IB SEHS: Nutrition, Energy Systems, and Training Principles

Balanced Diet

A balanced diet = correct amounts of carbohydrates, proteins, lipids, and water (macronutrients) + vitamins, minerals, trace elements (micronutrients).

Macronutrients

Nutrients required in large amounts: carbohydrates, proteins, and fats.

Carbohydrates

Main energy source. (4cal/g) Stored as glycogen in liver & muscles.

Fatigue

Occurs when glycogen stores are depleted.

High GI foods

Fast increase in energy with crash; lack fiber; replenishes glycogen stores fast (fast recovery).

Low GI food

Provides steady consistent energy; rich in fiber.

Fats

Stored as triglycerides in adipose tissue & skeletal muscle. Provide energy for long-duration, lower-intensity activity. (9cal/g)

Proteins

Required for repair, growth, hypertrophy, and energy (when carbs/fats are insufficient). Daily requirement ≈ 0.8 g/kg body mass, includes essential amino acids. (4cal/g)

Micronutrients

Essential for metabolic function, recovery, and performance.

RED-S

Relative Energy Deficiency in Sport: Energy imbalance → impaired physiological function.

Energy Systems

Processes that convert food into ATP through biochemical pathways.

ATP-PC System

Very fast, immediate energy. Body uses creatine phosphate + ADP to quickly make ATP + Creatine. Fuels ~10-20 seconds of high-intensity activity.

Glycolytic System

Breaks down glucose without oxygen. Produces ATP (2) quickly but limited duration and 2 pyruvate.

Aerobic System

Uses glucose & fat (Beta-oxidation= lipids → acetyl-coa) with oxygen. Slower ATP production (34-36 ATP), but sustainable for long durations.

VO₂max

Gold standard for aerobic capacity; improves with training.

Lactate threshold

Point where lactate accumulates rapidly; before this, the body can clear lactate as it is being made.

Critical Power

Max power sustainable without fatigue.

EPOC

Excess Post-exercise Oxygen Consumption: elevated oxygen use during recovery. Allows for faster recovery after exercise.

Training Principles

Guidelines for effective training: specificity, progressive overload, recovery, variety, reversibility, periodization.

Periodization

Structured cycles (macrocycle → mesocycle → microcycle) for peak performance.

Individual Differences

Training response depends on age, sex, training status, genetics, hormonal changes (e.g., menstrual cycle).

Non-responders

Individuals who do not respond immediately to a single training session like high responders do.

Water

Essential for transport, temperature regulation, and hydration; athletes have higher fluid needs.

LEA

Low energy availability; occurs when an athlete is undereating.

GI Problems

Common in athletes due to reduced blood flow to the digestive system during exercise.

Gut microbiome

Affects overall health and performance.

Catabolism

The process of breaking down molecules for energy.

Anabolism

The process of building and storing energy.

Specificity

Training principle that emphasizes training for specific sport demands.

Progressive Overload

Training principle involving gradual increase in training load.

Ordered Recovery

Training principle that highlights the importance of rest for adaptation.

Reversibility

Training principle stating that fitness gains can be lost if training ceases.

Variety

Training principle suggesting mixing up workouts to prevent boredom.

Undertraining

Condition resulting from too little stimulus, leading to no improvement.

Overtraining

Condition resulting from excessive load without adequate recovery, leading to performance decline.

OTS

Overtraining Syndrome; serious, long-term fatigue and underperformance.

Responders vs Non-Responders

Genetic and environmental factors affecting training outcomes; high responders improve quickly, while non-responders require more intensity.