Kinesiology and Biomechanics Introduction

Vocabulary terms covering basic kinesiology principles, kinetic chains, joint mechanics, physical forces, and levers based on the introductory lecture.

Kinesiology

The study of human movement, incorporating physics, anatomy, physiology, and biomechanics.

External Forces

Forces exerted on the body from outside sources, such as gravity or the weight of a dumbbell.

Internal Forces

Forces generated within the body, generally referring to the muscles.

Osteokinematics

The motion of bones or limbs through space around joints, including movements like abduction, adduction, flexion, and extension.

Arthrokinematics

The actual movement occurring between the joint surfaces, specifically described as roll, spin, or glide.

Line of Pull

The direction of the force exerted by a muscle based on its alignment or shape, which can change the movement of the joint and limb.

Closed Kinetic Chain

An activity where the distal segment is fixed while the proximal segment is free to move, such as in a squat or a push-up.

Open Kinetic Chain

An activity where the distal end of the limb moves while the proximal end is fixed or stable, such as a bicep curl or a long arc quad.

Uniaxial Joint

A joint that moves in only one plane around one axis, such as the elbow which performs flexion and extension.

Biaxial Joint

A joint where motions occur in two different planes around two axes, such as the wrist.

Triaxial Joint

A joint that allows movement through three planes around three axes, such as the shoulder or the hip.

Radial Deviation

Movement of the wrist toward the thumb side.

Ulnar Deviation

Movement of the wrist toward the pinky side.

Scalar

A quantity that represents magnitude only, such as a patient ambulating 50 feet with a rolling walker (RW).

Vector

A quantity that includes both magnitude and direction, such as a patient performing 20 reps of elbow flexion with a 10 pound weight.

Compression

A force that pushes joint surfaces closer together, also known as approximation.

Traction

A pulling force that causes joint surfaces to pull apart, also referred to as distraction.

Shear Force

A force involving sliding across a surface where one segment moves in one direction and another segment moves the opposite way.

Bending

A force involving compression on the concave side and traction on the convex side of a structure.

Torsion

A force involving a rotational or twisting component, such as the force that causes a spiral femur fracture.

Torque

The amount of force required to create rotation around a joint; it increases as resistance moves further from the axis.

First-Class Lever

A lever designed for balance, like a seesaw; in the body, an example is the head balanced on the neck.

Second-Class Lever

A lever designed for strength or power, like a wheelbarrow; in the body, an example is a heel raise.

Third-Class Lever

The most common lever in the body, designed for speed; an example is a biceps curl.

Equilibrium

A state where the sum of all internal and external forces acting on the body equals zero, resulting in no movement.

Center of Mass (COM)

The location where all mass of the body comes together, typically located at the second sacral vertebrae ($S_2$).

Base of Support (BOS)

The area between the points of the body that are in contact with the floor.