Exercise Physiology, Biomechanics, and Nutrition Lecture Notes

A comprehensive collection of vocabulary flashcards covering biomechanics, muscle physiology, bioenergetics, endocrine responses, training adaptations, sports nutrition, and ergogenic aids.

Proprioceptors

Specialized sensory receptors providing the central nervous system (CNS) with feedback to control movement and maintain muscle tone.

Muscle Spindles

Sensory receptors oriented parallel to extrafusal muscle fibers that sense changes in muscle length and rate of stretch, triggering the stretch reflex to contract the agonist muscle and protect against overstretching.

Golgi Tendon Organs (GTO)

Changes in muscle tension. Sensory receptors located in series within tendons near the myotendinous junction that sense changes in muscle tension and trigger autogenic inhibition, causing heavily loaded muscles to relax to prevent tearing or injury.

Type I Muscle Fibers

Slow-twitch fibers with slow contraction and relaxation speed, low force and power output, high resistance to fatigue, small motor neuron size, high capillary density (red color), and high aerobic enzyme profile relying on the oxidative system.

Type IIa Muscle Fibers

Fast-twitch fibers with fast contraction and relaxation speed, intermediate to high force and power output, intermediate resistance to fatigue, large motor neuron size, intermediate capillary density (red/white color), and an intermediate aerobic/high anaerobic profile.

Type IIx Muscle Fibers

Fast-twitch fibers with fast contraction and relaxation speed, high force and power output, low resistance to fatigue, large motor neuron size, low capillary density (white color), and high anaerobic profile relying primarily on the phosphagen system.

Origin

The proximal attachment of a muscle, located closest to the center of the body.

Insertion

The distal attachment of a muscle, located farthest from the center of the body.

Agonist

The prime mover muscle that is most directly involved in producing a given movement.

Antagonist

A muscle that opposes or slows down a movement.

Synergist

A muscle that indirectly assists in bringing about a movement.

Sagittal Plane

An anatomical plane that slices the body into left and right sections, accommodating flexion and extension movements.

Frontal Plane

An anatomical plane that slices the body into front and back sections, accommodating movements such as abduction, adduction, inversion, eversion, and lateral flexion.

Transverse Plane

An anatomical plane that slices the body into top and bottom sections, accommodating internal rotation, external rotation, horizontal abduction, and horizontal adduction.

Concentric Action

A muscle action wherein the muscle shortens because the contractile force generated is greater than the resistive force.

Eccentric Action

A muscle action wherein the muscle lengthens because the contractile force generated is less than the resistive force.

Isometric Action

A muscle action wherein muscle length remains constant because contractile force equals resistive force.

Pennation Angle

The angle between muscle fibers and an imaginary line between the muscle's origin and insertion, where a greater angle permits more sarcomeres in parallel to increase force output at the expense of contraction speed.

Fluid Ball

Support created by deep abdominal and diaphragm contraction that increases intra-abdominal pressure to stabilize and support the vertebral column.

Valsalva Maneuver

The technique of exhaling against a closed glottis to build intra-abdominal pressure, which provides spinal rigidity during heavy lifts but increases blood pressure.

Bioenergetics

The flow of energy in a biological system, specifically the conversion of macronutrients into biologically usable energy.

Catabolism

The breakdown of larger molecules into smaller ones, which releases energy (exergonic reaction).

Anabolism

The synthesis of larger molecules from smaller ones, which requires energy input (endergonic reaction).

Metabolism

The combined total of all catabolic and anabolic chemical reactions occurring within the body.

Phosphagen System

The primary energy pathway for extremely high-intensity activities lasting $0-6\,\text{s}$, utilizing stored ATP and creatine phosphate to yield the fastest rate of ATP production but lowest total capacity.

Glycolysis

The breakdown of carbohydrates to resynthesize ATP, yielding a net of $2\,\text{ATP}$ per molecule of blood glucose or $3\,\text{ATP}$ per molecule of muscle glycogen.

Cori Cycle

The metabolic pathway in which muscle lactate released into the bloodstream travels to the liver to be converted back into glucose via gluconeogenesis.

Lactate Threshold (LT)

The point during exercise where blood lactate abruptly rises above baseline levels, typically occurring at $50-60\%$ of $\text{VO}_2\,\text{max}$ in untrained individuals and $70-80\%$ in trained athletes.

Onset of Blood Lactate Accumulation (OBLA)

The second sharp systemic rise in blood lactate during exercise, occurring when blood lactate concentration reaches $4\,\text{mmol/L}$.

Combination Training

The addition of aerobic endurance training to a strength or power athlete's program, which can attenuate gains in maximal strength, power, and muscle girth due to exercise interference.

Lock and Key Theory

The endocrine concept stating that specific hormones interact only with specific complementary surface or intracellular receptors.

Free Testosterone

The unbound, active fraction of testosterone that accounts for $0.5-2\%$ of total circulating testosterone.

Cortisol

The primary catabolic adrenal hormone that stimulates the conversion of amino acids to glucose, increases proteolytic enzymes, inhibits protein synthesis, and exhibits greater catabolic effects on Type II fibers.

Minimal Essential Strain (MES)

The threshold mechanical stimulus required to initiate new bone modeling and formation.

Blood Doping

The practice of infusing autologous or heterologous red blood cells to elevate hemoglobin levels and $\text{VO}_2\,\text{max}$, carrying high risks of increased blood viscosity, clotting, and hypertension.

Glycemic Index (GI)

A scale that rates how rapidly a carbohydrate-containing food raises blood glucose levels compared to a reference standard.

Hyponatremia

A dangerously low blood sodium concentration of $<125\,\text{mmol/L}$, typically caused by excessive hydration with plain water during prolonged physical activity.

Carbohydrate Loading

A dietary strategy to maximize muscle glycogen stores prior to endurance events exceeding $90\,\text{min}$, involving consuming $8-10\,\text{g/kg}$ of carbohydrates daily for $3\,\text{days}$ alongside exercise tapering and a rest day.

Anorexia Nervosa

An eating disorder characterized by self-imposed starvation, an intense fear of gaining weight, bone thinning, lanugo, and severe cardiovascular distress.

Bulimia Nervosa

An eating disorder characterized by recurrent binge eating followed by purging at least once a week for $3\,\text{months}$, causing tooth enamel erosion and electrolyte imbalances.

Stacking

An anabolic steroid dosing regimen in which an individual administers multiple different drugs simultaneously to enhance their combined potency.

Pyramiding

A steroid dosing regimen where drug doses are stepped up over several weeks and then stepped down toward the end of a cycle to minimize withdrawal symptoms and side effects.

Human Chorionic Gonadotropin (hCG)

A hormone injected into males toward the end of an anabolic steroid cycle to stimulate endogenous testosterone production by the testes.

Erythropoietin (EPO)

An ergogenic hormone that stimulates red blood cell production; abuse increases hematocrit and blood viscosity, carrying risks of stroke, blood clots, elevated systolic blood pressure, and sudden death.

Beta-Alanine

A dietary supplement and rate-limiting precursor to carnosine that buffers intramuscular hydrogen ions ($\text{H}^+$) to enhance performance in high-intensity events lasting $1-4\,\text{min}$, with paresthesia as a known side effect.

Force velocity Relationship

concentric force capability decreases nonlinearly as contraction velocity increases

Fat Oxidation

Triglycerides broken down by hormone-sensitive lipase into free fatty acids

Protein Oxidation

Amino acids converted to glucose, pyruvate, or Krebs cycle intermediates; contributes minimally to total energy supply

Upregulation

increase in receptor availability/sensitivity due to physiological stimuli

hypertrophy

enlargement of existing fiber cross sectional area

hyperplasia

an increase in fiber count via splitting

Beta-Blockers

Reduce anxiety and tremors

human growth hormone (HGH)

stimulates bone and muscle growth and lipolysis