Torque

torques

-measure of extent to which a force will cause an object to rotate

-force is applied away from axis

-line of action is not through axis

moment arm

-perpendicular to force’s line of action and axis of rotation

-shortest distance between the axis of rotation and line of action of the force

lever arm

distance between the point of force application (perpendicular component) and the axis of rotation

line of action

imaginary line that extends from the force vector in both direction

-the line that the force pushes/pulls along

Torque (formula)

T=Fd(perpendicular) (Nm)

positive torque

acts counterclockwise about axis of rotation

negative torque

acts clockwise about axis

anatomical torques

positive and negative torques depend on the reference frame chosen

-joint torque typically described by the joint motion that occurs of the segment moves in the direction of the torque

resultant torques

-found by adding the torque about an axis (taking into account sign) of each torque into account

resultant joint torque

the sum of the torques about the joint axis due to these force

-provides a simplified picture of which muscle groups are most active about a joint

static equillibirum

a system is at rest and will remain at rest (Newton’s first law)

F=0

T=0