Exercise Physiology Flashcards

Flashcards for reviewing exercise physiology lecture notes.

Exercise Physiology

The study of how the human body responds and adapts to exercise.

Acute Response

The body's immediate reaction to a single bout of exercise (e.g., standing to running).

Chronic Response

The body's long-term adaptation to repeated exercise training (e.g., pre-training to post-training after 12 months of endurance training).

Homeostasis

The ability to maintain a relatively constant internal environment in the face of significant changes in the external environment.

Negative Feedback System

A mechanism in which the output of a system is used to decrease its own activity.

Positive Feedback System

A mechanism in which the output of a system is used to increase its own activity.

Energy

The capacity for work.

Mechanical Work

Physical actions such as lifting a dumbbell.

Chemical Work

Biological processes like turning glucose into glycogen.

Transport Work

Movement of oxygen and nutrients through the body.

First Law of Thermodynamics (Law of Energy Conservation)

Energy is neither created nor destroyed but transferred from one form to another.

Kilocalorie (kcal)

The amount of thermal energy (heat) required to raise the temperature of 1 kilogram of water by 1 degree Celsius.

Direct Calorimetry

Measures the heat produced from biological reactions.

Indirect Calorimetry

Measures the rate of oxygen consumption and carbon dioxide production from biological reactions to estimate heat production.

Work (W)

Represents the application of force (F) through a distance (d): W = F x d

Power (P)

Represents the work (W) performed per unit of time (t) - Rate of work P = W/t

Ergometry

The measurement of work.

Mechanical Efficiency (ME)

Percentage of the total chemical energy expended that contributes to external work output: ME (%) = Work Output ÷ Energy Expended x 100

Ergometry

Essential for accurate measurement of work rate and exercise response. It is used to evaluate fitness, physiological responses, and performance requiring controlled and calibrated equipment.

Adenosine Triphosphate (ATP)

Important for mechanical, chemical, and transport work.

ATP-PCr System

Resynthesizes ATP via breakdown of phosphocreatine (PCr).

Anaerobic Glycolysis

Resynthesizes ATP via breakdown of glucose without oxygen.

Sarcoplasm

Location of the ATP-PCr system in the muscle cell.

Anaerobic Energy Systems

Provide most of the energy for shorter duration, higher intensity exercise (eg, ATP-PCr and anaerobic glycolysis)

Aerobic Energy Systems

Provide most of the energy for longer duration, lower intensity exercise.

Glycogen

Main storage form of glucose in muscles.

Adipose Tissue

Main storage for free fatty acids

Nicotinamide Adenine Dinucleotide (NAD+)

A coenzyme that can accept 2 electrons and 1 hydrogen ion (H+) to form NADH and a hydrogen ion (H+)

Flavin Adenine Dinucleotide (FAD)

A coenzyme that can accept 2 electrons and 2 hydrogen ions (H+) to form FADH2

Lactate Dehydrogenase

Enzyme that catalyses the reversible reaction of pyruvate accepting hydrogen pairs from NADH + H+ to convert to lactate

Gluconeogenesis

The synthesis of glucose from lactate in the muscle or liver.

Blood Lactate Measurement

Measurements are important for determining aerobic endurance ability and for evaluating training measures to improve performance in various sports.

Lactate Dehydrogenase

In low-oxygen conditions, pyruvate is converted into lactate by the enzyme lactate dehydrogenase.

Normal Resting Values of Lactate in Capillary Blood

0.5 - 2.5 mmol/L

Normal Blood Glucose Levels

4-5.6 mmol/L

Hyperglycemia

≥7 mmol/L

Hypoglycemia

< 4 mmol/L

The Electron Transport Chain

Systems involved in the aerobic production of ATP.

The Krebs Cycle

Systems involved in the aerobic production of ATP.

The Beta Oxidation System

Systems involved in the aerobic production of ATP.

Electron Transport Chain Location

Inner membrane of the mitochondria.

The Phosphocreatine Shuttle

Links the aerobic energy systems with the ATP-PCr systems (anaerobic energy system)

Krebs Cycle Location

Mitochondrial matrix.

Beta Oxidation System Location

Mitochondrial matrix.

Substrate

A substance on which an enzyme acts

Enzyme

An enzyme is a substrate that catalyses biochemical reactions

VO2

The rate of oxygen consumption expressed in L.min-1 (absolute) or mL.kg-1.min-1 (relative) terms

VO2max

The maximal rate of oxygen consumption under maximal exercise conditions. Expressed in L.min-1 (absolute) or mL.kg-1.min-1 (relative) terms

VO2peak

The highest rate of oxygen consumption recorded during the test (may or may not be maximal). Expressed in L.min-1 (absolute) or mL.kg-1.min-1 (relative) terms

Lactate Threshold 1 (LT1)

The rise in blood lactate above baseline.

Lactate Threshold 2 (LT2)/Maximal Lactate Steady State (MLSS)

Represent the highest exercise intensity at which there is a balance between lactate appearance and disappearance in the blood

Actin

Thin protein myofilament

Myosin

Thick protein myofilament with ATPase activity

Length-Tension Relationship

Describes how joint angles affect force output due to sarcomere properties.

Force-Velocity Relationship

Shows that as the load (force) on a muscle increases, the speed (velocity) of contraction decreases. This occurs because rapid contractions allow less time for actin and myosin to form cross-bridges, reducing force output.

Type II Muscle Fibers

useful for higher intensity and higher velocity exercise

Type I Muscle Fibers

fatigue resistant and useful for lower intensity, longer duration exercise

Motor Unit

Functional movement unit including the alpha motor neuron and the muscle fibres it innervates

All-or-None Law

A stimulus strong enough to trigger an action potential in the motor neuron activates all the accompanying muscle fibres in the motor unit to contract synchronously

Size Principle

Smaller motor units are activated first, followed sequentially by larger units as contraction intensifies.

Cellular Respiration

Metabolic processes within the cell that generate energy via oxygen use and carbon dioxide production

Alveoli

Gas Diffusion

Fick’s law of diffusion

states that a gas diffuses through a layer of tissue at a rate: 1. Proportional to the tissue area, a diffusion constant, and the pressure differential of the gas on each side of the membrane ● Diffusion constant is a measure of how quickly a substance diffuses or spreads through a medium.

Boyle’s law

states that the volume of a gas is inversely proportional to its pressure at a constant temperature.

Spirometry

the measurement of the volume and flow of air during expiration and inspiration

FEV1 (Forced Expiratory Volume in 1 second)

Volume exhaled in the first second of FVC. A low value suggests obstruction

Compliance

Stiffness of the lungs and chest walls

Myocardium

Heart muscle

Cardiac Cycle

There are two main phases: Diastole when the myocardium relaxes and the heart fills with blood and Systole when the heart contracts and ejects that blood

Mean Arterial Pressure (MAP)

Blood Pressure = Cardiac output x Total peripheral resistance

Cardiac Output (Q)

Stroke Volume x Heart Rate

TPR

Total Peripheral Resistance = MAP/Q

Oxyhemoglobin Dissociation Curve

describes the relationship between the partial pressure of oxygen and oxygen saturation of haemoglobin.

Nitric Oxide (NO)

Key molecule that acts to vasodilate our blood vessels.