EF205 Scientific Foundations of Exercise and Fitness
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Transcript of EF205 Scientific Foundations of Exercise and Fitness
EF205 Scientific Foundations of Exercise and Fitness
Unit 3
Today’s Agenda
Quick Review and Look Ahead Lecture Summary and Q & A
Quick Review
What did we study last week?
Quick Review
What did we study last week? Why knowledge of anatomy is important Different types of joints and movements at
those joints Important facts about muscles Types of muscle actions
Why Do We Need to Understand Energy Metabolism?
Why Do We Need to Understand Energy Metabolism? ATP is used for muscle contraction
Adaptations to exercise training involve aspects of energy metabolism.
Different activities will require different energy systems and thus the body must be supplied with the correct fuels.
This is why the interaction between Nutrition & Exercise is so important.
Energy
Energy is the capacity to perform work Energy can come from a number of different
forms (Chemical, Electrical, Electromagnetic, Thermal, Mechanical, Nuclear)
The energy we derive from food is stored in a high-energy compound - ATP
Where do we get Energy from?
Where do we get Energy from?CHO provides about 4 kcal of E per gramFat provides about 9 kcal of E per gramProtein can also provide energy--about 4 kcal
per gram.
Aerobic vs. Anaerobic Metabolism
Aerobic metabolism: The production of ATP with oxygen
Anaerobic metabolism: The production of ATP without oxygen
Practically SpeakingAnaerobic refers to activities that are high in
intensity, but short in duration
Practically SpeakingAerobic refers to activities that are low-to-
moderate in intensity and longer in duration.
Difference If energy demand
exceeds oxygen delivery, you are performing anaerobic exercise
If oxygen delivery meets or exceeds energy demand, you are performing aerobic exercise
Anaerobic ATP Production
Two pathways: ATP-PC system Anaerobic glycolysis
The ATP-PC and glycolytic systems are major contributors of energy during the early minutes of high-intensity exercise.
ATP-PC System
Simplest of the energy systems
This process is rapid Does not require
oxygen (O2) and is therefore anaerobic.
Can only sustain maximum muscle work for 3-15 seconds.
Glycolysis
No oxygen is required for this system. It is an Anaerobic System Lactic Acid will eventually prevent
the muscles from contracting.
2ATP from Glucose 3ATP from Glycogen
Aerobic MetabolismThe oxidative system
involves breakdown of fuels with the aid of oxygen
This system yields much more energy that the ATP-PC or glycolytic systems
Aerobic Metabolism
The process produces carbon dioxide and water as by-products. Oxygen is required for this system It is an Aerobic System. The waste products are easily removed from the body
38ATP from Glucose (39 from Glycogen)
Interaction of Energy Systems
Interaction of Energy Systems
Area On Chart Performance Time Major Energy System(s)Involved
Example
A Less Than 30 Seconds
ATP-PC System 100m Sprint
B 30 to 90 Seconds ATP-PC SystemLactic Acid System
200m - 400m Sprint100m Swim
C 90 Seconds to 3 Minutes
Lactic Acid SystemOxygen System
Boxing (3m Rounds)800m Run
D Over 3 Minutes Oxygen System Aerobics ClassMarathon
Energy Used When Exercising
When exercising some muscles work aerobically (with oxygen), which means they can use fat or carbohydrate as a fuel. Others work mainly anaerobically for which they can use only carbohydrate.
The diagram summarizes what happens when exercising:
Muscle Fibers
Some are more aerobic, some are more anaerobic Type I (slow oxidative)—mostly aerobic,
contract slowly, produce little force, resist fatigue
Type IIa (Fast oxidative glycolytic)—fast contracting, produces a great deal of force, but also resists fatigue
Type Iix (fast glycolytic)—contract quickly, produce great force, but fatigue quickly
What type of muscle fibers do you have? Avg male and female
~52% Type 1 ~33% Type IIa ~13% Type IIx
This differs greatly across overall population Cannot convert fast twitch fibers to slow
twitch or vice versa with endurance training However, muscle fibers can take on aerobic
characteristics
Fat and Protein Metabolism
ATP production from fatty acid sources is important in many forms of exercise.
Protein metabolism can provide energy, but it accounts for less than 5 percent of total ATP production during exercise.
True or FalseOnly low intensity exercise causes you to burn fat
and lose weight so you should avoid high intensity exercise if you want to lose fat
True or FalseOnly low intensity exercise causes you to burn fat
and lose weight so you should avoid high intensity exercise if you want to lose fat
FALSE!
What factors influence caloric expenditure?
What factors influence caloric expenditure? Type of activity
Intensity of activity
Weight of individual
Fitness level/efficiency of individual
Other factors: music, size of muscles, etc
What is VO2 Max?
An interaction between your cardiovascular system and respiratory systems
Is the point at which oxygen uptake does not increase even with increases in work load
How do we measure/test CV Fitness? Graded Exercise Test (GXT)--Workload is
progressively increased until the client is exhausted and cannot
continue Requires exercise physiology lab with trained personnel Replaced by submaximal tests which don’t require expensive equipment
Submaximal Tests and Field Tests
Give good estimate of VO2max Monitoring heart rate is necessary Good for testing large
numbers of people at one time Require little equipment
Common tests: Rockport Walk Test YMCA step test 1.5-mile run-walk test
Facts about VO2Max
Endurance training can increase VO2max by 5-25%
CC skiers have some of the highest VO2max’s (~80ml/kg/min-1)
Women’s VO2 values are ~15% lower than men’s
Genetics accounts for ~40% of VO2max Aging decreases VO2max by 1%/year Disease (CV and Pulmonary) negatively
effects VO2max
Quiz Hints
Respiratory Exchange Ratio Facts about VO2max Metabolic pathways Blood lactate levels
Wrap Up
Summary Q & A