Kinematics and Joint Movement in Kinesiology

Kinematics

Motion without regard to forces.

Osteokinematics

Motion of bones (visible, gross motion).

Arthrokinematics

Motion between joint surfaces (micromovements).

Kinetics

Forces that cause motion.

Translatory (Linear) Motion

All parts move the same distance in the same direction.

Rotary (Angular) Motion

Motion around an axis.

Degrees of Freedom (DoF)

The number of independent movements a joint can perform.

Joint Types

Classification based on degrees of freedom and structural type.

Flexion

Decrease in joint angle, occurring in the sagittal plane.

Extension

Increase in joint angle, occurring in the sagittal plane.

Abduction

Movement away from the midline of the body, occurring in the frontal plane.

Adduction

Movement toward the midline of the body, occurring in the frontal plane.

Medial Rotation

Turning toward the midline of the body.

Lateral Rotation

Turning away from the midline of the body.

Pronation

Forearm rotation that turns the palm down.

Supination

Forearm rotation that turns the palm up.

Inversion

Foot rotation that turns the sole inward.

Eversion

Foot rotation that turns the sole outward.

Protraction

Movement of a body part forward.

Retraction

Movement of a body part backward.

Circumduction

Combination of flexion, abduction, extension, and adduction.

Anatomical Position

Standardized reference posture for describing motion.

Clinical Kinesiology

Application of kinesiology to healthcare.

Biomechanics

Use of mechanical principles to study the body.

Goniometry

Measures osteokinematic joint motion.

Goniometer

Uses a goniometer (like a protractor).

Clinical Rehab

Commonly used in clinical rehab.

Range of Motion (ROM)

Table 1-2 lists ROM for major joints (memorize key numbers for practical use).

Contralateral Comparison

Compare to the contralateral side to assess impairments.

End Feel

Normal and abnormal sensations felt at the end of joint motion.

Normal End Feel: Hard

Bone stops motion (elbow extension).

Normal End Feel: Firm

Ligament/capsule resistance (wrist flexion).

Normal End Feel: Soft

Soft tissue approximation (elbow flexion).

Abnormal End Feel: Empty

Pain limits movement before resistance.

Abnormal End Feel: Unexpected

Unexpected hard/soft feel = pathology (e.g., swelling, bone fragment).

Kinematic Chains

Types of movement patterns involving joint motion.

Open Kinematic Chain

Distal segment moves freely (e.g., kicking, reaching).

Closed Kinematic Chain

Distal segment fixed, proximal moves (e.g., push-up, squat, sit-to-stand).

Roll Motion

New points contact new points (e.g., femoral condyles on tibia).

Slide Motion

One point glides across another.

Spin Motion

Rotation around a fixed point (e.g., radius spinning in pronation).

Joint Classification

Types of joints based on structure and motion capability.

Synarthrosis

Fibrous joint with no or minimal motion (e.g., skull sutures, teeth).

Amphiarthrosis

Cartilaginous joint with limited motion (e.g., pubic symphysis, spine).

Diarthrosis

Synovial joint with free motion (e.g., shoulder, hip, knee).

Concave-Convex Rule

Convex on concave → roll and slide in opposite directions; concave on convex → roll and slide in same direction.

Clinical Application Tips

Guidelines for assessing joint motion and dysfunction.

Loss of Motion

Loss of motion in one joint can affect the entire chain.

Compensations

Compensations can help but increase strain and energy use.

Assessing Joint Dysfunction

Assess end feel and joint play for joint dysfunctions.

ROM Charts

Use ROM charts and goniometry for treatment planning.

Kinematics vs Kinetics

Kinematics describes motion without regard to forces; kinetics describes the forces that cause or resist motion.

Sagittal plane

Medial-lateral (x) axis.

Frontal plane

Anterior-posterior (z) axis.

Transverse plane

Vertical (y) axis.

Frontal plane movements

Abduction, adduction, ulnar/radial deviation, lateral flexion.

Translatory motion

All parts of the object move in the same direction at the same speed.

Rotary motion

Motion around a fixed axis (angular movement).

Degrees of freedom

The number of planes in which a joint can move.

Uniaxial joint

A joint that allows movement in one plane.

Biaxial joint

A joint that allows movement in two planes.

Triaxial joint

A joint that allows movement in three planes.

Arthrokinematic joint motions

Roll, Slide, and Spin.

Hard end feel

Bone-on-bone (elbow extension).

Firm end feel

Ligament/capsule stretch (wrist flexion).

Soft end feel

Muscle bulk contact (elbow flexion).

Synovial fluid function

Lubrication and nourishment of the joint surfaces.

Example of biaxial joint

Metacarpophalangeal joint.

Expected end feel in passive elbow extension

Hard.

Plane of trunk rotation

Transverse.

Open-chain vs closed-chain motion

Free movement of distal segment in open chain.

Humeral head movement during shoulder abduction

Rolls upward and glides downward on the glenoid fossa.

Not a synovial joint component

Disc nucleus pulposus.

Example of translatory motion in the body

Sliding of carpal bones.

Movement of reaching behind your back

Extension and internal rotation.

Joint type allowing greatest range of motion

Ball-and-socket joint.