more in line with 60s of effort?  Then this study would have more practical

application for HS girls than anyone else. 

I'm just wondering what we can take from this study if we are training people

faster than what was studied. 

Thanks

Mark

Camillus, NY USA

Subject: Re: The aerobic mechanism in the 400 metres

To: Supertraining

Date: Sunday, September 28, 2008, 6:52 PM

If the blood pH returns to normal in minutes, then the claim that

interval work reduces pH and therefore endurance seems to make no sense, but it

is one that is frequently repeated.  It would appear, that the loss of endurance

when switching to interval work is merely the function of having stopped doing

endurance work.  

That gets us back in a very round about way to the original post about the

aerobic/anaerobic contributions to various distance events and the Weyand study

that showed that a 30% reduction in oxygen did not effect race times in events

lasting less 60 seconds.  It seems to me that the only way the different studies

can be reconciled is to conclude that while a 60 second race may be

approximately 40% aerobic, the anaerobic system can make up for up to a 30% loss

in oxygen. This brings into question how much time should be spent developing

the aerobic system in certain events.

==============================

[Guest guest]

>

> Subject: Re: The aerobic mechanism in the 400 metres

> To: Supertraining

> Date: Monday, September 29, 2008, 9:37 AM

> I have a question- is there going to be a difference in

> aerobic system contribution for runners running closer to

> 50s than 60s?  Certainly the shorter the race and the

> faster speed will change anaeorobic/ aerobic system

> ratios.  The goal for my HS boys is to break 50- which is

> where national class women are.  Better men are running

> somewhere between 43 and 48 sec- was the research more in

> line with 60s of effort?  Then this study would have more

> practical application for HS girls than anyone else. 

>

> I'm just wondering what we can take from this study if

> we are training people faster than what was studied. 

>

> Thanks

> Mark

> Camillus, NY USA

>

Below I posted the summary of the article in question. They do not give the

actual times or the age of the participants however it is probably safe to

assume that they are college age athletes since the study was done at the

University and they show the difference between male and female athletes.

I believe that you are correct in assuming that the faster the times the less

there is an aerobic contribution to the effort however even in the male athletes

running the 400 meter race aerobic metabolism was calculated as 41/59% (male)

and 45/55% (female). I am not sure that the differences are significant enough

to warrant a different training regimen for each group any more than you would

train the slower (male) racers differently from the faster racers.

The authors make the following comment:

Significant (P < 0.05) negative correlations were noted between race performance

and anaerobic energy system involvement (lactate/PCr) for the male 800-m and

female 400-m events (r = - 0.77 and - 0.87 respectively).

I take that to mean that the higher the anaerobic capacity of the athlete the

faster the times will be.

What is often forgotten is that muscle cells store oxygen in the form of

myoglobin which is used in the aerobic production of ATP.

I suspect that when it is stated that a 30% reduction in oxygen did not effect

race times in events lasting less 60 seconds, the 30% reduction is the

accumulated oxygen debt (AOD) and not a 30% decrease in oxygen saturation.

Ralph Giarnella MD

Southington Ct USA

*********************

: J Sports Sci. 2005 Mar;23(3):299-307.

Links

Energy system contribution to 400-metre and 800-metre track running.

Duffield R, Dawson B, Goodman C.

School of Human Movement and Exercise Science, University of Western Australia,

Crawley, Australia. rduffield@...

As a wide range of values has been reported for the relative energetics of 400-m

and 800-m track running events, this study aimed to quantify the respective

aerobic and anaerobic energy contributions to these events during track running.

Sixteen trained 400-m (11 males, 5 females) and 11 trained 800-m (9 males, 2

females) athletes participated in this study. The participants performed (on

separate days) a laboratory graded exercsie test and multiple race time-trials.

The relative energy system contribution was calculated by multiple methods based

upon measures of race VO2, accumulated oxygen deficit (AOD), blood lactate and

estimated phosphocreatine degradation (lactate/PCr).

The aerobic/anaerobic energy system contribution (AOD method) to the 400-m event

was calculated as 41/59% (male) and 45/55% (female).

For the 800-m event, an increased aerobic involvement was noted with a 60/40%

(male) and 70/30% (female) respective contribution.

Significant (P < 0.05) negative correlations were noted between race performance

and anaerobic energy system involvement (lactate/PCr) for the male 800-m and

female 400-m events (r = - 0.77 and - 0.87 respectively).

These track running data compare well with previous estimates of the relative

energy system contributions to the 400-m and 800-m events.

Additionally, the relative importance and speed of interaction of the respective

metabolic pathways has implications to training for these events.

PMID: 15966348 [PubMed - indexed for MEDLINE]

[Guest guest]

>

> Subject: Re: The aerobic mechanism in the 400 metres

> To: Supertraining

> Date: Sunday, September 28, 2008, 6:52 PM

> If the blood pH returns to normal in minutes, then the claim

> that interval work reduces pH and therefore endurance seems

> to make no sense, but it is one that is frequently

> repeated. 

There is a saying that goes: If you repeat a lie often enough, it becomes truth.

The politicians know this saying well. RG

It would appear, that the loss of endurance when

> switching to interval work is merely the function of having

> stopped doing endurance work.  

You hit the nail on the head. Endurance is not like money where once you have

earned and put in the bank it stays there. The " use or lose it " rule applies

more so to endurance than it does to absolute strength. An old mantra in the

endurance community is that for every week that you don't do endurance work it

will take 3 weeks to return to the level you achieved prior to stopping work. I

don't know if it is true that there is always a 3:1 ratio but I can vouch from

experience that endurance drops off rather quickly once endurance work stops.

> That gets us back in a very round about way to the original

> post about the aerobic/anaerobic contributions to various

> distance events and the Weyand study that showed that a 30%

> reduction in oxygen did not effect race times in events

> lasting less 60 seconds.  It seems to me that the only way

> the different studies can be reconciled is to conclude that

> while a 60 second race may be approximately 40% aerobic, the

> anaerobic system can make up for up to a 30% loss in oxygen.

> This brings into question how much time should be spent

> developing the aerobic system in certain events.

>

> Jon Haddan

> Irvine, CA

That 30% loss in oxygen is the acquired oxygen debt and not a drop of 30% in

oxygen saturation. In the 60 second race 40% of the energy will be derived

aerobically and 60% anaerobically. The cells are able to work both aerobically

and anaerobically simultaneously.

The longer the race the less anaerobic work contributes to the total energy

requirement of the race. The reverse is also true, the shorter the race the more

anaerobic work contributes to the total energy requirement.

Ralph Giarnella MD

Southington Ct USA