1.5 Energy Systems

ATP

energy used for muscular contractions

ATPase

enzyme used to breakdown ATP

What do systems depend on

1. Intensity

2. Duration

3. Presence of oxygen

ATP-PC System

1. Uses PC as fuel

2. Found in sarcoplasm of the muscles

3. Broken down quickly and easily releases energy to resynthesize ATP

4. Rapid availability - good for short, quick movement

5. Anaerobic

6. High intensity

7. Short duration (5-10s)

8. Eg 100m

ATP-PC system AO2

1. Existing stores provide ATP

2. First part of race will be used

3. Exhaused by 8-10s

How does ATP-PC system provide energy

1. Anaerobic process

2. A coupled reaction

ATP-PC System Equation

PC -- Pi + C + Energy

Energy + Pi + ADP --ATP

Advantages of ATP-PC System

1. ATP can be resynthesized rapidly with ATP-PC

2. PC stores can be synthesized quickly

3. No fatigue by products

4. Creatine supplementation can extend the time ATP-PC system can be utilised

Disadvantages of ATP-PC System

1. Limited supply of pc in muscle cell - only last 10 sec

2. Only 1 molecule of ATP can be resynthesized by every PC molecule

3. PC re-synthesis can only take place in the presence of 02 when energy intensity has decreased

Anaerobic Glycolytic System

1. No oxygen

2. High-intensity activity (longer then ATP-PC System)

3. How long system depends on: athlete’s fitness, intensity

4. Normally up to 3 mins but can peak at 45 sec at high intensity

5. Shorter duration (10s - 3min)

6. Eg 400m

Anaerobic Glycolytic System Process

Glycogen -- Glucose -- Pyruvic acid -- Latic acid + 2ATP

Advantages of Anaerobic Glycolytic System

1. ATP resynthesized quickly due to few chemical reactions and lasts longer then ATP-PC system

2. When oxygen is available lactic acid can be converted back into liver glycogen or used as fuel oxidation into C02 and water

3. Produces extra burst of energy

Disadvantages of Anaerobic Glycolytic System

1. Latic acid is harmful by-product which denatures enzymes leading to lower ATP resynthesis

2. Only a small amount of energy can be released from glycogen under anaerobic conditions

Where does Glycolysis take place?

Muscle sarcoplasm

Aerobic Energy System

1. Low intensity

2. Long duration (3mins + )

3. Oxygen supply

4. Eg marathon

3 Stages of aerobic Energy System

1. Glycolysis

2. Krebs cycle

3. Electron transport chain

Glycolysis

• glucose is broken down into pyruvic acid

  1. glycogen -- glucose -- pyruvic acid + 2ATP

Krebs cycle

• Oxidation of acetyl coenzyme A

1. Acetyl Coenzyme A + Oxaloacetic acid -- citric acid + C02 + H + 2ATP

Where does Krebs cycle occur

Mitochondria

What is added during Krebs cycle?

Protein and fats (Beta oxidation)

Beta oxidation

Fatty acids are converted into acetyl coenzyme a

Electron Transport Chain

• Transfer of electrons down a carrier chain

1. H + O2 -- H20 + 34ATP

How much ATP in total is produced from Aerobic Energy System?

38

1. 2 ATP from glycolysis

2. 2 ATP from Krebs cycle

3. 34 ATP from electron transfer chain

Were does Electron Transfer Chain take place?

Cristae

Advantages of the Aerobic System

1. Large amount of ATP is produced (38)

2. No fatigue by products

3. Lots of glycogen stores allow o2 to last a long time

Disadvantages of the Aerobic system

1. Complicated system (lots of chemical reactions) so can’t be used straight away.

2. Takes a while for enough o2 to become available to meet demands of activity and ensure glycogen/fatty acids are broken down

3. Fatty acid transportation to muscles is low and also requires 15% more o2 to be broken down into glycogen

What initially provides energy to an athlete?

Existing stores of ATP

Slow twitch (Type 1)

1. ATP production is in aerobic systems

2. Produces max amount of ATP available from each glucose molecule (36)

3. Production is slow

4. Fibres are more endurance based - less likely to fatigue

Fast Twitch (Type 2X)

1. Main pathway for ATP production via lactate anaerobic energy system

2. ATP production in absence of o2 is not efficient - 2 ATP produced per glucose molecule

3. Production of ATP is fast

4. Fibres have least resistance to muscle fatigue - ATP doesn’t last long

Oxygen consumption

the amount of oxygen we used to produce ATP and is usually referred to as VO2

EPOC

• the amount of oxygen consumed during recovery above that which would have been consumed at rest during the same time

  1. Fast component

  2. Slow component

The Fast component

1. Restoration of ATP and PC stores

2. Vol of o2 consumed in recovery above resting rate

3. The alactacid component

4. Re-saturate myoglobin with o2

5. Complete restoration of PC is up to 3 mins

6. 2-4 Litres of o2

7. 50% of stores can be replenished in 30 seconds

8. 75% in 60 seconds

The Slow component

• Lactacid component

• Take up to 1hour (depends on intensity + duration)

• Lactic acid is removed in multiple ways:

1. When o2 is present, lactic acid can be converted back into pyruvate and oxidised into co2 + water in active muscles/organs

2. Transported in blood + liver where it’s converted to blood glucose and glycogen

3. Converted into protein

4. Removed in sweat + urine

5. Cool down oxidises it as exercise keeps metabolic rate high and capillaries dilated

Slow component (Maintenance Higher Breathing Rate + Heart Rate)

1. This requires extra o2 to replenish energy for respiratory and heart muscle

2. Replenish ATP + PC

3. Re-saturate myoglobin

4. Remove lactic acid

5. This returns body to pre-exercise state

Slow component (Increase Body Temp)

1. Enables respiratory rates to remain high - helps performer take in more o2

2. However, extra o2 is needed to increase temp

Slow component (Glycogen Replenishment)

1. Glycogen is depleted during exercise

2. This is dependent on type of exercise and when/how much carbs are consumed after exercise

3. Can take several days eg marathon

4. Can take less then an hour eg 100m sprint

5. Significant amount of glucose is restored when lactic back to blood glucose and glycogen in the liver

6. Carbs + Protein, high carb meal, eating within 1 hour of exercise - accelerates restoration

EPOC AO3

1. FC allows performer to complete high intensity exercise

2. Train more frequently

3. SC delays impact of DOMS

Sub-maximal oxygen deficit

when there isn’t enough oxygen available at the start of exercise to provide energy aerobically

1. Due to increase in o2 consumption

Nutritional windows for optimal recovery

1. First 30 mins after exercise - Carbs + Protein in 3:1/4:1 (combination helps re-synthesis of muscle glycogen)

2. 1 to 3 hours after exercise - Carbs + protein + healthy fats

Energy transfer during Short duration, High intensity

1. Stored ATP in body used first

2. Energy is produced rapidly

3. ATP PC + Anaerobic Glycolytic system used - this is because the aerobic system is too complicated

4. ATP PC + Anaerobic Glycolytic - can’t produce energy for too long unless exercise is a lower intensity

Lactate Accumulation

1. Anaerobic Glycolytic produces lactic acid

2. As intensity increases, more lactic acid is produced

3. LA accumulates in muscles - increases acidity

4. This slows enzyme activity - affects breakdown of glycogen causing muscle fatigue

5. LA produced in muscles diffuses into blood which can be measured

Lactate Threshold (OBLA)

The point during exercise at which lactic acid accumulates in the blood

1. 4mmol/litre

2. Occurs as body is unable to provide enough o2 to breakdown lactic acid (change from aerobic to anaerobic)

Factors that affect Lactate Threshold

1. Intensity of Exercise - high intensity, faster LA

2. Fitness of Performer - physiological adaptive responses due to training (more mitochondria, greater capillary density, improved gaseous exchange)

3. VO2 Max of Performer - higher level, delayed LA

4. Respiratory Exchange Rate (RER) - closer value to 1.00, quicker LA occurs

5. Muscle Fibers used - slow twitch, delays LA

Respiratory exchange rate

A method of measuring energy expenditure of an athlete (ratio of CO2 produced compared to O2)

RER

1. Estimate use of fats and carbs during exercise

2. Tells us if performer working aerobically, anaerobic , energy system used

3. Closer to 1 = carbs

4. 0.7 = fats

5. Greater then 1 = anaerobic respiration

Lactate Sampling

1. Taking blood samples

2. Ensure training is correct intensity + monitor improvements

3. Provides accurate/objective measure

4. Measures OBLA

Indirect Calorimetry

measures the production of carbon dioxide or the consumption O2

1. Accurate estimation of energy expenditure

2. Reliable + precise

VO2 Max

maximum volume of oxygen that can be consumed by the working muscles per minute

Importance of High VO2 Max (AO2)

1. High vo2 max delays OBLA

2. Lactate threshold occurs at higher percentage VO2 max

3. Increase o2 capacity to muscles

VO2 Max AO3

1. Prevent DOMS

2. Increase endurance

3. High intensity

4. More likely to win endurance events

5. Able to recover quickly

VO2 Max Tests

1. Multi-stage fitness test

2. Havard step test

3. Cooper run

A-VO2 Diff

• difference between partial pressure of oxygen in arterial and venous blood

  1. Increases during exercise

  2. Means more oxygen is needed + extracted by muscles

  3. Used ATP production for endurance

Link between VO2 max and lactate threshold

1. Lactate threshold is a percentage of VO2 max

2. Higher VO2 max, more delay in lactic acid

3. As VO2 max increases, so does lactate threshold

4. Trained athletes can exercise for longer periods of time

Link between VO2 max and Aerobic Endurance

1. Higher VO2 max, grater endurance capacity of performer

2. Level of VO2 max determined genetically - limits impact of training

3. More O2 available - lactic acid broken down quicker (delays OBLA , prevent lactic acid)

Relative VO2 max

takes into account body weight

Factors that contribute to performer’s VO2 max

1. Lifestyle - exercise, smoking, diet

2. Training - continuous, aerobic, fartlek

3. Age - VO2 max decreases with age

4. Physiology - capillary density, alveoli SA, number of mitochondria, number of slow twitch fibres

5. Genetics - inherited factors limit improvement

6. Gender - men have 20% higher VO2 max then women

7. Body Composition - higher body fat decreases VO2 max

How aerobic training improves performers ability to transport o2

1. More blood volume - increased haemoglobin + myoglobin

2. Increased VO2 diff - more O2 extracted by muscles

3. Increased capillarisation - more capillaries

Altitude training

1. 2000m above sea level

2. 30 days

3. 3 phases - acclimization, primary training, recovery

4. As altitude increases, PP O2 decreases - reduction in diffusion gradient of o2 between air to lungs and blood to alveoli

5. Detraining - less O2 delivered to working muscles leading to a reduction in aerobic performance

6. Eventually body produces EPO to produce more red blood cells

7. Develops aerobic system - increased aerobic power

8. Alternate methods - altitude tent, apartment

Altitude training AO2

1. Sport is aerobic event so AT will specifically boost aerobic power

2. Increased con of HG means increased capacity of o2

3. Disadvantage

Advantages of Altitude Training

1. Increased number of red blood cells

2. Increased concentration of haemoglobin + myoglobin - more aerobic power is difference in winning

3. Body produces EPO capillarisation

4. Increased O2 carrying capacity

5. Increased myoglobin in muscles - higher average speed

6. Increase tolerance to lactic acid + delays OBLA

7. Benefits last 6-8 week

Disadvantages of Altitude training

1. Altitude sickness - worse performance

2. Detraining

3. Benefits lost within a few weeks back at sea level - must be performed close to be effective but too close may have negative impact

4. Body produces limited amount of EPO

5. Psychological issues - homesick

High Intensity Interval Training

1. Alternating periods of short intense anaerobic exercise with less intense aerobic recovery periods

2. Short duration (20s)

3. Short rest (10s)

4. Mix of intensities

5. Increase anaerobic + aerobic capacity

6. Reduce body fat + obesity

7. Motivational - short duration

8. Specific - duration, recovery, intensity

HIIT AO2

1. Sport specific skills included

2. Work:rest ratio adapted to sport

3. Anaerobic power developed is required for specific sport

4. Exercises can be sport specific

5. Individual or team

Advantages of HIIT

1. Works anaerobic energy system required in games

2. Mixture of high/low intensity mimics demands of game

3. Work : Rest can be altered to meet specific demands

4. Improves range of fitness components needed in team games eg aerobic endurance

5. Develops performers ability to perform skills under fatigue

6. Increase aerobic endurance more then continuous

Disadvantages of HIIT

1. Not appropriate for all positions eg weight training for rugby

2. Risk of injury due to high intensity - miss games

3. Intensity can negatively impact skill

4. Work : Rest differ depending on sport - difficult to be accurate

5. Other components than anaerobic power maybe more important

Plyometrics

1. Aim - power, speed, explosive strength

2. Hopping, bounding, depth jumping, medicine ball

3. 3 Phases - pre stretch, amortisation muscle contraction

Plyometrics Muscle and Nervous System

1. Fast twitch fibres (2x)

2. Eccentric muscle contracion then concentric

3. Stretch reflex activated

4. Detected by muscle spindles

5. Send nerve impulse o CNS

6. Elastic energy stored

7. Protects over stretching - avoid injury

Speed, Agility, Quickness Training

1. Progression exercise to improve motor abilities - skills faster + more accurate

2. Coached correct techniques for movements

3. Multi-directional movement

Advantages of SAQ Training

1. Increase muscular power

2. Improved kinesthesis

3. Improved motor skills

4. Improved reaction time