Lactate during a mile race.

You've got it a little backwards.

The aerobic system is there from the beginning. It's just that it can only provide a fraction of the ouput you are demanding at sprint speeds, so a larger PROPORTION of the energy comes anaerobically. So in a sprint, you are basically demanding so much more than the aerobic system can provide that it is not an important contributor.

Things change in longer races. Let's take the whole thing from the view of the mile. The gun goes off, and you're out to run a 65sec quarter, say. Your aerobic system kicks in, but clearly it cannot provide the amount of energy necessary to sustain mile race pace. So your anaerobic system picks up the slack and begins producing lactate very quickly. Lactate will continue to build as the total amount of energy you have demanded over what your aerobic system can provide grows. At 1400m before you kick you are still running 65sec/quarter pace, and your aerobic system is still providing about the same proportion of energy as it was earlier in the race. You feel like you're relying on anaerobic though because you've been accumulating lactate for over 3min. You kick for the finish, and clearly this extra energy must be found anaerobically because you have already maxed out your aerobic system.

You are NEVER all one system or the other. Even on an easy run you will produce some small amount of lactate.

what happens during a mile run is that you run 4 laps (outdoors) or (usually) 8 laps (indoors) and then you throw up.

i'd like to add your aerobic system is much more efficient than your anaerobic, for every 1 molecule of glucose oxidized through aerobic respiration roughly 38 molecules of ATP are produced, in anaerobic respiration the glucose molecule can't follow the ETC because oxygen is not present so after pyruvate is formed its converted into lactate and small amounts of ethanol BUT the point of the matter is only 2 ATP molecules are produced during anaerobic respiration instead of 38 with aerobic. My question is though if its so inefficient how are you able to go a lot faster?

If you do an exercise past 30 seconds in duration no more lactate is going to be produced if you are keeping the same pace. The first 10 seconds are going to be comprised of dependence on your atp-pc system but a trained distance runner will make the jump up the energy systems faster. After anaerobic glycolysis which produces lactic acid as a byproduct you go into aerobic glycolysis which produces pyruvate as a byproduct then you will enter the regualar aerobic system. Towards the end of a mile you will be dependent mostly on aerobic assuming you keep the same pace, if you enter your kick over the last 200 meters then you will reenter the anaerobic glycolysis as you main energy system during that time and produce lactic acid again. Power output and such depends on what type of muscle is being used, not the energy system. You run so fast anaerobically because when you are sprinting that 100 meters you are using fast twitch muscle keep on running after the 100 as fast as you can and you'll fast twitch will fatigue and you will slow down to your pace that can be maintained by your more aerobically efficient slow twitch. If your body is trained well your fast twitch will be able to recover for another bout during the main use of only slow twitch. The lactic acid produced will only cause pain during the race, lactic acid is quickly removed because of the pH imbalance in your muscles, don't mistake being in pain with have a build up of lactic acid during all parts of races and afterwards.

AH is wrong in his assesment.

To make it easier to understand, check out the graphs in the link:

http://galenet.galegroup.com/servlet/SRC?ste=200&docNum=A137454232&locID=txshracd2542

jaybird wrote:

what happens during a mile run is that you run 4 laps (outdoors) or (usually) 8 laps (indoors) and then you throw up.

If you throw up, you ate too much too close to the race and you might be a moron. If you ran hard, you should be lying on the ground on the infield--or on the track, if too tired to make it over there--with an exertion headache and a death wish.

If you are throwing up, you either have weak abdominals or a less-than-deal diet, or you cannot process lactic acid very well and the only way for you to get rid of it is by vomiting. This means you need more aerobic work.

PantherRunner wrote:

The lactic acid produced will only cause pain during the race, lactic acid is quickly removed because of the pH imbalance in your muscles, don't mistake being in pain with have a build up of lactic acid during all parts of races and afterwards.

For the last time, you do not produce lactic acid during exercise. It is impossible to do so even under extreme exercise as the pKa of lactic acid is ~3.86 and the pH of active muscles does not drop below 6. This means that the net proton accumulation is not from the dissociation of lactic acid to lactate and a proton. In fact, it comes from the net breakdown of ATP, a reaction which produces protons as a product. Please try and actually read something before posting. Try this link: