AQA · A-Level · Physical Education
Course version: 7582 · Version from Sept 2016
Neuromuscular system: Fast oxidative glycolytic (type IIa).
Fast oxidative glycolytic (type IIa) motor units combine fast contraction speed with moderate force and greater fatigue resistance than type IIx.
Checked against the AQA 7582 specification (opens in a new tab) on .
- Point 5 of 16
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Fast oxidative glycolytic (type IIa) motor units combine fast contraction speed with moderate force and greater fatigue resistance than type IIx. They can resynthesise ATP both anaerobically, through the glycolytic and phosphocreatine systems, and aerobically, because they have more mitochondria and capillaries than type IIx. A 400 m runner or a midfield player who repeatedly sprints and recovers relies on type IIa units. In multiple-choice questions you must distinguish type IIa from type IIx and type I by matching each option to contraction speed, force, fatigue resistance and the dominant energy systems, then select the single best description of the type IIa profile.
What earns the marks
- Type IIa motor units have a fast contraction speed and produce high force, though slightly less than type IIx.
- ATP is resynthesised through both anaerobic glycolysis and aerobic oxidation.
Common mistakes and how to put them right
Confusing type IIa with type IIx.
Put it right: Type IIa is fast oxidative glycolytic and has greater fatigue resistance, whereas type IIx is fast glycolytic and fatigues quickly.
Claiming type IIa fibres are purely anaerobic.
Put it right: They can also resynthesise ATP aerobically, which supports their greater fatigue resistance.
Assuming type IIa fibres are the same as type I.
Put it right: Type I fibres are slow-twitch and highly fatigue resistant, while type IIa fibres are fast-twitch with moderate fatigue resistance.
Treating type IIa as the fastest fibre type.
Put it right: Type IIx has the fastest contraction speed, while type IIa is fast but slightly slower.
Exam tips
- Read each option and check it against all four features: contraction speed, force, fatigue resistance and energy systems.
- Eliminate options that describe type I or type IIx characteristics before choosing the best match.
- If two options seem similar, look for the one that correctly links fast contraction with moderate fatigue resistance and both anaerobic and aerobic ATP resynthesis.
Try the lesson
The start of the Neuromuscular system: Fast oxidative glycolytic (type IIa). lesson, made from checked teaching notes for this specification point.
Have a go first
Which set of characteristics best describes a fast oxidative glycolytic (type IIa) muscle fibre?
Listen
Fast oxidative glycolytic (type IIa) motor units combine fast contraction speed with moderate force and greater fatigue resistance than type IIx. They can resynthesise ATP both anaerobically, through the glycolytic and phosphocreatine systems, and aerobically, because they have more mitochondria and capillaries than type IIx. A 400 m runner or a midfield player who repeatedly sprints and recovers relies on type IIa units. In multiple-choice questions you must distinguish type IIa from type IIx and type I by matching each option to contraction speed, force, fatigue resistance and the dominant energy systems, then select the single best description of the type IIa profile. A strong answer earns marks for these points. Type IIa motor units have a fast contraction speed and produce high force, though slightly less than type IIx. ATP is resynthesised through both anaerobic glycolysis and aerobic oxidation. Exam tip: Read each option and check it against all four features: contraction speed, force, fatigue resistance and energy systems.
See it
Key words
Say what each word means before you turn the card.
Fast oxidative glycolytic (type IIa)
Try answering aloud or in your head before turning the card.
Fatigue resistance
Try answering aloud or in your head before turning the card.
Anaerobic glycolysis
Try answering aloud or in your head before turning the card.
Aerobic oxidation
Try answering aloud or in your head before turning the card.
See every definition
- Fast oxidative glycolytic (type IIa)
- Motor units that combine fast contraction speed with moderate force and greater fatigue resistance than type IIx.
- Fatigue resistance
- The ability to sustain repeated high-intensity efforts better than type IIx, described as moderate to high for type IIa.
- Anaerobic glycolysis
- One of the anaerobic pathways through which type IIa resynthesises ATP, alongside the phosphocreatine system.
- Aerobic oxidation
- The aerobic means by which type IIa resynthesises ATP, supported by having more mitochondria and capillaries than type IIx.
Label the diagram
Some boxes have lost their names. Pick the right name for each number.
1Box 1
2Box 2
3Box 3
There is more to this lesson
The full lesson goes on to check your understanding and help you earn the marks. Create a free account to carry on, with your progress saved.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge
Test your understanding of Neuromuscular system: Fast oxidative glycolytic (type IIa).
Active recall beats re-reading. Take an instant quiz now to test what you’ve learned and lock it into long-term memory.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge