VCE PE Unit 4 AOS 2 — Chronic Adaptations Cause & Effect Chains

Vocabulary practice flashcards covering chronic aerobic, anaerobic, and resistance adaptations, as well as exam pitfalls from VCE PE Unit 4 AOS 2.

Increased size and number of mitochondria

Mitochondria are the sites of aerobic ATP resynthesis. More and larger mitochondria increase the capacity to resynthesise ATP aerobically, resulting in a faster rate of aerobic ATP production at a given intensity, less reliance on anaerobic glycolysis, a delayed LIP, and allowing the athlete to work at a higher intensity before fatiguing.

Increased left ventricle size and volume (cardiac hypertrophy)

The left ventricle fills with and ejects a greater volume of blood per beat (increased stroke volume), leading to increased cardiac output ($Q = \text{SV} \times \text{HR}$), more oxygenated blood delivered to working muscles, increased aerobic ATP production, and increased $\text{VO}_2\text{ max}$.

Increased alveolar surface area (increased pulmonary diffusion)

Greater surface area for gas exchange allows more oxygen to diffuse from the alveoli into the blood, increasing oxygen uptake, transport to working muscles, aerobic ATP production, and $\text{VO}_2\text{ max}$.

Increased lactate tolerance

Increased muscle buffering capacity provides a greater ability to neutralise accumulated hydrogen ions ($\text{H}^+$), delaying fatigue and maintaining force production so the athlete continues generating ATP anaerobically at a higher intensity for longer.

Muscular hypertrophy (increased cross-sectional area)

An increase in the size and number of myofibrils and the protein filaments actin and myosin, which increases cross-sectional area to generate greater force per contraction, resulting in increased muscular strength and power.

Increased motor unit recruitment

An increase in the number of nerve axons and their corresponding muscle fibres activated, resulting in more muscle used during each contraction, greater force produced, and more powerful movements.

Increased a-VO₂ difference

A greater difference in oxygen content between arterial and venous blood, meaning working muscles extract and utilise a greater proportion of delivered oxygen for aerobic ATP production, contributing to increased $\text{VO}_2\text{ max}$.

Increased myoglobin stores

Myoglobin extracts oxygen from red blood cells and delivers it to the mitochondria within the muscle cell, shuttling more oxygen for aerobic ATP production.

Increased capillarisation of skeletal muscle

Greater capillary supply increases blood flow and surface area for gas exchange at the muscle, delivering more oxygen and nutrients while removing metabolic by-products to sustain aerobic ATP production longer.

Increased blood volume and haemoglobin

More red blood cells and haemoglobin increase the oxygen-carrying capacity of the blood, while increased plasma reduces viscosity for smoother flow, delivering more oxygen to working muscles.

Increased fuel storage and oxidative enzymes

Greater stores of glycogen and triglycerides plus more oxidative enzymes increase the capacity to metabolise fats aerobically, reducing reliance on glycogen at a given intensity (glycogen sparing) and delaying fatigue from glycogen depletion.

Increased muscular stores of ATP and CP

Greater stores of ATP and creatine phosphate increase the capacity of the ATP-CP system, allowing ATP to be resynthesised at a fast rate for longer so maximal efforts can be sustained longer and repeated more often.

Increased glycolytic capacity

Increased muscular storage of glycogen and increased glycolytic enzymes provide a greater capacity of the anaerobic glycolysis system to produce ATP, maintaining high intensity for longer.

Increased synchronisation of motor units

Different motor units fire at the same time and larger motor units requiring a bigger stimulus are recruited, producing a more powerful muscular contraction.

Increased firing rate / rate coding

Increased frequency of stimulation of a given motor unit increases the rate of force development (how quickly the muscle contracts maximally), benefiting rapid ballistic movements where maximal force is needed in minimal time.

Increased tidal volume

More air per breath, making more oxygen available at the alveoli for diffusion.

Increased ventilation at maximal exercise

A greater volume of air per minute at maximum effort, allowing greater oxygen delivery at maximal intensity.

Decreased resting/submaximal respiratory frequency

Improved pulmonary function resulting in fewer breaths needed for the same oxygen uptake.

Increased capillarisation of the heart muscle

Greater blood and oxygen supply to the myocardium, enabling the heart to contract more strongly and efficiently.

Faster heart rate recovery

A more efficient cardiovascular system that returns HR to resting levels in a shorter time, enabling faster recovery between efforts.

Decreased resting and submaximal heart rate

A greater stroke volume means fewer heartbeats are needed per minute for the same blood flow.

Increased ATPase and creatine kinase enzymes

ATPase breaks down ATP to ADP, and creatine kinase initiates CP breakdown, allowing energy to be released and ATP resynthesised at a faster rate.

Muscle fibre adaptation (type 2A)

Fast-twitch 2A fibres take on slow-twitch characteristics from aerobic training, allowing greater aerobic ATP production with fewer fatiguing factors.

Reduction in inhibitory signals

Improved coordination of agonists, antagonists, and synergists leading to less protective neural inhibition and greater force production.

Increased VO₂ max

An increase in the maximum amount of oxygen taken up (respiratory), transported (cardiovascular), and utilised (muscular) per minute, enabling a faster rate of aerobic ATP production so the athlete works at a higher intensity aerobically.

Increased LIP

An increase in the highest intensity at which lactate production and removal remain balanced, meaning anaerobic glycolysis does not contribute as much until higher intensities and allowing the athlete to work at a higher intensity for longer before accumulating hydrogen ions.

Traps That Cost Marks

A reference guide outlining common situations, VCAA pitfalls, and required phrasing guidelines for lactate curves, peak lactate, energy system contributions, fast-twitch changes, and performance outcomes.