Terminology of Kinesiology: Rotational and Translatory Forces

Compression force acts perpendicular to a bony segment.

Muscle produces a pulling force as it contracts during Eccentric activation.

Isometric activation involves a muscle maintaining a constant length while producing a pulling force.

Translatory forces applied across a joint and parallel to joint surfaces are called tension or traction forces.

The term 'muscle and joint interaction' refers to the effect that muscle force has on a joint.

Internal torque at a joint is less than external torque during Isometric activation.

Rotational torque applied perpendicular to the rigid body long axis is known as torsion.

Force components Mx represent translatory components that act parallel to a bony segment.

3rd Class Levers always have an MA < 1.

Muscles primarily serve a mobility function by producing or controlling the movement of a bony lever around a joint axis.

Human body contains over 300 skeletal muscles.

Muscle forces have both rotatory and translatory components.

In close-packed joint positions, the stability role of muscles is increased.

Passive supporting structures play a larger role in providing joint stability in loose-packed joint positions.

Muscles produce heat during cold stress.

The muscle must produce a force much smaller than the opposing external force to achieve torque equilibrium in 3rd Class Levers.

First Class Levers have the Axis of Rotation between two opposing levers.

Second Class Levers have the Axis of Rotation at one end of a bone.

Third Class Levers have the External Force possessing greater leverage than the Internal Force.

First Class Levers are the least common musculoskeletal lever.

Second Class Levers possess greater leverage for the External Force than for the muscle.

Third Class Levers are the most efficient type of musculoskeletal lever.

First Class Levers always have a Mechanical Advantage greater than 1.

The Internal Moment Arm is equal to the External Moment Arm in Second Class Levers.

Fusiform muscles have fibers running perpendicular to each other.

Pennate muscles have fibers that approach their central tendon obliquely.

The physiologic cross-sectional area of a muscle reflects the amount of passive proteins available for generating force.

In muscle architecture, the pennation angle refers to the angle between muscle fibers and blood vessels.

If muscle fibers are parallel to the tendon, the pennation angle is defined as 0 degrees.

Structural proteins have no role in supporting the structure of muscle fibers.

The ratio of eye muscles to nerve is 1:5

The hamstrings have a muscle to nerve ratio of 300:1

The ultimate function of muscles is not influenced by their shapes.

The neuromuscular junction is where a motor neuron meets a muscle fiber

The cross-section area of a whole muscle should be made parallel to each of the muscle fibers.

Acetylcholine causes hyperpolarization of the muscle fiber

Rate coding involves smoothly increasing muscle force by recruiting motor neurons

Recruitment is the process of altering the voltage potential across the membrane of the alpha motor neuron

An action potential is an electrical signal produced at a critical voltage

A muscle twitch occurs after the muscle fiber is hyperpolarized