KPE264 pre midterm

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Module 1: Research Designs

• Longitudinal research tests the same subjects, comparing results over time.
• Cross-sectional research collects data from different populations, comparing groups in that population.
• Acute exercise responses are the body's reaction to a single workout.
• Chronic exercise responses are how the body adapts to repeated exercise sessions.

Confounding Variables

• A confounding variable influences both the independent and dependent variables, creating a misleading association.

Graphs

• The x-axis represents the independent variable
• The y-axis represents the dependent variable.

Module 2: Energy Production

• Bioenergetics examines how energy is transferred through chemical reactions in living things.
• Chemical energy from food is transferred into work.
• Food is converted into ATP to do work.
• "thermodynamics" is the term used to describe energy transfer
• Energy can take the form of heat, chemical, mechanical, or electrical energy,
• Energy cannot be created or destroyed (1st law of thermodynamics)
• Energy is only transferred from one form to another with some energy lost as heat.
• The efficiency of breaking down glucose is 40%
• Gas cars are 25 % efficient
• Electrical cars are 80% efficient
• Adenosine Triphosphate (ATP) is the primary energy currency.

ATP and Energy Transfer

• ATP is essential for starting physiological processes
• Fuel such as glucose is broken down by various enzymes
• This result is broken down glucose molecules and heat
• ATP is used to regenerate fuel such as glucose
• Fuel, energy and work are a cycle that replenishes itself

Fuel Sources for ATP Regeneration

• Phosphocreatine (PCr) can be used as a fuel source
• Carbohydrates such as glucose and glycogen can be used as fuel sources
• Fats as a fuel source
• Proteins as a fuel source

ATP Storage

• The body does not store large amounts of ATP because it is molecularly heavy, about ~1 kg of ATP is consumed per hour at rest
• During exercise, ATP usage can increase 100-fold.
• Some ATP supplements work but some do not
• Certain supplements produce about ~0.04s of energy
• It may not survive in the digestive system

Bioenergetics and Enzymes

• Bioenergetics involves studying energy transfer through chemical reactions in living tissues.
• Chemical reactions are sped up by enzymes.
• Enzymes do not cause the reaction
• Enzymes do not alter free energy change
• The body uses ATP and PCr as buffers to help maintain energy.
• Enzymes lower the "activation energy" needed for a reaction to occur.

Enzyme Mechanisms

• Enzymes work by binding to substrates at the active site
• Substrates concentrations are key
• ADP is a modulator(e.g ADP) – control, not breakdown everything, break down when needed
• Temperature effects enzyme activity
• pH effects enzyme activity
• Higher Substrate concentration increases higher likelihood of enzyme activity

Enzyme Activity and Substrate Concentration

• Low substrate concentration results in low enzyme rate, inactive enzymes
• Medium substrate concentration increases binding and reaction speed.
• High substrate concentration results in a highest amount of enzyme activity, and all bound enzymes

Enzyme Activity and Products

• By-products of reactions can stop an enzyme from continuing its process via negative feedback.

Modulators

• Stimulators augment enzyme activity at a given substrate concentration
• Modulators can inhibit enzyme substrate from binding to the active site
• Modulators can also bind to the enzyme, which allows the site to be more aavilable

Temperature and pH

• Enzymes denature at certain temperatures and are more sensitive to an increase in temperature
• normal body pH = 7.1
• During sprinting pH drops which causes fatigue which slows down enzymes

Sodium Bicarbonate

• Effective as a buffering agent for short and long term high intensity exercise
• Buffers can contribute to GI upset and may not be tolerated well
• May benefit athletes in: short distance cycling, dragon boating, dancing, or hockey
• Decreases muscle activity at rest and increase pH at rest

Bioenergetics

• Bioenergetics examines how energy is transferred through chemical reactions in living tissues
• Living tissue relates to metabolism
• Metabolism: sum of all chemical reactions in the body
• Catabolism: breakdown of molecules such as during exercise
• Anabolism: synthesis of molecules such as during recovery.

Cellular Metabolism

• Metabolism includes anabolism and catabolism

Fuel for Exercise

• Carbohydrates are broken down into glucose and glycogen in muscles.
• Lipids as fuel are stored as fatty acids in the bloodstream or in intramuscular triglycerides.
• Body breaks down proteins into amino acids (AAs)

Key Tissues for Exercise Metabolism

• Skeletal muscle utilizes most of the oxygen and needs ATP
• Liver uses glycogen
• Fat is stores in the adipose tissue and can be broken down into adipocytes and triglycerides

Fuel and Energy

• These estimates are based one a 65kg person with 12% body fat)
• Carbohydrates provides 4 calories per gram of energy
• Liver glycogen consist of 110g and provides 451 kcal used for maintaining glucose levels
• Muscle glycogen consist of 500g and provides 2,050 kcal and stores the most
• Glucose consist of 15g in body fluids and provides 62 kcal
• Fat provides 9 calories per gram
• Adipose tissue triglycerides (subcutaneous & visceral) consist of – 7,800g and provides 73,320 kcal
• Intramuscular triglycerides consist of 161g and provides 1,513kcal

ATP Homeostasis

• ATP + H2O is catalyzed by ATPase to form ADP + Pi
• ATPase refers to an enzyme
• Ca2+ ATPase effects homeostasis
• Myosin ATPase is located in myosin heads
• Myosin ATPase allows crossbridge formation
• Na+/K+ ATPase provides energy to transport sodium
• ATP is supplied for energy through Phosphagen breakdown, Non-oxidative glycolysis, and Oxidative metabolism
• Exercise creates an energy and ATP demand
• ADP needs to increase and ATP to decrease to restore energy
• Energy and ATP are suppied by PCR system, Anerobic glycolysis and Oxidative metabolism

Muscle Fiber Types

• Type I fibers (slow twitch) maintain exercise for prolonged periods by using oxygen to produce ATP, used for low-intensity exercise and are heavily relied on.
• Type II fibres (fast twitch) fatigue quickly, produce more force and ATP anaerobically, split into more aerobic Type IIa and more explosive Type IIx.

Module 2: Energy Systems

• The phosphagen system provides more ATP and is not available for a longer period of time
• Glycolytic can be relied on for long periods of time
• Oxidative can be used longer

Phosphagen

• Stores "buffer" the decrease in ATP
• The instantaneous process requires an instantaneous process which which depletes the system quickly and limits usage

Phosphocreatine

• Creatine comes from meat
• Buffers decline in ATP
• Close to sites of ADP accumulation
• Limited and cannot effectively rely on for long periods of time

Phosphagen Stores

• Phosphagen stores are heavily relied on first 15s of intense forceful movement
• Rest to work transition
• Relied on during workload transition such as sprinting
• Time to replenish phosphagen stores happens in around 5-10mins

Creatine Supplementation

• The basic theory is that creatine + ATP -> ADP + PCr
• 90% of creatine is store in skeletal muscle
• Can work in the cases of those who rely on the PCR system with brief, intense exercise
• Older adults benefit from supplementation because it helps with daily living
• Can cause weight gain
• Can affect fluid balance which results in cramping
• The goal is for creatine to work in the end up in the muscles

Glycolysis

• Partial breakdown of glucose or glycogen without the use of oxygen
• It is rapid but limited
• Produces approximately 2-3 units of ATP per unit of substrate, use glucose or glycogen
• Glucose: C6H12O6, glycogen: glucose polymer
• Glycolysis breaks down 1 glucose to from 2 pyruvate
• Glycogenolysis breaks down "glucose units" from glycogen to from glucose-1-phosphate

The Glycolytic System

• "GLUT" transporter brings glucose into the muscle during exercise
• Hexokinase traps glucose in the muscle
• Phosphofructokinase (PFK) - key enyzme

ATP

• ATP generation in occurs even in a lack of oxygen
• NADH is used in ETC to gen ATP
• If glucose Net ATP gain is =2
• If glycogen NET ATP gain is =3
• The liver stores g6-P for glucose

Fate of Pyruvate

• Pyruvate becomes lactate
• Lactate dehydrogenase (LDH)
• This process is anaerobic, NAD is essential to glycolysis

Creating energy

• In order to create acetyl coA
• Pyruvate Dehydrogenase (PDH) is key
• Pyruvate Dehydrogenase (PDH) process is Oxidated in the mitochondria

Generating Energy

• Lactate formation regenerates NAD

Heavy Reliance on Non-Oxidative Glycolysis

• Heavy reliance is due to intense exercise, low and high demand (rest-to-work)
• Can depend on the workload transition

Lactic Acid Issues

• Lactic acid increases and creates problems with builds up of H+
• H+ Largely effects muscle pH

Metabolic Inhibition

• H+ Lowers enzyme activity
• Decreases ability to continue power
• H+ interferes with PFK

Contracile Inhibition

• Decreases crossbridge cycling
• Interferes with actin & myosin
• Reduces efficiency in crossbridge formation

Metabolism

• The lactate anion is formed under aerobic conditions
• It is a major source for mitochondrial respiration and a gluconeogenic precursor
• Signals molecules and stimulates mitochondrial growth

Metabolism Breakdown

• CHOs, fats, and AAs are broken down to CO2 and H2O
• Energy is used when one is only left w/ CO2 & O2
• Oxygen is requires but sustained energy is provided
• Essential processes occur in the Mitochondrion

• 30 units of ATP are formed per unit of substrate

Mitochondria

• the powerhouse of the cell
• H+ pumped across intermembrane

Oxidative Metabolism

• Acetyl coA forms (CHO, fat, AA or any substrate)
• Coenzymes are reduced by NAD+ and FADH
• Electrons are lost and gained for reduction and oxidation

ATP Formation

• Coenzymes are oxided and ETC components are reduced

Carbohydrate Oxidation

• Pyruvate (3C) + NAD --> acetyl coA (2C) + CO2 + NADH
• In absence of oxygen results in lactate
• Pyruvate dehydrogenase which is an enzyme located in the mitochondria
• NADH is used in oxidative phosphorylation

Krebs Cycle

• NADH is generated which results in a NET increase 3 ATP in ETC
• FADH2 is generated which results in increased 2 ATP in ETC and gen ATP with citrate synthase

Oxidation

• electrons and reduction are transferred

Electron Transport Chain

• Electrons are passed through NADH, FADH to O2
• Cytochrome oxidase transfers H+ to O2 to create H2O
• ATP facilitates generation of ATP at the end of ETC

Cell Transport (Chemiosmotic Theory)

• ATP generated due to H+ ions crossing the membrane with 2 H+
• FADH2 is 1.5 ATP
• NADH is 2.5 ATP

Cellular Respiration

• The summary is the cellular respiration of CHO

Aerobic ATP

• This results from the maximum yield from carbohydrate when starting with six-carbon glucose
• Glycolysis results in 3 ATP from is anaerobic
• PDH results in a reaction
• TCA results in 15 of NADH, 3 of FADH2 and 2 of ATP

Max Energy

• These systems result in a total 33 ATP

Fat Oxidation

• Triglycerides are a basic component and are a part of fatty acids
• Major TG sources are in the adipose tissue, stores fat and skeletal muscle

Stages of Lipid Catabolism

• Mobilization breaks down in adipose tissue
• Transport creates FA and circulates through the blood to the albumin
• FA enters the cytosol
• Activation prepare for breakdown and is required by the mitochondria
• FA enters mitochondria
• Beta Oxidation breaks down FA
• Mito oxidation occurs in TCA cycle/ETC activity

FA Transport

• Transports 3 fatty acids and liver can convert to glucose

Key Enzymes

• Hormone -sensitive lipase (HSL) assists with breakdown of the adipose and muscle and helps to stimulates the breakdown of TG
• Hormones, cortisol, lack of glucose and insulin helps to to shut off HSL
• 3 FAs - catabolize with energy
• Glycerol converted to fuel

Lipid Transport

• A recognizable fatty acetyl -coA by mitochondria
• Carnitine palmitoyl transferase (CPT) assists with shuttles in FA - into mitochondria
• Carnitine serves as escort and is a part of CPT but can not be a part of FA transport
• Is unaivalbe during intense exercise

Carnitine

• Great for fat conversion
• Great for weight loss
• Has to work and end up inside mitochondria

Better fuel

• CHO 10% more O2 efficient

Requirements

• CHO permits exercise at a higher pace
• CHO oxidation is the dominate substrate for elite athlete performance training in events greater than 30s
• CHO Compromised when carbs are not there
• Impaired activation of PDH when low carbs

When to use oxidative

• When at Rest
• During steady state exercise
• or when there activities that last >2mins

Fuel for Exercise

• CHO 10% more O2 efficient
• CHO permit High performance
• It's better to have carbs for optimal performance with CHO oxidation is dominating
• You don't compromises performance when carbs are there and help activate
• You have to rely heavily on carbohydrates since it helps

The Process of Proteins

• Glycolysis, Protein and the body

Lipids and Fuel

• Proteins and Fuel are important

AA catabolism

• The process helps reduce weight

Metabolism

• AA assists

Substraight

• Glycogen increases

ATP

• There factors influence the availability of ATP

Anaerobic exercise response

• Wingate bike test is a anaerobic performance measurement taken at high break force
• Can measure 5 sec of peak of power and fatigue decline

Response to Lactate

• Lactate concentration after

VO2 Max

• The higher lactate results in increase

Exercise

• Higher volume results in high volume

What are the results

• This will not require all energy use

Fuel use

• This will depend on energy use

  Module 3

• Exercise is a blending of Non Aerobic with Aerobic

During P.C

• H & temps help

Factors

• The higher one works with energy use

Oxygen

• There are factors that influence the test