When is building up lactic acid good/ok?
What is building up lactic acid good for?
When is building up lactic acid good/ok?
What is building up lactic acid good for?
Two perspectives:
1 - it's good at the end of a race, because it means you're trying hard.
2- it's bad at the end of a race because you're going to have to slow down.
Lactic acid is a waste product from the muscles burning energy. The only thing you can do about it train the body to remove it faster and more efficiently. That's where good old fashioned training comes in.
Burning carbohydrates is a 2 step chemical reaction. In the first step, glucose + ADP yields lactate + ATP. This happens even at low levels of exertion. In the second step of the reaction the lactic acid reacts with oxygen + ADP to yield carbon dioxide, ATP and water. The lactic acid is an intermediate product and will react very quickly if there is enough oxygen present. It is when there isn't enough oxygen that it builds up. But, if lactic acid levels build up in a run, because you went out too fast, then backing off the pace and running aerobically will cause the lactic acid to proceed with the second step of the reaction.
What an elegantly simple pair of questions.
Think of lactic acid as a good thing, and not the enemy. If you are unable to build significant quantities of lactate, you will never make it as a middle-distance runner.
You already know that you have basically two ways of creating energy; the first aerobic, and the second anaerobic. If mankind could ONLY run aerobically, the WR for all middle-distances would be a lot slower. Since we know that marathons are run at something like 99% aerobic pace, then if we could ONLY run aerobically, we would not be able to race any faster. The marathon WR pace per mile and the mile WR pace would be almost identical (maybe a few seconds diff to allow for tartan tracks etc).
"When is building up lactic acid good/ok?"
Well, as I explained above, anytime you want to run faster than approximately marathon pace, you must expect to build up a certain amount of lactic acid. But, and here is the caution, that build-up must always be controlled based on the race distance.
Basically, your La will always be higher the shorter the race distance (assuming you run faster). It should be obvious that you cannot complete a 10k race with the La you achieve in a 1500m race (you would not get much further than 4 laps...)
So, building a controlled amount of La in a race under 10k is "good".
But that is too simplistic an answer. You see, the whole point is to be able to run as fast as possible BEFORE needing to activate your anaerobic system. This is why so many studies report that your running speed at the LT (the point at which La begins to climb) correlates really well with your 10k PR. (Slower at the LT / slower in the 10k. Faster at the LT / faster...)
So while saying that La is "good" in a 10k, less is better. If you are passing the bell and the guy beside you has a La of 3mM, while yours is 8mM, then despite the fact you are both running at the same pace, he is a lot more comfortable than you and is about to leave you anytime he likes.
He would be an example of a guy who can run very fast WITHOUT building La.
Which suggests that for as long as you can in your training period, you should train to be able to run as fast as possible with low La. Then (as a M-D runner), as your competition period approaches you would train to improve your La system and be able to build as much as is suitable for your race distance.
Which really leads onto the second question: "What is building up lactic acid good for?"
In short, it allows you to run faster than your aerobic system on its own can allow. But, as we all learn, there is a payback. Build up too much acidity in your muscle cells and you tie up like crazy and it's all over. (Think the last 50m of an all-out 400m, or the final 100m of a flat-out 800m with a crazy-fast first 400m... wicked!)
The tie-up feeling is less as the distance climbs, but it is still there and is the reason why your competitors can kick away and leave you standing. Not because they can sprint faster, but because up until the precise moment their kick began, they had been dealing with their La build-up better than you.
If you are a short distance specialist (400-1500m - not really longer because your La is not meant to climb so high) then you can also undertake sessions that allow your body to create buffers against this rising acidosis. These enable you to withstand the negative effects of rising acidosis you will feel late in the race and allow you to maintain some good form in the final sprint. Top M-D runners finish races with levels of acidity that would make almost every other untrained human violently sick.
But it all comes back to this: if you want to run fast middle-distance, then you really must be able to build a high amount of La ON TOP OF a well-developed aerobic system. Mainly because your aerobic system cannot produce the energy you require FAST ENOUGH.
Your aerobic system might (for example) get you to 4:45m/m, but if you want to get to 3:45/m/m then you better have a top-rate anaerobic system you can call on.
Let's say I received the La results of a test conducted on two runners. This is 5 x 2000m test at ever-increasing paces with a short stop in between each stage to take a small blood sample. The final 2000m is to be "all-out".
The first guy's maximum La (all-out, remember) is 8mM. Without even knowing what pace he ran, we can already say "might be good at distance, but is never going to be a top 800m runner". The second guy's max La is 19mM, and we can already say "interesting, could have very good 400-1500m potential."
To recap: you want to be able to build La if you need to race fast. But you don't want to build any more than you need and you don't want to build it before you need it.