Biomechanics Exam 3 Content Flashcards
1
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Analysis Qualitative Biomechanics
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Breaking something into smaller parts, examining constituent parts
2
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Qualitative Biomechanical Analysis
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Breaking movement into basic elements; examining each element from a biomechanical perspective
3
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Quantitative Biomechanical Analysis
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Quantifying biomechanical elements
4
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Qualitative Vs. Quantitative
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Quantitative: requires equipment, is highly objective, precise
Qualitative; observational, more subjective, themes and patterns
5
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Example of Quantitative vs Qualitative
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for themes and patterns: see a lot of glut med weakness
6
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Qualitative analysis
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typically, visual analysis
can be aided by video recording
most common analysis by coaches/trainers/teachers
7
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Subjective Qualitative Analysis
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eyes; description of performance
8
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Comparative qualitative analysis
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faster/slower, higher/lower. shorter, longer
ex: may need to elevate humerus higher or lower
9
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Technique yields outcome
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analyze technique and outcome
10
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If technique is correct….
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outcome will be too
11
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Way too often individuals coach/teach to the outcomes rather than…
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coaching/ teaching the technique
12
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When you coach/teach the technique what will happen to the outcome
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the outcome will naturally improve
13
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Steps of Qualitative Analyses
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- Develop a theoretical model
- observe the performance
- compare performance to theoretical model (evaluate)
- Provide feedback/instruction
14
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What is the ideal technique?
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cuing words: can provide base for biomechanics, provide standard for how they are performing
provides a standard for performance comparison
15
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Fundamental Knowledge of Skills: what are the rules
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most activities have rules
rules impose constraints
limits in how a skill is legally preformed
16
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Traditional techniques/equipment
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trust but verify
curious but skeptical- ASK WHY
are traditional techniques biomechanically appropriate?
Should everyone attempt skill like an elite performer?
17
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Purpose/Goal of Skill: Desired Output
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performance measures (time, distance measured)
success criterion
18
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Purpose/Goal of Skill: interpret outcome in mechanical terms
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objective- how far? how fast? how long? (unbiased, solely on the observable or verifiable facts)
Subjective- quality of movement, not as easy to determine
19
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Two basic approaches to effective techniques
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- identify biomechanical characteristics of an elite performer
- develop cause and effect model of success
20
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Identifying biomechanical characteristics of an elite performer
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how does each action/position contribute to success?
is the action/position detrimental?
21
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Developing a cause and effect model of success
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use biomechanical principles
identify mechanical basis for each subgoal
these define most effective techniques
22
Q
What do we actually look for?
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- Body segment position (during force application)
- Duration of motion, (range of motion- positive or negative work, breaking vs propulsion, displacement of ball)
-Velocity and acceleration of segments (performance often determined by distal limb velocity/acceleration, constant acceleration vs phased acceleration)
-Relative timing of body segments (coordination, application of work and force)
23
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Observing Performance: visual
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Who are you observing?
Under what conditions will the subject perform?
Where will observation occur?
What are you attempting to observe?
24
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Who are you observing?
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as skill increases: size of error decreases
variability between trials decreases
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Novice athletes
easily recognizable errors
errors often repeated
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Highly skilled athletes
minor errors in performance
attention paid to errors between repeated trials
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Under what conditions
- environment influences performance
practice vs competition
- often observe under conditions= typical performance
- actual competition observation is difficult
class/team practice causes multiple distractions
-no conditions are ideal, compromise is required
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Where will observation occur?
Vantage points impacts visibility or performance
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How close to performance?
far enough away to observe well
want to be far enough away but not too far
observation is dependent on where you are.
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Skill analysis
good instructors analyze skill to improve athlete performance
Efficiency, effectiveness
feedback for athletes
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Analysis of skill is a sill and cant be established by
learn and practice
time and effort
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What is the two step approach?
Identify errors of performance
diagnose impact of magnitude of error
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Identify Error
compare performance to most effective techniques
Evaluate each phase
compare motion, positions, timing to effective technique
morphological constraints affect individual performance
anthropometrics, strength, age
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Evaluating Errors
consider cause and effect
does it increase injury risk? CORRECT IMMEDIATELY
Is client novice or an expert? if novice= fix errors in basic elements
How easy is it to correct the error= time needed to correct error
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Cause and effect of evaluating errors
are errors stacking (aka serial)= correct the earliest errors (will errors in the first part of the motion cause errors in the rest of the motion?)
how much does the error impact performance? correct impactful errors
Impact of equipment= change implements (often equipment is involved: different throughout life cycle, does the change in equipment make things better or worse?
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Developing teaching progression
discrete parts of the movement
drills/exercises that duplicate movement of forces of each part
implement drills to correct technique for each part
link drills and portions of movement
perform entire skill
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Job of biomechanist
study technique and improve performance
recording, analyzing, diagnosing
good technique for particular athlete in particular society
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problems with key factors
key factors= general guidelines
each athlete is unique
each activity is unique
incorporate growth and development of athlete- take into account individualization
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Job of movement analysts
recognize symptoms of bad performance
what is acceptable performance
is the goal attained
process vs product
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Troubleshooting cause of bad problems
critical ability
skill performance deficiency
psychosocial problems
look at process and product
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Phases of skill performance
Preparatory phase: getting into position, pre-stretch
Execution phase: skill performance, correct force application
Follow through phase: dissipation of forces, reset to start
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Why is this important? (summary of qualitative biomechanics)
develop theoretical model of most effective technique
observe the actual performance
evaluate performance- compare to most effective technique
instruct performer (provide feedback, discrepancies between actual performance and effective performance)
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What is Quantitative Analysis
involves actual measurement of human movement
description with numbers
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How to take a quantitative analysis
Need fine detail when changes in biomechanics variables are indistinguishable without tools : movements are too quick, changes are too subtle
Sports: monitor changes over season/career
Ergonomics: determine cause of overuse injuries
Clinical: guide diagnosis of treatment
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Quantitative biomechanics variables
temporal: time, change in time
Kinematic: position, displacement, velocity, acceleration.
Kinetic: force, torque, work, energy, power
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Qualitative vs Quantitative
Qualitative: require equipment, highly objective, precise
Quantitative: observational, more subjective, themes and patterns
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Gait Analysis Characteristics
Stability in stance
clearance in swing
proper foot position at initial contact
adequate step length
energy conservation
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What is the definition of a gait cycle
foot contact to foot contact of the same leg
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What are the two phases in gait
stance= 60%
swing= 40%
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As velocity increases what happens to swing and stance time
swing time increases and stance time decreases
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What is the step length in gait
the distance between the one heel strike to the other heel strike
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What is stride length in gait
distance between heel strike of one lower limb to next heel strike of same limb
its double of step length
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Cadence
number of step/minute
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What does cadence depend on
step length
speed of walking
sex
body build
obesity
walking surface
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walking velocity
speed of ambulation on smooth level surface
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Walking base
distance between two feet
also known as stride width
foot progression angle formed by the line of progression and longitudinal axis of foot
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Methods of analyzing gait
Kinematics and Kinetics
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Kinematic gait
observing or measuring the position of joints and segments through each phase of gait
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Kinetics
measuring the GRF at each joint and then calculating the muscle activity or soft tissue resistance present to stabilize the joint
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Temporal/Spatial gait
velocity, cadence, step, length
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Kinematics definition
the movement of the joints in space without any reference to forces
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Kinetics definition
the forces involved in producing these movements
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Dynamic Electromyography
the study of muscular activity patterns during walking
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Stance phase
1. heel strike
2. loading response
3. mid-stance
4. terminal stance
5. pre-swing
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Swing Phase
1. initial swing
2. midswing
3. terminal swing
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Phases of Gait
initial contact: heel strike
loading response: HS to foot flat
Midstance: FF to midstance
Terminal stance: mid-stance to heel off
Pre-swing: heel off to toe off
Initial swing: TO to acceleration
Mid-swing: Acceleration to mid-swing
Terminal Swing: midswing to deceleration
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Initial contact
initiates gait cycle-stance
double limb support
Critical events: heel contact
Hip: 40 degrees of flexion
Knee: extended
Ankle: neutral
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Heel strike to flat foot
reaction of the limb to absorb impact of weight acceptance
double limb support
Hip: flexed
Knee: flexing
Ankle: plantar flexion
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Mid-stance: Flat foot to mid-stance
period of single limb support
body progress over foot
foot flat on floor
Hip: extension
Knee; Extension but not zero
Ankle: closed kinetic chain dorsiflexion
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Terminal stance: Midstance to Heel Off
continuation of single limb support
body moves ahead of supporting foot
single limb support
Weight shifts over metatarsal heads
Hip: 0-20 degrees of extension
Knee: extension to flexion
Ankle: 5-10 degrees of dorsiflexion to neutral
71
Pres-wing: Heel off to toe off
transition period of double limb support
limb is rapidly unloaded
transfer load to other limb
prepare for swing
Weight shifts over metatarsal head
Hip: flexion
KneeL 0-40 flexion, rapidly
Ankle: plantar flexing 20-30 degrees
72
Initial Swing: Toe off to acceleration
lift of limb from floor
initial advancement of thigh for toe clearance, forward propulsion
single limb support
Hip: flexing
Knee: flexion, rapidly critical
Ankle: dorsiflexing to neutral
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Mid swing acceleration to Mid swing
limb advancement
clear foot
achieve vertical tibial position
single limb support
Hip: flexing
knee; extending
ankle: dorsiflexing to neutral
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Terminal Swing: Midswing to Deceleration
tibial advancement
toward full knee extension
create step
Deceleration of thigh
maintenance of foot position
single limb support
Hip: flexion
Knee: extending
Ankel: neutral
75
Running Gait Cycle
stance phase 40% compared to walking of 60%
swing phase has double slope phase/flight phase= 60%
in running there is never two feet on the ground
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Running characteristics
need greater balance
elevating center of mass more so you need more muscular energy
have to be able to control body and absorb shock
greater ROM
increased GRF
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Velocity drivers
stride frequency and stride length will increase velocity
long the stride the further you go
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Ground Reaction Forces
forces exerted by the ground on the foot
Impact forces: when foot comes to sudden stop upon impacting ground
concern has been with various foot strike patterns creating higher collision forces
peak magnitude is much larger in running
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loading rate
change in force over time
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Evaluating running
video analysis (treadmill running), motion capture 3D- not practical
body markers (tape) can be used to help analyze
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Sagittal View Parameters
foot strike
foot inclination angle
tibial angle at loading response
kne flexion stance
hip extension during late stance
trunk lean
over striding
vertical displacement of mass
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Frontal View Parameters
Base of Support
Heel eversion
Foot progression angle
Heel whips- swing in medially
knee window - space between knees when walking- tells you how much control you have of hip and pelvis
pelvic dip
83
Foot Strike Patterns
important for GRF
forefoot strike
mid-foot strike
rear foot strike (heel)
84
Vertical Alignment of Lower leg
Extended tibia is not ideal bc it gives you a higher GRF, want more vertical or flexed tibia to absorb shock
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Knee Flexion During Stance
peak knee flexion in stance and overall range of motion
lower peak knee flexion angles are associated with patello-femoral pain
abnormal knee flexion can result in tibial stress fractures bc you aren't absorbing shock as much
86
Inversion and Eversion
pronation is a common issue
measured through frontal place kinematics of heel
excessive heel eversion can be attributed to running injuries such as tibial stress fractures
87
Pelvic Drop
need strong glute medius
excessive pelvic drop during running can contribute to excessive adduction and running injuries
88
The overstrider
initial contact of the foot a=on the ground in front of a persons center of mass
energy inefficient
89
The collapser
pelvic drop with weak glute medius on the stance leg
knock kneed
excessive hip adduction, internal rotation
cannot come off the ground as much
90
The Weaver
runner whose legs cross the midline excessively while running
narrow base of support
tightrope gait
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The bouncer
excessive vertical oscillation
very heavy landing/ loud foot trike
energy inefficient
large center of mass has been shown to increase GRF
92
The Glut Amnesiac
weak posterior musculature
anterior demand on muscles
93
Location of injury
KNEE TAKES MOST BEATING
PFPS- patello-femoral pain
ITBF syndrome- IT band
Plantar fasititis
medial tibial stress syndrome
knee meniscal injuries
Most injuries are overuse rather than acute
94
Running Extrinsic Factors
influences from outside- foot wear and running surfaces
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Running Intrinsic Factors
from individuals- age, sex, biomechianal functions of body
96
Extrinsic Risk Factor Training
12-60% of injuries are due to training errors
the harder the surface, more GRF, more chance for injury
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Previous Injuries are what type of risk factors
intrinsic- contributes to re-injury
98
Malaligment intrinsic risk factors
pes-cavus- more rigid foot
overpronation
leg length discrepancy
muscular flexibility
knee alignment
99
Muscular imbalance in intrinsic risk factor
closed kinetic chain theory
if one joint of lower extremity is not functioning properly, injuries manifest in other joints
proximal core hip strength needed to control distal segment
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Muscular imbalance in intrinsic risk factor
closed kinetic chain theory
if one joint of lower extremity is not functioning properly, injuries manifest in other joints
proximal core hip strength needed to control distal segment
