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Metabolic Conditioning - page 1

Interval Generator - page 5

Pukie’s Glossary of Metabolic Conditioning - page 6

Introduction

In the second issue of CrossFit Journal, “What is Fitness?” we explored the nature of metabolic conditioning, or

“cardio”, and highlighted some of the qualities of and distinctions between aerobic and anaerobic exercise, and

touched on interval training.

In this issue we’ll reexamine metabolic and interval training in a little more detail.

Review

Let’s begin with a review of metabolic training. Metabolic training refers to conditioning exercises intended to increase

the storage and delivery of energy for any activity.

There are three distinct biochemical means by which energy is provided for all human action. These “metabolic

engines” are known as the phosphagen pathway, the glycolytic pathway, and the oxidative pathway.

The first, the phosphagen pathway, provides the bulk of energy used in highest-powered activities, those that last less

than ten seconds.

The second, the glycolytic pathway, dominates moderate-powered activities, those that last up to several minutes.

The third, the oxidative pathway provides energy for low-powered activities, those that last in excess of several

minutes.

You may recall that the first two pathways, the

phosphagen and glycolytic, delivering energy for

high and moderate powered activities, are known

collectively as “anaerobic” whereas the third

pathway, the oxidative is known as “aerobic.” The

significance of the term “anaerobic” lies in the fact

that the phosphagen and glycolytic systems generate

energy without benefit of oxygen where the oxidative

or “aerobic” pathway requires oxygen for energy

production.

The subject of metabolic pathways and energy

production for human activity is known as

“bioenergetics” and is loaded with details from

biochemistry and discussions of ATP, ADP, substrates,

reaction mechanisms, Krebs cycle and a lot of other

stuff that you tried, and probably succeeded, to avoid

learning in high school or college biology.

100

130

Phosphagen

Glycolytic

Oxidative

Time (seconds)

June 2003

THE

CrossFit Journal

IN THIS ISSUE:

If you feel the compulsion to learn more on the biochemistry of bioenergetics here are two convenient starting points:

The

N.S.C.A.’s Essentials of Strength and Conditioning

, an authoritative reference, has a chapter on bioenergetics by

Mike Conley with many of the gory details.

And, from the University of Connecticut here is a brief summary of

bioenergetics

Anaerobics and Aerobics Made Simple

Our purpose in this issue of CrossFit Journal is to avoid the complexities and nuances of molecular biochemistry and

render a useable foundation for understanding “cardio” and specifically the CrossFit approach to conditioning.

To that end we will forgo considerations other that the sustainability of maximum efforts and, so, concern ourselves with

all out efforts of varying durations and ignore issues of power, pathways, and energy production.

We only need to remember that anaerobic exercise is metabolically unsustainable exercise whereas aerobic exercise is

sustainable. Sustainability is the key.

Generally, all out efforts of two minutes or less are anaerobic while efforts lasting more than several minutes are

aerobic.

Reducing the whole of bioenergetics to this level isn’t just convenient it allows for examination at a level of granularity

that allows for maximum useful understanding of metabolic conditioning. Biochemists, while able to recite intricacies

of energy substrates and ATP production are all too often blind to the interplay of varying exercise protocols and their

resulting fitness.

A metaphor may aid in understanding our position on the science of bioenergetics. We are striving to give you a racecar

driver’s sense of auto racing not a mechanical engineer’s. Both have their place but only one drives the car on race

day.

Anaerobic efforts are relatively high powered, and aerobic efforts are relatively low powered. This should be self

evident from our understanding that anaerobic work is unsustainable past several minutes. It would be hard to escape

the observation that power, or intensity, and duration of effort are inversely related. One hundred meter dash pace is a

considerably faster pace than a mile pace.

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June 2003

Aerobic exercise is nearly universally regarded as being heart protective, but there is compelling evidence that shows

that anaerobic exercise is at least as

heart protective

as aerobic exercise.

Though aerobic exercise is widely recognized as being the ideal vehicle for fat loss, recent studies have shown that

anaerobic exercise is a vastly superior protocol for

fat burning

Anaerobic exercise builds muscle; aerobic exercise burns muscle - period. On this point there is no intelligent debate.

Compare the look of

sprinters

long distance runners

– here a picture is indeed worth a thousand words.

The muscle wasting nature of aerobic exercise is both cause and symptom of the deleterious effect that endurance

work can have on anaerobic performance. Sadly, this lesson has been slow to spread to many anaerobic sports. It is still

common to find boxers and other martial artists who think that long slow endurance work –

roadwork

– is essential to

their fight endurance. Nothing could be further from the truth.

On the other hand anaerobic training is of enormous benefit to endurance athletes. Not only does it support and build

muscle, but it gives the “kick” needed to win close races. Importantly, not only does anaerobic work benefit aerobic

performance, but anaerobic training can be used to develop high levels of aerobic fitness without the usual muscle

wasting. This is accomplished through interval training and is an integral part of sports training for most sports.

Interval Training

Interval training alternates bouts of high intensity work with rest in repeated timed intervals. The general idea is to

perform a high volume of high intensity work in a limited time. Ultimately, it is nothing more than anaerobic training

with controlled rest periods.

The benefits of interval training are to both anaerobic and aerobic systems. The obvious question is how much benefit

and to which system?

We can orchestrate intervals so that they predominantly stress either aerobic or anaerobic systems. The table below

gives interval strategies to target desired metabolic systems.

Sprint

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June 2003

But, even more interesting is the prospect of a

hybrid interval that would greatly stress and thereby

substantially condition both anaerobic and aerobic

systems simultaneously. Finding such an interval and

demonstrating its dual potency would be a great find.

It may have been done.

Tabata Interval

Dr. Izumi Tabata experimented with intervals and

published in the journal Medicine in Sports and Exercise

the results of an experiment in which he produced

excellent improvements in anaerobic and aerobic

conditioning in a group of accomplished athletes with

a four minute (3:50) protocol of 20 seconds of all out

work followed by 10 seconds of rest repeated 8 times.

Significantly, Dr. Tabata’s 4 minute high intensity

group got better V02 max improvement than the control

group, which followed a 60 minute moderate intensity

regimen.

Clarence Bass

, and

Peak Performance

both give great

accounts of Dr. Tabata’s research and understand the

important implications.

Tabata Applications

Dr. Tabata’s research subjects exercised on stationery

bikes; we decided to test other applications.

Our favorite and most effective application has been

the “Tabata” squat – a 20 seconds on, 10 seconds off

repeated 8 times squatting effort scored by the lowest

number of reps performed in any of the eight intervals.

This single drill tests for and develops elite athletic

capacities. Rankings for this drill accurately predict

ranking performance on a wide variety of fundamental

athletic skills and performance.

Another of our crew’s favored applications is to use the

Tabata interval in a workout where an athlete moves

from the Concept II Rower to squats then pull-ups, sit-

ups, and push-ups. Each exercise is performed like the

Tabata squat – 20 on/10 off X 8. Adding the weakest

link from each exercise tabulates a final score. The

Rowing is scored in “calories” and the other events by

reps. We allow a minute’s break between exercises.

Both of these simple workouts are very demanding and

surprisingly potent. Trying either will convince you of

their potency. Our experience is that improvements in

Exerpt from NSCA’s Essentials of

Strength Training and Conditioning

Thomas R. Baechle - Editor

Chapter 5 Bioenergetics - pages 78, 79

Some authors have suggested that aerobic training

should be added to the training of “anaerobic athletes”

(a process that can be termed combination training)

to enhance recovery (101) because recovery primarily

relies on aerobic mechanisms. However, aerobic train-

ing may reduce anaerobic performance capabilities,

particularly high-strength, high-power performance

(52). Aerobic training has been shown to reduce an-

aerobic energy production capabilities in rats (128).

Additionally, combined anaerobic and aerobic training

can reduce the gain in muscle girth (24), maximum

strength (24, 46, 52), and especially speed-and power-

related performance (28), although the exact mecha-

nism is not known (114). It does not appear that the

opposite holds true; some studies and reviews suggest

that anaerobic training (strength training) can improve

low intensity exercise endurance (53, 54, 114). Al-

though oxidative metabolism is important in recovery

from heavy anaerobic exercise (e.g., weight training,

sprint training) (12, 109) care must be used in prescrib-

ing aerobic training for anaerobic sports. In this con-

text it should be noted that specific anaerobic training

can stimulate increases in aerobic power and enhance

markers of recovery (114, 116, 129). Thus, extensive

aerobic training to enhance recovery from anaerobic

events is not necessary and may be counterproductive

in most strength and power sports.

Don’t

hold

your

breath

during

anaerobic

efforts!

June 2003

scores for both Tabata workouts suggest strongly that

an athlete is likely to show substantial improvements

wherever we test them.

Try the Tabata workouts, experiment with varying

interval design, and repeat noticeably difficult protocols

from time to time. Trust that particularly challenging

efforts speak directly to your opportunities for physical

gains, and that improved performance in those efforts

is the best measure of those gains. Chase the toughest

intervals.

The most important point to remember is that high

intensity efforts can produce dramatic aerobic benefit

without the muscle wasting seen with endurance

training.

Dr. Stephen Seiler on Intervals and

Endurace Work

Dr. Seiler is a renowned exercise physiologist and

rowing coach. In a piece entitled “Understanding

Intervals” Dr. Seiler explains that there are winning

rowing programs that train all intervals as well as

those that do some, and programs that do none. Each

approach has been shown to produce winners.

Dr. Seiler has concerns about the wisdom of programs

that do too much interval work only because intervals

may produce what he calls first and second wave

adaptation to endurance training but not third wave

adaptations. Third wave adaptations are largely

specific to the training modality, and have nothing to do

with aerobic conditioning but endurance performance.

The difference is critical. But do we want third wave

adaptations?

Third wave gains in endurance performance are

entirely specific to that sport and have training effects

disadvantageous to much of other sport performance.

Dr. Seiler’s admission that elite aerobic performance

can be trained by high intensity intervals and his

concerns that intervals don’t produce third wave

adaptations form a terrific rationale for avoiding steady

state aerobic work.

The idea that later adaptations to endurance work are

highly specific to the training modality and portend

little impetus to further cardiovascular development

hints at the possibilities for generating additional

cardiovascular benefit by means of shifting training

Interval Generator

There are no bad intervals, only weak efforts. Variety and

intensity will ultimately determine preparedness. Here is a

scheme to give variance to your anaerobic work.

Intervals generated by this experiment will certainly be

anaerobic yet are certain to pack a substantial aerobic

punch.

Play with these intervals before or after your regular

workouts or on “rest” days.

Roll single die (or three dice) and for first roll multiply

number by 10 for work interval.

Then roll second die and multiply by 5 for the rest

interval.

Roll again and multiply by 2 total for number of

intervals.

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June 2003

modalities sufficiently to avoid “third wave” adaptations

and focus instead on 1st and 2nd wave adaptations

from a multitude of protocols and modalities. Our hope

and suspicion is that this broadens the cardiovascular

stimulus.

CrossFit Position

As ridiculous as the idea that extended endurance efforts

optimally confer cardiovascular and fitness benefits is

the notion that a stressor like a bike is good “cardio”

whereas a Kettlebell, obstacle course, or CrossFit-like

workout performed at similar exertion levels carries a

lesser cardiovascular benefit!

Ultimately the CrossFit position on metabolic

conditioning, or “cardio”, is summed in two points:

• Anaerobic training can match endurance training

for aerobic benefit.

• Metabolic training with varying and mixed

exercise modalities avoids specificity of

adaptation allowing for additional first wave

– cardiovascular/respiratory adaptations, and

increased functional strength.

The clincher is that CrossFit athletes have demonstrated

improved endurance performance without endurance

training, and even more amazingly, in clinical trials

CrossFit’s high intensity regimen has produced

improvements in endurance measures that rivaled

those achieved through programs comprised largely of

endurance efforts.

Police training programs in Florida have found that

CrossFit produced better distance run times than prior

programs comprised largely of distance runs.

CrossFit athletes live in a steady state of physical

preparedness that leaves them primed for specialized

training and unknown physical challenges regardless of

whether the demands are aerobic, anaerobic, or both.

There are cars that get 100 miles to the gallon. They are

low powered, slow, and fuel-efficient. Others cars are

high powered and fast while being less fuel-efficient.

CrossFit is building powerful fast athletes not slow, low

powered, fuel-efficient athletes.

Athletes that train predominantly anaerobic pathways in

a wide range of intervals and modalities have at least the

cardiovascular or aerobic fitness of endurance athletes.

Pukie’s Glossary of Metabolic Conditioning:

I want to help with some of the basic terminology of

metabolic conditioning, so here’s Pukie’s guide to easy

bioenergetics complete with commentary

- Pukie

V02 max:

Maximum amount of oxygen that can be used continuously

divided by body mass. Long the gold standard of aerobic

fitness, the slight advantage that endurance athletes have

over anaerobic athletes in V02 max can be attributable to

the low body mass of endurance athletes. I can use a similar

definition of strength – by dividing lifts by weight - to show that

little guys are stronger than big guys.

Aerobic:

Low powered, low intensity, long duration – more than several

minutes. This is the easy stuff. Introduced to real efforts these

guys crumble!

Anaerobic:

Higher-powered, higher intensity, shorter duration efforts–

those less than several minutes. Anaerobic is Greek for “worth

while.” Pukie wants to know why there are 1 million recreational

traiathletes but only 7 recreational 800 meter athletes.

Lactate Threshold:

The point as work intensity increases where lactic acid levels

in the blood rise faster than can be controlled. Lactic acid is a

waste product of anaerobic work. Also known as “anaerobic

threshold”, the lactate threshold marks the point in intensity

where work has become largely anaerobic. This is also the

“pussy rest-stop”.

Interval training:

Exercise protocol of set periods of high intensity rest and

work. This is how anaerobic athletes develop tremendous

levels of aerobic fitness – through intervals. I want to meet

the scientist who invented this. How else could you do high

intensity work?

Heart rate monitor:

It’s all about the performance. Forget heart rate. The heart

rate monitor is a fun toy, though. Mix dehydration, beer, steep

hill, bicycle, hot humid day and see who can get the highest

number. I’ve seen seven people over 200 at once on the same

hill. What can you and your friends do?

June 2003

Editor-In-Chief Editorial Director

Greg Glassman Lauren Glassman

Design

Art Director Lauren Glassman

Photography

Chief Photographer Greg Glassman

Picture Editor Lauren Glassman

Technical Advisors

Derek Wray

Danny John

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References

- NSCA’s Essentials of Strength Training and Conditioning

12. Brooks, G.A., and T.D. Fahey, Exercise Physiology; Human Bioenergetics and Its Applications. New York: Wiley. 1984.

24. Craig, B.W., J. Lucas, R. Pohlman, and H. Stelling. The effects of running, weightlifting and a combination of both on growth hormone release.

J. Appl. Sport Sci. Res. 5(4):198-203. 1991.

28. Dudley, G.A., and R. Djamil. Incompatability of endurance- and strength-training modes of exercise. J.Appl. Physiol. 59(5):1446-1451. 1985.

46. Hadmann, R. The available glycogen in man and the connection between rate of oxygen intake and carbohydrate usage. Acta Physiol. Scand.

40:305-330. 1957.

52. Hickson, R.C. Interference of strength development by simultaneously training for strength and endurance. Eur. J. Appl. Physiol. 215:255-263.

1980.

53. Hickson, R.C., B.A. Dvorak, E.M. Gorostiaga, T.T. Kurowski, and C. Foster. Potential for strength and endurance training to amplify

endurance

performance. J. Appl. Physiol. 65(5):2285-2290. 1988.

54. Hickson, R.C., M.A. Rosenkoetter, and M.M. Brown. Strength training effects on aerobic power and short-term endurance. Med. Sci. Sports

Exerc. 12:336-339. 1980.

101. Plisk, S.S. Anaerobic metabolic conditioning: A brief review of theory, strategy and practical application. J. Appl. Sport Sci. Res. 5(1):22-34

. 1991.

109. Scala, D., J. McMillan, D. Blessing, R. Rozenek, and M.H. Stone. Metabolic cost of a preparatory phase of training in weightlifting: A

preactical observation. J. Appl. Sport Sci. Res. 1(3):48-52.1987.

114. Stone, M.H., S.J. Fleck, W.J. Kraemer, and N.T. Triplet. Health and performance related adaptations to resistive training. Sports Med.

11(4):210-231. 1991.

116. Stone, M.H., K. Peirce, R. Godsen, D. Wilson, D.Blessing, R. Rozenek, and J. Chromiak. Heart rate and lactate levels during weight training

in trained and untrained men. Phys. Sportsmed. 15(5):97-105. 1987.

128. Vihko, V., A. Salmons, and J. Rontumaki. Oxidative and lysomal capacity in skeletal muscle. Acta Physiol. Scand. 104:74-81. 1978.

129. Warren, B.J., M.H. Stone, J.T. Kearney, S.J. Fleck, G.D. Wilson, and W.J. Kraemer. The effects of short-term overwork on performance

measures and blood metabolites in elite junior weightlifters. Int,J.SportsMed. 13(5):372-376. 1992.

June 2003