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Antonio Cabral
RE: Mr. Renato Canova: Could You Please Answer a Question About Effective Ways to Improve the Lactate Threshold?

Racer1 wrote:

No examples, Antonio?


<<…Way back in the late 1960s a professor called John Holloszy got some rats to run on a treadmill for various lengths of time up to 2hrs per day at around 50-75% of the rats' VO2max (easy running, therefore). After 12 weeks, he found that the rats had increased the mitochondria (vital for aerobic energy production) in their running muscles (compared to control rats that did no training). This was a seminal piece of work, because it explained why runners get better with training.

The next question was logical. How long should people run for to optimally cause this effect?
Back to Holloszy and his fellow researchers who formed 4 groups of rats to train: one group running 10mins/day, a second running 30mins/day, a third running 60mins and a fourth running 2hrs/day. All at the same easy 50-60% VO2max, and for 5 days/week for 13 weeks.
Perhaps logically, the 2hr-group had the greatest increase in mitochondria at the end of the training period.
In a tough endurance test at the end of the training, the 10-min rats managed 22 mins, the 30-min group 41 mins, the 60-min rats could run hard for 50 mins and the 2hr-rats kept going for 111 mins. It was now apparent that time to exhaustion (all rats running the same pace) was directly related to mitochondria development (which itself was directly related to time spent training).

But what about intensity? Were mitochondria only created while running long and slow?
In 1982, a guy called Gary Dudley decided to explore this question. He had several groups of rats training five days/week (but only for 8 weeks). Like Holloszy, he also used a range of different training durations, from 5-90 mins per day. However UNLIKE Holloszy (whose rats all trained at the same pace) he also used a range of training intensities. Dudley's rats trained at either 100%, 85%, 70%, 50% or 40% VO2max. He also examined how different intensities and different durations affected different muscle types (fast twitch white, fast twitch red or "intermediate", and slow twitch).

The results were interesting and each fibre type responded differently:
Improvements in mitochondria in fast twitch white fibres began while running at 80% VO2max (but not slower, presumably because they were not recruited) and increased exponentially as the pace climbed to 100% VO2max.
However improvements in fast twitch red (intermediate) fibres maximised at sub-max paces (85% VO2max) and did not get better with increased speed.
And the best way to cause improvements in slow-twitch fibres was to run long and slow at 70% VO2max (adaptation began from as low as 50% VO2max pace). Faster was not better. Although Dudley found that 90 mins was not better than 60 mins, Holloszy had shown that 2hrs was definitely better than one hour (which ties in nicely with Lydiard-type training recommendations that one 2hr run was better than 2 x 60 mins — you have to admit that the guy had great intuition born of his experience trying out different training on himself).

So, (some of you may be way ahead of me already). Why was my 8.00m/m run so difficult?
Well, all my training in the 3 months leading up to it had been relatively hard. I had not trained slow enough for my slow twitch fibres to become stimulated to build huge amounts of mitochondria. My fast twitch red were becoming okay (I was reasonably good for 3-6m fast), but I could not access those fast powerful fibres at 8.00m/m. The intensity was too low. I was being forced to use my slow-twitch fibres... and they were not trained for any kind of endurance, and certainly not 2hrs.


Laboratory findings
Groundbreaking research on the effects of training at VO2max was conducted in 1982 by Gary Dudley, et al. at State University of New York at Syracuse. Dudley induced rats to run once per day, five days per week, at intensities ranging from 40% of VO2max to 100% of VO2max and for various durations (the faster-running rats completed the shortest work bouts) and examined how these durations and intensities affected mitochondrial enzyme activity across the spectrum of muscle fiber types. His findings contrasted somewhat with conclusions from prior work (Holloszy and Booth, 1976) inasmuch as 10-minute bouts at 100% of VO2max were much more influential in mitochondrial production than were longer work bouts (up to 90 minutes) at slower speeds.
Dudley's 1982 research is often cited to bolster the argument that running at VO2max eliminates the need for running longer distances at slower speeds in order to maximize aerobic development. The practical fruits of this myopic and spurious reasoning were harvested in the United States during the latter years of the 1980s and the first half of the 1990s, as high mileage training fell out of favor and hard track work - sans aerobic base - became the norm. During this time, U.S. distance running performances declined significantly. The truth is that both high-volume, low- to moderate-intensity training and skillfully integrated low-volume, high-intensity training are necessary to completely prepare for any event in which oxygen transport and oxygen consumption contribute to energy production.
Dudley, et al. did demonstrate that from a mitochondrial standpoint, higher intensity is generally preferable to duration. However, running performance is ultimately more complex - a gestalt that depends on the interaction of a myriad of factors, a few of which may not yet be identified (or may indeed not be identifiable at all).
Moreover, the use of rats as test subjects presents a number of problems when attempting to draw conclusions for the human athlete. Rats are often used for laboratory experiments due to their low cost, small space requirements, short time span of generations, large litters, and the fact that they are easy to handle - reasons which have nothing to do with any physiological similarity to humans. The training and study of laboratory rats for no more than a few months also depicts a mere snapshot of a complete running career, so any conclusions drawn only serve to shed light on a short-term piece or two of a long-term puzzle.



Physiologist Veronique Billat suggests jogging between reps for an equal duration and at exactly half the speed used for the work bouts themselves. For example, our hypothetical 14:55 runner (whose vVO2max is 70 seconds per 400) could run 12-16 x 400 at about 5% faster (66-67) with a 200 jog in 66-67 between 400s.
Longer bouts (e.g., 5 x 5-6 minutes) at a somewhat slower pace (roughly 5% slower than vVO2max) and with relatively shorter rest periods (2-3 minutes) will also train the same systems with a slightly different emphasis. Mile repeats (even if they are run faster than 5:00 each) should usually be executed at this approximate effort level for maximum profitability. You can accumulate nearly 30 minutes at this more sedate pace with relatively low risk of excessive acidosis. The runner whose vVO2max is 70 seconds per 400 might choose to perform 5 x 1,600 at 4:54 each (5% slower than vVO2max) with recovery intervals consisting of 2-3 minutes of light jogging. If this pace provides little challenge, the recovery period could be reduced or the work bouts could be extended to nearly 6:00 in duration.


Of course I am not suggesting that elite runners jog around at 7-8 mins/mile (although they might, depending on where they are in their build-up). There was a recent interview with Lydiard in which he said his guys ran their 22-milers at 5.55m/m. I pointed out that this was only M+55secs (assuming they were 2.11-type guys). For a well-aerobically-trained runner, M+55 is no big deal for a Sunday run pace. They also ran their 10-miler in 55 mins (M+30 pace). Again, if you are aerobically trained, this is no big deal (check it against your own marathon pace).
But they won't run these paces all the time. I would expect even an elite athlete to run (as easy as) M+75 secs (maybe even M+90 if the day before was 10-13 miles at M-pace). So it really all depends on what they did the day before and where they are in their build-up. But that would be easy recovery work. Some of the week they will hit M-pace, M+20 (for an hour or more)... and faster.
If you checked that lactate link I put up, you should understand that an elite runner runs a marathon at around 2-2.5mM lactate. Just very very slightly before the curve turns upwards.
Someone like Paula (5.14 pace marathon) will be able to do a lot of her training at 6.00m/m. But at that pace her blood lactate is "calm", as calm as an untrained person sitting in a chair. So of course, once you are well trained aerobically you can benefit from what appears to be very fast paced training (but is actually not so "intense" in terms of effort for the runner involved).

Actually Billat came up recently in a discussion with MN Chris. Check here for how it went, maybe answer your question.


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