Question

Which of the following is true?

-The internal torque angle of pull remains constant throughout a joint range of motion
-The internal torque muscle force remains constant throughout a joint range of motion
-The muscle moment arm length changes throughout a joint range of motion
-The internal and external torque moment arm lengths are always the same

Answer 1

The true statement is that the muscle moment arm length changes throughout a joint range of motion, affecting the torque produced by the muscle.

Step-by-step explanation:

The statement that is true among the options is: The muscle moment arm length changes throughout a joint range of motion. This is because as a joint moves, the pivot point can change, altering the perpendicular lever arms and the mechanical advantage. For example, when you flex your forearm, the force your biceps muscle needs to exert changes as the moment arm length varies, affecting the torque produced by the muscle. In contrast, the internal torque angle and muscle force do not necessarily remain constant, and the internal and external torque moment arm lengths are not always the same as they depend on various factors such as force magnitude, direction, and point of application.