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Physiology and Training
Physiology and Training

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Presentation on theme: "Physiology and Training"— Presentation transcript

Slide1

Physiology and Training

subtitleSlide2

Why do we train????

The human body is an amazing ‘machine’ that will adapt I’s systems to maintain homeostasis. As a result of this and our intelligence we have the ability to survive in a variety of environments:

Hot

Cold

Humid

Etc

We have also used this knowledge to manipulate our bodies to perform at higher levels in a number of sporting disciplines. We do this predominately by training and training smart!Slide3

It all begins with energy

Energy is required for all kinds of bodily processes including growth and development, repair, the transport of various substances between cells and of course, muscle contraction. It is this last area that Exercise Scientists are most interested in when they talk about energy systems.

Whether

it's during

a

marathon run or one explosive movement like a tennis serve, skeletal muscle is powered by one and only one compound... adenosine triphosphate (ATP

).

However

, the body stores only a small quantity of this 'energy currency' within the cells and its enough to power just a few seconds of all-out exercise

.

So the body must replace or resynthesize ATP on an ongoing basis. Understanding how it does this is the key to understanding energy systems.Slide4

An ATP molecule consists of adenosine and three (tri) inorganic phosphate groups. When a molecule of ATP is combined with water (a process called hydrolysis), the last phosphate group splits away and releases energy. The molecule of adenosine 

tri

phosphate now becomes adenosine 

di

phosphate or ADP

To replenish the limited stores of ATP, chemical reactions add a phosphate group back to ADP to create ATP. This process is

called phosphorylation

. If this occurs in the presence of oxygen it is

labelled aerobic metabolism or oxidative phosphorylation. If it occurs without oxygen it is labelled anaerobic metabolismSlide5

The Glycolytic System

Glycolysis

literally means the breakdown (lysis) of glucose and consists of a series of enzymatic reactions. Remember that the carbohydrates we eat supply the body with glucose, which can be stored as glycogen in the muscles or liver for later use

.

The end product of glycolysis is 

pyruvic acid

. Pyruvic acid can then be either funnelled through a process called

the

Krebs cycle or converted into 

lactic acid.

Traditionally

, if the final product was lactic acid, the process was labelled 

anaerobic glycolysis

 and if the final product remained as pyruvate the process was labelled 

aerobic glycolysis

.

However

, oxygen availability only determines the 

fate

 of the end product and is not required for the actual process of glycolysis itself. In fact, oxygen availability has been shown to have little to do with which of the two end products, lactate or pyruvate is produced. Hence the terms aerobic meaning with oxygen and anaerobic meaning without oxygen become a bit misleading

.

Alternative terms that are often used are 

fast glycolysis

 if the final product is lactic acid and 

slow glycolysis

 for the process that leads to pyruvate being funnelled through the Krebs cycle. As its name would suggest the fast

glycolitic

system can produce energy at a greater rate than slow glycolysis. However, because the end product of fast glycolysis is lactic acid, it can quickly accumulate and is thought to lead to muscular

fatigue.Slide6
Slide7

Mitochondria…………

And energy begins within cells which contain mitochondria…

Mitochondria are cellular organelles that function as power plants within a cell.  In the same way that a local power plant produces electricity for an entire city, mitochondria are responsible for the production of energy derived from the breakdown of carbohydrates and fatty acids.  Mitochondria oxidize or “burn” carbohydrates, amino acids and fatty acids for energy, yielding ATP.  ATP (Adenosine Triphosphate) is the cellular form of energy utilized by cellular processes all throughout the body, providing the energy to pump your heart, power neurons in your brain, contract muscles in your limbs, exchange gases in your lungs, extract nutrients from food and regulate body temperature, just to name a few.

Simply stated, mitochondria produce ATP, and ATP is absolutely essential for survival.  Without a sufficient generation of ATP, life would cease to exist.Slide8

Two Content Layout with Table

Where are Mitochondria Found?

Mitochondria are located in every cell type and tissue in the human body, from your brain to your thyroid gland to your Achilles tendon.  In short – trillions of mitochondria are distributed all throughout your body with the sole purpose of generating ATP.  Red blood cells are the only cell type that do not contain mitochondria.

Muscles contain the highest mitochondrial content of any tissue in your body, in order to provide massive amounts of ATP for movement and exercise.  Muscle is generally divided into three types – white muscle, red muscle and mixed muscle.  The terms “red” and “white” are derived from the way these muscles appear during surgery or autopsies, but largely refer to the mitochondrial content of the muscle itself.Slide9

Mitochondrial Biogenesis

What is Mitochondrial Biogenesis?

Mitochondrial biogenesis is a process that was first described over 40 years ago by a pioneer in the field of exercise physiology named 

John

Hollosczy

,

a professor at Washington University in St. Louis, MO.  Think of him as the godfather of exercise physiology.  In his seminal paper on the effects of exercise on mitochondrial structure and function, he found that endurance training induced large increases in muscle mitochondrial content and increased the ability of muscle to uptake glucose during and after exercise.

The result of mitochondrial biogenesis is an expansion of the network of mitochondria within a cell, and an increase in the maximal amount of ATP that can be generated during intense exercise.  In short – more mitochondria means more ATP production at peak exercise conditions

.Slide10

Exercise is the Most Effective Way to Make New Mitochondria

Exercise is the Most Effective Way to Make New Mitochondria

Exercise is the most potent signal for the increased production of mitochondria in muscle, by increasing the ability of the muscle to burn carbohydrates and fatty acids for ATP.

When you perform exercise, muscle cells generate a low-energy signal known as AMP, and the accumulation of AMP over time signals for increased ATP production. 

occurs

in the resting state immediately following exercise.

In response to a large demand for ATP production, muscle cells respond by overcompensating in their ability to produce energy for the next round of exercise, by inducing mitochondrial biogenesis in the resting state. 

By doing this, mitochondria are able to consume larger amounts of oxygen, carbohydrates and fatty acids, the fuels needed to power the production of ATP.  The ability of muscles to overcompensate for exercise “stress” is exactly why frequent exercise results in increased strength, endurance, resistance to fatigue and whole body fitness.

Muscle Mitochondria: Use Them or Lose Them!

Chronic disuse of muscle, sedentary

behaviour

and aging each independently result in a decline in mitochondrial content and function, leading to the production of free radicals and cell death.  The muscle tissue of people with type 2 diabetes has also been extensively studied, revealing gross defects in mitochondrial number and function.Slide11

So what exactly is occurring in them mitochondria?

The

Krebs

cycle

aka citric acid cycle

aka TCA cycle

The pyruvic acid (3C) enters the matrix of the mitochondrion where it is oxidized (i.e. 2H removed) and a carbon dioxide is lost. Thus forming a two carbon molecule called acetyl-CoA (2C).The hydrogens which have been removed join with NAD to form NADH2.

It begins when the 2-carbon acetyl CoA joins with a 4-carbon compound to form a 6- carbon compound called Citric acid.

Citric acid (6C) is gradually converted back to the 4-carbon compound ready to start the cycle once more.

The carbons removed are released as CO

2

.

The hydrogens, which are removed, join with NAD to form NADH

2

.Slide12

What the????

In essence post the pyruvic acid going through the complex chemical reaction in the Krebs cycle the body can in fact walkaway with 36 ATP armed and ready to use!!!! At a mere cost of 2 ATP BOOOM!!!

Thus, the aerobic system produces 18 times more ATP than does anaerobic glycolysis from each glucose molecule.

Basically this means you can keep swimming just keep swimming keep swimming……Slide13

Okay so now we got the energy what do our muscles do with it???

To understand this we need to understand the structure of the muscle

The skeletal muscles are usually made up of a muscle body and two tendons which attach to the bones. These muscles contract to create movement,

The muscle body is made up of thousands of muscle fibres known as

fasciculi.

Fascuculi

are then made up of many

myofibrils

which are similar to the wires in a telephone cable.Slide14

Okay so now we got the energy what do our muscles do with it???

The myofibrils are divided into sections known as

sarcomeres.

Sarcomeres run the length of the myofibrils and each are separated by what we refer to as the

z line.

Each myofibril sarcomere is further divided into what are know as myofilaments;

A thick filament (

myosin)

A thin filament (actin)These in turn are surrounded by a

gelatin

like substance sarcoplasm, which contains mitochondria, myoglobin (

reasponsible

for carrying O2 from the blood to the

mitachiondria

) CP, glycogen, fat and ATP.Slide15

Okay so now we got the energy what do our muscles do with it???

Actin and

myosi

filaments take up different parts of the length of the sarcomere.

The light section that only contains the thin actin filaments are known as the I-Band.

A-Band refers to where both actin and myosin filaments overlap and is a darker section.

The H-Zone is very small and is located in the middle of the A band, this is where only the thick myosin filaments occur.Slide16

So how do we control these muscles?

Sensory neurons send messages from the sense

recpetors

to the brain, motor neurons carry messages from the brain to the Central Nervous

sytem

and ultimately to the muscle.

Many nerve cells extend the length of a myofibril a bit like sarcomeres.

Each motor unit controls one small portion of the muscleSlide17

The all or nothing principle

The all or nothing principle means that muscle fibres either contract maximally along their length or not at all.  So when stimulated muscle fibres contract to their maximum level and when not stimulated there is no contraction.  In this way the force generated by a muscle is not regulated by the level of contraction by individual fibres but rather it is due to the number of muscle fibres that are recruited to contract.  This is called 

muscle fibre

recruitment

.

Hence contraction strength is regulated by the message sent from the brain in terms of how many fibres are required for the movementSlide18

Sliding Filament Theory

Here is what happens in detail. The process of a muscle contracting can be divided into 5 sections:

nervous impulse

 arrives at the neuromuscular

junction

In the presence of high concentrations of Ca+, the Ca+ binds to Troponin, changing its shape and so moving Tropomyosin from the active site of the Actin. The Myosin filaments can now attach to the Actin, forming a cross-bridge.

The breakdown of ATP releases 

energy which enables the Myosin to pull the Actin filaments inwards and so shortening the muscle. This occurs along the entire length of every myofibril in the muscle cell.

The Myosin detaches from the Actin and the cross-bridge is broken when an ATP molecule binds to the Myosin head. When the ATP is then broken down the Myosin head can again attach to an Actin binding site further along the Actin filament and repeat the 'power stroke'. This repeated pulling of the Actin over the myosin is often known as the ratchet mechanism.

This process of muscular contraction can last for as long as there is adequate ATP and Ca+ stores. Once the impulse stops the Ca+ is pumped back to the Sarcoplasmic Reticulum and the Actin returns to its resting position causing the muscle to lengthen and relax.Slide19

Partially Contracted

Muscle

The diagram

shows

a partially contracted muscle where there is more overlapping of the myosin and actin with lots of potential for cross bridges to form. The I - bands and H - zone are shortenedSlide20

Fully Contracted

Muscle

The

diagram

shows a fully contracted muscle with lots of overlap between the actin and myosin. Because the thin actin filaments have overlapped there is a reduced potential for cross bridges to form again. Therefore there will be low force production from the muscle.Slide21

Aerobic Limitations

Why do we not use the Aerobic system all the time? Basically because it is not fast!

100 metre sprint an athlete requires around 8 litres of oxygen in 10 seconds, a trained male can supply

approx

5 litres of oxygen per minute when working aerobically.

It takes a couple of minutes for the body to respond to the demands and requirements of exercise, i.e. heart rate to be at ‘steady state’ thus we work aerobically until all systems catch up, we call this

oxygen deficit

, the body generally stores lactic acid as a result of this in manageable amounts, when we complete exercise we take some time before returning to a resting state, we call this oxygen debt as the body is repaying the oxygen used in the oxygen deficit stage. Slide22

Oxygen Delivery to the Working Muscles

We now know that for the

krebs

cycle to occur oxygen needs to be present. There are a number of systems which deliver this oxygen to the working muscles. The more efficient the bodies ability to deliver oxygen to these muscles the greater the working capacity, we call this

aerobic capacity. Slide23
Slide24

Lung CapacitySlide25

Gas Exchange

Gas will diffuse from areas of high concentrations to low concentrations.

Blood arriving at the lungs is high in CO2 and low in Oxygen, therefore C02 will be diffused into the lungs from the blood to be breathed out

Oxygen will be diffused from the lungs to the blood to be carried around the body.Slide26

The Pump

The heart has two sides, separated by an inner wall called the septum. The right side of the heart pumps blood to the lungs to pick up oxygen. The left side of the heart receives the oxygen-rich blood from the lungs and pumps it to the body.

The heart has four chambers and four valves and is connected to various blood vessels. Veins are blood vessels that carry blood from the body to the heart. Arteries are blood vessels that carry blood away from the heart to the body.Slide27

Stroke Volume

Stroke volume:

 The amount of blood pumped by the left ventricle of the heart in one contraction. The 

stroke

 volume is not all the blood contained in the left ventricle; normally, only about two-thirds of the blood in the ventricle is expelled with each beat. Together with the heart rate, the stroke volume determines the output of blood by the heart per minute (cardiac output).

Heart Rate

When

your heart pumps blood through your arteries, it creates a pulse that you can feel in the arteries close to the skin's surface. Pulses can be most easily felt at the wrist, elbow, groin, feet and neck.

Heart rates increase in response to the body needing more oxygen or nutrients e.g., when exercising, or when you may need it to run for your life when being chased by a lion (the fight or flight response)!Slide28

The Pump

Cardiac Output

Cardiac

output (CO) is the term used to show the amount of blood pumped per minute by each ventricle. When your body's at rest, your heart beats about 75 times per minute. Each time it pumps, it pushes out about 75

milliliters

of blood, which is about a third of a cup - it's about the amount that you could hold in your cupped hand. When you multiply the number of heartbeats per minute times the amount of blood being pumped during each heartbeat, we get the cardiac output.

If we do the math using the examples above, we see that 75 heartbeats per minute times 75

milliliters

of blood pumped during each heartbeat equals the average cardiac output of about 5.6

liters

of blood pumped through your heart each minute. That's a lot of blood, and if you consider that large bottles of soda often come in 2

litre

containers, that means that your heart pumps the contents of more than 2 and a half of these soda bottles every minute.Slide29
Slide30

Areteriovenous Oxygen Difference

The arteriovenous oxygen difference is the difference between the oxygen contents of the arterial blood and mixed venous blood. It is a reflection of the amount of oxygen extracted from the blood by the muscles. Obviously, the more oxygen that is actually extracted from the blood, the more oxygen there is for aerobic energy production. The oxygen content of venous blood can be reduced to one-half to one-third of an individual’s resting levels by the exercising muscles.Slide31

Maximum Oxygen Uptake

Stoke Volume, Heart Rate, Cardiac Output and Arteriovenous Oxygen difference all combine to create our Maximum Oxygen Uptake or VO2max it is a beautiful thing!!!!!

VO

2

 max is the maximum amount of oxygen in millilitres, one can use in one minute per kilogram of body weight. Those who are fit have higher VO

max values and can exercise more intensely than those who are not as well conditioned.

Age

Male

Female

10-19

47-56

38-46

20-29

43-52

33-42

30-39

39-48

30-38

40-49

36-44

26-35

50-59

34-41

24-33

60-69

31-38

22-30

70-79

28-35

20-27

Average

VO

max (ml/kg/min)

for non-trained athletes

Sport

Age

Male

Female

Baseball

18-32

48-56

52-57

Basketball

18-30

40-60

43-60

Cycling

18-26

62-74

47-57

Canoeing

22-28

55-67

48-52

Football (USA)

20-36

42-60

 

Gymnastics

18-22

52-58

35-50

Ice Hockey

10-30

50-63

 

Orienteering

20-60

47-53

46-60

Rowing

20-35

60-72

58-65

Skiing alpine

18-30

57-68

50-55

Skiing nordic

20-28

65-94

60-75

Soccer

22-28

54-64

50-60Speed skating18-2456-7344-55Swimming10-2550-7040-60Track & Field - Discus22-3042-55 Track & Field - Running18-3960-8550-75Track & Field - Running40-7540-6035-60Track & Field - Shot22-3040-46 Volleyball18-22 40-56Weight Lifting20-3038-52 Wrestling20-3052-65Slide32

Specific Sports

Sport

Age

Male

Female

Baseball

18-32

48-56

52-57

Basketball

18-30

40-60

43-60

Cycling

18-26

62-74

47-57

Canoeing

22-28

55-67

48-52

Football (USA)

20-36

42-60

 

Gymnastics

18-22

52-58

35-50

Ice Hockey

10-30

50-63

 

Orienteering

20-60

47-53

46-60

Rowing

20-35

60-72

58-65

Skiing alpine

18-30

57-68

50-55

Skiing nordic

20-28

65-94

60-75

Soccer

22-28

54-64

50-60

Speed skating

18-24

56-73

44-55

Swimming

10-25

50-70

40-60

Track & Field - Discus

22-30

42-55

 

Track & Field - Running

18-39

60-85

50-75

Track & Field - Running

40-75

40-60

35-60

Track & Field - Shot

22-30

40-46

 

Volleyball

18-22

 

40-56

Weight Lifting

20-30

38-52

 

Wrestling

20-30

52-65Specific AthletesSlide33

Individuals

O

2

 max (ml/kg/min)

Athlete

Gender

Sport/Event

96.0

Espen Harald Bjerke

Male

Cross Country Skiing

96.0

Bjorn Daehlie

Male

Cross Country Skiing

92.5

Greg LeMond

Male

Cycling

92.0

Matt Carpenter

Male

Marathon Runner

92.0

Tore Ruud Hofstad

Male

Cross Country Skiing

91.0

Harri Kirvesniem

Male

Cross Country Skiing

88.0

Miguel Indurain

Male

Cycling

87.4

Marius Bakken

Male

5K Runner

85.0

Dave Bedford

Male

10K Runner

85.0

John Ngugi

Male

Cross Country Runner

 

 

 

 

73.5

Greta Waitz

Female

Marathon runner

71.2

Ingrid Kristiansen

Female

Marathon Runner

67.2

Rosa Mota

Female

Marathon Runner

Why do you think that Cross Country

skiiers

have the highest VO2max?Slide34

Means to Test V02max

Measuring

VO2 max accurately requires an all-out effort (usually on a treadmill or bicycle) performed under a strict protocol in a sports performance lab. These protocols involve specific increases in the speed and intensity of the exercise and collection and measurement of the volume and oxygen concentration of inhaled and exhaled air. This determines how much oxygen the athlete is using

. An

athlete's oxygen consumption rises in a linear relationship with 

exercise intensity

 -- up to a point

.

Multistage Fitness TestThe objective of the Multi-Stage Fitness Test (MSFT), developed by Leger & Lambert (

1982

),

is to monitor the development of the athlete's maximum

oxygen

uptake.

This test is very good for games players as it is specific to the nature of the sport but, due to the short sharp turns, it is perhaps not suitable for rowers, runners or cyclists.Slide35
Slide36

So how come I will be forced to stop?!

So my Cardio Respiratory system is supplying plenty of oxygen to the lungs, my blood has heaps of haemoglobin to carry this around, my lung is strong and has a powerful stroke volume plus a quality cardiac output, my muscles are efficient and have plenty of mitochondria to promote the Krebs cycle and produce more ATP, basically my aerobic system is the

shiz

nit……..why can’t I just keep swimming?Slide37

Causes of Fatigue

Lactic Acid Accumulation

Lactic

acid is rapidly broken down into a compound called lactate, resulting in the release of hydrogen ions. Your body can clear lactate by metabolizing it for energy, but when lactate production exceeds the clearance rate, it accumulates in your muscles and bloodstream. While rising levels of lactate are associated with tired muscles, lactate does not actually cause fatigue. Rather, it is the increased acidity in your tissues, due to the

buildup

of hydrogen ions, that contributes to the sensation of fatigue.Slide38

Depletion of Energy Stores

Glycogen Depletion

If glycogen stores are not being replenished with carbohydrates from food or drinks, glycogen stores can run out. Once this occurs, the body will find alternative ways to create more glucose. This process is called gluconeogenesis, or the formation of glucose from new sources. The liver will begin to break down fat and protein to form glucose, which can then be used for energy. However, this process takes longer than

glycogenolysis

, and is therefore considered a less efficient way of producing energy

.

Hypoglycemia

After glycogen stores have been depleted and before gluconeogenesis kicks in, an athlete may experience symptoms of

hypoglycemia

, which occurs when blood glucose levels are low. During

hypoglycemia

, a person may feel extreme fatigue and a near complete loss of energy, often referred to as "bonking". When this occurs, it is not uncommon to see athletes collapse from the extreme fatigue. Dizziness and hallucinations may also occur under these conditions.

https://www.youtube.com/watch?v=g_utqeQALVESlide39

Elevated Body Temperature

As the

corebody

temperature increases vasodilation occurs which is when blood is directed to the veils located near the skin in an effort to cool it down.

As a result this blood is directed away from the working muscles which will cause fatigue due to no oxygen arriving for ATP

resynthesis

. Slide40

Central Nervous System Inhibition

Brsin

senses fatigue and as a matter of self preservation it

transmiots

less messages to the working muscles to contract. Hence an athlete slows down.

Transmitter Tiredness

Nerve fibres do not connect directly to the muscles but transmit it through acetylcholine a substance which is released which crosses the gap. As the muscles fatigue the amount of this substance released is reduced.Slide41

Muscle Fibre Type

Fast Twitch Fibres contain high stores of PC which mean they

fatiugue

less quickly when operating Anaerobically

Slow twitch muscle fibres contain greater amounts of Glycogen and Triglycerides meaning that they can convert ATP longer in the aerobic system

Generally our fibre type make up is a result of genetics.Slide42

Responses to Exercise

When you begin to exercise your body must immediately adjust to the change in activity level. Energy production must increase to meet demand with changes to the predominant energy system and fuel source

occuring

throughout the exercise in order to maintain the required level of performance.Slide43

Short term effects of exercise

Acute Responses

When

we begin to exercise the body has to respond to the change in activity level in order to maintain a constant internal environment (homeostasis). Here are the changes which must take place within the 

muscles

respiratory

 and 

circulatory system:Slide44

Long term responses to exercise

Chronic Responses

Long-term Effects of Exercise

Regular exercise results in adaptations to the circulatory, respiratory and muscular systems in order to help them perform better under additional stress. Here are the changes which must take place within the 

muscles

respiratory system 

and

circulatory system:Slide45

Biomechanics of Running

Summary of Running Form:

1. Body Position- upright, slight lean from ground. Head and face relaxed.

2. Feet- As soon as knee comes through, put the foot down underneath you. Land mid or forefoot underneath knee, close to

center

of the body.

3. Arm stroke- controls rhythm, forward and backwards from the shoulder without side to side rotation

4. Hip extension- extend the hip and then leave it alone.

5. Rhythm- Control rhythm and speed through arm stroke and hip extension.http://www.scienceofrunning.com/2010/08/how-to-run-running-with-proper.htmlSlide46

Biomechanics of Cycling

M

ost

of us don’t spend enough time setting up our bikes correctly to get the optimum position for speed. With a little time and understanding, you may be able to go faster without any hard training sessions or extra cost.

The most important factor is saddle position: if the saddle is too low, you won’t be able to make full use of the power in your legs, and if the saddle is too high you’ll feel your hips roll from side to side as your legs stretch too far at the bottom of each pedal stroke.

The fore and aft position of the saddle is also very important to ensure effective use of your quadriceps and prevent any knee injuries.

Another common problem for riders is a stiff neck or shoulders – check your posture throughout your rides to make sure your neck and shoulders are relaxed to prevent unnecessary aches and pains, and keep yourself in the right position to unleash your speed potential.Slide47

Simple Bike Setup

Saddle height:

 Sit on the bike with one of the pedals at 6 o’clock. Position your foot so it’s parallel to the floor. In this position, your leg should be almost straight.Slide48

Saddle fore and aft:

 Sitting on the bike, position one foot forwards so the crank is parallel to the floor at 3 o’clock. Hold a length of string with a weight on the end at the front of your knee. The string should drop down in line with the pedal axle. Adjust if necessary.Slide49

Handlebar height:

 This depends on a number of factors such as suspension travel and the type of terrain. The higher the bars are, the more comfortable you’ll feel but you’ll lose that sense of being in a race positionSlide50

Handlebar reach:

 Make sure you can reach the bars with your arms slightly bent. If the bars are too close your back will not be in neutral and will become rounded. If the bars are too far away, you’ll have to work your core muscles to stay in position, which can lead to lower back pain.