Lifting a Book Off the Desk is an Example of What

Question

Lifting a book off the desk is an example of what type of contraction?
A) isometric
B) twitch
C) isotonic
D) both A and B

Accepted Answer

Lifting a book off the desk involves an isotonic contraction, where the muscle is able to overcome the resistance of the book and the muscle length changes as it lifts the book. Isometric contractions (option A) would involve holding the book steady with no change in muscle length, while twitch contractions (option B) are rapid, brief contractions seen in response to a single nerve impulse. Therefore, option D is not applicable.