Movement Analysis

What are the three elements of the Movement System Framework?

Environment, task, and organism.

How do the environment, task, and organism interact?

They work together to influence movement quality, performance, and adaptation.

What is qualitative movement analysis?

Descriptive observation of movement quality, such as smoothness, accuracy, confidence, and consistency.

What is quantitative movement analysis?

Measuring movement variables like distance, velocity, acceleration, and angles numerically.

Examples of quantitative variables in movement.

Distance, speed, velocity (angular and linear), acceleration, and work.

Define linear velocity.

The rate of change of position in a straight line.

Define angular velocity.

The rate of change of an angle over time, measured in radians per second (r/s).

What is the relationship between linear and angular velocity?

v = ω × r (linear velocity = angular velocity × radius).

What happens to linear velocity when the radius increases?

Linear velocity increases if angular velocity stays constant.

Quantitative description of gait involves what?

Measuring step length, cadence, and speed using linear and angular variables.

Quantitative measurement of ROM means what?

Measuring joint motion in degrees using a goniometer or motion analysis system.

What is the formula for angular velocity?

Angular velocity = change in angle ÷ time (Δθ/Δt).

What does “v = ωr” describe in biomechanics?

The relationship between angular velocity and the linear velocity at a given radius from the axis.

Define stability.

The resistance of an object or person to displacement when a force is applied.

What increases stability?

Increased mass, a wider base of support, a lower center of mass, and a center of mass within the base of support.

When is an object unstable?

When a small force causes it to move easily due to a high or shifted center of mass.

Define balance.

The ability to maintain the center of mass over the base of support.

How can assistive devices affect balance?

They enlarge the base of support, improving stability.

Can balance be maintained in any position?

Yes, as long as the center of mass remains over the base of support.

Can the center of mass be outside the body?

Yes, depending on body position and movement (e.g., bending or leaning).

What is transfer of momentum?

The movement of energy or motion from one body segment to another during movement.

Example of transfer of momentum.

A golf swing or throw, where momentum transfers from trunk to arm to hand.

Why is momentum transfer important?

It allows efficient and powerful motion across segments.

What are constraints on movement?

Factors within the organism, environment, or task that limit or shape how movement occurs.

Examples of organism constraints.

Strength, flexibility, coordination, balance, neurological control.

Examples of environmental constraints.

Surface type, gravity, lighting, equipment, or surroundings.

Examples of task constraints.

The purpose, rules, and goals of a movement or activity.

What does qualitative movement analysis assess?

Smoothness, confidence, consistency, timing, and coordination of motion.

What are key signs of skilled (expert) movement?

Fluid, efficient, coordinated, consistent performance with minimal unnecessary motion.

What are signs of unskilled (novice) movement?

Inconsistent, jerky, or inefficient motion with excessive effort.

What are early effects of motor learning?

High variability, low efficiency, and conscious control of movement.

What changes occur with practice in motor learning?

Improved timing, reduced variability, and smoother, more automatic performance.

How does expert performance differ from novice performance?

Experts show automatic, efficient motion with smooth energy transfer and minimal wasted effort.

What is analyzed in sit-to-stand movement?

Balance, stability, sequencing, and smooth transfer of momentum from lower to upper body.

What is the biomechanical role of friction and inertia in movement analysis?

Friction provides resistance to motion; inertia resists changes in movement.

What external forces are analyzed during movement?

Gravity, load, weight, friction, resistance, buoyancy, and elastic resistance.

How can friction be beneficial?

Provides stability and traction for controlled movement.

What role does elasticity play in movement?

Stores and releases energy for efficient motion (e.g., plyometric stretch-shortening).

What is inertia?

A property that resists changes in motion; directly related to mass.

How is acceleration related to force?

Force = mass × acceleration (F = ma).

How can movement analysis guide therapy?

Helps identify abnormal mechanics, guide interventions, and enhance performance outcomes.

How does motor learning relate to biomechanics?

Practice refines motor control, improving efficiency and timing of movement patterns.

In PT practice, what is the benefit of combining qualitative and quantitative analysis?

It gives both measurable data and practical observation for complete movement understanding.