Energy systems (ATP-PC, anaerobic glycolysis, aerobic), fitness components, and the integration of energy and fitness principles into training programs for a chosen physical activity

QCE Physical Education Unit 4 integrates energy systems, fitness components, and training principles into a coherent training program for a chosen physical activity. This is the most-tested area in the external exam and is the foundation for the high-stakes Unit 4 internal assessment.

The three energy systems

ATP-PC system

• Fuel: creatine phosphate.
• Duration: roughly 10-12 seconds of all-out work.
• ATP yield: very rapid resynthesis but limited capacity.
• Recovery: 50% in 30 seconds, full in 3-5 minutes.

Dominant in short, explosive efforts (a sprint, a maximal jump).

Anaerobic glycolysis system

• Fuel: muscle glycogen via anaerobic glycolysis.
• Duration: 30 seconds to roughly 3 minutes at high intensity.
• ATP yield: 2 ATP per glucose. Faster than aerobic but inefficient.
• Fatigue: accumulation of hydrogen ions causing acidosis.
• Recovery: 20-60 minutes for lactate clearance and pH restoration.

Dominant in 30-second to 3-minute maximal efforts (400m run, 100m swim).

Aerobic system

• Fuel: carbohydrates and fats fully oxidised.
• Duration: minutes to hours.
• ATP yield: 36-38 ATP per glucose. Slow but high yield.
• Fatigue: glycogen depletion, dehydration, heat, central nervous system fatigue.
• Recovery: 24-48 hours for full glycogen restoration.

Dominant in sustained efforts beyond 3 minutes (marathon, soccer, AFL match).

Interplay

All three systems run simultaneously; their relative contribution shifts with intensity and duration. The mistake to avoid in exam responses is treating the systems as switching on and off cleanly.

Fitness components

The QCAA syllabus expects you to know fitness components and which physical activities prioritise which.

Health-related components

• Aerobic capacity (cardiorespiratory endurance). Sustained submaximal work.
• Muscular strength. Maximum force production.
• Muscular endurance. Repeated submaximal force production.
• Flexibility. Range of motion at joints.
• Body composition. Proportion of lean tissue to fat.

Skill-related components

• Speed. Rate of movement.
• Power. Rate of force production. Strength times speed.
• Agility. Rapid change of direction.
• Coordination. Combined use of body parts.
• Balance. Maintaining centre of mass over base of support.
• Reaction time. Time from stimulus to response.

Mapping components to sports

The strongest training programs match training methods to the components their sport demands.

• Marathon: aerobic capacity dominant, body composition important, flexibility for injury prevention.
• 100m sprinter: power dominant, speed essential, strength, reaction time.
• Soccer: aerobic capacity (substantial), speed, agility, power, muscular endurance.
• Powerlifting: strength dominant, flexibility important for technique.
• Tennis: agility, speed, power, muscular endurance, reaction time.

Training principles

The QCE syllabus expects you to apply:

• Specificity. Train the muscles, energy systems, movement patterns, and speeds the sport demands.
• Progressive overload. Gradual, systematic increase in stimulus over time.
• Reversibility. Adaptations are lost when training stops or reduces.
• Variety. Different sessions and modes to prevent staleness.
• Individuality. Programs reflect individual athlete responses.
• Periodisation. Structured planning across phases (base, specific, competitive, transition).
• FITT. Frequency, Intensity, Time, Type as the prescription framework.
• Warm-up and cool-down. Standard practice for every session.

Training methods

Methods are matched to the energy system and fitness component being targeted.

Aerobic training

• Continuous training (sustained moderate intensity). Builds aerobic base.
• Fartlek (continuous with deliberate intensity changes). Combined aerobic and anaerobic stimulus.
• Aerobic interval (structured repeats at lactate threshold). Builds VO2 max and threshold.
• Circuit training (multiple stations with limited rest). Aerobic plus muscular endurance.

Anaerobic training

• Short anaerobic intervals (10-30 seconds with full recovery). ATP-PC system.
• Long anaerobic intervals (30-120 seconds with limited recovery). Anaerobic glycolysis system.

Strength training

• Resistance training (loads against gravity or external resistance).
• Plyometric training (rapid stretch-shortening cycle for power development).

Flexibility training

• Static stretching (held positions, 15-60 seconds).
• Dynamic stretching (controlled movement through range).
• PNF (partner-assisted contract-relax).

Integration into a training program

A QCE Unit 4 program for a soccer player might look like:

Weekly structure during pre-season:

• Monday: field aerobic interval session + strength training.
• Tuesday: skills + small-sided games.
• Wednesday: continuous aerobic run + dynamic flexibility.
• Thursday: anaerobic interval (sprints, repeat-sprint ability) + strength.
• Friday: skills + tactical drills.
• Saturday: trial match or extended skills.
• Sunday: rest or active recovery.

The program integrates:

• All three energy systems (aerobic via continuous and interval; anaerobic glycolysis via long intervals and game work; ATP-PC via sprints and skills).
• Multiple fitness components (aerobic capacity, speed, agility, power, muscular endurance).
• All principles (specificity to soccer, progressive overload across the pre-season, FITT, variety, warm-up/cool-down embedded).

How this dot point applies

A typical QCE external exam question asks you to apply energy system and fitness component understanding to a chosen physical activity, or to design a training program with explicit principle justification. Strong responses:

1. Identify the chosen physical activity and its energy system and fitness component profile.
2. Match training methods to the demand profile.
3. Apply principles explicitly with reasoning.
4. Show how the program elements integrate rather than working in isolation.

The internal assessments build on this foundation, typically requiring an extended program design or analysis report on a chosen activity.