What is the energy continuum?

The energy continuum shows how much each energy system contributes to activities of different intensity and duration. Activities range from mainly anaerobic, such as a sprint, to mainly aerobic, such as a marathon.

Why is it wrong to say that only one energy system works at a time?

All three systems resynthesise ATP together from the start of exercise. Intensity and duration decide which one contributes most.

What is meant by the threshold between two energy systems?

A threshold is the point at which one energy system can no longer meet demand and another becomes predominant. The ATP-PC threshold is reached after about 10 seconds of maximal work.

How does exercise intensity affect which energy system predominates?

High intensity demands ATP faster than oxygen can be supplied, so the anaerobic systems predominate. Lower intensity allows the aerobic system to meet demand.

How does a performer's fitness affect the thresholds between energy systems?

A trained endurance athlete can work harder before the lactic acid system predominates. A sprinter with larger phosphocreatine stores can extend the ATP-PC phase slightly.

What is the anaerobic threshold?

The anaerobic threshold is the intensity at which the aerobic system can no longer meet demand, so lactate begins to accumulate. The performer then relies increasingly on anaerobic glycolysis.

Eduqas A-Level Physical Education A550QS

Health, Fitness and an Active Lifestyle

Topic overview Health, fitness and the UK activity guidelines Physical, psychological and social benefits of exercise Sedentary lifestyles and the risks to health

Short-Term Responses to Exercise

Topic overview The heart as a dual-action pump and the cardiac cycle Stroke volume, heart rate and cardiac output during exercise Nervous and hormonal control of heart rate Blood vessels, blood pressure and the vascular shunt Ventilation, gas exchange and neuromuscular responses

Long-Term Adaptations to Exercise

Topic overview Bone, connective tissue and muscle adaptations Bradycardia, cardiac hypertrophy and ejection fraction Lung volumes, pulmonary diffusion and aerobic capacity

Fitness Testing and Components of Fitness

Topic overview Health-related and skill-related fitness components Field test protocols for each component Laboratory tests and maximal versus sub-maximal testing Validity, reliability and interpreting results

Training Methods, Principles and Periodisation

Topic overview Specificity, progressive overload, reversibility, variance and FITT Continuous, fartlek, interval and high intensity training Weight, plyometric, circuit and flexibility training Altitude training and training in hot and cold climates Training zones, heart rate monitoring and periodisation

Energy Systems

Topic overview ATP, the ATP-PC system and the lactic acid system Aerobic energy production, fuels and maximal oxygen uptake The energy continuum, thresholds and training design

Fatigue and Recovery

Topic overview Fuel depletion, dehydration and fatigue Lactate accumulation, OBLA and DOMS Oxygen deficit and the stages of EPOC Lactate removal and recovery aids

Diet, Nutrition and Supplements

Topic overview Macronutrients and a balanced diet Energy balance, glycaemic index and fuel use Diets for different sports and carbohydrate loading Hydration strategies and sports drinks Protein, creatine and caffeine supplements

Injury Prevention and Rehabilitation

Topic overview Warm-up and cool-down physiology Risk assessment and the PAR-Q Causes and predictors of injury PRICE and rehabilitation methods

Joints and the Musculo-Skeletal System

Topic overview Joint classification and synovial joint types The skeleton, bone types and connective tissue Major skeletal muscles in sporting actions Muscle fibre types, muscle roles and contractions

Planes, Axes and Movement Patterns

Topic overview The sagittal, frontal and transverse planes Axes of rotation in sporting movements Joint movement terms in sporting actions

Biomechanical Principles and Levers

Topic overview Newton's laws of motion in sport Momentum, impulse and force–time graphs Stability, centre of mass and equilibrium Lever systems and mechanical advantage

Linear and Angular Motion

Topic overview Distance, displacement, speed and velocity Acceleration and graphs of motion Angular displacement, velocity and acceleration Moment of inertia and conservation of angular momentum

Projectile Motion and Fluid Mechanics

Topic overview Factors affecting the flight of a projectile Lift forces and the Bernoulli principle Spin and the Magnus effect Drag, streamlining and laminar flow

Performance Analysis

Topic overview The coaching process and approaches to analysis Video analysis Notational analysis, time-motion analysis and GPS

Technology in Sport

Topic overview Technology for the performer Technology for officials Technology for spectators Technological doping and the level playing field

Personality

Topic overview Trait, social learning and interactionist theories Extroverts, introverts and Type A and Type B personalities Personality profiling and the profile of mood states

Attitudes

Topic overview Attitudes, prejudice and stereotyping The triadic model of attitudes Changing attitudes through cognitive dissonance and persuasion

Goal Setting

Topic overview Why performers set goals Outcome, performance and process goals SMART goals and short, medium and long-term targets

Stress, Arousal and Anxiety

Topic overview Stress, arousal and anxiety defined Drive, inverted-U and catastrophe theories The zone of optimal functioning and peak flow Measuring stress, arousal and anxiety Controlling stress, arousal and anxiety

Motivation

Topic overview Intrinsic and extrinsic motivation Achievement motivation: need to achieve and need to avoid failure Competitiveness and developing achievement motivation in young performers

Aggression

Topic overview Aggression, assertion and types of aggression Theories of aggression Causes and control of aggression

Social Facilitation

Topic overview Audiences, co-actors and performance Theories of social facilitation Home field advantage and reducing social inhibition

Group Dynamics and Leadership

Topic overview The 6 Is and the formation of groups Task and social cohesion Group productivity, social loafing and the Ringelmann effect Leadership theories and styles Chelladurai's multi-dimensional model and the Leadership Scale for Sports

Attribution Theory

Topic overview Weiner's model of attribution Errors in attribution Learned helplessness and attribution retraining

Self-Efficacy and Confidence

Topic overview Self-efficacy, self-confidence and self-esteem Bandura's four sources of self-efficacy Developing self-efficacy

Skill, Ability and Skill Classification

Topic overview Skill, ability, learning and performance Gross motor and psychomotor abilities Classifying skills on continua

Learning Curves, Theories and Stages

Topic overview Learning curves and plateaus Observational learning Reinforcement and drive reduction theory Fitts and Posner's stages of learning

Transfer, Practice and Guidance

Topic overview Types of transfer Methods of practice Methods of guidance

Information Processing, Memory and Feedback

Topic overview Information processing models and feedback Memory stores and selective attention Strategies for improving memory Reaction time, response time and Hick's law The psychological refractory period, anticipation and motor programmes

Sport, Culture and Society

Topic overview Culture, society and social institutions Sport as social control and socialisation Sport, national identity and government

The Emergence of Modern Sport

Topic overview Public schools and the three stages of athleticism Universities, codification and the spread of games From amateurism to professionalism and commercialisation Olympism, shamateurism and sport as a political tool

Ethics, Deviance and Doping

Topic overview Fair play, sportsmanship and gamesmanship Deviance, Coakley's sports ethic and violence Reasons for doping and its ethics WADA, drug testing and biological passports

Social Differentiation in Sport

Topic overview Social stratification and class in sport Prejudice, stereotyping and discrimination Barriers to participation for disadvantaged groups Strategies to widen participation

Sport and the Mass Media

Topic overview Functions and forms of the media in sport The symbiotic relationship and the golden triangle Media stereotypes and the dramatisation of sport

Commercialisation and Globalisation

Topic overview Sport as a commodity and consumerism Sponsorship, marketing and the sporting goods market Americanisation and globalisation theory Globalisation, financial gain and global migration

Mass Participation and Excellence

Topic overview Mass participation versus excellence Participation, lifestyle and movement between levels Talent identification and the elite pathway Sport organisations and recreational pathways

Energy Systems

The energy continuum, thresholds and training design

3 things to know
Components 1 and 2

Overview

The energy continuum and thresholds, intensity, duration and fitness, the anaerobic threshold, runners with the same VO₂ max, the 400 m, the 1500 m and the football midfielder, repeated sprints, and planning training from the continuum.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

How does a football midfielder use each energy system, and how do the systems' contributions change in maximal exercise?

Key term

How does the duration of exercise affect which energy system predominates?

Key term

Which energy system dominates a 400 m race, and why?

Questions from this subtopic

Each one with the model answer underneath.

1
What is the energy continuum?
Model answer
The energy continuum shows how much each energy system contributes to activities of different intensity and duration. Activities range from mainly anaerobic, such as a sprint, to mainly aerobic, such as a marathon.
2
Why is it wrong to say that only one energy system works at a time?
Model answer
All three systems resynthesise ATP together from the start of exercise. Intensity and duration decide which one contributes most.
3
What is meant by the threshold between two energy systems?
Model answer
A threshold is the point at which one energy system can no longer meet demand and another becomes predominant. The ATP-PC threshold is reached after about 10 seconds of maximal work.
4
How does exercise intensity affect which energy system predominates?
Model answer
High intensity demands ATP faster than oxygen can be supplied, so the anaerobic systems predominate. Lower intensity allows the aerobic system to meet demand.
5
How does a performer's fitness affect the thresholds between energy systems?
Model answer
A trained endurance athlete can work harder before the lactic acid system predominates. A sprinter with larger phosphocreatine stores can extend the ATP-PC phase slightly.
6
What is the anaerobic threshold?
Model answer
The anaerobic threshold is the intensity at which the aerobic system can no longer meet demand, so lactate begins to accumulate. The performer then relies increasingly on anaerobic glycolysis.

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Health, Fitness and an Active Lifestyle

Short-Term Responses to Exercise

Long-Term Adaptations to Exercise

Fitness Testing and Components of Fitness

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AA larger base of support makes a performer more stable.

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