Chapter 3 - Bioenergetics of Exercise and Training

Question 1

Bioenergetics

Answer 1

flow of energy in a biological system; conversion of macronutrients into biologically usable forms of energy.

Question 2

Catabolism

Answer 2

breakdown of large molecules into smaller molecules, associated with the release of energy.

Question 3

Anabolism

Answer 3

synthesis of larger molecules from smaller molecules; can be accomplished using the energy released from catabolic reactions.

Question 4

Exergonic reactions

Answer 4

energy-releasing reactions that are generally catabolic.

Question 5

Endergonic reactions

Answer 5

require energy and include anabolic processes and the contraction of muscle.

Question 6

Metabolism

Answer 6

total of all the catabolic or exergonic and anabolic or endergonic reactions in a biological system.

Question 7

Adenosine Triphosphate (ATP)

Answer 7

allows transfer of energy from exergonic to endergonic reactions.

Question 8

Chemical Structure of ATP

Answer 8

adenosine (adenine+ribose), triphosphate group, and locations of high energy chemical bonds.

Question 9

Hydrolysis of ATP

Answer 9

The breakdown of 1 ATP molecule to yield energy. Requires 1 H2O molecule.
Breaks the terminal phosphate bond, releases energy, and leaves ADP – an inorganic phosphate (Pi) and a hydrogen ion (H+)

Question 10

Hydrolysis of ADP

Answer 10

Breaks the terminal phosphate bond, releases energy, and leaves AMP, Pi, and H+

Question 11

Biological Energy Systems

Answer 11

Phosphagen
Glycolysis
Oxidative

Replenishes ATP in skeletal muscle

Question 12

Phosphagen System

Answer 12

Body does not store enough ATP for exercise.
ATP needed for basic cellular function.
Uses creatine kinase reaction to maintain concentration of ATP.
Replenishes ATP rapidly.

Question 13

Law of mass action

Answer 13

Concentrations of reactants or products (or both) in solution will drive the direction of the reactions.
Phosphagen System.

Question 14

Glycolysis

Answer 14

Breakdown of carbs, either glycogen stored in muscle or glucose delivered in blood, to resynthesizes ATP.

Question 15

End Result of glycolysis (pyruvate) may proceed in 1 of 2 directions

Answer 15

1) Pyruvate converted to lactate – ATP resynthesis occurs faster but is limited.
2) Pyruvate can be shuttled into mitochondria if sufficient O2 is available (slow glycolysis) – When pyruvate undergoes Krebs, ATP resynthesis is slower, but occurs for longer duration if exercise intensity is low enough (aka aerobic/slow glycolysis).

Question 16

Glycolysis and the Formation of Lactate

Answer 16

The formation of lactate from pyruvate is catalyzed by the enzyme lactate dehydrogenase.
End result his NOT lactic acid.
Glucose + 2Pi + 2ADP > 2Lactate + 2ATP + H20
Lactate can be transported in the blood to the liver, where it is converted to glucose (Cori Cycle).

Question 17

Glycolysis Leading to Krebs

Answer 17

Only if sufficient O2 is available.
AKA Slow Glycolysis.
Pyruvate that enters mitochondria is converted to acetyl-CoA by pyruvate dehydrogenase (resulting in loss of CO2)
Acetyl-CoA can then enter Krebs.
NADH molecules enter the electron transport system, where they can also be used to resynthesize ATP.
Glucose + 2Pi + 2ADP + 2NAD+ > 2Pyruavte + 2ATP + 2NADH + 2H20

Question 18

Energy Yield of Glycolysis

Answer 18

Glycolysis from one molecule of blood glucose yields a net of 2 ATP.
Glycolysis from muscle glycogen yields a net of 3 ATP.

Question 19

Control of Glycolysis

Answer 19

Stimulated by high concentrations of ADP, Pi, and ammonia and by a slight decrease in pH and AMP.
Inhibited by markedly lower pH, ATP, CP, citrate, and free fatty acids.
Also affected by hexokinase, phosphofructokinase, and pyruvate kinase.

Question 20

Lactate Threshold (LT) and Onset Blood Lactate (OBLA)

Answer 20

LT: exercise intensity at which blood lactate begins an abrupt increase above baseline concentration. Represents significantly increased reliance on anaerobic mechanisms for energy production (likewise with ventilatory threshold).
OBLA represents second increase in rate of lactate accumulation.

Question 21

Lactate Threshold (LT)

Answer 21

Exercise intensity or relative intensity at which blood lactate begins an abrupt increase above baseline concentration.
Begins at 50%-60% max 02 uptake in untrained.
Begins at 70%-80% max 02 uptake in trained.

Question 22

Onset Blood Lactate (OBLA)

Answer 22

Second increase in rate of lactate accumulation.
Occurs at higher relative intensities.
Occurs when concentration of blood lactate reaches 4 mmol/L.

Question 23

Oxidative (Aerobic) System

Answer 23

Primary sources of ATP at rest and during low-intensity exercise.
Uses Primarily carbs and fats as substrates.

Question 24

Glucose and Glycogen Oxidation

Answer 24

Metabolism of blood glucose and muscle glycogen begins with glycolysis and leads to Krebs (Reminder: if O2 is present in sufficient quantities, the end product of glycolysis, pyruvate, is NOT converted to lactate but is transported to the mitochondria, where it’s taken up and enters Krebs).
NADH and FADH2 molecules transports H+ atoms two ETC, where ATP is produced from ADP.

Question 25

Fat Oxidation

Answer 25

Triglycerides stored in fat cells can be broken down by hormone-sensitive lipase. This releases FFA from fat cells into the blood, where they can circulate and enter muscle fibers. Some FFA come from intramuscular fibers. FFAs enters mitochondria, are broken down, and form acetyl-CoA and hydrogen protons.

Question 26

Protein Oxidation

Answer 26

Protein is NOT a significant source of energy for most activities. Protein is broken down into amino acids, and the amino acids are converted into glucose (gluconeogenesis), pyruvate, or various Krebs cycles inter-mediates to produce ATP. Amino acids contribution to producing ATP estimated to be minimal during short-term exercise, but 3-18% during prolonged activity.

Question 27

Control of the Oxidative (Aerobic) System

Answer 27

The ETC and Isocitrate dehydrogenase are stimulated by ADP and inhibited by ATP. Rate of Krebs cycle is reduced if NADH+ and FAD2+ are not available in sufficient quantities to accept hydrogen. The ETC is stimulated by ADP and inhibited by ATP.

Question 28

Energy Production and Capacity

Answer 28

In general, there's an inverse relationship between a given energy system's max rate of ATP production (i.e. ATP produced per unit of time) and the total amount of ATP it's capable of producing over a varying exercise duration.

Question 29

Exercise Duration and Intensity of Primary Energy System Used

Answer 29

Phosphagen: 0-6s, extremely high intensity Phos. & Fast Glycolysis: 6-30s, very high intensity. Fast Gly.: 30s-2min, high intensity. Fast Gly. & Oxidative (Slow Glycolysis): 2-3min, moderate intensity Oxidative: >3min, low intensity.

Question 30

Energy System Rank of Rate of ATP Production and ATP Capacity (Production/Capacity)

Answer 30

``` (Production/Capacity) 1 =fastest/greatest, 5=slowest/least Phosphagen: 1/5 Fast Gly.: 2/4 Slow Gly.: 3/3 Oxidation of CHO: 4/2 Oxidation of Fats/Proteins: 5/1 Extent to which each energy system contributes ATP production depends primarily on the intensity of muscular activity and secondarily on duration. One systems will NEVER provide all of the ATP. ```

Question 31

Substrate Depletion and Repletion - Phosphagens

Answer 31

CP can decrease markedly (50%-70%) during first stage of extremely high-intensity exercise (5-30s) and can almost be eliminated as a result of very intense exercise to exhaustion. ATP may decrease only slightly or may decrease up to 50-60% of preexercise levels. Post-exercise Phos. repletion can occur in a relatively short period; complete resynthesis of ATP appears to our within 3-5 min, and complete CP resynthesis occurs within 8 min.

Question 32

Substrate Depletion and Repletion - Glycogen

Answer 32

Rate of glycogen depletion is related to exercise intensity. At relative intensities of exercise above 60% of max O2 uptake, muscle glycogen (MG) becomes an increasingly important energy substrate; the entire glycogen content of some muscle cells can become depleted during exercise. Repletion of MG during recovery is related to post exercise CHO ingestion. Optimal oof 0.7g-3.0g CHO/kgBW ingested every 2 hours post exercise.

Question 33

Bioenergetic Limiting Factors in Exercise Performance - LIGHT (Marathon) 1= least probable limiting factor, 5= most probable limiting factor ``` ATP and CP Muscle Glycogen Liver Glycogen Fat Stores Lower pH ```

Answer 33

``` ATP and CP: 1 Muscle Glycogen: 5 Liver Glycogen: 4-5 Fat Stores: 2-3 Lower pH: 1 ```

Question 34

Bioenergetic Limiting Factors in Exercise Performance - MODERATE (1500m run) 1= least probable limiting factor, 5= most probable limiting factor ``` ATP and CP Muscle Glycogen Liver Glycogen Fat Stores Lower pH ```

Answer 34

``` ATP and CP: 1-2 Muscle Glycogen: 3 Liver Glycogen: 2 Fat Stores: 1-2 Lower pH: 2-3 ```

Question 35

Bioenergetic Limiting Factors in Exercise Performance - HEAVY (400m run) 1= least probable limiting factor, 5= most probable limiting factor ``` ATP and CP Muscle Glycogen Liver Glycogen Fat Stores Lower pH ```

Answer 35

``` ATP and CP: 3 Muscle Glycogen: 3 Liver Glycogen: 1 Fat Stores: 1 Lower pH: 4-5 ```

Question 36

Bioenergetic Limiting Factors in Exercise Performance - VERY INTENSE (Discus) 1= least probable limiting factor, 5= most probable limiting factor ``` ATP and CP Muscle Glycogen Liver Glycogen Fat Stores Lower pH ```

Answer 36

``` ATP and CP: 2-3 Muscle Glycogen: 1 Liver Glycogen: 1 Fat Stores: 1 Lower pH: 1 ```

Question 37

Bioenergetic Limiting Factors in Exercise Performance - VERY INTENSE (Repeated snatch exercise at 60% 1RM) 1= least probable limiting factor, 5= most probable limiting factor ``` ATP and CP Muscle Glycogen Liver Glycogen Fat Stores Lower pH ```

Answer 37

``` ATP and CP: 4-5 Muscle Glycogen: 4-5 Liver Glycogen: 1-2 Fat Stores: 1-2 Lower pH: 4-5 ```

Question 38

O2 Uptake and the Aerobic and Anaerobic Contributions to Exercise

Answer 38

Excess Postexercise Oxygen Consumption (EPOC) -Factors Responsible- Replenishment of O2 in blood and muscle. ATP/CP resynthesis Increased body temp., circulation, and ventilation. Increased rate of triglyceride-fatty acid cycling. Increased protein turnover. Changes in energy efficiency during recovery.

Question 39

Excess Postexercise Oxygen Consumption (EPOC).

Answer 39

O2 uptake above resting values used to restore body to preexercise condition. Also called post exercise uptake, O2 debt, of recovery O2.

Question 40

Metabolic Specificity of Training

Answer 40

Use of appropriate exercise intensities and rest intervals allows for the "selection" of specific energy systems during training and results in more efficient and productive regimens for specific athlete events with various metabolic demands. Includes: Interval Training, HIIT, and Combination Training.

Question 41

Interval Training

Answer 41

A method of training that emphasizes bioenergetic adaptations for a more effect energy transfer within the metabolic pathways by using predetermined intervals of exercise and rest periods. More training can be accomplished at higher intensities. Difficult to establish definitive guidelines for choosing specific WORK:REST ratios

Question 42

Interval Training WORK:REST ratios and Primary Energy Systems Stressed

Answer 42

Phosphagen (1:12 - 1:20), 5-10s -- 90-100% max power Fast Glycolysis (1:3 - 1:5), 15-30s -- 75-90% max power Fast Glycolysis/Oxidative (Slow Glycolysis) (1:3 - 1:4), 1-3 min. -- 30-75% max power. Oxidative (1:1 - 1:3), >3 min. -- 20-30% max power

Question 43

High Intensity Interval Training (HIIT)

Answer 43

Involves brief repeated bouts of high-intensity exercise with intermittent recovery periods.

Question 44

HIIT Variables to Manipulate

Answer 44

``` Intensity of active phase. Duration of active phase. Intensity of the recovery phase. Duration of recovery phase. Number active/recovery phases in each set. Rest time between sets, numbers of sets. Recovery intensity between set. Mode of exercise for HIIT. ```

Question 45

Combination Training

Answer 45

Adds aerobic endurance training to the training of anaerobic athletes in order to enhance recovery (because recovery relies primarily on aerobic mechanisms).

Question 46

Combinations Training Impact on Anaerobic Training.

Answer 46

May reduce anaerobic performance capabilities, particularly high-strength, high-power performance. Can reduce the gain in muscle girth, maximum strength, and speed- and power-related performance. May be counterproductive in most strength and power sport.