SL: A.2.3 Energy Systems

ATP

Energy currency for cellular processes.

Phosphagen System

Immediate ATP production via creatine phosphate.

Glycolytic System

ATP production through the use of glucose. Used for high intensity activity primarily between 30seconds- about 3 minutes

Oxidative System

ATP production using oxygen for aerobic metabolism.

VO2max

Maximum oxygen uptake during intense exercise.

Running Economy

refers to the amount of oxygen (V̇O₂) a person uses at a given submaximal speed during running

Cell Respiration

Process converting organic molecules into ATP.

Insulin

Hormone regulating glucose uptake post-meal.

Glucagon

Hormone increasing blood glucose levels during fasting.

Epinephrine

Hormone enhancing energy availability during stress.

Mitochondrion

Cell organelle where ATP production occurs.

Macronutrients

Nutrients providing energy: carbohydrates, proteins, fats, & water.

Anaerobic Pathways

Energy production without oxygen, includes glycolysis.

Aerobic Pathways

Energy production using oxygen, includes oxidative phosphorylation and beta oxidation.

Anabolic Reactions

Building complex molecules from simpler ones.

Catabolic Reactions

Breaking down complex molecules into simpler ones.

ATP= ADP +P+energy

An example of a catabolic reaction

Recovery Capabilities

Ability of energy systems to replenish ATP.

Energy Continuum

Describes energy system contributions based on activity.

Cristae

Inner mitochondrial folds increasing ATP synthesis capacity.

ADP

Adenosine diphosphate, product of ATP breakdown.

Phosphate group

Molecule that can be added or removed from ATP.

Creatine Phosphate

High-energy molecule used to re-synthesize ATP.

Phosphorylation

Reattachment of a phosphate group to ADP.

Krebs Cycle

Aerobic pathway for energy production from carbohydrates.

Creatine kinase

Enzyme that speeds up ATP re-synthesis from CP.

Energy release

Occurs when ATP loses a phosphate group.

Affects the energy system in use

Intensity of exercise, Duration of exercise, availability of fuel sources, and amount of recovery time available

Coupled reaction

Linked reactions where one drives another.

ATP yield per 1 PC molecule

1 ATP

Duration of Phosphagen

Lasts up to 20 seconds during high-intensity efforts.

Recovery Time for PCr

Full replenishment takes approximately 2-3 minutes.

Benefits of Phosphagen System

Provides immediate energy for high intensity bouts without oxygen requirement.

Limitations of Phosphagen System

Very limited supply, not sustainable beyond seconds.

Duration of Glycolytic System

Effective for 15-30 seconds of high-intensity exercise.

ATP yield in Glycolysis

Produces 2 ATP per glucose molecule.

Glycogen

Storage form of carbohydrates in the body.

Glycogenolysis

Breakdown of glycogen to release glucose.

Glycolysis

First step in glucose breakdown, anaerobic process.

Hydrogen Ions (H⁺)

Accumulation leads to fatigue and decreased pH.

Aerobic System

Requires oxygen, occurs in mitochondria for ATP.

Kreb Cycle

Produces 2 ATP and electron carriers per cycle.

Electron Transport Chain

34 ATP using electrons just from this stage

Beta Oxidation

Breakdown of fatty acids into Acetyl CoA.

Waste Products of Aerobic Metabolism

Carbon dioxide and water produced during respiration.

ATP Yield from Glucose

38 ATP produced from one glucose molecule.

ATP Yield from Fatty Acids

100-150 ATP from one triglyceride molecule.

Benefits of Oxidative System

Sustainable energy for long-duration, low-intensity activities.

Limitations of Oxidative System

Slow activation and requires oxygen for function.

Fatigue by-products of Glycolysis

Lactate and hydrogen ions accumulate, causing fatigue.

Vertical Jump

Dominated by the phosphagen system due to intensity.

Submax Cycle

Primarily uses the oxidative system for energy.

Fatty Acids Usage

Only utilized during lower intensity aerobic activities lasting 3-4 hours.

Transition from Aerobic to Anaerobic

Occurs during increased intensity, like sprinting.

Factors Affecting VO2max

Includes age, sex, body composition, lifestyle, fitness.

Absolute VO2max

Total oxygen consumption regardless of body size.

Relative VO2max

Oxygen consumption normalized to body weight.

Children's VO2max

Lower absolute values than adults due to body size.

VO2max Peak Ages

mid-teens for females, early 20s for males.

Sex Differences in VO2max

Females generally have lower values than males.

Adult VO2max Decline

Declines approximately 1% annually after adulthood.

Cardiac Output

Lower in females due to smaller heart size, affects VO2max

Lung Capacity Differences

Females generally have smaller lung volumes.

Body Composition Effects

Higher body fat in females affects relative VO2max due to the impact of less fat-free mass (less capillarization, less mitochondria, etc.)

Body Fat

Higher fat reduces relative VO2 max efficiency.

Fat-Free Mass

Increased muscle mass enhances oxygen usage potential.

Capillary Density

More capillaries improve oxygen delivery to muscles.

Mitochondria

Increased mitochondria boost aerobic metabolism rates.

Stroke Volume

Volume of blood pumped per heartbeat.

Lifestyle factors that negatively affecting VO2max

Smoking, alcohol, lack of sleep

Smoking

Reduces lung capacity and gas exchange efficiency by thickening the alveolar membranes.

Carbon Monoxide Binding

Decreases oxygen transport by binding to hemoglobin, caused by smoking.

Sleep Quality

Poor sleep impairs recovery and training adaptation.

Alcohol Use

Disrupts recovery and muscle protein synthesis.

Glycogen Replenishment

Delayed by alcohol, reducing energy restoration.

Movement Efficiency

Optimizing movement reduces energy waste during performance.

Maximal Aerobic Power

Another term for maximal oxygen consumption.

Movement Efficiency Considerations

Reducing unnecessary motion,

Optimizing stride length and frequency,

Enhancing neuromuscular coordination,

Improving ground contact time,

Maintaining good posture and core control,