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Part 2 - The VO2max test

Course video 63 of 105

The level of expertise with which an athlete is able to perform sports skill depends on how well the coach molds the correct ratio of endurance, strength, power and speed to meet the demands of the sport. In this section you will learn the science behind developing these important motor performance abilities as the young athlete moves through puberty.

Seventy percent of kids drop out of sports before their high school graduation. Only 15% leave because they feel they are not good enough. Almost 70% leave because they were not having fun, or due to problems with the coach. Injuries cause 30% to give up sports. This course is packed full of practical sports science information that provide youth coaches and parents with the practical pediatric sports science insights to successfully retain young athletes and develop their sport potential while avoiding injury and overtraining. We begin by examining the multidimensional nature of coaching, the relevant sport motor performance abilities, the impact of growth and development on motor skills, the gene versus practice controversy, and briefly overview the body structures strengthened through training. Then we explore the athlete's energy supply, where this energy comes from, and how it matures along with the athlete. Finally, we examine the development of strength, power, anaerobic capacity, coordination and flexibility through the life span. The optional text manual for this course is available at: http://www.learnitez.com/HighPerformanceScience/manuals/

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Compétences que vous apprendrez

Training, Coaching, Planning, Training Programs

Enseigné par

Dr. Chris Brooks
Instructor

Transcription

Now we're going to talk about the VO2max test itself.

In the lab, an athlete's VOmax is tested using a treadmill or a bicycle ergometer.

Coaches typically don't use the lab VO2max test due to its expense.

Instead they use the common sports specific field based test just

as the bleep test that we just discussed.

However, it's worth having some understanding of the lab test because

the protocol for the field test are developed from day to obtained from

the lab test as well understanding the lab VO2max

test helps you understand the theory upon which the field tests are based.

So here's a graphic of typical data gathered during a lab VO2max test.

It includes heart rate, which is the blue line, carbon dioxide

which is the green line and oxygen consumption which is the maroon line.

The maximum VO2 consumption is the highest amount

of oxygen the athlete's aerobic energy system is capable of using.

And theoretically, athletes with a very high VO2max are able to

produce more ATP than those with a lower VO2max,

and can therefore run at a higher speed before exhaustion.

When performing the lab VO2max test,

the athlete is fitted with a mask that is attached by a hose to a device

that's capable of measuring how much air the athlete is breathing each minute.

It also measures the amount of carbon dioxide and

oxygen that is in the exhaled air.

The oxygen passes through the alveoli in the lungs and

into the blood vessels that I have illustrated here.

This area down here is representing the blood tissue the athlete is using.

And the known amount of oxygen in the atmospheric air is 21%.

And as the blood passes through the muscle cells,

the oxygen needed by the mitochondria for the aerobic energy system is extracted and

the carbon dioxide is deposited into the blood stream.

The oxygen that's not needed remains in the blood stream and

travels along with the carbon dioxide back to the lungs, where it is exhaled.

The oxygen in the blood returning back to the lungs contains somewhat

less than 21% oxygen depending on how much the athlete's muscles have used.

We can gain some insight into how much oxygen the mitochondria extract

by measuring the quantity of oxygen left in the exhaled air.

Which is subtract the oxygen and

the air remaining in the lungs from the 21% that entered into the lungs.

We are also able to measure the amount of carbon dioxide produced by the cells

from the same exhaled air.

We know how much carbon dioxide was in the air when the athletes breathed in and

how much is in there when the athlete breathes out.

The hose that is in the athlete's mouth is connected to equipment that measures

both oxygen and carbon dioxide that is in the expired air.

So let's take a look at the athlete's oxygen consumption with increasing speed.

So this line here represents the increasing oxygen consumption

as the athlete increases speed every couple of minutes.

When the athlete increases speed more muscle fibers are recruited, and

therefore a higher quantity of oxygen is extracted from the blood

to meet the mitochondrial needs of the muscle fibers.

At some point, the ability of the mitochondria to

use the oxygen reaches its upper limit.

And the athlete is unable to increase speed any further.

And this is the athlete's VO2max.

At any point in time,

the difference between the amount of oxygen entering the lungs and

amount left in the lungs exhaled is referred to as the oxygen uptake, or VO2.

Now the V just simply stands for volume and the peak amount

of oxygen used is a really good indication of the athlete's endurance potential.

It also tells us quite a bit

about the health status of the athlete's aerobic energy system.

We can also graph the carbon dioxide that is produced,

as you see here in the green line.

As the athlete moves faster more carbon dioxide is being produced.

A carbon dioxide provides quite a bit of information but

we're not going to talk about this for now.

So let's get rid of the carbon dioxide curve.

Besides oxygen and carbon dioxide,

the athlete's heart rate is also monitored during the lab test.

Having the heart rate data allows us to

estimate the athlete's oxygen consumption when moving at different speeds.

Theoretically, if you have heart rate and oxygen consumption,

you can estimate the athlete's oxygen consumption by simply looking at their

heart rate when they're training.

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