Alactic energy first 50m

Do you see elite runners go all out the first 50m?

Thought so.

Look, I raced at a pretty high level so I know how races go out (and yes, many elite 800 m. runners do go all out the first 50 m., I'm wondering ***from an energy production standpoint and taking into consideration what this does to heartrate, etc. *** if this holds true for the longer distances since the "settling in" pace is a lot lower percentage of max depending on the distance. I always intuitively understood racing but am really trying to delve into the nuts and bolts of the science as I start coaching others.

gdsgfd wrote:

Do you see elite runners go all out the first 50m?

Thought so.

bump hoping for response

I know that Steve Magness has written about this but I don't recall where. I don't think it's in his book, it may have been on his old website or perhaps even on this message board.

Good luck.

There is no acid-based fatigue (you have to lower muscular pH anyhow to get moving aerobically) but there is also ammonia to consider. Intense fast-twitch exercise produces more ammonia.http://www.sciencedirect.com/science/article/pii/S0301008210000237

Plasma concentrations of ammonia during exercise often achieve or exceed those measured in liver disease patients, resulting in increased cerebral uptake. In this article we propose that exercise-induced hyperammonemia may lead to concomitant disturbances in brain function, potentially through similar mechanisms underpinning pathology, which may impact on performance as fatigue or reduced function, especially during extreme exercise.

It doesn't take very many all-out short sprints to enter a daze of fatigue that I think is due to ammonia.

The 7 second free alactic energy is old idea that has been proven wrong: All energy systems turn on almost immediately, and there is NO alactic energy "free lunch".

What happens in sprinting is that ATP production from CPK tops in TWO seconds. After that point, CPK sources decline and glycolysis increases. After 10 seconds, energy production is 44% glycolytic and 53% CPK, and the lactate level at the end of a 100m sprint is 8 mmol/l in laboratory research subjects and up to 10 mmol/l (Locatelli data) in elite sprinters (and 15 mmol/l for elite sprinters after 200m).

http://www.hindawi.com/journals/jnme/2010/905612/#B15

Sprinting has terrible running economy, and what you get from this is a lot of lactate at the start of a race, which will cost you later. That's why this technique isn't used much any more by knowledgeable coaches.

coach d wrote:

what you get from this is a lot of lactate at the start of a race, which will cost you later.

What you get is a lower intramuscular pH which increases the flow of oxygen to those muscles. You can't hit peak aerobic performance until pH is lowered to optimal levels. If you start slow you are merely wasting time.

A short sprinter might go into acidosis from a short all-out start. But middle distance runners have less type 2 muscle to generate acid with, while their greater aerobic capacity helps clear acid faster. And experienced MD runners know when to ease up and coast before acidosis can develop.

This is an awesome question, no matter what the people who think they're being clever respond. A full speed sprint for ~50m is not as damaging as one might imagine in a marathon (or 5-10k), but still not advisable. There are a couple reasons for this but most fall into the "you can't unring a bell" philosophy. While ATP is the primary fuel used in the first 7-8 seconds of exercise, the intensity of a full spring will set various physiological processes into motion (glycogen usage, oxygen consumption, heart rate etc.) that will continue at a higher rate than normal even if you shut down and go back to race pace after 50m.

These processes will cost energy as the race goes on, more energy than if a slower start had been utilized.