Question for Jack Daniels

AnT is also used interchangeably with the terms "lactate threshold" and "ventilatory threshold," although the points by which these terms are defined are not identical. It can likewise be estimated by heart rate or VO2. With experience, you can tell when you've crossed the AnT or even when you are nearing it. Recognizing the onset of the AnT is a skill which is invaluable, as it allows you to optimize your day-to-day training and minimize risk of overtraining.

A proper tempo run basically is a progressive run, but these days, people let pace override relaxation. If it's done right, a progressive run should be completely spontaneous.

Rather than think of "lactate tolerance" and "lactate buffering," think of running at moderate to high intensities as "dealing with lactate." This basically means processing it as a fuel source at a fast enough rate to forestall the lowering of either muscle pH or blood pH.

The presence of lactate (the negative ion) actually may not be directly linked to lowering pH, since the associated protons (the positive ions) are apparently taken up in another reaction before they can interfere with muscle movement. But let's not throw the baby out with the bath water - blood lactate is still an excellent barometer for ensuing distress and lowered pH.

There are a number of ways your body can combat a lowering pH; the prinicipal method is via bicarbonates and phosphates present in the blood. There are also ways you can deal with lactate. Lactate can be reconverted to glucose in the liver (gluconeogenesis) or it can be used as fuel by the heart (reconverting to pyruvate via dehydrogenase enzymes). It can also be transported out of certain skeletal muscle fibers and into other skeletal muscle fibers for use as fuel. The monocarboxlylate transport (MCT) proteins are instrumental in this process, specifically the MCT-1 and MCT-4 "isoforms," whose expressions are increased via certain types of training and associated recovery stages. Expression of these isoforms during training is also dramatically increased by supplementation with testosterone and by thyroid hormone.

Two basic types of workouts which affect expression of the MCT-1 and MCT-4 isoforms are:

1) "Crest-load" running at an effort intensity slightly above (stronger than) the "ventilatory threshold" but not exceeding the "respiratory compensation point." ***Note that since lactate can be processed, the "lactate threshold" may be blurred in many runners; i.e., blood lactate may rise more suddenly at a certain effort intensity or it may continue to rise gradually without having an easily definable point of inflection. Ergo, the term "lactate threshold" seems to be falling out of favor, but "ventilatory threshold" remains very definable and measurable.*** When operating at this effort level, you basically want to hold steady at as close to the respiratory compensation point as possible without surpassing it for more than two minutes at a time and if it is exceeded, the effort should remain constant and manageable at a strong pace rather than spiraling quickly into a state of discomfort.

What's happening at this effort intensity? You're experiencing levels of lactate which barely exceed what you would normally consider to be within your "steady state" of effort, but you are operating at this intensity for a brief enough time (or are managing the pace well enough) to avoid a lowered blood pH, which would be associated with difficult, labored movements. This affords you the opportunity to generate a strong stimulus for incresing expression of MCT proteins, which assist in processing lactate. If you stop the moderately hard running before you get in trouble, take a short rest period, then resume the effort for repeated segments, you can accumulate more time at the strong pace than you would be able to do in a continuous run at the same pace without excessive laboring. This leaves you with an overall effort intensity (the session taken as a whole) which is similar to that of a continuous run of the same duration at about 8-12 seconds per mile slower. The state of effort between the ventilatory threshold and the RCP is also called the "isocapnic stage" of exercise - a stage in which blood lactate levels rise in a non-linear fashion but pH is not lowering because the effort is curtailed before the blood's buffering systems become overwhelmed by the infusion of positive ions.

Ideally, you'd accumulate 25-35 minutes of running at this kind of pace (about 8-12 seconds per mile faster than your theoretical "threshold" or "maximum steady state" pace) in a session, broken into segments of anywhere from 8 to 15 minutes and with rest periods between segments which are about 2-3 minutes long. Normally, this pace is one which you could run for 39-45 minutes in a race, but you can also run a tad slower and do 4 x 10 minutes on, 2 minutes off or 2 x 20 minutes on, 3 minutes off. Or you can go a little quicker and reduce the segment lengths to 3 minutes with a recovery of 30-60 seconds. Go by feel. Do the first 10 minutes of running (out of a total of 25-35 minutes) a little easier, then find a strong, steady groove during the middle of the session. Start each segment when you feel ready to go again, but keep the pace such that the rests can remain short relative to the run periods. Finish faster if desired, but do not race it.

2) Flooding the muscles with lactate. This involves a short but highly intense workout - something like 2 x 400 at 3-4 seconds faster than 800 race pace with a 1 minute rest period. Not many reps at all, but the warmup needs to be very thorough, so there will be a decent amount of fast strides prior to the 2 x 400, and you may wind up getting about a mile of stuff at a fast pace if you count all those strides. There isn't much explanation necessary for this one; you just go for it and tie up. This should provide a stimulus for increased expression of the MCT-4 isoform in the Type II fibers (or whatever they call those things these days), making it a good session for 800 runners or maybe milers who lean toward the speed side, but distance runners don't normally need anything quite that intense in conjunction with higher orthopedic stress loads, other workouts being sufficient to mesh with their metabolic needs and cover this base of MCT-4 expression.

To discuss where these workouts fit into a schedule could easily become a tome. The schedule is infinitely more important than the individual workouts. Properly balanced, the whole can become much greater than the combined weight of the individual parts.

Where science can help us is by finding physical indicators that correlate with those intuitive "feelings" about running. Without a guide to how you should feel and what general pace you should run on certain days, it might take you years of trial and error to find the most cost-effective zones for training. Or you might never get it. As an example, most people do "tempo" runs incorrectly, either progressing to a decent pace too quickly or just jumping right into their pace without progressing at all or running too long at too fast a pace too often for best results. How can the guys in the white lab coats help us find the right feeling?

Well, it turns out that most runners, even many experienced ones, can't discern what kind of effort level represents their true "threshold," a safe effort for regular use, one which is so cost-effective that it basically "cheats" the overtraining gods by virtue of skirting the edge so finely - even crossing it in such brief stints - that the runner gets most of the benefits of fast-paced running with few of the risks. Some runners may literally feel that all running is too easy unless they're forcing things, or they may feel like even a "slow" pace is a bit of an effort. Or they may be somewhere in between, but still without a definable feeling of what "on the brink" running is. So how can they really know what's too slow or too fast?

Along come the exercise scientists to find a few measurable physical processes which occur in conjunction with that "maximum steady state" or "on the brink" feeling reported by the runners who are in tune with that feeling, even providing points of definition for the effort level. Subsequently, some number values (imperfect as they may be) can be assigned to the true "threshold." The pertinent data, such as blood lactate and respiratory exchange ratio, can then be correlated reasonably well with other standards, such as percentage of 5k or 10k or half marathon or marathon race pace, or with heart rate, to provide a more "field-suitable" set of numbers for everyday use. Of course, these numbers still aren't infallable. Since heart rates are affected by more stressors than perceived exertion is, they are more variable in actual practice, and therefore less reliable, but they can be used in a "general neighborhood" fashion. The same is true of pace as a workout parameter. Jumping right into a predetermined pace on a "tempo" run is usually less effective than progressing to the right feeling, but a "lower limit" starting pace (just like a "neighborhood" heart rate) can often guide you to that feeling. If nothing else, regular failure to come close to the pace you should be able to sustain (or, conversely, running without difficulty at a quick "steady state" pace but racing poorly) can be a sign that something is amiss and that you might need to back off for awhile or you might need more work in a different area of fitness.

Realize that laboratory science (not counting the roads, tracks and trails as one big laboratory) can never replace the trial and error of thousands and thousands of runners when it comes to finding the best duration for "threshold" running and (more importantly) how frequently it can be repeated and how it blends in best with the other running you do. But exercise science can attach quantifiable measurements to those effective training zones runners have come to know.

To illustrate the limits of exercise science in truly understanding the big picture of running, consider this: Even if you do know the right feeling for repeatable, cost-effective training, it's often easy to go overboard, thinking that you might as well go ahead and hammer it really, really hard while it feels good, so as not to "waste the super feeling," so to speak. If you're in great shape and are at the ideal weight and are eating and sleeping right and recovering well in the short term, hammering it pretty often might work for awhile but, alas, there are no perfect bodies. Something has to give, and (like Icarus flying a little too close to the Sun) your awesome fitness can definitely override your structural (and, eventually, your metabolic) limits. You will never get it right if you can't learn from your mistakes and the mistakes of your predecessors. Exercise science can be an aid when it comes to some specifics, but it's those mistakes and successes of your predecessors that will prove vastly more valuable to you than anything exercise science can provide.

In a previous post, I mentioned MCT proteins and their association with "above threshold" running. Those concepts only reflect what people currently think is a major contributing factor to producing energy during moderately high-intensity exercise. But guess what, Chief Two Dogs Humping ... I was running in that exact zone several decades ago, long before there was a name for it. Other runners were as well, and the collective experiences of these runners has already done far more to refine the use of this zone in a broader training scheme than exercise science will ever do. And if, a hundred years from now, exercise scientists "finally understand what's really happening" (like they always seem to be doing) and propose "new, innovative" workouts to attack these "previously undiscovered energy systems," you can bet every red cent you've ever had that runners have already done those workouts enough times to figure out how to incorporate them into a schedule (if they need to be done at all).