Woodland Christian High School EnergySystems Energy for Muscular Activity Unit 1: Human Anatomy

Woodland Christian High School

EnergyEnergy

SystemsSystems

Energy for Energy for Muscular ActivityMuscular Activity

Unit 1: Human Anatomy


How a Muscle Uses EnergyHow a Muscle Uses EnergyEnergy Systems

The ability to move, work or play sports is dependant on supplying sufficient energy for the duration of the activity.

To achieve muscle contraction, chemical energy has to be converted into mechanical energy. The source of this energy is stored in the high energy phosphate bonds of ATP.An ATP molecule consists of an adenosine molecule bonded to three phosphate groups.

Adenosine P P P



To release energy, a phosphate molecule breaks away from the phosphate group to form adenosine diphosphate (ADP).

Adenosine P P P Hydrolysis

Breaking ATP into ADP releases energy and allows cross bridge formation to occur inside the muscle.

Energy

Heat

PAdenosine P P



A cell stores only a small amount of ATP. It can provide energy for only 5 seconds of strenuous exercise. ATP has to be continuously replenished since it is the only direct energy source for muscle contraction. When ADP accumulates the body begins the process of restoring ATP.

Adenosine P P + P

• To accomplish this synthesis, energy must be available;

• Energy is supplied through the breakdown of complex molecules, such as fats and carbohydrates.

Energy +

Adenosine P P P



The biochemical reactions in each system are complex, and the body’s preference for anaerobic or aerobic metabolism depends on several factors including the :

• type of muscle fibre involved in the activity;

• intensity and duration of exercise;

• level of training.

The production of ATP involves different energy systems designated as anaerobic or aerobic each producing ATP at a distinct rate and duration.

Anaerobic – without oxygen

Aerobic – with oxygen


Restoration of ATPRestoration of ATPEnergy Systems


The Three Energy SystemsThe Three Energy SystemsEnergy Systems

Anaerobic Alactic

A short term energy of both fast and slow twitch muscle fibres that does not require oxygen and does not produce lactic acid.Anaerobic Lactic

A fast twitch muscle energy system which does not require the immediate use of oxygen but does produce lactic acid

Aerobic

A slow twitch muscle energy system which is used in prolonged continuous activity in the presence of oxygen and does not produce lactic acid.

Anaerobic

Energy systems that do not rely on the immediate use of oxygen. There are two types of anaerobic energy systems.


Anaerobic Alactic: Anaerobic Alactic: ATP-CP SystemATP-CP System

Energy Systems

An immediate - high energy phosphate system

Energy

Heat

Adenosine P P P

Involves activities such as weight lifting, high jump, long jump, shot put, discus 50 metre sprint, 25 metre swim

Involves high power output activities that require an immediate high rate of energy production for a short period of time


Anaerobic Alactic: Anaerobic Alactic: ATP-CP SystemATP-CP System

Energy Systems

As muscle contraction begins, the body may not be able to supply ATP to the contracting muscle cells as rapidly as required. Creatine phosphate serves as a quick available energy reserve for muscles as it is broken down into creatine and phosphate.

Adenosine P P CreatineP

CP CP

CP CP

CP CP

+

ATP

The free phosphate ions bonds with ADP to produce ATP and leave behind creatine. The new ATP molecule is stored as potential energy. Creatine phosphate can only support muscle contraction for another 3 to 4 seconds.

Energy


Anaerobic Alactic Anaerobic Alactic CharacteristicsCharacteristics

Energy Systems

• Only a small amount of ATP and CP is stored in muscle fibres;

• Uses very large amounts of energy in a short period of time;

• The rate of recovery is rapid. After a brief rest, the system is recharged and ready for the next sprint;

• Oxygen is not required;• Lactic acid is not produced;• Provides energy for muscles for the first 5-10 seconds of

high intense activity;• Uses both fast and slow twitch muscles;• Work output is relatively high.


Characteristics of the Characteristics of the Anaerobic Alactic SystemAnaerobic Alactic System

Energy Systems

Energy System Anaerobic Alactic

Type of Activityshort sprints used in baseball,

pole vault, long jump, triple jump

Range of Maximum Work Times

0 – 10 seconds

Oxygen Required None

Lactic Acid Produced None

Energy Source

Chemical energy stored in muscles

Adenosine TriphosphateCreatine and Phosphate

End Products of Fuel Breakdown

Adenosine DiphosphateCreatine Phosphate plus energy

Muscle Fibre Recruited Fast and Slow Twitch

Work Output per Unit of Time High


Anaerobic Lactic: Anaerobic Lactic: The Lactic Acid SystemThe Lactic Acid System

Energy Systems

If an athlete continues to work beyond 10 s, a second energy system uses glucose to provide energy. Glucose, which is stored in muscle cells and in the liver (glycogen), can provide immediate energy without oxygen.

ADP + P ATP Energy

GlucoseLacticAcid

When glucose is converted into energy lactic acid is produced.


The Effects of Lactic AcidThe Effects of Lactic AcidEnergy Systems

Moderate

Fast-twitch type A fibres are recruited

E X E R C I S E I N T E N S I T Y

Low

Slow twitch fibres dominate

High

Fast-twitch Type B fibres dominate

The anaerobic threshold is the highest intensity of workload at which lactate clearance still keeps pace with lactate production.

Once this level is reached the intensity level must decrease to reduce the amount of lactic acid build-up

During intense exercise, lactic acid builds up in the blood faster than it can be removed. As lactic acid build up an athlete will reach their anaerobic threshold.


Anaerobic ThresholdAnaerobic ThresholdEnergy Systems

At the anaerobic threshold the muscle loses its ability

to contract resulting in muscle fatigue.

Anaerobic threshold is the point where a person begins to feel discomfort and a burning sensation in their muscles.



Lactic acid causes pH changes in the muscle fibres and they can no longer respond to stimulation.

A high production of lactic acid ultimately limits continued performance in intense activities

Lactic acid interferes with cross-bridge bonding by limiting the strength of the fibre contraction.



When lactic acid accumulates, extreme fatigue sets in and oxygen deficit develops.

• After you stop anaerobic exercise, your body needs extra oxygen to burn up the excess lactic acid and return your energy reserves to normal.

• Lactic acid cannot be removed until extra oxygen is supplied to convert it to harmless, re-usable products.

• Oxygen deficit is the reason you must breathe rapidly and deeply for a few minutes after strenuous exercise.


Characteristics of the Characteristics of the Lactic Acid SystemLactic Acid System

Energy Systems

• The energy source comes entirely from glucose;

• Oxygen is not required;

• Energy is provided for 10-60 or 120 seconds depending on conditioning;

• Uses predominately fast twitch muscle fibres;

• Work output is moderate;

• Used in sports such as football, basketball and hockey.


Characteristics of the Characteristics of the Lactic Acid SystemLactic Acid System

Energy Systems

Energy System Anaerobic Lactic

Type of Activitygames such as football,

basketball, hockey


10 seconds to 60 or 120 seconds depending on

conditioning

Oxygen Required None or very little

Lactic Acid ProducedYes, accumulated faster than it can be removed

Energy Source Entirely carbohydrate


Lactic Acid

Muscle Fibre Recruited Predominately Fast Twitch

Work Output per Unit of Time

Medium


Effects of Training on Effects of Training on the Lactic Acid Systemthe Lactic Acid System

Energy Systems

• The individual can work out at a higher rate of activity before lactic acid build-up begins.

• The individual is able to “handle” a higher level of lactic acid.

• Trained individuals are able to remove lactic acid faster from exercising muscles.

• The anaerobic threshold rises.

At any level of work, the rate of lactic acid build-up is decreased through training. Improvements in the cardiovascular system deliver an increased blood flow to the working muscle and,


The Aerobic System:The Aerobic System:Long Term EnergyLong Term Energy

Energy Systems

As the length of an exercise session continues the athlete requires a steady power output over a long period of time

Exercise performed at a lower intensity level relies almost exclusively on the aerobic system for energy production and required the athlete to use oxygen as its source of energy.

• Most daily activities use energy provided by the aerobic energy system

• The oxygen energy system is the most important energy system in the body.

While this pathway cannot generate the speed of the anaerobic, it does provide a great deal more efficiency and endurance.


The Aerobic System:The Aerobic System:Long Term EnergyLong Term Energy

Energy Systems

The aerobic system energy requires the metabolism of

Fats ProteinsOxygen

Glucose stored in muscles

combine to produce

CO2Water using energy

produces

ADP + P ATP

Energy


Characteristics of the Characteristics of the Aerobic SystemAerobic System

Energy Systems

• it prevents the build-up of lactic acid;

• an individual can work out longer before lactic acid build-up begins;

• it is able to remove lactic acid from muscles allowing the muscle to continue to contract allowing exercise to continue;

• it promotes the re-synthesis of ATP for energy when work output is low.

The oxygen system is highly efficient. When oxygen is used in muscle cells:



Energy Systems

Due to this, there are two limitations to the aerobic system:

As the duration of activity increases, the contribution of the aerobic system to the total energy requirement increases.

The system requires a continuous supply of oxygen and fuel sources necessary for the aerobic metabolism.

The use of ATP must be relatively slow to allow the process to meet the energy demands.



Energy Systems

Energy System Aerobic

Type of Activitylong distance running, cross

country skiing, swimming


120 seconds plus

Oxygen Required Yes

Lactic Acid Produced Depends on intensity

Energy SourceMixture of fat and

carbohydrate


CO2 and H2O

Muscle Fibre Recruited Slow twitch and some fast twitch

Work Output per Unit of Time Low


Aerobic PowerAerobic PowerEnergy Systems

As the intensity of work increases the capacity of aerobic system reaches a maximum. The greatest rate at which oxygen can be taken in and used during exercise is referred to maximal oxygen consumption or (VO2max)

Oxygen uptake

The power of the aerobic system is generally evaluated by measuring the maximum volume of oxygen that can be consumed in a given amount of time. This can be measured by determining the amount of oxygen exhaled as compared to the amount inhaled.


Aerobic Power – Max VOAerobic Power – Max VO22

Energy Systems

• The maximal rate at which oxygen can be used is genetically determined.

• A normal VO2 max for most high school athletes

would fall somewhere between 30 and 50 range.

• The VO2 max values of trained athletes will reach 65-75 for males and 50-60 for females

Each person has his or her own maximal rate of oxygen consumption (VO2 max)

The more active we are the higher the VO2 max will be in that range.


Max VOMax VO2 2 StandardsStandards for 2.4 km for 2.4 km RunRun

Energy Systems

Time Max VO2 Time Max VO2

8:00 65.2 10:45 48.9

8:15 64.9 11.00 47.6

8:30 63.2 11.15 46.1

8:45 61.3 11:30 44.7

9:00 59.1 11.45 43.2

9:15 57.9 12:00 41.7

9:30 56.7 12:15 40.3

9:45 55.6 12:30 38.9

10:00 53.1 12:45 37.4

10:15 51.8 13:00 36.2

10:30 50.1 13:15 35.1


Max VOMax VO2 2 StandardsStandards for Beep for Beep TestTest

Energy Systems


Max VOMax VO2 2 NormsNormsEnergy Systems

Female (values in ml/kg/min)

AgeVery Poor

Poor Fair Good Excellent Superior

13-19 <25.0 25.0 - 30.9 31.0 - 34.9 35.0 - 38.9 39.0 - 41.9 >41.9

20-29 <23.6 23.6 - 28.9 29.0 - 32.9 33.0 - 36.9 37.0 - 41.0 >41.0

30-39 <22.8 22.8 - 26.9 27.0 - 31.4 31.5 - 35.6 35.7 - 40.0 >40.0

40-49 <21.0 21.0 - 24.4 24.5 - 28.9 29.0 - 32.8 32.9 - 36.9 >36.9

50-59 <20.2 20.2 - 22.7 22.8 - 26.9 27.0 - 31.4 31.5 - 35.7 >35.7

60+ <17.5 17.5 - 20.1 20.2 - 24.4 24.5 - 30.2 30.3 - 31.4 >31.4

Male (values in ml/kg/min)

AgeVery Poor

Poor Fair Good Excellent Superior

13-19 <35.0 35.0 - 38.3 38.4 - 45.1 45.2 - 50.9 51.0 - 55.9 >55.9

20-29 <33.0 33.0 - 36.4 36.5 - 42.4 42.5 - 46.4 46.5 - 52.4 >52.4

30-39 <31.5 31.5 - 35.4 35.5 - 40.9 41.0 - 44.9 45.0 - 49.4 >49.4

40-49 <30.2 30.2 - 33.5 33.6 - 38.9 39.0 - 43.7 43.8 - 48.0 >48.0

50-59 <26.1 26.1 - 30.9 31.0 - 35.7 35.8 - 40.9 41.0 - 45.3 >45.3

60+ <20.5 20.5 - 26.0 26.1 - 32.2 32.3 - 36.4 36.5 - 44.2 >44.2

Table Reference: The Physical Fitness Specialist Certification Manual, The Cooper Institute for Aerobics Research, Dallas TX, revised 1997 printed in Advance Fitness Assessment & Exercise Prescription, 3rd Edition, Vivian H. Heyward, 1998.p48


VOVO22 Max in Athletes Max in Athletes and Non-Athletesand Non-Athletes

Energy Systems

VO2 max varies greatly between individuals and even between elite athletes that compete in the same sport. In previously sedentary people, training at 75% of aerobic power, for 30 minutes, 3 times a week over 6 months increases VO2 max an average of 15-20%


Improving VOImproving VO22 MaxMaxEnergy Systems

Genetics plays a major role in a person’s VO2 max and heredity can account for up to 25-50% of the variance seen between individuals. The highest ever recorded VO2 max is 94 ml/kg/min in men and 77 ml/kg/min in women. Both were cross-country skiers The extent by which VO2 max can change with training also depends on the starting point. The fitter an individual is to begin with, the less potential there is for an increase and most elite athletes hit this peak early in their career. There also seems to be a genetic upper limit beyond which, further increases in either intensity or volume have no effect on aerobic power. This upper limit is thought to be reached within 8 to 18 months.


VOVO22 Max as a Max as a Predictor of PerformancePredictor of Performance

Energy Systems

In elite athletes, VO2 max is not a good predictor of performance. The winner of a marathon race for example, cannot be predicted from maximal oxygen uptake. Perhaps more significant than VO2 max is the speed at which an athlete can run, bike or swim at VO2 max. Two athletes may have the same level of aerobic power but one may reach their VO2 max at a running speed of 20 km/hr and the other at 22 km/hr.

While a high VO2 max may be a prerequisite for performance in endurance events at the highest level, other variables such as anaerobic threshold are more predictive of performance.


Oxygen DeficitOxygen DeficitEnergy Systems

While exercising intensely the body is sometimes unable to meet all of its energy needs. Specifically, it is unable to take in and absorb enough oxygen to adequately 'feed' the muscles the amounts of energy needed to adequately perform the tasks the athlete is requesting from the body.

In order to make up thedifference without sacrificingoutput, the body must tap intoits anaerobic metabolism. This where the body uses bothaerobic and anaerobic energy production. While not hugely detrimental, oxygen deficitscan grow to a level that the anaerobic energy system cannot cover. This can cause performance to deteriorate.


Oxygen DebtOxygen DebtEnergy Systems

Oxygen debt refers to post exercise oxygen consumption where the body needs to pay back its debt incurred above after the exercise is over

You will notice that even after you are done racing you will continue to breath hard.

At this point your body is still trying to repay the oxygen debt that was created when you were working hard.


Effects of Training onEffects of Training on the Aerobic System the Aerobic System

Energy Systems

Long, slow distance training or exercise at the low end of your target heart rate tends to use slow twitch fibres. Walking, jogging or any other light exercise, uses mainly slow-twitch fibres to do the work. ST fibres are slower to fatigue and are well suited for endurance activities.

The performance of any activity requires a certain rate of oxygen consumption. A person’s ability to perform an activity is limited by their maximal rate of oxygen consumption; Therefore, the most efficient method for improving the aerobic energy system is endurance training/exercise.



Energy Systems

Notes: A highly trained or elite athlete should be able to sustain a heart rate of 85% of their VO2 max.

This type of training does not raise your anaerobic threshold.

Generally, the higher the intensity, the greater the oxygen consumption. When exercising the target heart rate (THR) should be raised to 70% of max. Examples include:running, swimming or biking for 40 minutes

or more at a heart rate of 130-140 bpm

Endurance exercise consists of repeated, sustained effort of long duration several times per week;



Energy Systems

Endurance training has four major effects on the aerobic system:

• Improved delivery of oxygen and nutrients to the muscles

• Increase the size and number of mitochondria in muscle fibres

• Increased activity of enzymes involved in the aerobic pathway

• Preferential use of fats over glucose during exercise which saves the muscles limited store of glycogen


Using the Systems TogetherUsing the Systems TogetherEnergy Systems

While running at a comfortable pace you use both systems, but the anaerobic - aerobic ratio is low enough that the lactate generated is easily removed, and doesn't build up.

Note: Depending upon the distance, and effort, the body can use different proportions of both of these systems. For example, the 800 m race is too long to be a sprint, but too short to be a distance race. Therefore, it is run at the cross-over between the aerobic and anaerobic systems.

As the pace is increased, eventually a point is reached where the production of lactate, by the anaerobic system, is greater than its removal. The anaerobic threshold is the point where lactate (lactic acid) begins to accumulate in the bloodstream.


Training the Systems TogetherTraining the Systems TogetherEnergy Systems

The best method to train all of the systems together is interval training. Interval work consists of repeating a series of short, high intensity, runs alternating with rest (recovery) periods.

Whichever interval training method is used, the athlete must continually push themselves into a state where lactic acid builds, forcing their body’s to adapt.

Regardless of the race distance you are training for, 5k or marathon, interval work will help you run faster.


Interval TrainingInterval TrainingEnergy Systems

Pushing the body past the 'comfortable' speed of running increases aerobic capacity, trains the fast twitch muscles to operate at a higher/faster level and makes the athlete more tolerant of lactic acid build up.

The result of interval training is that a runner who can comfortably run a six-minute/mile pace and runs their intervals at a five-minute/mile pace will be able to increase their steady comfortable pace under an six-minute/mile pace.


Roles of the Three Energy Roles of the Three Energy Systems in Competitive SportSystems in Competitive Sport

Energy Systems

EnergyPathways

Anaerobic Pathways Aerobic Pathways

Primary Energy Source

ATP produced without the presence of oxygen

ATP produced with the presence of oxygen

Energy System

Immediate Alactic

Short-term Lactic Long-term Oxygen

Fuel ATP and CP Glycogen + glucose Glycogen, glucose, fat and protein

Duration

0s 10s 40s 70s 2 min 6 min 25 min 1 hr 2hr 3hr

Sport Event

Sprinting 100 m dash

Throwing

Jumping

Weightlifting

Ski jumping

Diving

Vaulting in Gymnastics

Track 200-400 m

500m Speedskating

Most gymnastics events

Cycling (track)

50 m swim

100 m Swim

800 m track

Gymnastic floor exercise

Alpine skiing

Cycling 1000 m pursuit

Middle distance track, swimming, speedskating

1000 m canoe

Boxing

Wrestling

Rowing

Figure skating

Cycling, pursuit

Long Distance track swimming, canoeing, speedskating

Cyclingroad racing

Marathon

Triathlon

Most team Sports/Racquet Sports


SummarySummaryEnergy Systems

Energy System Anaerobic Alactic Anaerobic Lactic Aerobic

Type of Activityshort sprints used inbaseball, pole vault

long jump triple jump

games such as football, basketball hockey

long distance running

cross country skiing

swimming


0 – 10 seconds10 to 60 or 120 seconds

(depending on conditioning)

120 seconds plus

Oxygen Required

None None or very little Yes

Lactic Acid Produced

NoneYes, accumulated faster than it can be removed

Depends on

intensity

Energy SourceChemical energy stored in muscles, ATP and CP

Entirely carbohydrateMixture of fat and

carbohydrate


Adenosine DiphosphateCreatine Phosphate

plus energyLactic Acid CO2 and H2O

Muscle Fibre Recruited

Fast and slow twitchPredominately fast

twitch Slow twitch and some fast twitch

Work Output per Unit of Time

High Medium Low


SummarySummaryEnergy Systems

• Energy for muscular activity depends on a supply of ATP that can be broken down into ADP and phosphate

• All of the body’s biochemical processes and the three energy systems require ATP

• Trained individuals are able to use ATP and remove lactic acid more efficiently than untrained individuals

• Endurance training can significantly improve the aerobic system


Example of Interval TrainingExample of Interval TrainingEnergy Systems

Anaerobic Alactic Capacity/Power (sprints):

E:P ratio 1:3-6, >130%Vo2 max. 5-30sec. work. Time Phase - maintain all year

1. 10 x 80-100m strides, 90-95% effort. Jog return recovery. 2. 5 x 4 x 100m strides, 95-100% effort, 2min./4 min. recovery. 3. 6-10 x 20-30m hills, max effort, 1 1/2-2 min. recovery.

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Woodland Christian High School EnergySystems Energy for Muscular Activity Unit 1: Human Anatomy