Kinesiology Test One Review

Flashcards covering key concepts from the Kinesiology Test One Review notes (kinematics, kinetics, planes, axes, displacement, motion, forces, open/closed chain, COM, BOS, stability).

What is the difference between kinetic and kinematic analysis in the study of human movement, and can you provide an example of each?

Kinetics studies the forces that cause or accompany motion (e.g., joint moments, ground reaction forces).

Kinematics studies the motion itself without regard to forces (e.g., joint angles, velocities, accelerations).

Example: analyzing knee flexion angle during running (kinematics) versus analyzing knee extensor moments and ground reaction forces during the same run (kinetics).

Sagittal plane

Medial to Lateral Axis

Flexion/Extension

Frontal plane

Anterior to Posterior axis

Abduction/Adduction

Transverse plane

Superior to inferior axis or vertical axis

Interior/exterior rotation

Horizontal abduction/adduction

What are translational (linear) and rotary (angular) displacement?

Translational displacement is linear movement of a body point along a straight or curved path. Rotary displacement is angular movement around an axis (joint rotation).

Why do anatomical joints move with a combination of rotary and translatory motion?

Joint surfaces roll and slide relative to each other, producing a combination of rotation (about an axis) and translation (sliding). No joint is a pure hinge in normal function.

What is the convex-concave rule and how do joint shapes affect motion?

If a convex surface moves on a fixed concave surface, roll and glide occur in opposite directions. If a concave surface moves on a fixed convex surface, roll and glide occur in the same direction. This influences end ROM and joint tracking.

What do the X, Y, and Z axes represent in human movement?

X = mediolateral (left-right); Y = anteroposterior (front-back); Z = vertical (up-down). Note: axis orientation can vary by convention.

How is the magnitude of displacement expressed for rotary versus translational movement?

Rotary displacement is measured in degrees or radians; translational displacement is measured in meters or inches.

What are speed, velocity, and acceleration, and how are they used in studying human motion?

Speed is the scalar rate of distance traveled

velocity is speed with direction (a vector)

acceleration is the rate of change of velocity.

They are used to quantify how fast movement occurs and how motion changes over time.

Define concentric, eccentric, and isometric muscle actions, with a quick example.

Concentric: muscle shortens while producing force (e.g., lifting a dumbbell during a curl).

Eccentric: muscle lengthens under tension (e.g., lowering the dumbbell).

Isometric: muscle produces force with no change in length (e.g., holding a weight steady at a fixed angle).

What is open-chain versus closed-chain movement, and provide examples?

Open-chain: distal segment moves freely (e.g., seated knee extension).

Closed-chain: distal segment is fixed to the ground (e.g., squat or push-up).

Define force and how it is measured.

Force is a push or pull that can cause or influence motion. It is measured in newtons (N) using devices like force plates or load cells.

How is weight different from mass?

Mass is the amount of matter in an object.

Weight is the gravitational force acting on that mass (W = m × g); weight varies with gravity, mass does not.

What are external and internal forces?

External forces originate outside the body (gravity, ground reaction forces).

Internal forces are generated by the body's own muscles and structures (muscle forces, joint contact forces).

What is a vector, and how are vectors represented to describe magnitude and direction?

A vector has both magnitude and direction and is represented graphically by an arrow whose length indicates magnitude and orientation indicates direction.

What is a resultant force?

The vector sum of all forces acting on a body at a given time.

What is a line of gravity, and how is it used to represent gravity on a human body or segment?

The vertical line extending from the center of gravity (or center of mass) downward; used to assess stability and how gravity acts through the body.

Where is the center of mass for the human body, and how are segment centers of mass determined?

The whole-body COM in an average standing person is typically near the pelvis region around the sacral level (approximately near S2). Each body segment has a known, fixed fraction along its length where its center of mass is located, used in biomechanical modeling.

What is the base of support (BOS), and how does it influence stability?

BOS is the area of contact between the body and support surface (feet, hands, etc.). A larger BOS increases stability; a smaller BOS decreases stability, especially when the center of mass is high or outside the BOS.

How would you align the body to maximize stability given a certain center of mass and base of support?

Keep the line of gravity (LOG) within the base of support; widen the base if needed; lower the center of mass by bending the knees; align the trunk over the feet to maintain balance and minimize the LOG excursion beyond BOS.