Sports Nutrition, Fitness, and Human Energy Systems

Vocabulary flashcards covering health and sports nutrition concepts, human energy systems, macronutrient fueling, and fatigue mechanisms based on lecture slides.

Prudent Healthy Diet

A set of dietary guidelines designed to promote long-term health and athletic performance based on three core principles: balance, variety, and moderation.

Nutrient Density

The ratio of key essential nutrients per serving of a given food relative to its total caloric value, often referred to as quality $\text{kcal}$.

Dietary Reference Intakes (DRIs)

The umbrella term for quantitative reference values used to plan and assess nutrient intakes for healthy populations, established by the Food and Nutrition Board.

MyPlate

A dietary guidance system developed by the USDA to encourage healthful eating habits by visually organizing food into five major groups: fruits, vegetables, grains, protein foods, and dairy.

Daily Value (%DV)

A standardized label metric indicating the percentage contribution of one serving of food toward a daily diet based on a $2000$\,$\text{kcal}$ reference diet; a value of $5\%$ or less is considered low for nutrients like saturated fat and sodium.

Dietary Supplement

As defined by the Dietary Supplement Health and Education Act (DSHEA) of 1994, a product taken by mouth that contains a dietary ingredient (such as a vitamin, mineral, herb, amino acid, or enzyme) intended to supplement the diet.

Adenosine Triphosphate (ATP)

A complex chemical compound composed of adenosine and three phosphate groups that serves as the immediate source of energy for cellular work, including muscle contractions.

Phosphocreatine (PCr)

A high-energy phosphate compound stored in muscle tissue in small quantities that donates a phosphate group to ADP to rapidly regenerate ATP during high-intensity exercise.

ATP-PCr System

The immediate anaerobic energy pathway governed by creatine kinase that provides the highest rate of ATP production, but is limited by low storage capacity that depletes within $5\text{--}10\,\text{seconds}$ of maximal exertion.

Lactic Acid System

The anaerobic glycolytic pathway that breaks down glucose or muscle glycogen to resynthesize ATP rapidly without oxygen, sustaining maximal efforts for $15\text{--}90\,\text{seconds}$ until limited by hydrogen ion accumulation.

Oxygen System

The aerobic metabolic system operating within the mitochondria via the Krebs cycle and electron transport chain, capable of generating large amounts of ATP from carbohydrates, fats, and minor amounts of protein.

Type 1 Muscle Fiber

A slow-twitch red muscle fiber (slow oxidative) characterized by high mitochondria and myoglobin content, giving it high aerobic capacity and resistance to fatigue.

Type 2a Muscle Fiber

A fast-twitch red muscle fiber (fast oxidative-glycolytic) that possesses both good aerobic capacity and high anaerobic phosphagen capacity for intermediate power outputs.

Type 2b Muscle Fiber

A fast-twitch white muscle fiber (fast glycolytic) with low aerobic capacity that relies predominantly on anaerobic energy production for explosive power and sprinting.

Anabolism

The metabolic process involving constructive biochemical reactions that synthesize larger, complex molecules and body tissues from smaller precursors.

Catabolism

The metabolic process involving destructive biochemical reactions that break down complex body substances into simpler structures, releasing stored chemical energy.

Excess Post-Exercise Oxygen Consumption (EPOC)

The volume of oxygen consumed during the post-exercise recovery period above resting baseline levels to restore metabolic homeostasis.

Crossover Concept

The metabolic model describing the shift in primary exercise fuel, where fat serves as the dominant source at low intensities ($<50\%\,\text{VO}_2\,\text{max}$) and carbohydrate becomes dominant at higher exercise intensities.

Central Fatigue Hypothesis

The theory stating that a decline in blood BCAA levels during prolonged exercise raises the free tryptophan to BCAA ratio, driving tryptophan uptake into the brain to synthesize serotonin and induce central fatigue.

Health-Related Fitness

Physical fitness components targeted at disease prevention and overall physical well-being, comprising muscular strength, muscular endurance, cardiovascular-respiratory fitness, healthy body composition, and flexibility.

Sports-Related Fitness

Athletic fitness components required to maximize performance in sports, consisting of specialized power, speed, agility, endurance, and neuromuscular motor skills.

Sports Nutrition

The application of evidence-based nutritional principles to support athletic training adaptations, optimize recovery, maintain optimal health, and enhance competitive sports performance.

Ergogenic Aid

Any technique, device, strategy, or substance (whether mechanical, psychological, physiological, pharmacological, or nutritional) used to enhance physical work output and athletic performance.

Certified Specialist in Sports Dietetics (CSSD)

The premier board-certified professional credential awarded by the Commission on Dietetic Registration to Registered Dietitians demonstrating expert expertise in sports nutrition.

Gluconeogenesis

The metabolic synthesis of new glucose molecules from non-carbohydrate carbon substrates, such as amino acids, glycerol, lactate, or pyruvate.

Hypoglycemia

A condition characterized by blood glucose dropping below $45\,\text{mg/dL}$ following liver glycogen depletion, resulting in dizziness, cognitive fatigue, and impaired performance.

Nutrient Timing

The deliberate ingestion of specific nutrients (primarily carbohydrates and proteins) in proximity to training sessions to maximize glycogen resynthesis, stimulate muscle protein synthesis, and optimize recovery.