Explain the relationship between muscle fibre types and the production of movement. (4 marks)
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Sample Answer
- Muscle fibres have different structural characteristics that determine their function in movement production.
- Type I fibres contain abundant mitochondria and myoglobin, which enable them to use oxygen efficiently for sustained contractions. As a result, these fibres are recruited for endurance movements like distance running.
- Type II fibres are larger with fewer mitochondria. Due to their structure, they rely on anaerobic energy systems. Consequently, they produce powerful, explosive movements but fatigue quickly.
- The reason for selective recruitment is that the nervous system activates specific fibre types based on movement demands. Therefore, slow movements primarily use Type I fibres, while explosive movements recruit Type II fibres. Such coordination ensures the body produces appropriate movements efficiently.
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Sample Answer
- Muscle fibres have different structural characteristics that determine their function in movement production.
- Type I fibres contain abundant mitochondria and myoglobin, which enable them to use oxygen efficiently for sustained contractions. As a result, these fibres are recruited for endurance movements like distance running.
- Type II fibres are larger with fewer mitochondria. Due to their structure, they rely on anaerobic energy systems. Consequently, they produce powerful, explosive movements but fatigue quickly.
- The reason for selective recruitment is that the nervous system activates specific fibre types based on movement demands. Therefore, slow movements primarily use Type I fibres, while explosive movements recruit Type II fibres. Such coordination ensures the body produces appropriate movements efficiently.