Training Effects – linked with Aerobic System

September 2011

Training Effects – linked with Aerobic System

• At the end of this section, you should be able to:

• Define and explain the term Oxygen Deficit

• Understand the recovery process and explain Slow and Fast systems

• Identify the different characteristics of the slow and fast component of the recovery process

• Explain the relationship between VO2 Max and sporting performance

September 2011

Physiological effects of training…• Why do you train? • What differences do you notice?• Internal/External?

• When training stresses the aerobic system, adaptations make ‘systems’ more effective:

- Cardiac hypertrophy = RSV - RHR = reduced exercising and maximal HR - blood volume and haemoglobin - Muscle stores of glycogen/triglycerides, myoglobin

contentCapilliarisation of muscle, number/size of mitochondriaConcentration of oxidative enzymes

September 2011

Maximal Oxygen Consumption

• As a result – VO2 Max also increases

• What is VO2 max? taken inMaximum amount of Oxygen transported

used (ml)

• During rest/exercise, we require Oxygen to resynthesiseATP

• Heart, contraction of muscles during respiration, brain function

• The total amount required is known as Oxygen Consumption

• During the onset of exercise, there is insufficient oxygen available to produce the amount of ATP required aerobically

September 2011

Oxygen consumption during exercise

• When oxygen consumption is lower than the amount actually required, it creates an oxygen deficit

• Insufficient oxygen available at the start of exercise to provide all the ATP needed aerobically

• (See next side)

• Amount of ATP required for muscles to contract varies =

VO2 varies

September 2011

Graph showing Oxygen consumption during rest and exercise

September 2011

• Why do we take in more Oxygen when we exercise than when at rest?

• To supply mitochondria in muscle fibres, to manufacture ATP aerobically.

• If the level of exercise intensity increases, so does the level of oxygen uptake ……..until….

• Extreme exercise where we reach a level of Maximal Oxygen Consumption – the maximum amount of oxygen an individual can consume during strenuous exercise

September 2011

VO2 and sustained performance

• The greater amounts of Oxygen taken to and used within the Mirochondria, the longer a performer can work without accumulating Lactic Acid

• LA accumulates because there is insufficient oxygen to combine with the hydrogen released during the breakdown of glucose. Excess Hydrogen combines with Pyruvic acid produced during glycolysis to form LA

• Swimming example – p.23:• When swimming at a faster pace, lactic acid is accumulating, which

will eventually cause fatigue

• If fatigue hits too early, she will have to slow her pace – which could mean the difference between gold and silver

September 2011

Lactate Threshold/OBLA

• You do not work at your VO2 max – this intensity can only be tolerated for few seconds – a lack of fitness/motivation plays a part

• The harder you exercise, the more LA you generate within your muscles, eventually your blood

• Athletes must monitor the intensity of their exercise, to ensure they do not accumulate too much lactic acid within their blood, but at the same time, working at an intensity close to their VO2 max

high VO2 Max• Highly trained endurance athlete

ability to work closer to VO2 before LA threshold occurs

September 2011

Lactate Threshold/OBLA

• As we begin to exercise more intensely, a point is reached at which lactate starts to accumulate:

Onset of Blood Lactacid Accumulation

• The point at which LA starts to accumulate within the blood.

• As a performer increases their level of intensity, they cross a point known as the LA Threshold

• Why does it happen?• The anaerobic lactate energy system produces more LA than can

be dealt with – therefore acid starts to accumulate in the muscles and the blood

September 2011

Fatigue and Lactate tolerance

• Lactate tolerance, is about how well an athlete can withstand the effects of the accumulation of lactic acid

• Evidence suggests that L.T is linked with psychological factors – elite athletes more highly motivated more willing to ignore the fatiguing effects of LA

• Bicarbonates combine with the free Hydrogen ions, making them less acidic – as bicarbonates have an alkalising affect

• The alkalising agents draw the hydrogen ions and the lactic acid from the muscle cell into the blood – reducing the effects of fatigue

• Blood flow away from muscles also contributes to the process – which can be improved through training by increasing capillary density at muscle site

After Intense exercise

September 2011

What is happening to the athletes body at this point?

• Alister Brownlie collapses

• (://news.bbc.co.uk/sport1/hi/other_sports/triathlon/8853123.stm)

September 2011

• Restore levels of ATP and PC• Reduce levels of Lactic Acid back to normal• Reload Myoglobin• Restore levels of muscle glycogen

• When the body is recovering from intense exercise, MORE Oxygen is required ABOVE the normal level used at that workload

“Excess Post-Exercise Oxygen Consumption”

(EPOC)

September 2011

Oxygen

Recovery

• What happens during EPOC:

September 2011

• Restoring ATP levels:

- Constantly restoring ATP by resynthesis – 48/72 hrs to restore to normal.

- This requires:

which in turn requires:

• Restoring PC:- When energy for ATP resynthesis is requires rapidly (sprinting), it is

provided by the breakdown of PC – a reaction

The energy provided for the PC resynthesis comes from the breakdown of glucose – therefore making an oxygen demand

September 2011

Glucose

Oxygen

• Dealing with Lactic Acid:

• As a result of the body moving from working aerobically to anaerobically – the lactate threshold point is crossed – this is the point at which OBLA is reached.

• The amount of LA accumulating depends on HOW LONG you work above the threshold.

• This has to be monitored because:

1) It will cause muscle fatigue

2) Lactic Acid can be a useful source of energy

September 2011

2 methods for dealing with excess LA

1) Converting LA to Pyruvate (oxidation)

Pyruvate then goes through to produce energy for ATP reformation

Process requires oxygen and occurs in the mitochondria

2) Transporting LA to the liver via bloodstream – reconverted to glucose via CORI cycle

(Series of chemical reactions in which LA is converted to blood glucose in the liver)

Also indirectly involved the use of Oxygen.

September 2011

Recovery – 2 components:

• The alactacid debt – (fast component)

• The Lactacid decbt – (slow component)

• Graph – p91

September 2011

The alactacid (fast)Component

• Restoration on muscle phosphagen stores (ATP/PC)

(broken down and energy used)

Oxygen consumption remains high to allow elevated rates of aerobic respiration to continue.

Energy released aerobically is used to continue ATP production – then to reform stores of PC depleted by exercise

Uses up to 4 litres of oxygen

Takes 2-3 minutes to complete restoration after intense exercise

Stores are replaced to 50% of normal levels after 30 secs

September 2011

The alactacid (fast)Component

• If exercise was submaximal – replenishment is even quicker

• Muscle phosphagen stores provide energy for short intensive bouts of exercise – therefore stores can be replenished quickly.

• Link to performance: See Video clip

• In a game that relies heavily on the anaerobic energy systems such as Basketball – the coach may schedule T.O’s to help the team recover.

• Time available may not be sufficient to gain full recovery, but the athlete will be able to ‘offset’ fatigue

• PC stores will reduce contribution from LA – limit amount being produced

Sept-Oct 2011

The lactacid (slow) component

• Responsible for the removal of LA

• Full recovery can take up to 1 hr – depending on duration and intensity

• LA accumulates in the working muscles/blood. It can be removed in 4 ways:

• Removed by cells - using it as a metabolic fuel (Pyruvic acid)• Conversion to protein or to glycogen in muscle/liver or excretion

via urine or sweat• Elevated breathing and heart rates – CO2 expelled through

increased circulation and respiration• Body temp – remains high, therefore keeps respiratory and

metabolic rates higher than normal

September 2011