Download BIOMECHANICS APPLICATIONS

OVERALL: Great Job on Video Exam
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Median: 74% (half of the class scored 71% or higher)
Mean:
74% (class average)
72% of class scored 70% or higher
31% of class scored 80% or higher
50% of class improved over October Mid-Term grade
Those that did not do as well as expected
let’s get together to see what happened
and move onward & upward
Upper Extremities Parts
Shoulder Girdle
 Shoulder Joint
 Elbow Joint
 Radioulnar Joint
 Wrist Joint
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Types of
Synovial Joints
from “Basic
Biomechanics”
by Susan Hall
page 121
Muscle Contribution to Joint
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Stronger Muscles = More Joint Stability
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Angles of Pull influence Joint Stability
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Stabilizing Angles = < 90 angle of pull
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Dislocating Angles = > 90 angle of pull
Shoulder Girdle
Involved in Reaching/Grasping Motions
 Designed for Mobility
 Unstable joint
 Strength of Muscles VERY important
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Shoulder Joint
Involved in a wide variety of motions
 Designed for Mobility, Unstable joint
 Rotator Cuff & Deltoids = small angle pull
 Wheel-Axle Mechanism
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Overarm Throw Pattern
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“cocking action” = extreme lateral rotation
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rapid medial rotation and protraction
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Strengthen Medial Rotators BOTH
Concentrically and Eccentrically
Elbow Joint
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Only Flexion and Extension
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Stable joint due to bony structure
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Muscle arrangement = stabilizing effect
How to Strengthen Elbow Extensors
Elbow
Extensions with
shoulder flexed
figure 2.5e on page 61
Shoulder Hyperextensions
with elbow extended
figure 2.5d on page 61
3 Ways to Strengthen Elbow Flexors
1.
Elbow flexion from
anatomical position
2.
Elbow flexion with
shoulder Hyperextended
3.
shoulder flexion
figure 2.5j on pg 62 
Radioulnar Joint
Unstable due to weak bony arrangement
 Pronate = turn inward [medial] away from
anatomical position
 Supinate = turn outward [lateral] back
toward anatomical position
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figure 5.12 left side of picture pronated
page 185 right side of picture supinated
Wrist Joint
MSDs - musculoskeletal disorders
1. angle of the work surface
2. position requirements of the work
3. magnitude & direction of applied forces
4. Degree of repetition
 CTS - Carpal Tunnel Syndrome
 see Force guidelines per task on page 189
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Hip Joint
Medial rotation involved in kick, throw & strike
 Wheel-Axle - figure 6.5 and 6.6 [page 197]
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A: medial
B: lateral hip rotation
Hip Joint
Bending/Stooping = increase FA resistive
 to achieve equilibrium, hip extensors must
provide high Tension/Force [hams, back]
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FIG 9-30
“Basic Biomechanics”
3rd Edition
by Susan J. Hall
Knee Joint
Biarticulate Muscles - work knee and hip
 Muscular Imbalances:
1. Hams - lateral vs. medial lateralis
2. Quads - vastus lateralis and medialis
 Positions for potential injury
1. Foot fixed while hip/trunk rotates
2. Squats [FIG 6.11 pg 204]
3. Whip kick in Breaststroke [FIG 6.12 pg 205]

Knee Joint: Potential Injury Positions
page 205
Knee Joint: Potential Injury Positions
turning the body
while foot is fixed
FIG 6.8 page 200
Knee Joint: Potential Injury Positions
Deep Squat
changing axis of rotation
from knee joint
to
calf/thigh area
FIG 6.11 page 204
Knee Joint: Potential Injury Positions
rehabilitation of knee injuries
page 260: studies on ACL stress, shear forces, petellofemoral contact