No Zone Training: Part 3

In my first post on this subject, I first tried to measure the "No Zone" for myself using lab and race heart rate data. This resulted in too wide a swath of intensity to avoid; in effect the information was useless. In the second post, I addressed some of the support of the Polarized Training Model. In this post, I'm going to resume with a summary of the argument in favor of this model and contrast that with some arguments in favor of threshold training.

A Brief Summary of the Case For The Polarized Training Model
Stephen Seiler et al make the following points in a variety of different articles:

1. Elite endurance athletes in a variety of sports independently converge on a polarized training intensity distribution, with ~80% at relatively low intensity with remaining ~20% at either threshold or between 90-100% of VO2max
2. Research shows the benefits of high intensity training (~90-100% of VO2max )
   But the benefits of high intensity training are limited in frequency; increasing number has no extra benefit.
3. Research shows the benefits of low intensity training (below 2mmoles of lactate)
4. Research shows benefits from training at or near lactate threshold, however that research used untrained and/or elderly subjects
5. Some research shows the benefits of polarized training over threshold type training
6. And finally, time-constrained athletes tend to converge on threshold intensity too much of the time.

All in all, it seems like a well-researched, cogent and logical series of arguments (and I'm not doing them justice with this summary).


What's Good for the Goose is Good for the Gander? 
If you're paying attention, you'll notice the seeming contradiction in points 1 and 6. To paraphrase Seiler et al:

1. elite endurance athletes through experiment and innovation naturally converge on a polarized training mix.
2. Time-constrained athletes naturally converge on a "training error" of too much--lactate threshold. He writes: "We can call it falling into a training intensity “black hole. It is hard to keep recreational people training 45-60 min a day 3-5 days a week from accumulating a lot of training time at their lactate threshold."

It seems odd that one group would naturally converge on productive polarized training to optimize their training effect, while the other group would naturally converge on an unproductive single mode of too much threshold training. Seiler writes that, for elite athletes:

any consistent pattern of training intensity distribution emerging across sport disciplines is likely to be a result of a successful self-organization (evolution) towards a “population optimum.” 

If true, why wouldn't the same be hold for time-constrained athletes: couldn't they too be demonstrating self-organization toward some optimum strategy?

This really begs the question: assuming all of Seiler's (and his fellow authors') points to be true, does it necessarily follow that training at threshold is a bad thing? Moreover, if  you have plenty of time for recovery, e.g., several days each week like many recreational (and even competitive) masters athletes, then maybe, in fact, threshold training is the optimum training strategy for time-constrained people. Given a finite amount of time, would you want to go for the most bang for the buck. Unfortunately, as Seiler points out, it's hard to find threshold training research that isn't about the untrained.


The Evidence Against Training at Threshold for Time-Constrained Athletes
In Intervals, Thresholds, and Long Slow Distance:  the Role of Intensity and Duration in Endurance Training cites a personal communication from researcher Esteve-Lanao about a study of recreational athletes showing that the polarized model worked better than more training at threshold intensity. I've searched for this study and have not found it published anywhere (Pubmed's list of Esteve-Lanao's research).

The Evidence Against Training at Threshold for Sub-Elite Athletes
Removing the training time consideration and moving along the recreation-elite spectrum,  Seiler and Lanao, et al, compared two training programs in sub-elite runners. In Impact of training intensity distribution on performance in endurance athletes, they had one group train using a polarized program and one with more threshold intensity. The polarized group performed significantly better than the threshold training group, "supporting the value of a relatively large percentage of low-intensity training over a long period ( approximately 5 months), provided that the contribution of high-intensity training remains sufficient."

More Evidence Against Threshold (or for Polarized Training)
Seiler continues to seek empirical data that the polarized model works while too much threshold seems to hinder. In Lactate profile changes in relation to training characteristics in junior elite cyclists published in Sept 2010, he and A. Guelich studied the training of 51 German junior cyclists and found that "training at <2 mM blood lactate appears to play an important role in improving the power output to blood lactate relationship. Excessive training near threshold intensity (3-6 mM blood lactate) may negatively impact lactate threshold development."

The Case for Threshold Training
1. Researchers
On the other sides of the aisle, one researcher and athlete who seems unabashedly in favor of threshold training is Andrew Coggan. He depicts a variety of benefits accruing from training at or near threshold (level 4 in his schema) in this pdf (see Table 2). Not surprisingly, one of the benefits cited is increased lactate threshold. In other words, train at threshold, benefit your threshold. While this seems intuitive, this publication and the subsequent "Training and Racing with a Power Meter" don't cite specific research in favor of this concept.  Coggan and fellow author, Hunter Allen, do cite a study of fiber recruitment: around threshold is when fast-twitch muscle fibers start being recruited. While that is interesting and may be important, it doesn't really constitute the research we would like to have in support of threshold training.

Another researcher (and author with Seiler) who has been a proponent of threshold training is Jack Daniels. In Threshold Training: Finding your T-pace, he writes: "Threshold or Tpace running is one of the most productive types of training that distance runners can do." Daniels describes this intensity as "equal to a pace they could race at for 50 to 60 minutes."

2. Research Findings
According to one training website "There is a substantial body of research that shows training at or close to the lactate threshold increases the intensity at which it occurs." This statement is accompanied by a list of published research (see below). However, if you read these studies (check out the abstracts) you will see the participants consist mostly of untrained, elderly. This presumably makes them less relevant to trained athletes, masters or otherwise. The studies that use trained athletes seem to support high intensity training, not training at the lactate threshold.

3. Anecdotal
Many athletes including cyclists, runners, rowers and cross-country skiers have been doing considerable threshold training and reporting excellent results. Many cyclists are performing 2 x 20-minute intervals at threshold pace; this has been one of the more popular workouts of many of those who have adopted cycling power meter training.

In fact, Stephen Seiler, himself used to row 3 x 20 minute intervals at friendly club race pace as part of his training. One can only assume this was harder than low intensity, but too easy to be high intensity training. Maybe he wouldn't do that any longer, however.

Definitions or What is Threshold Intensity?
In the first post, I began with the calculation of threshold intensity based on the definitions, as offered in the Outside Magazine article "Beware the Black Hole". Below is the a re-formatted table with those calculations.

Method and associated heart rate	Calculated "No Zone"
75-80% of maximum heart rate. Max = 200	150-160
Talking becomes difficult guesstimate = 165	165-175
HR at Measured Lactate Threshold = 178	178-189
HR during last 20-minutes of all-out 30-minute effort = 185	185-196

If my experience is representative, then identifying, let alone avoiding, threshold will be challenging.

Seiler, in many of his articles, uses a definition of 2millimoles of lactate for low intensity exercise and 4 millimoles as roughly threshold intensity exercise. So, to employ the polarized model, an athlete would aim to stay below 2mmol for 80% of training. For the remainder, the training would be at 4 mmol or considerably higher.  Avoiding training in the 2 to 4mmol area is the implication. Can you figure this out?

I can say for myself that that zone is easily avoided. As I mentioned in the previous post, in lab testing my blood lactate only reached 2mmol at a heart rate of 176, an intensity which I would consider a challenging effort, not low intensity, and definitely not something I would naturally settle into. I have to actively make myself exert up to this level. The exercise physiologist there described that as my lactate threshold.

Seiler, Coggan, Daniels and others seem to agree that threshold is roughly the intensity you could sustain for about an hour in a race. This is certainly hard. However, if you perform that intensity for 20-minutes or less at a time, it may be considerably more manageable, thus the idea of 2 x 20 minute intervals at threshold pace.

Conclusions

1. Seiler makes a strong case for the polarized model of training
2. The evidence against threshold training is not particularly strong, however
3. The case against threshold training for time-constrained athletes, based on private communication, seems weak
4. Ascertaining threshold efforts based on suggestions in Outside Magazine article seem flawed, at least based on my lab data
5. The evidence for threshold training is not particularly strong either.

This is most unsatisfying. The argument in favor of avoiding threshold doesn't seem strong. Based on nothing other than the principle of specificity, one would think that to improve lactate threshold, one could  train at or near that intensity. However, the evidence in favor seems minimal.

-------------------------------------------------------------
Research cited by the "Sport-Fitness" website in favor of training at lactate threshold to improve lactate threshold (their footnote numbers) and accompanied by my bold notes in parenthesis.


7) Yoshida T, Suda Y, Takeuchi N. Endurance training regimen based upon arterial blood lactate: effects on anaerobic threshold. Eur J Appl Physiol Occup Physiol. 1982;49(2):223-30 (college students, not specifically athletes)
8) Davis JA, Frank MH, Whipp BJ, Wasserman K. Anaerobic threshold alterations caused by endurance training in middle-aged men. J Appl Physiol. 1979 Jun;46(6):1039-46 (sedentary middle-aged males)
9) Belman, MJ, Gaesser, GA Exercise training below and above the lactate threshold in the elderly. Med Sci Sports Exerc. 1991;23,562-568 (elderly, not likely athletes)
10) Evertsen F, Medbo JI, Bonen A. Effect of training intensity on muscle lactate transporters and lactate threshold of cross-country skiers. Acta Physiol Scand. 2001 Oct;173(2):195-205 (athletes, but not clearly in favor of training at lactate threshold, may be case for higher intensity)
11) Weltman A, Seip RL, Snead D, Weltman JY, Haskvitz EM, Evans WS, Veldhuis JD, Rogol AD. Exercise training at and above the lactate threshold in previously untrained women. Int J Sports Med. 1992 Apr;13(3):257-63 (untrained women)
12) Acevedo EO, Goldfarb AH. Increased training intensity effects on plasma lactate, ventilatory threshold, and endurance. Med Sci Sports Exerc. 1989 Oct;21(5):563-8 (athletes, but a case for higher intensity, not training at or near lactate threshold)
13) Henritze J, Weltman A, Schurrer RL, Barlow K. Effects of training at and above the lactate threshold on the lactate threshold and maximal oxygen uptake. Eur J Appl Physiol Occup Physiol. 1985;54(1):84-8 (college students, not specifically athletes)

No Zone Training: Part 1

The relative importance of training volume, frequency and intensity are in seemingly constant flux. The popular training pendulum swings wildly in different directions depending on various factors, including specific athletes' performances (think Lance Armstrong, Michael Phelps, Dara Torres), a compelling coach's articulation of a training theory (think Arthur Lydiard, Chris Carmichael, Joe Friel, Tim Noakes) and finally widely circulated articles such as those that appear in the popular press (think NY Times, sports magazines, etc).

A recent article in Outside Magazine, called Beware the Black Hole, addresses a training intensity that, it is suggested, is way overused and under-productive. Reading this article prompted several rowers in my club to ask: am I mis-training?

Synopsis of the Black Hole
The article starts out describing world champion rower, Olaf Tufte. After acquiring a new boat, the Norwegian apparently found himself eager to experience some speed and ended up going a bit hard on his rest days, thereby undermining his recovery efforts. He was apparently training hard and then training medium hard, with fewer really true easy days. After mending his ways ("After being told to cool it with his new boat"), Tufte went on to win the 2003 World Championships and the Athens and Beijing Olympics in the single. Stephen Seiler, an exercise physiologist and rower, argues that "To get better, you have to go really hard and really easy—but not in between." It is the medium intensity workouts, according to the article that are the bane of competitive athletes.

The so-called No Zone
This medium intensity black hole is described in an accompanying article as "a narrow no-go range, a span of about seven to ten heartbeats per minute" that can be calculated in a couple of different ways:

1. use 75-80% of maximum heart rate. E.g, if your max is 180 then 135-144 is your "no-zone"
2. increase exercise intensity from talking to the point to where talking becomes difficult. At that point your heart rate is the lower bound or your threshold. Add 6% to that number for the upper bound. Example: lower bound/threshold is 140, then add .06 x 140=8.4, so upper bound is 148.
3. Do an all-out 30-minute effort and use the heart rate of the last 20-minutes as your lactate threshold heart rate. Add 6% of that to calculate your upper bound.

Personally, I find these 3 methods result in dramatically different ranges to the point of being useless. I've had my lactate threshold and a bunch of other measurements tested in a lab. Done on 3 different occasions, the lab tests offered fairly consistent data. My heart rate at lactate threshold was calculated to be around ~178 and my max heart rate was ~200.  I also have some recorded race heart rate data from that time as well. Plugging those numbers into the above methods results in the following:

Method (all data in beats per minute)	Calculated "No Zone"
Measured Lactate Threshold= 178	178-189
75-80% of maximum heart rate. Max = 200	150-160
Talking becomes difficult guesstimate: 165	165-175
HR during last 20-minutes of all-out 30-minute effort: 185	185-196

Which "no zone" is the right one? 
Clearly, my "no zone" calculations result in vastly different results ranging from a low of 150 to a high of 196 beats per minute. Which methodology is the right one? I have no idea. Your results may be more consistent than mine, but personally I'm not sure I would know where to begin with this information. I certainly wouldn't want to base my training on this.

Still, let's not throw the baby out with the bath water. In the next post in this series, I'll take a look at some of the science behind the "black hole."

Training Level Calculator: Coggan

This post accompanies a post on the Coggan training levels. Below is a training calculator based on these levels, applied to rowing on the Concept II ergometer. Some caveats are in order. First, Coggan calculated his levels paced on empirical cycling data, not from Concept II ergometer rowing data. The Concept II ergometer may not measure all power (watts) applied during an effort (i.e., the ergometer may miss the power employed on the recovery). Finally, the basis for Coggan's levels is threshold power, which is optimally derived from an hour-long effort (see his discussion here). We use a derivation based on a 20-minute effort; it is assumed that threshold power is 94% of 20-minute power. Read the above article for more discussion of this.


The calculator below is actually my first attempt and it displays the watts associated with pace. I thought some folks might find this second calculator more confusing because as watts increase, the splits decrease (and vice versa). Also, we rowers are more accustomed to using 500m splits instead of watts.

Watts are the basis of both calculators. Both calculators take the 20-min pace and convert it to power (watts). Then the training levels are calculated using percentages of power which are subsequently converted to pace. The calculator below more clearly shows the relationship between pace and power.

The relationship between rowing ergometer pace and power is discussed in many places, e.g., the Physics of Rowing; it is a non-linear relationship such that you must apply 8 times as much power to go twice as fast. So, for example, rowing at 4:00 pace uses about 25 watts on a Concept II machine, while rowing at 2:00 pace uses about 200 watts.

Training Levels: Coggan

Training levels (aka categories or zones) are guidelines of intensity, heart rate, percent of power at lactate threshold, or percent of VO2max intensity, etc that help us figure out what kinds of training we should be doing to elicit certain physiological benefits. There are many training schemas, but one that is particularly interesting to me is that of Andrew Coggan, a competitive cyclist and a published exercise physiologist. This schema uses power (watts).

The most accessible version of his training levels conception appears in this power training levels article. You can read about it in more detail in the book, Training and Racing With a Power Meter as well as frequently in the Wattage training forum.

Can his training levels, which are based on power (watts) on a bicycle, be adapted to the Concept II rowing machines, which also can display power? I believe this may be possible and I have created a training level calculator to help.

Some key points in the Coggan approach

1. the power that you use in an all-out hour effort is a logical choice for deriving other training levels because it "integrates VO2max, the percentage of VO2max that can be sustained for a given duration, and ... efficiency"
2. Physiological responses to training "fall on a continuum", so that the adaptations that occur from one intensity blur with those of another intensity. This shows up particularly in the chart of physiological benefits accrued from different intensity exercise.

Below is a quick review of some of the pluses and minuses of Coggan's approach as applied to the rowing community. That is followed by a longer discussion.

The upside

• Physiological benefits elicited at different training intensities are displayed in easy-to-read chart. Coggan is quick to point out that these are descriptive levels not prescriptive.
• Sample workouts give you an idea of intensity, duration, and frequency.
• Supported by research. This is evidence-based training advice and while research isn't cited on the web page, it is abundant in the power training forum and in the book.

The downside

• Designed for cyclists. Descriptions like "easy spinning" or "just above TT effort" may not easily translate into rowing intensity. However, Coggan provides a perceived exertion rating (Borg Scale), as well as a heart rate reference (see below), so you can transmogrify from that. 
• Figuring out your training zones is optimally based on an hour effort. Imagine doing an all-out hour-long piece on the rowing ergometer! We have a hard enough time doing a 20-minute test! Cyclists must be more patient, tolerant (or stupid) than rowers.
• Heart rate zones are provided as a percentage of HR at threshold power (your heart rate at a pace you could maintain for an hour). Coggan is not a big fan of heart rate as a training tool, because it is susceptible to many other variables (heat, emotional state, caffeine and other drugs, etc).
• Training level power numbers are provided as a percentage of hour power. In other words, you need to know your "hour power" to optimally calculate your training levels. It turns out that many people have figured out how to derive their levels with 20-minute all out efforts. More on this later.
• Power (as in watts) is the main focus. For rowers used to 500m splits, this may require some adaptation, but power is available at the click of a button on the ergometer.

Are watts on the rowing ergometer the same as watts on a bike?
Power on the bicycle is typically calculated by measuring torque with strain gauges in one of several places and combining that with angular velocity. If your eyes are about to glaze over with this terminology, don't despair: the bottom line is that if you are doing something to the pedals, a watt-meter on a bike will likely measure it.

By comparison, the rowing ergometer measures power by what happens at the flywheel (source), which is to say, it measures what happens on and as a result of the drive. You pull the handle, which pulls the chain, which pulls the flywheel and that is the power that is measured. It does not measure the amount of work done - however small - on the recovery. Thus, watts on the rowing machine may understate power. Just how many watts are missed depends on various factors, including rower's mass, distance moved by the rower's center of gravity, and most importantly, stroke rate. Carl Douglas, boat designer and inveterate tinkerer of things physical, spent some time calculating how many watts might be missed and you can read that discussion here. If you accept his assumptions and calculations, a rower might lose anywhere from 5 to 27 watts with stroke rates between 20 and 30. However, at a stroke rate of 40, you might lose up to 100 watts.

Is "hour power" a reasonable basis for deriving training zones?
The power you can maintain in all-out effort (time-trial or "test") for 60-minutes is deemed to be a good measurement by many exercise physiologists of lactate threshold (LT) power. In Threshold power: what is it, why is it important, and how do I measure it? Coggan suggests that an all-out 1 hour effort is the best way to ascertain "threshold power." According to Coggan. "Power at lactate threshold (LT) is the most important physiological determinant of endurance cycling performance..." He adds more decisively:

LT - especially when expressed as a power output...is the single most important physiological determinant of performance in events ranging from as short as a 3 km pursuit to as long as a 3 week stage race. Just as importantly...this parameter provides a physiologically sound basis around which to design any power meter-based training program.

In a bit of rowing corroboration, Stephen Seiler,  rower and exercise physiologist, emailed me to say that a 60-minute effort on the rowing machine is the best way to ascertain lactate threshold intensity for rowers.

Of course, you can also have your lactate threshold and power at lactate threshold measured at labs such as this one at UCDavis, but they may involve a bit of blood letting. The hour-power test may seem more appealing.

Can you derive "hour power" from some shorter test?
An amazing amount of time and energy has gone into figuring out a shorter alternative to the 60-minute all-out test, particularly on the wattage cycling forum. Authors like Joe Friel and Eddie Monier favor a critical power duration curve, such that you test some representative times and derive others. So, for example, if you know your "critical" power at 6 minutes and 12 minutes, you can likely figure out a reasonable approximation of your 60-minute power. Below is an example of such a curve.

Source: Eddie Monnier Critical Power 

Following this approach, many cyclists (as expressed in the wattage forum) have found that 60-minute power is somewhere between 93% and 97% of 20-minute average power. Many just settle for 95%, acknowledging that an exact number may not be that important (and many are using software that will help them hone in on better numbers).

Here is an example of how you might figure out your threshold power using a 20-minute piece. If your average power in watts for 20-minutes is 200, then your average power for 60 minutes might be 5% less or 190 watts.

Does this system work for rowers?
The answer is not so clear. I created an Excel spreadsheet a few years ago to try this out. More recently, I created a javascript level calculator. You can enter your 20-minute average 500m split and the calculator derives your training levels based on 94% of the power associated with this split. My own experience is that the lower intensity levels seem to represent something fairly reasonable, but when you get to level 5 and 6, the prescribed pace range actually lags what I would expect. In other words, I would expect to have to go harder. And, given Carl Douglas' point about the ergometer understating watts, particularly at higher rates, one would expect the intensities to be too hard relative to the cycling-derived power levels. However, that does not seem to be the case.

How does the Coggan arrangement stack up against, say, Royle's?
Coggan's descriptive levels and Royle's prescriptive categories are different in a few regards, but similar as well. The most obvious difference is that Royle's categories go in the opposite direction (intensity increases as the category number decreases) from Coggan's levels (intensity increases as the number level increases).

A fundamental difference between the Coggan and Royle approaches is the expected physiological adaptations. For instance, in Royle's schema, "Cat III rowing increases VOmax." (from November 2002 Technical Tip). You get the sense that if you want to develop VO2Max, Cat III is the only category to do this. In fact, the categories seem to be non-overlapping and highly specific. Coggan, on the other hand, shows in his Expected physiological/performance adaptations (Table 2), that you get VO2max benefits from levels 2, 3, 4, 5, and 6, with the most coming from level 5.

Royle suggests you develop increased capillarization and greater numbers of mitochondria at the lower intensities (Cat V and VI). This is accompanied with admonition that "Going too fast at the lower rates denies your body the opportunity to develop optimum capillary and mitochondria density" (source), while Coggan suggests level 4 (threshold) and level 5 (VO2Max intensity) as the training intensities most associated with these adaptations (source). In other words they seem to be at opposite ends of the intensity spectrum on this apparently important issue. This basic disagreement deserves further examination in another post.

My adaptation of Coggan's levels as shown in the levels calculator and the training category calculator ala Marlene Royle are both based on a 20-minute piece, so it is easy to compare Royle's prescribed training category pace with the levels as derived from Coggan. CAVEAT: I think it's important to note that the levels calculator is experimental and based on a somewhat arbitrary calculation (94% of watts of a 20-minute piece to signify threshold power). I do not claim this represents Coggan's thinking or his approach. In fact, he might well tell you that you should row for an hour. Since I know few rowers who will do this, we'll just go with the experiment and try to disassociate this effort with Coggan himself, while giving him credit for many of the underlying ideas. Finally, he would label these levels as descriptive rather than prescriptive. So, when  I say "ala Coggan" this is what I mean.

Phew! With that caveat aside, I looked first at the respective level or category targeting VO2max improvement: Royle's Cat III and Coggan's level five. I compared a 20-minute 500m split of 1:51.0 in both schemas. Royle's system suggests a Cat III split of 1:49, while Coggan's level five--as represented in the levels calculator--suggests a range from 1:46.6 - 1:51.1. In effect, the results are very similar. The example workouts aren't particularly different either. Both seem to like 5 x 5-minutes and related.

For lactate threshold development, Royle calls for Cat IV and Coggan calls for level four. Royle's system suggests a workout pace of 1:53, while the level calculator suggests a range between 1:51.5 - 1:56.9. Again, that seems remarkably similar - Royle's number is smack dab in the middle of the level calculator's range. However, when you compare workouts, it is a different matter. Royle's suggested workout of 3 x 20 minute intervals is way, way too hard - essentially impossible - for myself and others I know. Several people who have been employing Royle as a coach have corroborated this. She also lists 4 x 10 and 1 x 30-minute workouts (see "Workouts: Category IV Anaerobic Threshold Training") . Coggan's recommended threshold workouts include intervals or repeats in the 10-30-minute duration, with a common workout being 2 x 20-minutes. These workouts, with a 5.5 second 500m split range, seem considerably more plausible.

In conclusion, the Coggan training levels deserve further consideration, particularly for those training on a rowing ergometer. This training schema affords a rational, science-based arrangement that, while designed for cycling, may have applications in rowing.

Detraining: Fitness is Fleeting

“De-Train, boss, de-train.” 
Remember the Herve Villechaize character, Tattoo, in “Fantasy Island” alerting Ricardo “Corinthian Leather” Montalbán to the arriving plane. Ok, maybe you don’t and kudos to you. Still, I like the notion of Tatoo announcing to all rowers in November: "De-Train, De-Train", and then all the rowers would sit back, sip umbrella drinks and enjoy the detraining vacation of their choice, maybe on Fantasy Island.

Detraining is the word exercise physiologists use to describe what happens when you stop training for some period of time; it’s the reversal of adaptations to exercise. It likely happens to many of us after the end of our competitive seasons, when we think we should take some time off.

How much fitness is lost and over what period of time? 
One of the major tenets of exercise physiology-- the reversibility principal--says that even for athletes with years of training, adaptations can be lost. My exercise physiology text book states that "only 1 or 2 weeks of detraining significantly reduces both metabolic and exercise capacity." And, after 3 weeks of detraining (less than the time between Thanksgiving and Christmas) things get markedly worse. The authors (McArdle, Katch and Katch) provide a dismal laundry list of fitness losses:

• VO2Max declines by 8%
• Lactate threshold drops by 7%
• Heart stroke volume decreases by 10%
• Plasma volume diminishes by 12%
• Capillary density drops by 7%
• Oxidative enzyme capacity is down by 29%
• Muscle glycogen synthesis drops by 29%
• Time to fatigue is 10% sooner. 

I'll focus a bit on the first: VO2max. One of the key physiological adaptations for athletes is the increased ability to transport and use oxygen. Also known as aerobic capacity or maximal oxygen consumption, VO2max is the commonly used term for the most oxygen an athlete uses (as opposed to breathes in). It is often considered the benchmark of aerobic fitness. Not surprisingly, VO2max is highly correlated with rowing performance, particularly for 2000m. For example, a study on the Concept II ergometer (it's easier to conduct this type of study on the ergometers than on the water) concluded that:

"VO2max was the best single predictor of the velocity for the 2000 m time-trial".

A study of "highly trained runners and cyclists" showed a 7% decline in VO2max in just 12 days and 14% decline in 56 days (see graphic below). I had to include this because I spent time making the chart. It is sort of redundant, but reinforces the point about a loss in VO2max.

Adapted from Coyle et al. J Appl Physiol.1984; 57: 1857-1864

You can imagine that it is difficult for scientists to find competitive athletes who take much time off, but occasionally researchers apparently find someone who is either injured and wants to get back or someone who is contemplating retirement and then reconsiders after some time off. The researchers poke, prod and measure these poor people and get some interesting data. These "case studies" are not the large subject studies that scientists prefer, but they can be illuminating.

One such study involves a single Olympic caliber rower. The detraining and retraining of an elite rower: a case study shows an example of a loss of VO2max (8% drop), this after 8 weeks of inactivity following the Sydney Olympic games.

Possibly more tangible for readers here might be the 25% drop in power this rower experienced on the Concept II ergometer at "reference blood lactate concentrations". The reference points are typically at 2 and 4 millimoles of lactate, the latter of which is considered by many to be the lactate threshold (a subject for another post). Without knowing the meaning of this last phrase, you can still figure out that this rower experienced a huge loss of power. In his case, the 25% drop happens to be 100 watts. This means that at full fitness, he was pulling 400 watts or roughly a 1:35/500meter split. A 25% decrease in power would translate to 300 watts (400-100) and a more pedestrian (!) 1:45/500meter split. That's a significant difference.

OK, but how long does it take to regain lost fitness?
The last study is interesting for the amount of VO2max lost and for the loss in power on the rowing ergometer, but it is particularly interesting because the rower in question decided to return to training and continued with physiology testing. While he recovered much of his fitness quite quickly, it took approximately 20 weeks to regain what he had lost in just 8 weeks. The researchers summarized:

"These results show that detraining in the elite athlete can be pronounced, with rapid improvements upon retraining which slow, so that retraining takes considerably longer to achieve than detraining did."

This result--that retraining takes longer than the detraining--has been repeated elsewhere to some extent, but with variation.

Most of us are not elite athletes, though, so we wonder what would happen to us. Here is an example of detraining and retraining that may be closer to our own experience. In this case study, the subject is a 49-year old, competitive masters level cyclist who breaks her clavicle. Conveniently for us and the researchers, she has some physiology testing 2 days before getting into that accident. She is off the bike for 32-days and then resumes training. It takes her approximately 6 weeks to return to pre-accident fitness, although her peak power output takes 72 days to re-establish.

The time course of retraining appears, in general, to take longer than the detraining. Take a month off and it might take you two to get fully back in shape.

What is the least amount of training one can do to maintain fitness?
So, you want to train a bit less, but you're not willing to lose all that hard-earned fitness.

A study of runners demonstrated that gains in VO2max over a 10-week period could be maintained by training as little as 2 days a week, for 40-minutes each time, as long as the intensity was high enough.

"it is possible to maintain the increased VO2max for at least 15 wk by training at high intensity for 2 d/wk or 4 d/wk"

Another study, with the same initial training protocol (10 weeks of 40-minutes a day) tested a reduction in training duration (as oppposed to frequency). After the first 10-weeks of training, participants were put in two training groups, one that trained for only 26-minutes a day, and one that trained for only 13-minutes a day. Remarkably, the authors found that:

"it is possible to maintain almost all of the performance increases with up to a two-thirds reduction of training duration"

A study of swimmers showed that training just 3-days a week was sufficient to maintain aerobic capacity (VO2max).

A study titled "Reduced training maintains performance in distance runners" reduced training volume of elite runners by 70% for 3 weeks, but included workouts at an intensity of close to 95% of VO2max to maintain fitness.

However, a later study by some of the same researchers diminished not only the volume of training but also the intensity, such that no training was executed above 70% of VO2max. In this case, endurance performance dropped even though some metrics such as VO2max remained unchanged. The authors write:

"It is concluded that aerobic capacity was maintained in these runners, despite the combined reduction in training volume and intensity. However, it appears that training intensity during RT (reduced training) is important for the maintenance of 5 km running performance."

So, what do we make of all of this?

• If you take time off--more than a couple of weeks(?)--you risk losing some fitness. This shows up particularly in a decreased VO2max, which is clearly important to rowing performance.
• You can maintain VO2max and still substantially reduce training frequency and volume, but you will need to include some higher intensity workouts.
• 70% of VO2max intensity was the lowest intensity to maintain VO2max. Other studies used 80-95% of VO2max intensity to maintain VO2max. Workout durations varied.
• VO2max is only one fitness metric. Clearly if you reduce training duration and frequency, you will lose endurance if not other aspects of fitness. 

There are many references here to percentages of VO2max, so I have created a VO2max % calculator.

What about on the water rowing intensity for maintaining aerobic capacity (VO2max)?
I can think of a way to calculate on the water intensities (e.g., heart rate) but I think it is too fraught with potential inaccuracies to be worthwhile. More on that in another post.

Other questions:

1. If you get sick and miss training, what is the best way to resume?
2. Does cross-training (running, xc skiing, or cycling) help maintain rowing VO2max or is it activity-specific?
3. Assuming one just wants to maintain VO2max, how long and how frequent should one perform an 80% VO2max intensity workout? 20 minutes once a week?

Bye-bye for now. Happy detraining. Or not.