Theory 52/Organism/Muscle physiology
Fibre Type Follows Duty Cycle
The claim
Muscle fibre composition is set by the ratio of duty cycle to fatigue resistance, so a muscle used briefly becomes fast and one used continuously becomes slow.
01Mechanism
Fast fibres fatigue quickly but produce more power; the ratio determines which property the muscle must optimise.
02Prediction
Fibre type should track the ratio.
03Refutation
Fibre type tracking load would remove duty cycle.