The centripetal force provided is less than the centripetal force required for uniform circular motion and tends to move outward. Coupled with circular rotation, centrifugal motion is caused.

Simply put, the supply is less than the demand, and we can't stay in the circle but go out.

Look at a muscle in isolation

Centripetal contraction is that the force produced by muscle contraction is greater than the resistance.

Isometric contraction means that the force and resistance produced by muscle contraction are equal.

Centrifugal contraction means that the force produced by muscle contraction is less than the resistance.

This resistance is not necessarily an external force, but may also be the role of antagonistic muscles. A simple example is the stiff state of exerting force when showing muscles, that is, isometric contraction without external force.

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