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Lactate Threshold Testing.. for dummies!

Guys and Gals,

I am afraid i have to hold my hands up and say i dont understand!
My club has secured a deal with a local Uni to do our Lactate Threshold levels for cycling and running.
The problem is that i dont really understand what it all means! These levels are supposed to help you with training etc. In laymans terms i.e me, does this mean that once you level threshold is determined, does this give you a max heart rate you must keep below during training, or a min heart rate to maintain to achieve good results etc? Could somebody break it down for me? I dont think i will get it done, but i have been given a heart rate monitor so mauy utalise that.

thanks in advance


  • Ok, I'm not an expert but I'll start the ball rolling. For one thing go and get it done, if you want to do longer distance races this measurement is very useful for both training and racing and you will probably learn a lot from the guy doing the test. In a short race you can blast away as hard as you can, I think the rule of thumb is you can do 60-90 mins giving it socks before your lactic acid builds up and your sugar levels get used up. So all fine for a sprint, but if you're doing an Olympic it means if you blast out the bike you'll get off for the run and wonder who switched your legs for an eighty year olds (I'm hoping I'm not the only one who's first OD was like this!). So it's good to stay under your lactate threshold target for the bike so that you can run at a reasonable pace.
    For training it's also useful, because this time of the year you don't want to be doing too much above your threshold or you'll get overtrained ( this is one topic I can claim a bit of expertise) and you step it up closer to race time. Otherwise you're just guessing your training sessions.
    Like I said, I'm no expert and there's a lot of guys out there who know a lot more,but getting yourself tested and getting a HRM makes all the training sessions recommended in 220 and elsewhere a lot more relevant
  • HarryDHarryD Posts: 425
    Ah! Lactate Threshold! So much potential & so much confusion.

    As you exercise harder the proportion energy produced anaerobically increases. Anaerobic energy produces lactic acid as a waste product. Small amounts can be metabolised quickly with no ill effect. However there comes a level of intensity where the level of lactate in your blood starts to increase. This is your Lactate Threshold. Lactate disrupts muscle function, i.e. it limits how fast you can run, bike or swim a given distance.

    Endurance athletes should race above their LT ideally with lactate building up to an intolerable level on the finish line. The shorter the distance the more above LT the race effort can be.

    The good news is that the body adapts to training at LT by raising it. There are significant benefits from having a LT of 90% of HR max rather than 65%. Only by knowing your LT can you train at it. As Conehead points out you do need to regularly retest as your LT changes with training.

    You can do your own LT estimation if you have a treadmill or turbo & a heart rate monitor. Warm up for about 15 minutes at around 65% of HR max. Then every minute increase your speed by 0.5 (treadmill) or 1.0kmph (bike). At the end of each minute note the speed & your HR. When you can do no more plot HR against speed. The point at which the line bends should be your LT - note the HR. Not the most accurate test but pretty reliable and cheap. You can also use race pace & HR data to estimate LT but that's another topic.

    LT training being below race pace is counter intuitive to athletes who have always been taught that only hard work pays dividends. Teaching cats synchronised swimming would be easier! It is an example of training smarter not harder. LT interval sessions (up to 30min/week at LT) mixed with hills, speed & VO2 as part of a planned training programme can pay dividends. A 5% improvement for most age groupers over an olympic distance event is a 7:30 improvement. If you're going to train you may as well do it properly.

    Hope this helps
  • BritspinBritspin Posts: 1,655
    Lactic/lactate?..not quite you say tomato I say tomato. Lactic acid has been discounted as a limiter since the late 60s I believe, infact it is a substrate yet still we cling to the old science, the burn is hydrogen ions I believe. Anyhoo, I concur with Mr.C why pay someone to tell you the time when you have a watch (altho I will happily take money off people to do this stuff.)
    You can 'test' threshold anytime you like either 'race pace' or specific benchmark sessions, be in pool, bike or run.
    Choose a time or distance & go..max sustainable pace for that distance, as sprint threshold is not olympic is not IM. As long as it is repeatable as near identically as poss, jobs a good 'un & you have a great training session to boot.
  • Ok, that makes sense, but is your sustainable pace the same when doing a run or a bike on it's own compared when you're doing them in a tri? Do you factor it down, or do you measure during a brick?
  • BritspinBritspin Posts: 1,655
    Excellent question, the answer is again back down to specificity...what you train is what will improve.
    So a run session will improve your run threshold, which will impact your bike/run threshold, but not as much as a bike/run session as the fatigue from the bike has to factor in the run.
    So in theory yu can have a single sport threshold, which will differ (altho by how much I have no idea)from a combined sport threshold..(swim-bike, bike-run etc) & a 'triathlon' threshold. Factor in hydration, temperature etc etc....could go on together forever..
  • Trying to clear up what I've learnt so far - I've previously used lactate threshold as a Heart rate target for OD and HIM races, but now I see this level can change over time. Regardless of what you call it, I'm looking for an max heart rate I can race atw without burning out, and this will vary for the different length races. I can try to pinpoint this heart rate for bike and run using the tests suggested above and then try this out with the threshold sessions above as well, fine tune and recognise the differences for different length races, much like you'd establish your 5k, 10k, HM, etc run speeds. I should also start to use RPE during this to identify how this level of effort 'feels' so I can recognise it during a race particularly if my HRM goes on the blink. Because this is all good training anyway, I should regularly try to re-measure and it all goes well the speed at these levels should all gradually increase. Am I in the ball park here?
    This has got me all keen to try some of these sessions out, which I guess is why I use this forum - at the very least I'll have a few different training sessions to do.
  • BritspinBritspin Posts: 1,655
    Superbly put, in all its simplicity & complexity, you have it nailed down.
  • HarryDHarryD Posts: 425
    Britspin is correct in that the burn is caused by a build up of Hydrogen ions but that is not the whole story. Are you sitting confortably? Then I'll begin.

    When muscle cells start to generate energy anaerobically glucose is only partially oxidised and is changed to pyruvic acid. In water, remember what most of our cells are made up of, pyruvic acid dissociates (splits) into pyruvate and Hydrogen ions. The muscle cell has two mechanisms for getting rid of it. Mitochondria in the cell metabolise the pyruvate which releases more energy which is good for us. The second mechanism kicks in once the mitochondria are working at full capacity - the enzyme lactate dehydrogenase converts the pyruvate into lactic acid. In water lactic acid dissociates into lactate and hydrogen ions. It is the intramuscular build up of hydrogen ions (hydrogen ions are what makes an acid acid) that are thought to disrupt the functioning of enzymes that control muscle contraction and give the burn. The lactate is removed to the blood where it can be measured in excercise labs or converted in the liver back to glycogen. No doubt a more uptodate biochemist can confirm or correct the above.

    By training at Lactate Threshold the body adapts by increasing the number of mitochondria and their support mechanisms. This means that more pyruvate can be converted straight to energy so delaying the onset of lactic acid production. This means we can exercise more intensely before the onset of of muscle function disruption.

    As to whether it is correct to call it lactic acid build up or not is possibly pure semantics. We could always call it the intracellular build up of hydrogen ions derived from the dissociation of lactic acid in an aqueous medium. If you put a piece of calcium carbonate into hydrochloric acid carbon dioxide is given off. It is not wrong to say that hydrochloric acid and calcium carbonate react to give off carbon dioxide although it would be more correct to say that the hydrogen ions react with the calcuim carbonate etc. In the same way it is the hydrogen ions generated from the disscciation of lactic acid that give the burn.

    The good news is that LT training does work whatever the chemistry behind it.
  • Not too far away HarryD but I think you may have oversimplified a little.
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