@Lindsay, here's what an exercise physiologist has to go through in creating a model. We like to think that well, they overlook things etc, but I do not think it is the case.
Just about anything you and I can think of in term of caveat etc, they can find out too. This post can be found somewhere on cyclingforums. It is not an attempt at demonstrating his skills etc, or to do any bling-bling. And of course, it is far from being exhaustive. Exercise physiology is a very complex matter that would require a full book.
Not only that, but the algorithm isn't really based on production and clearance rates of lactate at all (or at least not directly). It's like I told Kirk Willett the other day: the algorithm is intended to "track" numerous physiological responses, but none of them in particular. Changes in steady-state (or quasi-steady-state) blood lactate concentrations were simply used as a proxy to estimate the degree of curvature of numerous physiological and metabolic responses that respond in a non-linear fashion as a function of exercise intensity. This approach/logic (which is also the basis for TRIMP) is made possible by the fact that they all seem to follow a comparable pattern - that is, there is a high correlation between blood lactate levels and the rate of lactate release from exercising muscle, between the rate of lactate release and the rate of lactate production/accumulation, between the rate of lactate production/accumulation and the rate of glycogenolysis, between the rate of glycogenolysis and changes in muscle "energy charge" (e.g., (=)/), between muscle "energy charge" and the rate of glucose oxidation, between the rate of glucose oxidation and the rate of glucose uptake, between the rate of glucose uptake and the rate of glucose production, between changes in sympathetic nervous system activity (as indicated by changes in plasma norepinephrine and epinephrine) and changes in carbohydrate utilization, etc., etc., etc., etc., etc., etc. To focus excessively on blood lactate (e.g., on the pattern of accumulation during the "30/30" intervals that Billat has studied) is, quite simply, missing the point. (With apologies to RapDaddyo and frenchyge, because in all fairness there's really no reason to expect them to have realized this, unless perhaps they happen to be trained in exercise physiology.)
It probably took him a full decade to complete his works, lots of lab testing, and several hundreds of file analysis, married to a trackie, himself a top level time trialist etc etc etc etc. Also let us not forget that this model is kind of based on Timp somehow, which also took more than a decade to elaborate. All this work done by extremely smart people, Banister already has some entries in sports history literature, and Coggan, obviously it's just a matter of time. They both focused solely on one thing: achieving a model that respects the principles of exercise physiology as they learned it during the course of their PhD.
@sstuart
No data available about TSS. Andy told me that most data (if not all) available on the Trimp system was done using short duration event. I didn't ask him to define "short duration" though. He says that there's an exhaustive list of reference available somewhere on TrainingPeaks. I'll get the info and report back.
@Lindsay, here's what an exercise physiologist has to go through in creating a model. We like to think that well, they overlook things etc, but I do not think it is the case.
Just about anything you and I can think of in term of caveat etc, they can find out too. This post can be found somewhere on cyclingforums. It is not an attempt at demonstrating his skills etc, or to do any bling-bling. And of course, it is far from being exhaustive. Exercise physiology is a very complex matter that would require a full book.
Not only that, but the algorithm isn't really based on production and clearance rates of lactate at all (or at least not directly). It's like I told Kirk Willett the other day: the algorithm is intended to "track" numerous physiological responses, but none of them in particular. Changes in steady-state (or quasi-steady-state) blood lactate concentrations were simply used as a proxy to estimate the degree of curvature of numerous physiological and metabolic responses that respond in a non-linear fashion as a function of exercise intensity. This approach/logic (which is also the basis for TRIMP) is made possible by the fact that they all seem to follow a comparable pattern - that is, there is a high correlation between blood lactate levels and the rate of lactate release from exercising muscle, between the rate of lactate release and the rate of lactate production/accumulation, between the rate of lactate production/accumulation and the rate of glycogenolysis, between the rate of glycogenolysis and changes in muscle "energy charge" (e.g., (=)/), between muscle "energy charge" and the rate of glucose oxidation, between the rate of glucose oxidation and the rate of glucose uptake, between the rate of glucose uptake and the rate of glucose production, between changes in sympathetic nervous system activity (as indicated by changes in plasma norepinephrine and epinephrine) and changes in carbohydrate utilization, etc., etc., etc., etc., etc., etc. To focus excessively on blood lactate (e.g., on the pattern of accumulation during the "30/30" intervals that Billat has studied) is, quite simply, missing the point. (With apologies to RapDaddyo and frenchyge, because in all fairness there's really no reason to expect them to have realized this, unless perhaps they happen to be trained in exercise physiology.)
It probably took him a full decade to complete his works, lots of lab testing, and several hundreds of file analysis, married to a trackie, himself a top level time trialist etc etc etc etc. Also let us not forget that this model is kind of based on Timp somehow, which also took more than a decade to elaborate. All this work done by extremely smart people, Banister already has some entries in sports history literature, and Coggan, obviously it's just a matter of time. They both focused solely on one thing: achieving a model that respects the principles of exercise physiology as they learned it during the course of their PhD.
@sstuart
No data available about TSS. Andy told me that most data (if not all) available on the Trimp system was done using short duration event. I didn't ask him to define "short duration" though. He says that there's an exhaustive list of reference available somewhere on TrainingPeaks. I'll get the info and report back.
