Biomechanics exam

1. Biomechanics Master Cheat Sheet

Linear Kinematics

Studies motion without considering forces.

Key Variables

Core Equations

Remember

• Distance = total path travelled

• Displacement = straight-line change in position

• Velocity includes direction

• Speed does not include direction

Anatomical Analysis

Anatomical Planes

Axes of Rotation

Joint Movements

• Flexion

• Extension

• Abduction

• Adduction

• Internal Rotation

• External Rotation

• Pronation

• Supination

Exam Tip

Movement occurs:

• In a plane

• About an axis perpendicular to that plane

Angular Kinematics

Key Variables

Core Equations

Linear-Angular Relationships

Important:

Biomechanical Analysis

Common Steps

1. Identify movement phase

2. Determine plane and axis

3. Identify joints involved

4. Identify muscles producing movement

5. Determine type of contraction

6. Describe forces acting

Muscle Contractions

Linear Kinetics

Studies forces causing linear motion.

Newton's Laws

1st Law

Object remains at rest or constant velocity unless acted on by a net force.

2nd Law

3rd Law

For every action there is an equal and opposite reaction.

Types of Forces

• Weight

• Ground reaction force

• Friction

• Muscle force

• Air resistance

Equilibrium

Conditions

Static Equilibrium

• No movement

• Net force = 0

• Net torque = 0

Dynamic Equilibrium

• Constant velocity

• No acceleration

Stability Factors

Increase stability by:

• Wider base of support

• Lower centre of mass

• Greater friction

Angular Kinetics

Torque (Moment)

Where:

• F = force

• d = perpendicular distance

Rotational Equivalent Table

Rotational Newton's 2nd Law

Tissue Mechanics

Stress

Strain

Stress-Strain Curve

Order:

1. Toe region

2. Elastic region

3. Yield point

4. Plastic region

5. Failure point

Tissue Properties

• Stiffness

• Elasticity

• Plasticity

• Viscoelasticity

• Toughness

Injury Biomechanics

Injury Mechanisms

Acute

Single traumatic event

• ACL tear

• Fracture

• Concussion

Chronic

Repeated loading

• Tendinopathy

• Stress fracture

Factors Affecting Injury

• Magnitude of force

• Rate of loading

• Direction of force

• Tissue condition

Common Terms

• Compression

• Tension

• Shear

• Bending

• Torsion

Fluid Mechanics

Density

kg

L

m is mass; V is volume.

Pressure

Buoyancy

Upward force exerted by fluid.

Drag Force

Resistance opposing movement through fluid.

Factors increasing drag:

• Higher velocity

• Larger surface area

• Less streamlined body position

Lift

Force perpendicular to fluid flow.

Applications:

• Swimming

• Cycling

• Skiing

• Rowing

2. High-Yield Flashcards

Q

Difference between distance and displacement?

A

Distance = total path travelled; displacement = straight-line change in position.

Q

What plane does flexion occur in?

A

Sagittal plane.

Q

What is Newton's 2nd Law?

A

Force equals mass times acceleration.

Q

What is torque?

A

Rotational effect of a force around an axis.

Q

Three types of muscle contraction?

A

Concentric, eccentric, isometric.

Q

What causes greater stability?

A

Lower centre of mass and wider base of support.

Q

What region follows the elastic region on a stress-strain curve?

A

Yield point.

Q

What loading type pulls tissue apart?

A

Tension.

Q

Main force opposing swimmers?

A

Drag force.

Q

What is viscoelasticity?

A

Time-dependent mechanical behaviour of biological tissues.

3. Exam "Spot-the-Question" Guide

If you see...

4. 10-Minute Pre-Exam Formula Dump

Memorise these first:

The principle of conservation of momentum restates which of Newton's laws? a. Acceleration b. Gravitation c. Action/reaction d. Inertia ✓

Choose the term that describes the force acting perpendicular to two surfaces in contact.

Question 1Select one:

A.

normal reaction force

B.

perfectly plastic impact

C.

perfectly elastic impact

D.

maximum static friction

Which of the following affects the time that a horizontally projected object remains in the air?

Select one:

A. projection height

B. weight

C. mass

D. all of these answers are correct

Choose the term that describes an energy of motion.

Question 6Select one:

A.

potential energy

B.

kinetic friction

C.

kinetic energy

D.

strain energy

Which of the following relationships is correct?

Question 13Select one:

A.

F = m / a

B.

a = m / F

C.

m = F / a

D.

none of these answers is correct

Which of the following factors does not affect the amount of friction generated between two dry surfaces?

Question 17Select one:

A.

the coefficient of friction between the two surfaces

B.

the surface area in contact

C.

the normal force

D.

the reaction force

Which of the following is/are false statement(s) regarding the law of gravitation?

Question 19Select one:

A.

All bodies are attracted to one another with a force proportional to the product of their masses.

B.

The law of gravitation ceases to exist outside the earth's atmosphere.

C.

All bodies are attracted to one another with a force inversely proportional to the square of the distance between them.

D.

All of the above.

Choose the term that describes the constant-magnitude friction generated between two surfaces in contact during motion.

Question 20Select one:

A.

kinetic friction

B.

friction

C.

coefficient of friction

D.

maximum static friction

The principle of conservation of momentum restates which of Newton's laws?

Question 26Select one:

A.

inertia

B.

action/reaction

C.

gravitation

D.

acceleration