Anaerobic Threshold -
The Key to Developing Elite Endurance
Understanding anaerobic threshold will make you a
better endurance athlete. If your VO2max is your
aerobic potential, your anaerobic threshold
determines how much of that potential you tap. More
importantly you can improve your lactate threshold
considerably with athletic training.
If you haven't already
reviewed the chapter on
VO2max
please do - before you read on. If you have, here's
a quick recap.
VO2max is the point at which your body cannot
increase its intake of oxygen despite an
increase in exercise intensity. Exercise
beyond this point has to be anaerobic
(without oxygen). The result?
High levels of blood lactate that puts a halt
to your progress. Does that mean then if you
exercise at an intensity below your VO2max
you'll be able to continue indefinitely? Not
really. For
most people debilitating blood lactate starts to
accumulate at an exercise intensity much lower
than at VO2max. At rest and during gentle exercise
the body still produces lactate, however it can
remove it just as quickly. Hence no lactate builds
up.
As
the exercise intensity increases and anaerobic
pathways are called upon more and more, the body
struggles to remove lactate as quickly as it's
produced. Hence blood lactate begins to accumulate.
The point at which this occurs is called your;
Anaerobic threshold.
Technically speaking there's controversy over the
term 'anaerobic threshold'. As a result a whole host
of terms have formed to describe essentially the
same phenomenon. You may have heard of some of
them...
-
Lactate threshold
-
Aerobic threshold
-
Onset of blood lactate accumulation (OBLA)
-
Onset of muscle lactate accumulation (OMLA)
-
Expiratory compensation threshold
We'll stick to anaerobic threshold for simplicity's
sake. To
improve your endurance performance doesn't require
an intricate understanding and appreciation of every
technicality!
Just like VO2max, anaerobic threshold occurs at
different exercise intensities for different people.
It is expressed as a percentage of your VO2max.
Imagine the graph below represents you running.
After testing, your VO2max is measured at
55mL.kg.min. For you, blood lactate begins to
accumulate at 65% of your VO2max or
35.75mL.kg.min. How can you apply this to your
performance?
If
you read down the graph from your anaerobic
threshold you will see it corresponds to a speed of
about 12.5kmh. You know that you can run at a
pace up to 12.5kmh for a prolonged period of time
because blood lactate won't be accumulating. In
fact, knowing your anaerobic threshold allows you to
predict with great accuracy your time in any given
distance event.
Specific endurance training (outlined below) can
increase your anaerobic threshold significantly. The
average, untrained individual has an anaerobic
threshold at 55-60% of their VO2max. For
elite athletes anaerobic threshold occurs around
85-90% of their VO2max. How will you benefit
from training?
Training won't slow down the rate at which blood
lactate accumulates but what it will do is delay
it's onset until a higher exercise intensity. In
short, you
will tap more of your 'aerobic potential'.
So
how do you improve you anaerobic threshold? The
first step is to find out where it lies for you.
Determining Your
Anaerobic Threshold
If
you have access to expensive and sophisticated
laboratory equipment and a skilled lab technician,
testing your anaerobic threshold is simple. Assuming
that you don't.
There are a couple of alternatives worth
considering. For each of them you do require a
heart rate monitor. Having said that in order to
improve your anaerobic threshold and your endurance
a heart rate monitor is essential anyway.
1. 10 Minute Run
Run or cycle for at least 20 minutes. Gradually
increase your speed and heart rate. You will
eventually reach a point where your breathing rate
suddenly increases sharply and your legs feel a bit
jelly like.
Instinctively you'll know that you can't maintain a
steady state any longer -- at this pace you will
become more and more fatigued. Glance at your
monitor and note your heart rate. Although this is
quite a subjective test it can be very accurate.
2. One Hour Time Trial
This is probably the most common anaerobic threshold
test used in the field. You need to be able to run
or cycle at the highest intensity you can sustain
for one hour. Inexperienced athletes will either
start off too fast and have to slow down, or perform
the entire test too slowly. Runners can substitute
the one hour time trial for a 10k race.
You
should record your heart rate regularly -- ideally
every 2 minutes. Average your heart rate over the
hour or 10k to give you an indication of your
anaerobic threshold heart rate.
3.
Conconi Test
The Conconi test is more complicated than the above
two methods and not necessarily any more accurate.
In fact the test has been shown to OVER-estimate the
anaerobic threshold considerably in many athletes.
Accuracy is also highly dependant on your ability to
gradually increase speed smoothly and consistently.
All things considered you are best using one of the
other tests.
4. Portable Lactate Analyzer
Using a portable analyzer will give you the same
accuracy as a lab test providing you know what you
are doing. This is only worth considering if you are
a serious athlete. The cost starts at around $400.
Once you have determined a heart rate that you feel
corresponds to your anaerobic threshold you can
start to design athletic training sessions to
improve it.
Anaerobic Threshold
Training
Anaerobic threshold training is relatively straight
forward once you have established your target heart
rate zone. The intensity of training sessions should
be at or just below your anaerobic threshold.
Anaerobic threshold training sessions can take the
form of either interval or continuous training.
Interval training should consist of three to five,
6-12 minute intervals. The rest period between
intervals should be 2-3 minutes. Ideally you would
reach your target heart rate as quickly as possible
-- inside a minute.
A
continuous training session to improve anaerobic
threshold should last for 20-45 minutes. This is
more demanding than the interval session so build up
to it gradually.
|
Interval Training Session |
|
Frequency |
2x week |
|
Intensity |
95-100% ATHR |
|
Time |
20-45mins |
Anaerobic threshold is more reliable indicator of
your performance than VO2max. More importantly, anaerobic threshold is generally more responsive to
training, especially if you are regularly active.
Course Contributor
Phil Davies
