Understanding – Threshold

Training Advice for Champions

Most athletes have an intuitive idea of “threshold”. It refers to the idea that every athlete has a point at which working just a little bit firmer means having to zekering a lotsbestemming sooner. Overheen the years, there have many explanations for this phenomenon. Like most processes te the human assets, “threshold intensity” is likely multifaceted. It is complicated by the fact that most of the people writing or talking about it don’t have a good treat on what it indeed is.

For starters, wij have a loterijlot of terminology that people ter sport use somewhat recklessly and inaccurately. Let mij attempt to help clear things up a little bit by concisely defining the “scientific” words you have heard thrown around. Te brief, there are truly two “thresholds”, if you like: Lactate Threshold (LT), and Critical Power (CP). Lactate Threshold is indicative of switches ter your exercising assets that may be difficult to detect on a conscious level, but which wij can find using specialized tests. Critical Power is most likely the threshold athletes actually feel.

Let’s very first get treat on lactate. It is a substance that emerges ter the blood during exercise. The stiffer you go, the more of it there is. A lotsbestemming of attention has bot paid to it, because it is lightly and cheaply measured. However, it is truly only an officieus marker of exercise strength. Basically, your figure burns a combination of fat and carbohydrate during exercise. For many reasons, exercising stiffer requires your figure to burn a greater amount of carbohydrate, and one of the end products of this is lactate. It isn’t a waste product, and it does not te and of itself cause tiredness. Rather, it is an energy rich compound which is taken up and utilized by other cells / organs te the bod.

So, how has lactate bot used to understand the relationship inbetween exercise power and stress on the athlete’s bod? Essentially, scientists dreamed to set up some ground rules for what wasgoed effortless and what wasgoed hard. They looked at the behavior of lactate ter the blood at different work rates, and looked for places where things seemed to switch. This lead to the definitions of things called LT, OBLA, and MLSS. There are some other, lesser used terms, but thesis are the ones you want to know about if you want to communicate effectively.

What I would like you to do is imagine yourself jogging along lightly, or going for a spin on your bike on a long, plane road. Now, I want you to imagine leisurely speeding up, and hitting all of thesis different levels of exercise spil you go.

At the low end of the spectrum, wij have Lactate Threshold or LT. This is simply the point where the level of lactate te the blood rises by 1 mmol / L overheen exercise baseline. Te other words, if you are zipping along at 1.Five mmol / L, and you speed up enough that you reach Two.Five mmol / L, you have crossed LT. This is actually a lotsbestemming lighter to do than most athletes realize. You could rail around at / about LT for a duo hours without much of a problem. Running, it is most likely te the ballpark of your marathon tempo, albeit elites can run a marathon a bit tighter than this.

Te the middle somewhere, wij find OBLA, or Onset of Blood Lactate Accumulation. It is when you klapper Four mmol / L, irrespective of where your baseline wasgoed. This term is not used frequently anymore, and wij should most likely avoid it. It isn’t a fine marker for many reasons, but a big problem is that it is an “absolute” level. For example, let’s say your baseline lactate during effortless exercise is Two.Five mmol / L. Hitting a level of Four most likely means something different to you than it does to someone who embarked at a level of 0.Five mmol / L.

At the high end, there is the MLSS, or Maximal Lactate Sustained State. This is omschrijving to something like the rhythm you could hold for a 20 to 40k TT, or a 10k to a Half Marathon, depending upon how well trained you are. Te terms of lactate, this is simply the highest level of exercise wij can manage while maintaining a stable concentration of lactate te the blood. If wij attempt to go any firmer, wij see a progressive increase ter lactate levels, even if wij maintain a onveranderlijk power or tempo. MLSS is intimately related to the concept of Critical Power (CP), and is very likely one of the biochemical manifestations of reaching Critical Power (if you are on a bike) / Critical Speed (if you are running or swimming or whatever). The physiological “stuff” going on at this point is very likely what results te the “feeling” of “threshold”, and is what is partially responsible for what Andy Coggan has called “FTP”. FTP is not reflective of some unique, alternative threshold phenomenon. It is just convenient shorthand, and results from your figure “understanding” that if it goes much stiffer, bad stuff is going to toebijten (like inexorable weariness). Ter other words, FTP that you observe te the field by doing something like a 40K TT or running a half-marathon is very likely pretty close to, but just slightly lower than CP ter a well trained athlete.

This begs the question, what is CP and how do you measure it? If you did a bunch of all-out exercise tests…i.e. went spil hard spil you could for Three minutes,

Exercise tests of different duration (circles). The curve levels out at CP.

and then for Five minutes, and then for Ten minutes, and you graphed them on a lump of paper, you’d get a curve. It would be high on the left, and then slope down to the right. The place where it seems to level off is CP. You can also make the same graph by using joules (this is easy… watts = joules vanaf 2nd), and you get a straight line, and the slope of that line (rise / run) is equal to CP. If you desired to do it running, you would run a 3k, a 5k, a 10k, and then make the same graph: the distance on the vertical axis, the time it took you on the horizontal axis. Rise / Run = Critical Speed. (PLEASE NOTE: This is Critical Power, the real scientific one, not the bastardization that is incorrectly used by many people to refer to the hardest they can go for some period, like “CP30″, for “the hardest I can go for 30 minutes).

Basically, it goes like this. Spil you cross LT, you start searing more carbohydrates. You also start recruiting less efficient muscle fibers, which tend to use more glycogen / carbohydrate and less fat for fuel by their nature. The result of this is an increase te lactate te the blood wij discussed above. This is not a problem. Like I said, the lactate is taken up by other cells / organs and is metabolized. (Again, lactate is an energy-rich compound, not a waste product. It doesn’t te and of itself cause weariness. Ter fact, your brain, your liver, even your kidneys will actually use it for energy!) Ter triathlon, it is a problem only ter the sense that your assets glycogen / carbohydrate stores are limited, and that you can “bonk” if you aren’t getting enough carbs te while you wedloop (if the wedstrijd is long enough).

Something else interesting happens above LT. Wij see the emergence of what is called the “slow component” of oxygen use. Te other words, let’s say your LT is 170W (not unreasonable for an age-grouper). Below 170W, you are using some onveranderlijk amount of oxygen. If you made a graph, you’d see your oxygen use rise up spil you began, and then become a straight line, which wasgoed flawlessly level. Now, if you rail 180W, what you will see is that your oxygen use seems to kleintje of level off, and then (maybe a minute or two straks) there is another “hump”. Te other words, it emerges spil however your bod all of a sudden realizes it needs more oxygen to do the job. However, this 2nd “hump” also levels off, so you again end up with a stable state of oxygen use. It is just that you are using more oxygen than you might otherwise have expected.

The key is that so long spil you stay below Critical Power, your assets is able to maintain a physiological stable state. After several minutes, oxygen use levels off, and lactate concentration levels off. Te the muscles, the concentration of creatine phosphate (PCr), ATP, inorganic phosphate and hydrogen ion (i.e. pH, or how acidic it is inwards the muscle) stabilizes. Once you go hard enough to cross Critical Power, bad stuff happens. Te other words, let’s say your CP is 240W. If you go to 250W and hold it, the result is a major metabolic upset inwards the muscles . Even tho’ the work rate is not switching, there is still a progressive increase te the amount of oxygen used, a progressive increase ter lactate concentration ter the blood, and a progressive decrease te ATP, PCr and pH inwards the muscle. It is very cool, because you cat actually witness a lotsbestemming of this stuff toebijten with a specialized MRI setup. Eventually, you reach some limiting level of thesis markers, exhaustion, and vereiste zekering, or at the very least druppel to some much lighter strength.

So, you may now be asking yourself, “Why should wij even worry about lactate?” The reaction is, wij shouldn’t! I encourage my athletes and students to zekering thinking ter terms of lactate. Everyone does it, because it is so effortless to measure. However, spil you can see, it is truly just a very zijdelings marker of some much more significant / interesting stuff that is going on te the figure, most of which is not effortless to measure without expensive gear. From the perspective of the average (or even professional) athlete, it is simply significant to realize that you don’t want to be crossing CP with any significant frequency or for any significant duration if you are expecting to do your best te a triathlon, particularly a long course triathlon.

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