89 out of 95
In Preload, there is
|A||isotonic contraction without shortening of muscle fibres|
|B||isotonic contraction with shortening of muscle fibres|
|C||isometric contraction without shortening of muscle fibres|
|D||isometric contraction with shortening of muscle fibres|
Ans. B isotonic contraction with shortening of muscle fibres (Ref: Ganong’s-23rd Edition, Pg101)
- A contraction which occur without an appreciable decrease in the length of the whole muscle is called isometric (“same measure” or length).
- Contraction against a constant load with a decrease in muscle length is isotonic (“same tension”).
- In preload , the load acts on the muscle even before contraction, which causes stretching of muscle fibre and results in increased force of contraction and shortening, called as Frank Starling Law.