Case 9 How do we move? Powerful muscles
, 1. Relation between muscle force and joint torque:
Joint torque:
The force exerted by a muscle during contraction on the bony levers to which it is
attached is known as the muscle tension, and the external force exerted on the muscle
is known as resistance or load. As the muscle exerts its force, it generates a turning
effect, or moment(torque), on the involved joint, as the line of application of the
muscle force usually lies at a distance from the center of motion of the joint.
Moment's arm:
Muscles attach to bones at a distance from anatomical joints so that they have
sufficient leverage to move the limbs. This leverage is called the muscle's moment arm.
The moment arm can be increased by increasing the distance between the muscle
attachment site on the bone and the joint's axis of rotation.
M=F*d
Positive (counter clockwise)
Negative(clockwise)
, 1. Relation between muscle force and joint torque:
Joint torque:
The force exerted by a muscle during contraction on the bony levers to which it is
attached is known as the muscle tension, and the external force exerted on the muscle
is known as resistance or load. As the muscle exerts its force, it generates a turning
effect, or moment(torque), on the involved joint, as the line of application of the
muscle force usually lies at a distance from the center of motion of the joint.
Moment's arm:
Muscles attach to bones at a distance from anatomical joints so that they have
sufficient leverage to move the limbs. This leverage is called the muscle's moment arm.
The moment arm can be increased by increasing the distance between the muscle
attachment site on the bone and the joint's axis of rotation.
M=F*d
Positive (counter clockwise)
Negative(clockwise)
