EDU2EXP Exercise & Performance Energy Systems. EDU2EXP Exercise & Performance Types of...

EDU2EXP Exercise & Performance

Energy Systems

Types of energy

•Chemical

•Mechanical

•Heat

•Light

•Electric

•Nuclear

Laws of ThermodynamicsLaws of Thermodynamics

• energy transfer always proceeds in the direction of increased entropy and the release of free energy

• 1- Energy cannot be created or destroyed– Chemical energy

mechanical energy

DefinitionsDefinitions• Enzymes

– Highly specific protein catalysts– Accelerate the forward and reverse reactions– Are neither consumed nor changed in the reaction

• Coenzymes– Complex nonprotein organic substances – facilitate enzyme action by binding the substrate

with its specific enzyme – transport chemical groups from one enzyme to

another.

Catabolism :

Metabolic pathways that break down molecules into smaller units and release energy

Catabolism and Anabolism

Overview of CatabolismGlucoseFFA’s Amino acids

glycolysis

mitochondria

-oxidation

TCACycle

deamination

NADH + H+

FADH + H+CO2

Acetyl CoA

Electron Transport

Figure 3.4, simplified

Anabolism

Covalent bonding of electrons, protons and small molecules to produce larger molecules building up

- Catabolism and anabolism function in a dynamic balance.

More definitions

• Exergonic is a spontaneous reaction that releases energy.

• Endergonic is an anabolic reaction that consumes energy.

Energy systems

Generate ATP under different conditions•ATP-PC

•Lactic acid/ glycolysis•Aerobic/ Oxidative

ATP- Adenosine Triphosphate

– Powers all of cell’s energy-requiring processes

– Potential energy extracted from food

– Energy is stored in

bonds of ATP– 80-100g is stored

Energy Systems Energy Systems

• Immediate energy 8 seconds– ATP-PC

• Short-term energy 1 or 2 minutes– Lactic acid system– Glycolytic system– Anaerobic glcolysis

• Long-term energy>3 minutes– Aerobic system

http://www.online-stopwatch.com/full-screen-stopwatch/

• All gone after 2 seconds maximal intensity

ATP-PC system

• Anaerobic resynthesis of ATP- 5-8 seconds of energy

• Hydrolyzed by the enzyme, creatine kinase

• ADP is phosphorylated to ATP

• Creatine may be phosphorylated back to PCr

Adenosine Diphosphate

• ADP is ATP minus one phosphate group

• 14 calories of energy is released each time ATP ADP

Remember the Spare Phosphate??

• The Spare P that was released from ATP ADP hooks up with Creatine to form …

• Creatine Phosphate (CrP)

• Cells store ~ 4 – 6 times more PCr than ATP

Creatine Supplementation

• If Phosphocreatine (PCr) is depleted, it cannot regenerate ATP

• Ingestion Creatine monohydrate (20 g per day) over 5 days increased stores PC

• Therefore improves performance short intense exercise in non weight bearing exercise

• Also enhanced physiologic adaptation to resistance training Increased dynamic muscular strength and muscle mass

• Beware of side effects long term still unknown

GlycolysisGlycolysis

• During performances of short duration and high intensity that require rapid energy transfer that exceeds that supplied by phosphagens – 400-m sprint– 100-m swim – Multi-sprint sports

• Anything up to 3 minutes• Lactate is the by product “Lactic acid system’

Glycolysis

• Breakdown of glucose or glycogen to form 2 molecules pyruvate and 4 ATP

• Requires 2 molecules ATP for the process to occur

• = Net gain 2 molecules ATP

Lactic acid? Lactate?

• Not the same

• Lactate that accumulates during anaerobic metabolism does not cause acidosis

• Lactate Pyruvate Acetyl CoA Kreb’s cycle & Aerobic production ATP

Lactic Acid System Lactic Acid System

• Blood lactate @ rest is usually 1-2 mmol/L but can rise to over 20 mmol/L during intense exertion.

• Lactate accumulation– rate of lactate production

exceeds the rate of lactate removal

• Lactate removal– Gluconeogenesis-

conversion to glucose through Cori cycle in the liver

If oxygen present:– Oxidation to pyruvate

• Fuels citric acid cycle

Lactate Inflexion Point- LIP

• Intensity of exercise above which anaerobic energy system is required to meet energy demands.

• Lactate accumulates as removal cannot exceed production

• Measurable as blood lactate levels increase substantially

of text

AerobicAerobic

• Oxidative Phosphorylation

• Lipids– Lipolysis– Beta oxidation– Kreb’s cycle

• Carbs– Glycolysis – Pyruvate Acetyl CoA– Krebs cycle (citric acid

cycle or tricarboxylic acid cycle)

– Electron transport chain

Krebs Cycle

• Also known as the TCA cycle, or citric acid cycle

• Continues oxidation of – Carbohydrates following glycolysis– Fatty acids following beta oxidation– Some amino acids following deamination

http://www.youtube.com/watch?v=1aYPo5xNVIA

Anaerobic/ aerobic systems

• 12 chemical reactions to convert carbohydrate (either stored glycogen or circulating blood glucose) to pyruvate

No Oxygen

Pyruvate converted to Lactate

Produces 2-3 mol ATP

Oxygen

Pyruvate enters Krebs cycle and is used to generate ATP

Produces 38-39 mol ATP

What you need to know:

Transition to Exercise

• O2 consumption

Recovery-EPOC

• O2 consumption remains elevated

• O2 Dept = payment for O2 deficit

Pg 118 text

Vo2 Max

• Determines cardiovascular fitness

• O2 uptake increases with intensity of exercise up until a certain point

• ml/kg/minute• Factors influencing:

– Delivery– uptake

Yield: 1g = 4.1 Cal

Yield: 1g = 9.4 Cal

Chronic Adaptations to TrainingMetabolic pathway Adaptation Consequence

Mitochondrialrespiration

Small May improve recovery

Glycogen Concentration Fuel for glycolysis

Glycolysis Activity ofphosphorylase

Rate of glycolysis

Activity of PFK Rate of glycolysis

ATP Small Tolerance of intenseexercise

Metabolic pathway Adaptation Consequence

Creatinephosphate

Small Capacity to rapidlyregenerate ATP

Buffering capacity Capacity Delays fatigue fromacidosis ATP from glycolysis

Implications

Sources of Fatigue- p 113 text

• PCr depletion• Muscle glycogen depletion• Neuromuscular- nerve impulses• CNS- muscle recruitment• Metabolic by-products

– Lactate– Hydrogen ions low ph– Buffers- bicarbonate

Muscle Fibre Types

• Type 1 = Slow twitch– Generates energy aerobically– For endurance exercise

• Type 2 = fast twitch• 2a- some aerobic power / anaerobic• 2b-predominantly anaerobic

– Generates energy anaerobically– For short intense exercise

Recovery from exercise

• Remove lactate

• Re-oxygenation muscle myoglobin

• Replace– Muscle glycogen– PCr– Lipid levels

Active recovery

• Movement at a lower intensity/ submax performed immediately after exercise

• Assists with oxidation of lactate (Lactate shuttling)

• But as is aerobic may impair

glycogen synthesis

Passive recovery

• Lie down complete inactivity

• Theory is that this ‘frees’ oxygen for the recovery process

• Downfall no lactate shuttling

Which is best?

• Research inconclusive• Depends on exercise to recover from• Steady rate exercise

– PCr stores not depleted– Lactate levels not increased– Depends on post exercise glucose intake

• Intense/Non-Steady rate exercise– Large O2 deficit

Lactate Removal

Exercise Recovery

Passive

Active Passive

Summary

• Energy is never created nor destroyed. • Complex chemical process synthesize

glucose/ glycogen from our foods• Immediate energyATP-PC• Short-term energy Lactic acid system• Long-term energy Aerobic system• Dynamic balance• Training• Recovery

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