Unit 3
Energy Systems Muscle Fibres Nervous System Cardiovascular System Respiratory System
Energy Systems & Muscle Fibres
PSE4U
Energy Systems
Carbohydrates: Most abundant
organic substance in nature they are essential for human an animal life
Glucose: Is broken down to form ATP
(adenosine triphosphate) Is stored in muscles and
liver as GLYCOGEN – can be broken down under conditions of stress or the demands of muscular activity Created by photosynthesis
CO2 + H2O + sunlight E C6H12 O6 + O2
Law of Conservation of Energy Energy is neither created nor destroyed
only transformed from one form to another ▪ Ex. Light energy from the sun is “captured” by plants
during the process of photosynthesis and converted to chemical energy (food)
CHEMICAL ENERGY (food) – is used to make ATP (free energy)
Adenosine adenosine Triphosphate diphosphate phosphate ATP -------------> ADP + P
A-P - P - P -------------> A- P-P + P
ATP
Energy Energy In Out
ADP
2 Methods for Resynthesis of ATP
1. ANAEROBIC (without oxygen) – short high intense activity
2. AEROBIC (with oxygen) – endurance
These two systems coexist, overlap and interact in various combinations
Most activities rely on a combination of both systems
ANAEROBIC
Occurs relatively quickly in the muscle fibres, utilizing chemical and enzymes readily at hand for powerful but relatively short lived activitites
Anaerobic can be broken down into 2 systems: ▪ PATHWAY 1: Anaerobic Alactic (ATP-PC)▪ PATHWAY 2: Anaerobic Lactic (Glycolosis)
PATHWAY 1: Anaerobic Alactic
Name ATP-PC(Anaerobic Alactic System)
Location of Activity CytoplasmEnergy Source Creatine Phosphate (PC)Uses Oxygen or Not Anaerobic (without oxygen)ATP created 1 moleculeDuration 10-15 secondsNumber of Chemical Reactions
1-2
By-Products None
PATHWAY 1: Anaerobic AlacticName ATP-PC
(Anaerobic Alactic System)Basic Formula PC + ADP ATP + creatine Type of Activities Power surges, speed eventsTypes of exercise that rely on this system
Sprints, jumps, weightlifting
Advantages Very quick surge of powerLimitations of energy system
Short duration, muscles store small amounts of ATP and creatine phosphate
Muscle fibre type recruited Type IIB (fast-twitch• Is important as it provides the highest rate of ATP
synthesis that cannot be matched by other, more complex energy systems
• Recovery Period of PC 2-5 min – requires ATP to resynthesize PC
PATHWAY 2: Anaerobic Lactic
Name Glycolysis(Anaerobic Lactic System)
Location of Activity CytoplasmEnergy Source Glucose (Glycogen)
* Glycolysis is the first step in the breakdown of glucose
Uses Oxygen or Not Anaerobic (without oxygen)ATP created 2 molecules per glucose moleculeDuration 15 seconds to 3 minutesNumber of Chemical Reactions
11* Has a lot more steps but yields twice as much ATP over Anaerobic Alactic sytem
By-Products Lactic Acid
Name Glycolysis(Anaerobic Lactic System)
Basic Formula C6H12O6 + 6O2 + 36ADP + 36 P 6CO2 + 6H2O + 36 ATP
Type of Activities Intermediate activities/sprint finishes
Types of exercise that rely on this system
200-800 metre runs, shift in hockey
Advantages Quick surge of power
Limitations of energy system
Buildup of lactic acid causes pain and fatigue
Muscle fibre type recruited
Type IIA (fast twitch)
PATHWAY 2: Anaerobic Lactic
PATHWAY 2: Anaerobic Lactic
PYRUVATE is the by-product of glycolysis when oxygen is not present it continues to breakdown into LACTIC ACID▪ LACTIC ACID –decreases muscles ability to
contract
GLUCOSE
PYRUVATE (without O2) LACTIC ACID(with O2) (Kreb’s Cycle)
Name Cellular Respiration (Aerobic System)
Location of Activity MitochondriaEnergy Source Glycogen, Fats, ProteinsUses Oxygen or Not Aerobic (with Oxygen)ATP created 36 Molecules per glucose molecule Duration 120 seconds and beyondNumber of Chemical Reactions
Glycolysis Kreb’s CycleElectron Transport Chain
By-Products Water and Carbon Dioxide
AEROBICPathway 3: Aerobic Pathway
Name Cellular Respiration(Aerobic System)
Basic Formula C6H12O6 + 6O2 + 36ADP + 36 P 6CO2 + 6H2O + 36 ATP
Type of Activities Prolonged activities
Types of exercise that rely on this system
Marathons, exercise classes
Advantages Long duration, complete breakdown of glucose
Limitations of energy system
Slow, requires large amounts of oxygen
Muscle fibre type recruited
Type I (slow-twitch)
AEROBICPathway 3: Aerobic Pathway
AEROBICPathway 3: Aerobic Pathway
Glucose fuels this system but,▪ Fats can be broken down when exercise occurs for
longer than 20 min▪ Proteins can be broken down in chronic situations –
starvation
Complete breakdown of glucose, unlike anaerobic lactic that stops after glycolysis
This system can be sustained as long as oxygen is present and physiological limits are not reached.
CELLULAR RESPIRATION – 36 ATP
Glucose
Pyruvate (with Oxygen)
Electron Transport Chain
2 ATP are Made
2 ATP are Made
32 ATP are Made
Lactic AcidBlood Lactate Threshold (anaerobic
threshold) Point at which lactate levels in the blood increase
abruptly beyond resting values
Onset of Blood Lactate Accumulation (OBLA)▪ Point at which blood lactate levels begin to accumulate
very rapidly.
Raising the Lactic Acid Threshold – Need to do power training ▪ Raising the lactic acid threshold will allow you to utilize
your anaerobic lactic system for a longer period of time as the build up of lactate will be slower.
Cori Cycle Lactic Acid creation and breakdown
MUSLCE
Glucose
Pyruvic Acid
Lactic Acid
LIVER
Glucose
Pyruvic Acid
Lactic Acid
Can be Stored in liver or
muscles as glycogen
Energy from Fats FATS – ideal as they contain large quantities
of stored energyTriglycerides Fatty Acids
Lipolysis
Fatty Acids Acetyl CoA
Beta Oxidation enter KREB’s CYCLE
Energy from Protein PROTEIN – same amount of energy as
carbohydrates (glucose) but ½ as much as fat
No protein reservoirs in the body like carbs and fats, all proteins are part of existing body tissue or actively engaged as in metabolic systems
Made up of long chains of amino acids
Individual amino acids are broken down further and enter energy system
Muscle Fibres
We have different types of muscle fibres in our body and each type of muscle fibre is more adapted to a certain energy system. Slow Twitch Muscle Fibres▪ Generate and relax tension slowly but are able to
maintain lower levels of tension for a long period of time.
Fast Twitch Muscle Fibres▪ Have the ability to tense and relax quickly and can
generate large amounts of tension but have low endurance levels.
Muscle Fibre Distribution for Athletes in Different Sports
Slow - Twitch Fast – Twitch
Cyclist 61% 39%
Canoeist 61% 39%
Middle – Distance Runner
59% 41%
Swimmer 58% 42%
Weightlifting 46% 54%
Sprinter 26% 74%
Soccer Player 53% 47%
Myoglobin The difference in muscle fibre types are mainly
due to the extent to which a particular muscle relies on oxygen in the production of energy.
MYOGLOBIN – is the oxygen storage unit that
delivers oxygen to working muscles.
The more a muscle utilizes aerobic processes for energy production the more myoglobin it has. ▪ Slow twitch muslce fibres (red) are high in myoglobin ▪ Fast twitch muscle fibres (white) are low in myoglobin
Characteristics of Different Muscle Fibre Types
Type I Slow Oxidative (SO)
Type IIAFast Oxidative Glycolysis (FOG)
Type IIBFast Glycolysis(FG)
Colour Red Red/White WhiteFibre Diameter Small Medium LargeContraction Speed
Slow (110ms) Fast Very Fast (50ms)
Force Production
Low Intermediate High
Energy Efficiency
High Low Low
Myoglobin Content
High Moderately high Low
Myosin ATPase Low High HighFatigue Resistance
High Moderate Low
Aerobic Capacity
High Moderate Low
Anaerobic Capacity
Low High High
Tonic vs. Phasic Muscles
Tonic Muscles – assists the body with maintaining posture or stability during activities such as standing, walking and throwing. ▪ High percentage of Type I fibres
Phasic Muscles – characterised by a higher percentage of Type IIA and Type IIB