Week 2: Biomechanical Analysis

Question 1

What is the purpose of biomechanical analysis? (4 points)

Answer 1

• To improve technique
• To improve performance
• To prevent injury
• To improve equipment

Question 2

What are the main approaches to biomechanical analysis? (4 points)

Answer 2

• There are two primary approaches:
  1. Qualitative
  2. Quantitative
• In addition, some methods can combine these two approaches, making them semi-quantitative

Question 3

Describe Quantitive Analysis (12 points)

Answer 3

• Involves the measurement of biomechanical variables using technology to precisely describe performance.
• It tells us how much (e.g. time, distance, angles, forces, muscle activity levels).
• Advantages:
  1. Removes subjectivity
  2. Provides an abundance of data
  3. Particularly useful for rapid movements
  4. Can be used to predict moments (torque at a joint)
• Disadvantages:
  1. Requires considerable expertise
  2. Cost
  3. Ecological validity and feasibility
  4. Time

Question 4

Describe qualitative analysis (10 points)

Answer 4

• Systematic observation and judgement of the quality of human movement in non-numerical terms.
• Advantages:
  1. Non-numerical
  2. Often better for use in the field
  3. Based on observation of gross movement patterns (the overall quality of the movement)
  4. Inexpensive, minimal equipment
• Disadvantages:
  1. Subjective – reliability and validity?
  2. Limited data
  3. Specific knowledge of the analysed skill is needed

Question 5

Describe the models for Qualitative analysis (5 points)

Answer 5

• Many models (over 20) have been proposed for the qualitative analysis of human movement
• These models can be classified as observational or comprehensive
• Examples of a qualitative analysis models:
  1. 19 Visual Evaluation Technique (Brown, 1982)
  2. Hay and Reid Model

Question 6

Describe 19 Visual Evaluation Technique (8 points)

Answer 6

• (Brown, 1982)
• A type of qualitative analysis model
• Involves 19 steps to develop a qualitative analysis, which is divided into 6 components
  1. Vantage points
  2. Movement specifications
  3. Balance & stability
  4. Movement relationships
  5. Range of motion

Question 7

Describe vantage point (8 points)

Answer 7

• One of the components when using Brown’s 19 Visual Evaluation Technique to develop a qualitative analysis
• When determine the vantage point, it is important to:
  
  • Select the proper viewing distance
  • Observe from different angles
  • Observe the performance from a carefully selected angle
  • Select with few distractions
  • Select setting with a vertical or horizontal reference
  • Observe a skilled performer as a model

Question 8

Describe Movement specifications (5 points)

Answer 8

• One of the components when using Brown’s 19 Visual Evaluation Technique to develop a qualitative analysis
• When determine Movement specifications, it is important to:
  
  • Observe slow-moving parts
  • Observe separate components of complicated skills
  • Observe the timing of performance components

Question 9

Describe Balance & stability (4 point)

Answer 9

• One of the components when using Brown’s 19 Visual Evaluation Technique to develop a qualitative analysis
• When determine Balance & stability, it is important to:
  
  • Look at supporting parts of the body
  • Look at the height of the body and body parts

Question 10

Describe Movement relationships (8 point)

Answer 10

• One of the components when using Brown’s 19 Visual Evaluation Technique to develop a qualitative analysis
• When determine the Movement relationships, it is important to:
  
  • Look for unnecessary movements
  • Look for movement opposition
  • Observe motion and direction of swinging body parts
  • Select with few distractions
  • Look at the motion of the head
  • Note the location and direction of applied force

Question 11

Describe Range of motion (4 point)

Answer 11

• One of the components when using Brown’s 19 Visual Evaluation Technique to develop a qualitative analysis
• When determine Range of motion, it is important to:
  
  • Look for stretching of the muscles
  • Look for a continuous flow of motion

Question 12

Describe the Hay and Reid Model (14 points)

Answer 12

• A type of qualitative analysis model that is divided into 4 steps
  1. Preparation – Gathering relevant knowledge
  
  • Of activity
  • Of performer
  • Of effective instruction
    
    2. Observation - Observe the performance
  • Development of a deterministic model
  • Application of your model
    
    3. Evaluation/Diagnosis
  • Strength and weakness
  • Diagnose - Rank the faults
    
    4. Intervention - Instruct the performer
  • Provide feedback
  • Modifying the practice

Question 13

Describe deterministic models (11 points)

Answer 13

• Determines the relationship between a movement outcome (results of the performance) and the biomechanical factors that produce that measure
• Used to consider the mechanical forces and how they look to a successful performance of a skill
• Uses a flow diagram to help illustrate proper relationships
• Steps to creating flow diagram
  1. Begin with first box: the mechanical goal
  2. This goal is broken down into parts and sub parts until all relevant mechanical relationships are shown
• Four important rules when determining a deterministic model
  1. Top of the model is the goal for the performance
  2. The variables at the bottom can be easily changed to impact performance
  3. Model is subjective
  4. Model is incorrect of the mechanical connections are incorrect

Question 14

Describe validity (4 points)

Answer 14

• Is the ability to correctly identify strengths and weaknesses of the movement
• Logical validity – expert opinion
• Criterion-referenced validity – criterion measure
• Example in hurdles, knee flexion is determined to be an important technique point (logical) but the actual amount of knee flexion required is criterion-referenced

Question 15

Describe reliability (3 points)

Answer 15

• Refers to the consistency or repeatability of the subjective ratings
• Intra-rater is within the person
• Inter-rater is between different people

Question 16

Describe the role of the senses in qualitative analysis (12 points)

Answer 16

• Vision
  
  • Visibility
  • Acuity
  • Peripheral vision
  • Selective nature of visual attention
• Audition
  
  • Important for rhythmic movements
  • Landings
  • Examples?
• Touch (haptic)
  
  • Haptic senses of touch and the pressure receptors
  • Examples? Balance.

Question 17

Describe the four step process in qualitative analysis (15 points)

Answer 17

1. Description – describe what the movement should look like – develop a theoretical model
   
   • What is the mechanical purpose of the action?
   • Identify ~4 critical features of the action
2. Observation – observe what it looks like
   - Organisation
   * What is the environment?
   * What position do you take to observe?
   * What observational strategy do you employ?
   - What are you looking for?
   * Timing of segments
   * Ranges of motion
   * Velocity and acceleration
   * Employing other senses
3. Evaluation – compare the ideal with the observed
4. Instruction – provide feedback and instruction to correct errors

Question 18

List potential issues with using quantitative analysis (4 points)

Answer 18

• Can interfere with the movement
• Often in a controlled setting
• Equipment may not be portable
• Need to adjust sampling rates

Question 19

Describe types of quantitive analysis and devices used in them (22 points)

Answer 19

1. Timing
   - Timing gates
   - Stop watches
   - Linear position transducers
   - Contact mats
2. Force
   - Load cells
   - Force plates
3. Accelerometry
   - Different devices can pick up how fast a particular movement or change in direction is completed
   - Many GPS devices have an in built accelerometer
   - Push band will give a reading of how fast the subject is moving
4. Electromyography
5. Kinematics
   - GPS systems will give top speed, different distances cover and how frequently the subject is in various speed ranges
   - Radar gun
6. Optical imaging
   - Average video camera
   - High speed camera
   - Using multiple cameras for a multidirectional system
   - Reflective markers can be used additionally to capture different points and angles
7. Ultrasound

Question 20

What is done with the quantitive analysis data? (7 points)

Answer 20

• It is usually processed: Filtered to remove noise, statistical procedures are performed to get a usable measure
• The final processed data can be used to:
  
  • Measure performance (e.g. velocity, peak force)
  • Understand the mechanisms underpinning performance (e.g muscle activation, timing of phases)
  • Monitor training (e.g. distance covered in a training session, changes in movement strategy)
  • Direct training interventions (e.g. identifying characteristics of an action that are well/not so well developed
  • Modelling/Simulations – optimise movement