Compare the types of muscle fibre and explain the factors determining muscular strength.
How to lay out the answer. Follow the frame, then write it in your own words.
1 · Open in two lines. Skeletal muscle has slow-twitch and fast-twitch fibres that differ in speed, fuel use and fatigue. Strength is the maximum force a muscle can produce.
2 · Draw the fibre-type table. [Table: Type I, IIa, IIx against speed, colour, mitochondria, energy system, force, fatigue, sport]
3 · Fibre mix and sport. Distance runners: mostly Type I. Sprinters and throwers: mostly Type II. The mix is largely inherited.
4 · Effect of training. Endurance and strength training shift IIx towards IIa; recruitment goes from small to large motor units.
5 · Factors determining strength.
Cross-sectional area and fibre type.
Neural recruitment and firing rate.
Muscle length, joint angle and speed.
Age, sex, training, nutrition and motivation.
6 · Strength vs power. Strength is maximum force; power is force × velocity.
7 · Nutrition link. Protein near the upper end of 1.2-2.0 g/kg with resistance training; glycogen for repeated efforts.
8 · Close in one line. Fibre type sets the athlete's natural bent; training and nutrition decide how far strength develops.
Scoring tip: Put the fibre comparison in a three-column table; examiners can mark it at a glance.
