Because every human movement is created by one or more joints rotating around an axes, it’s not enough to discuss forces; torques must be discussed.¹
The ability of any force to cause rotation of a lever is known as torque. Thus, a torque is a force applied at some distance from an axis that either causes or prevents rotation of a lever.²
It is the product of the magnitude of the applied force and the distance that force lies from the axis of rotation; thus, it is directly proportional to both the magnitude or amount of force and its distance from the axis.
Regardless of the class of lever, the rotation of the bone segment is dependent on the torque (both the magnitude of the force exerted by the effort and resistance forces and on the distance from the axis of these two forces).¹
Basically every force applied to the human body (external force) or created within the human body (internal force) is creating torque.