Biomechanics

Question 1

Biomechanics

Answer 1

• Study of internal and external forces acting on the human body and their effects
  
  • Application of the scientific principles of mechanics to understand movements and actions of human bodies and
    sport implements.
• Biomechanics contributes significantly to our knowledge of human movement
  
  • Movement analysis
  • Equipment design
  • Mechanism of injuries
• Kinesiology and biomechanics are integrally related.

Question 2

BIOMECHANICS AS AN INTERDISCIPLINE

Answer 2

• Kinesiology
• Natural Sciences
• Mathematics
• Engineering
• Health Sciences

Question 3

Kinesiology

Answer 3

• Anthropometry
• Physiology
• Psychomotor
• Sports performance

Question 4

Natural Sciences

Answer 4

• Biophysics
• Physics
• Zoology

Question 5

Mathematics

Answer 5

• Algebra
• Calculus
• trigonometry

Question 6

Engineering

Answer 6

• Biomedical
• Electrical
• Mechanical
• Robotics

Question 7

Health Sciences

Answer 7

• Medicine
• Ergonomics
• Physical therapy
• Prostethics

Question 8

Why Study Biomechanics?

Answer 8

• To better understand and the various internal and external forces that affect movement and the human body.
• To improve individual’s movements and skill performance.
• To design and conduct programs to enhance movement skills

Question 9

Areas of Specialization

Answer 9

1. Developmental biomechanics
2. Clinical biomechanics
3. Equipment design

Question 10

Developmental biomechanics

Answer 10

• Studies movement patterns and how they change
  across the lifespan and with people with disabilities.
  
  • Example: Cerebral Palsy (CP) research

Question 11

Clinical biomechanics

Answer 11

• Prevention of injury or diseases that result in movement disorders
• Rehabilitation of people who are injured or have a movement disorder
  disease or disability.

Question 12

Equipment design

Answer 12

• Increases in performance through changes in equipment.
  
  • Example: Wheelchair racers, like this Boston Marathoner, have benefited greatly from improvements in equipment design and research designed to help them streamline and refine their body position to improve performance.

Question 13

Major Areas of Study in Biomechanics

Answer 13

• Quantitative Biomechanics
• Qualitative Analysis
• Kinematics
• Kinetics

Question 14

Quantitative Analysis

Answer 14

• Using high-tech instrumentation
• Measuring variables to optimize function or athletic performance
  
  • Foot forces on sprinter’s starting block (Force Platforms)
  • Muscle contraction sequence during
    running (EMG)
  • 3-D arm movements of a stroke survivor (Motion capture)

Question 15

Qualitative Analysis

Answer 15

• Using sight and hearing (also with video recording)
• Use a performance checklist to guide the
  observation.
• Usually done by coaches and teachers
  
  • Who typically do not have access to complex equipment
• To identify and correct errors:
  
  • “Observe, analyze and correct.”

Question 16

Kinematics vs. Kinetics

Answer 16

Two ways to describe and analyze human motion:
- Without reference to forces causing motion
- Describing motion in terms of forces that cause it

Question 17

Kinematics

Answer 17

• Without describing human motion without reference to force causing motion
• Focusing on motion’s spatial and timing characteristics
• Dynamics: Study of mechanical factors that relate to systems in motion.
• Measurements:
  
  • Time
  • Displacement
  • Velocity
  • Acceleration

Question 18

Kinetics

Answer 18

• Describing motion in terms of forces that cause it
• Internal forces
  
  • Muscles pulling on bones
  • Bone-on-bone, inside joints
• External forces acting on the body
  
  • Without contact (e.g., gravity)
  • From contact with ground, opponent or equipment

Question 19

Types of Motion

Answer 19

1. Linear Motion
2. Angular Motion
3. General Motion

Question 20

Linear Motion

Answer 20

• All body parts move same distance and direction, at the same time
• Translation: linear motion of the whole body
  
  • E.g., Bobsled

Question 21

Angular Motion

Answer 21

• Body moves on a circular path and rotates about axis of rotation
• Body segments rotate about their joints
  
  • E.g., twisting somersault

Question 22

General Motion

Answer 22

• Body / segments move linearly and rotate at the same time
• True for most athletic and
  everyday activities
  
  • E.g., walking

Question 23

Force

Answer 23

• Force is any action, push or pull, that tends to cause an
  object to change is state of motion by experiencing
  acceleration
  
  • Produced by the actions of muscles.
  • The stronger the muscles, the more force the body can produce
• In biomechanics we study the application of internal or
  external forces on the body

Question 24

Absorption of Force

Answer 24

• Common in many physical activities and sports
• The impact of a force should be gradually reduced and spread
  
  • Oer a large surface
  • Over time
  • Example: drop vertical jump (DVJ)

Question 25

Force application determines the type of movement

Answer 25

1. Linear motion = force acting on centre of mass/ pivot point 2. Angular motion = force not acting on centre of mass/ pivot point and result in torque (moment of force)

Question 26

Velocity

Answer 26

Speed and direction of a body.

Question 27

Acceleration

Answer 27

Change in velocity over time.

Question 28

Angular Velocity

Answer 28

Angle that is rotated in a given unit of time.

Question 29

Angular Acceleration

Answer 29

Change of angular velocity for a unit of time

Question 30

Mechanical Principle: Motion

Answer 30

1. Newton’s First Law - Law of Inertia 2. Newton’s Second Law - Law of Acceleration 3. Newton’s Third Law - Law of Action and Reaction

Question 31

Newton’s First Law - Law of Inertia

Answer 31

Objects will not change their state of motion unless acted on by an unbalanced external force

Question 32

Newton’s Second Law - Law of Acceleration

Answer 32

Objects will experience a change in velocity (acceleration) proportional to the unbalanced external force

Question 33

Newton’s Third Law - Law of Action and Reaction

Answer 33

For every action there is an equal and opposite reaction; forces act in pairs that are equal in magnitude and opposite in direction

Question 34

Lever systems and Motion Mechanics

Answer 34

- Mechanical device performing angular motion - Components: - Axis of rotation/fulcrum (aka pivot point) - Load (or resistance) arm attached to fulcrum - Force arm attached to fulcrum - Applied force (muscle in the human body) - Load (Resistance) - Human muscles, bones and joint work together as lever systems

Question 35

How Levers Work

Answer 35

- Force is applied -> if the turning effect of the force is greater than resistance -> Rotation at the axis / fulcrum occurs - To determine turning effect, consider the length of force arm and resistance arm - Levers offer either a mechanical advantage (FA > RA) or a speed advantage (FA < RA)

Question 36

TYPES OF LEVERS

Answer 36

- Levers perform different functions - Three basic types of lever exist - First class - Second class - Third class - Differ based on mechanics and how these components are positioned - Axis - Resistance - Force

Question 37

FIRST CLASS LEVERS

Answer 37

- Applied force and resistance on opposite side of axis, at un/equal distance from one another - Example: crowbar - Human body: head flexion - Either gives a mechanical or speed advantage depending on where the axis is placed

Question 38

SECOND CLASS LEVERS

Answer 38

- Applied force and resistance on same side of axis; resistance closer to axis - Example: wheelbarrow - Human body - rare: toe raise - Always gives a mechanical advantage (FA>RA)

Question 39

THIRD CLASS LEVERS

Answer 39

- Applied force and resistance on same side of axis; force closer to the axis - Example: fishing - Human body – many: forearm flexion - Always gives a speed advantage (FA