AEROBIC ... ANAEROBIC
: the nitty-gritty of training.
Article by Steve Baker
This article is presented that it will add purpose and understanding
to our workouts. To wit, you will train at the prescribed pace, knowing that
faster is not always better. Hence forth, the sight of a mass of athletes
(with identical AT), breathing heavily, five abreast and six deep fighting
for the lead, storming around Beacon Hill Park will be a thing of the
past.
Aerobic is defined as ‘in the presence
of oxygen’, meaning that sufficient oxygen is delivered by the cardiovascular
system to maintain a steady state of energy production through the breakdown
of glycogen and fats. Aerobic activity is generally associated with slow speeds,
jogging or running long distances.
The biomechanical mechanisms that produce glycogen, which fuels
the muscles, are complex and require various fuel sources. When exercise is
moderate, ( comparative: depends to a great extent on level of
fitness/health of the athlete) aerobic metabolism predominates. Glycogen is
broken down completely. Oxygen combines with free hydrogen ions to
produce water and carbon dioxide, which are easily dispersed.
A new system kicks in after exercise increases in intensity, so the demands
of energy exceed the rate at which oxygen can be delivered. Glycogen is broken
down anaerobically, but the process is not complete. Lactic acid, as well
as free hydrogen ions, accumulate.
Anaerobic is defined as ‘without oxygen’, meaning
that exercise is so intense, comparatively speaking, that the cardiovascular
system cannot provide sufficient oxygen for efficient energy production. The
waste products can not be flushed out quickly enough. Consequently, lactic
acid accumulates in the muscles and the blood stream and eventually makes
it impossible to run farther.
The big question is when does aerobic activity become anaerobic
activity? Is there a distinct dividing line? What is the ‘anaerobic threshold’?
To answer these questions we have to take a more indepth look at the processes
involved.
The most common use of the term ‘anaerobic threshold’ is to describe
a phenomenon that takes place in all athletes: namely the maximal speed
that an athlete can maintain for a long period of time. At this speed or effort,
lactate levels in the blood remain constant. Any increase in effort
above this level will cause lactate and its associated high acid levels to
increase steadily. This will eventually force the athlete to slow down or
stop.
Lactate threshold puts the emphasis on ‘lactate’ and not ‘anaerobic’. Both
describing the same point of exertion.
Below the lactate threshold all the lactate produced is being
used as fuel for aerobic energy or other purposes. The rise in lactate levels
as exercise intensity increases is an indication that some muscle fibers are
not able to handle all the exercise load aerobically. The excess lactate produced
from these muscle fibers moves to areas of lower concentration such as the
blood stream, neighboring muscle fibers and the space between the muscles.
Other muscle fibers have plenty of excess capacity for aerobic energy and
these fibers can use the lactate produced by the fibers with limited aerobic
capacity. Lactate is shipped in the blood stream from muscle fibers
that produce the lactate to those parts of the body that can utilize it.
Eventually the body reaches a point where it cannot utilize all the lactate
produced. At this point, called the maximum lactate steady state (MLSS) or
lactate threshold (LT), lactate starts to accumulate rapidly as exercise intensity
increases. It should be noted that the rate at which lactate accumulates above
the threshold varies between athletes. Generally, the slower the rate lactate
accumulates above the threshold the better the conditioning/fitness level
of the athlete.
With aerobic training or detraining the lactate threshold will change as
the muscle fibers or other parts of the body gains or loses the capability
to clear lactate. Also anaerobic training, or the lack of it, will affect
how fast the lactate is produced. Training that affects the rate of anaerobic
energy production is often overlooked when trying to evaluate aerobic endurance.
The lactate threshold is the result of both these processes.
Lactate is a naturally occurring organic compound produced in
everyone's body and is both a by-product of and a fuel for exercise. The primary
source of lactate is the breakdown of a carbohydrate called glycogen. Glycogen
breaks down into a substance called pyruvate and in the process produces
energy. It is found in the muscles, the blood and various organs. Our bodies
needs it to function properly. During the first portion of the long
run, the body gradually depletes its supply of glycogen in the slow-twitch
muscles. Once that supply is used up the body must turn to the fast-twitch
muscles to continue to run efficiently. Towards the end of the
long steady runs, those muscles essential for speed are also exercised.
“At first it was thought that long continuous
running helped perfect only the aerobic processes, but specialists have since
come to the conclusion that it also helps develop the anaerobic potentials
of the runner.” A. Yakimov, Soviet Coach. Track Technique.
“The problem is that the athlete must be able to distribute his
effort in order to run the whole way at an even pace. If the pace drops
off at the end, the problem has not been solved.” In other words, a
workout that starts fast and finishes slow may fail to train the fast-twitch
muscles properly. But a danger also exists if runners train only with long
runs, they eventually may develop a slow gait and rhythm that fails to develop
the neurological patterns of muscle fiber recruitment that will be needed
when the pace gets faster. Since the selective use of muscle fibers
differs according to running speed, runners who train only at a slow
‘turn-over’ and speeds slower than race pace will not train all the muscle
fibers needed for competition.”
To run fast, you must have a cardiovascular system
capable of efficient oxygen delivery. Within certain limits, the more oxygen
your muscles receive, the faster you can run. Scientists do not entirely understand
the reasons, but an efficient oxygen delivery system - aerobic base - is
best developed by training within 65 - 80% of your maximum heart rate.
Beyond 80 - 85% MHR crosses anaerobic threshold, or lactate threshold.
Training anaerobically, you can develop
your muscular system’s ability to readily release energy from your muscles,
but you must possess a solid aerobic base first. Trained only anaerobically,
without a sound aerobic base, it is not possible to maintain peak conditioning
long into the season.
Efforts above the lactate threshold generate excess
lactate and will shut down the muscles in a short time. So the total volume
of exercise will be less. Also, frequent efforts at levels above threshold
may damage the muscle cells structure. If training in the ‘here and now’ encourages
you to ‘boogy’ , race every session, we must discourage this practice
if our long term goals are going to be attained..
To develop speed we must begin with,
and establish, a ‘slow’ aerobic base (endurance), then move gradually to the
faster anaerobic training (‘speed’). Endurance is the ability to continue
an activity, running in this case, of a designated intensity for a prolong
period. You go far. But speed endurance couples the ability to go far
with the ability to go fast. You attain the ability to go “FARTHER
AND FASTER”.
Now, we are talking about the ability to maintain intensities
ranging from 85 - 90% MHR for a period of 30 mins. plus.
Three major physiological factors contribute to speed endurance,
says Dr. Pate, Human Performance Lab. University of South Carolina.
Oxygen Uptake: The maximum
volume of oxygen your body can transport and absorb. VO2 max.
Lactate Threshold: The point
at which individuals start to accumulate lactic acid in the system. A trained
person can perform longer and harder at sub-max levels than an untrained person
Efficiency: This relates to
biomechanics and economy of motion. The smoother you run, the less oxygen
you consume at a particular running speed. “The lower
the rate of oxygen consumption, the lower the amount of metabolic and cardiorespiratory
stress, and the farther you can run.” Jerky running form requires more
mechanical energy at a greater physiological cost.
The optimum would be to have a high VO2 max, have
a high lactate threshold, and be very economical.
Some of your endurance capacity is natural: a higher percentage of slow-twitch
to fast-twitch muscles. However, anyone regardless of their muscle composition
can improve endurance with training.
Improving endurance requires muscle adaptations: the key says
Fink/Costill, Human Perf. Lab. at Ball State, is producing more mitochondria,
a specialized membrane structure within a cell that provides energy, adenosine
triphosphate, ATP, the energy that fuels the muscles. Exercising aerobically
increases the activity in a number of specific enzymes involved in the
utilization of ATP. The muscles also develops more capillaries, which
enhance the delivery of blood and oxygen to the muscle. There is a
certain amount of endurance associated with increased strength,
which comes with endurance training, as well as weight training. The
muscle develops more connective tissue and a larger cross section. All of
this improves endurance.
The key to endurance training is to gradually
increase your exercise stress level. In order to induce an adaptation, you
have to force the system to do something it is not currently
adapted to. The trick is to apply a stress sufficient to adapt the
system without the undesirable side effects and injuries that come with doing
too much.
Depending on training level, types of recent workouts, muscle composition,
diets, tolerance for discomfort, the environment and other factors, a
pace just above baseline can be sustained for hours. The athlete is burning
a high percentage of fat at this pace and there is enough fat in us for hours
of exercise (even those athletes with low body fat).
A lot of training for long distance endurance athletes is aimed at training
the muscles to burn more fat.
An athlete can usually train at the lactate threshold (LT or MLSS: the fastest
pace that an athlete can hold for an extended period of time without accumulating
additional lactate) for about 40 - 70 minutes. The limiting factor is fuel
for energy (glycogen) and this will depend mainly on recent workouts and diet.
When the athlete runs very low on glycogen the muscles cannot sustain the
LT pace or effort and will slow down. I believe that training regularly at
the lactate threshold for a prolonged time can be very counter productive.
An athlete that does an extended workout at LT or higher will be unable to
complete a similar workout until the body's glycogen is replaced. This can
often take 36 - 72 hours.
For most athletes the "lactate threshold" is the most important
pace or effort level to know, and to be able to judge progress by how
much this point is changing with training. ( The lactate threshold,
maximum lactate steady state, is the fastest pace that an athlete can hold
for an extended period of time without accumulating additional lactate. )
A large percentage of athletic training has the objective of
producing adaptations in the body's energy systems both, anaerobic and aerobic.
We train so that we can perform for a longer period of time and at higher
intensities. The production and control of lactate is essential for both
of these objectives. Let us train at a pace/s that
best give these systems the optimum opportunity to develop.
Don’t push yourself past the proper training intensity. Human nature being
what it is, you will often want to see progress in your workouts and will
be tempted to perform a particular workout at faster and faster speeds over
the course of a very short span of time. One of the best way to monitor your
progress is to see how much easier you can perform a particular workout as
time progresses. If what use to be a tough workout becomes not so tough after
several weeks, then that is a sign that training is working. At this time
we can gradually up the ante: pace, time, or frequency. When the time comes
you can then prove that you are getting better ... not in a workout, but
in a ... time trial, or race.
For pace details check and make mental notes of your
‘Magic Training Paces’ from 'The Chart / Formula'.
Have faith, guys.