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