Mark's Blog

Two questions:

Are the HR montiors wireless and therefore interfering or just additioning with each other (of the same brand)?

Your blog records and this LT measurement are based on heart-rate, which must be indirect. Yet I can see cases where effort is not related to body function, at least instantaneously. For example in the case of intervals, I could imagine that some graph of the lactate cycle in your body would not coincide at all with a graph of HR?

I've always been suspicious of those calorie counters and even the scientific measurement of Wattage. The energetic output is of course accurately measured, but how can this average reflect the varying efficiencies of individuals? It seems like mass, muscle mass, femur length (in most sports), blood sugar, and the thousands of variables in metabolism would all be needed inputs to calculate how you should optimize. I guess it's like fluid dynamics: assume it's linear because we have no way of calculating the non-linear flows of liquids and gases.

Yes, HR monitors are wireless. You put a strap around your chest underneath the heart and the watch device picks up the pulse from that.

LT is, technically, the inflection point where your muscles produce lactic acid faster than your buffer system, mainly the liver, can process it leading to a sudden surge in the amount of lactic acid remaining in the blood. Tim Noakes writes he thinks LT is not the primary factor preventing you from going faster. Instead his model says your central nervous system has a governor that protects your brain and heart, and won't let you endanger these by overexercising.

LT is related to heart rate, though as you get more fit, it happens potentially at a higher heart rate.

As far as watts are concerned, the power you need to produce depends hugely on your mass, and for cycling, your wind resistance. Isn't your efficiency more a question of how fast you can move your particular mass for a particular amount of power applied?

I think it would be more accurate to say that both _reaching_ LT and HR are related to physical effort. I was doubting that it is a constant and linear correlation, but I guess you're saying it's close enough. From what you say, the LT itself depends on your muscles, circulation and liver. You suggest that a person's LT can change significantly, so I also wonder which of the 3 adapts the most. For example, in the process that produces LA, is it possible to be more efficient, can you train your muscles to give more power while producing less?

While I'm not a big fan of supplements in the sports world (aka messing with your body's chemistry) you'd think there would be some sort of buffering solution one could drink at the LT to prevent it.

According to Noakes's theory then, many people are putting themselves in grave danger trying to measure their LT in the test you describe. I've read about those tests: they put you on a treadmill with EKG electrodes and increase the speed gradually until you can't take it anymore. The EKG is to make sure your heart doesn't go irregular, which must be what happens when you override your body's warning mechanism in Noakes's model. So having a lab tech or companion nearby might not be enough, they might be dialing 911 for you.

Sorry to go on about this, but I think physiology is fascinating, and at the same time filled with charlatans and gullible athletes. It seems like you hear "tout et son contraire" (everything and its opposite) when it comes to, essentially, customizing your body. Da Vinci may have said all there is to say about the static/dead body (anatomy), but so little progress has been made on the moving/live body since. It is interesting that athletes, mainly amateurs are drivinging the research in this field. Like the early dragsters that pushed automotive technology to the limit, amateur athletes are pushing their bodies to the limit and are a reservoir of untapped data for science. There definitely needs to be more real research in this field, not just authors handing out their theories of what works for them.

More on Wattage: Yes, as a body (closed system) it is easy to measure your power _output_ based on how you move you whole mass against gravity and other things that drag you down (rolling friction, mechanical friction, wind, etc.). But the definition of efficiency is the relation of _input_ to output.

We don't need to count calories (though for science we should) because we just assume that everyone has the same input (because it would be easy enough to do). What I'm interested in here is what makes some athletes more efficient. For example, looking at a marathon winner should tell you the ideal height to weight to muscle mass ratio for endurance running (and scientifically, you can't say it is the same for half-marathoners or ultra-marathoners).

You suggest the same thing, that body build is most indicative of efficiency, but what if that were not all. You suggest that training can change the LT, so changing body chemistry also has something to do with it. I suggest there are a million other factors that allow you to get more (distance, height, endurance, etc.) out of your energy. Perhaps that marathon winner has a gait that keeps him from lifting his body up that extra hundredth of an inch with each stride, thereby saving energy. Everybody knows about EPO and getting more O2 into your blood, but what about more efficient waste transport, as suggested by the LT discussion.

That's why I believe that someone putting you on a treadmill/stationary bike and measuring your output is deceptive. It's a good baseline, I imagine, but the result doesn't capture the complexity of the equation.

I'm virtually certain not only that you can get more efficient, but that it's actually happened to me. I can run faster now with less effort than 3 years ago. But I don't know what's happened to my lactate threshold.

Speaking of the stress test with EKG, Matt's wife Colette was scheduled to get one before an important race. The trainer said that was a very bad idea, because for a very fit athlete to push to the limits on that sort of test is almost as stressful on the body as a heart attack. (Very fit athletes are more able to push themselves right to the limit than untrained people.)

According to Noakes's model, few people can muster enough drive to override what he calls the central governor. Exceptions include Alberto Salazar, who in one marathon lost 12 lbs. sweating and collapsed at the end. In another shorter race Salazar won but ran himself into heatstroke, passed out, and needed medical attention. Noakes thinks one of the reasons Salazar had a short marathon career is because he had drive to go past the normal limits of his body.

In his book Friel cited a survey of olympic hopefuls asked if they'd choose to take a pill sure to win them gold medals but just as sure to kill them in 5 years. Without exception those athletes were ready to die to win. Apparently one of the buffers for lactate is baking soda. But you have to take so much the side effects are problems like uncontrollable diarrhea.

More and more research is underway if I understand correctly. Amateur athletes these days have more money ($70 off for a pair of bicycle tires). I'd bet there's more money in research, too. I think you hit the nail on the head, however, concerning the complexity of the problem. Even something as straightforward as running can occupy researchers and trainers endlessly. It's no doubt much worse than finding a formula for tuning Directory Server (another unsolved problem).