Compare and contrast the characteristics and functions of slow-twitch and fast-twitch muscle fibres in relation to different sporting activities. (5 marks)
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Sample Answer
Similarities:
- Both fibre types
-
- exist in all skeletal muscles, working together for varied movement demands.
- contract through the sliding action of actin and myosin filaments.
- can be trained to improve performance within their genetic limitations.
- contribute to overall muscle function, with most activities requiring some combination of each type.
Differences:
- Structure:
-
- Slow-twitch fibres contain abundant mitochondria and capillaries, appearing red from high myoglobin content.
- Fast-twitch fibres have fewer mitochondria and limited blood supply, appearing white.
- Energy systems:
-
- Slow-twitch fibres use aerobic metabolism efficiently for sustained energy.
- Fast-twitch fibres rely on anaerobic pathways for rapid ATP production.
- Contraction characteristics:
-
- Slow-twitch fibres contract slowly but resist fatigue for hours.
- Fast-twitch fibres generate explosive force but fatigue within seconds.
- Sporting applications:
-
- Marathon runners and cyclists benefit from predominant slow-twitch fibres for endurance events.
- Sprinters and weightlifters require fast-twitch dominance for power and speed.
- Team sports like soccer utilise both – slow-twitch for continuous running, fast-twitch for sprinting and jumping.
- Training adaptations:
-
- Endurance training enhances slow-twitch oxidative capacity.
- Power training increases fast-twitch force production, though fibre type proportions remain largely genetic.
Show Worked Solution
Sample Answer
Similarities:
- Both fibre types
-
- exist in all skeletal muscles, working together for varied movement demands.
- contract through the sliding action of actin and myosin filaments.
- can be trained to improve performance within their genetic limitations.
- contribute to overall muscle function, with most activities requiring some combination of each type.
Differences:
- Structure:
-
- Slow-twitch fibres contain abundant mitochondria and capillaries, appearing red from high myoglobin content.
- Fast-twitch fibres have fewer mitochondria and limited blood supply, appearing white.
- Energy systems:
-
- Slow-twitch fibres use aerobic metabolism efficiently for sustained energy.
- Fast-twitch fibres rely on anaerobic pathways for rapid ATP production.
- Contraction characteristics:
-
- Slow-twitch fibres contract slowly but resist fatigue for hours.
- Fast-twitch fibres generate explosive force but fatigue within seconds.
- Sporting applications:
-
- Marathon runners and cyclists benefit from predominant slow-twitch fibres for endurance events.
- Sprinters and weightlifters require fast-twitch dominance for power and speed.
- Team sports like soccer utilise both – slow-twitch for continuous running, fast-twitch for sprinting and jumping.
- Training adaptations:
-
- Endurance training enhances slow-twitch oxidative capacity.
- Power training increases fast-twitch force production, though fibre type proportions remain largely genetic.