Upper Extremities Parts

Shoulder GirdleShoulder JointElbow JointRadioulnar JointWrist Joint

Muscle Contribution to Joint

Stronger Muscles = More Joint Stability

Angles of Pull influence Joint Stability

Stabilizing Angles = < 90 angle of pull

Dislocating Angles = > 90 angle of pull

Shoulder Girdle

Involved in Reaching/Grasping MotionsDesigned for MobilityUnstable jointStrength of Muscles VERY important

Shoulder JointInvolved in a wide variety of motionsDesigned for Mobility, Unstable jointRotator Cuff & Deltoids = small angle pullWheel-Axle Mechanism

Overarm Throw Pattern

“cocking action” = extreme lateral rotation

rapid medial rotation and protraction

Strengthen Medial Rotators BOTH Concentrically and Eccentrically

Elbow Joint

Only Flexion and Extension

Stable joint due to bony structure

Muscle arrangement = stabilizing effect

How to Strengthen Elbow Extensors

Elbow Extensions with Elbow Extensions with shoulder flexed shoulder flexed figure 2.5e on page 61figure 2.5e on page 61

Shoulder Shoulder Hyperextensions with elbow Hyperextensions with elbow extended extended figure 2.5d on page 61figure 2.5d on page 61

3 Ways to Strengthen Elbow Flexors

1.1. Elbow flexion from Elbow flexion from anatomical positionanatomical position

2.2. Elbow flexion with Elbow flexion with shoulder Hyperextendedshoulder Hyperextended

3.3. shoulder flexionshoulder flexion figure 2.5j on pg 62 figure 2.5j on pg 62

Radioulnar Joint

Unstable due to weak bony arrangementPronate = turn inward [medial] away from

anatomical positionSupinate = turn outward [lateral] back

toward anatomical position

figure 5.12 figure 5.12 left side of picture left side of picture pronatedpronatedpage 185 page 185 right side of picture right side of picture supinatedsupinated

Wrist Joint

MSDs - musculoskeletal disorders1. angle of the work surface2. position requirements of the work 3. magnitude & direction of applied forces4. Degree of repetition

CTS - Carpal Tunnel Syndromesee Force guidelines per task on page 189

Hip JointMedial rotation involved in kick, throw & strikeWheel-Axle - figure 6.5 and 6.6 [page 197]

A: medial B: lateral hip rotation

Hip JointBending/Stooping = increase FA resistiveto achieve equilibrium, hip extensors must

provide high Tension/Force [hams, back]

FIG 9-30 page 296

“Basic Biomechanics”4th Edition

by Susan J. Hall

Knee Joint

• Biarticulate Muscles - work knee and hip• Muscular Imbalances:

1. Hams - lateral vs. medial lateralis2. Quads - vastus lateralis and medialis

• Positions for potential injury1. Foot fixed while hip/trunk rotates2. 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 bodywhile foot is fixed

FIG 6.8 page 200

Knee Joint: Potential Injury Positions

Deep Squat

changing axis of rotation

from knee jointto

calf/thigh area

FIG 6.11 page 204

Knee Joint: Potential Injury Positionsrehabilitation of knee injuries

page 260: studies on ACL stress, shear forces, petellofemoral contact

ANKLE JOINTBony arrangement = stabilityLigaments play major role in stability

flexion = dorsiflexionextension = plantar flexion

FIG 6.13page 207

SUBTALAR JOINT

allows foot to navigate uneven surfacesinversion (sole in) and eversion (sole out)inversion with plantar flexioneversion with dorsiflexion

FIG 6.15page 209

Inversion during Plantar Flexion

Muscles of Ankle & Foot

Strength important on all sidesMuscular imbalance = misalignmentmisalignment = line of g eccentric to jointsweak dorsiflexors may cause shin splintsoverdeveloped inversion/plantar flexion muscles

= prone to lateral ankle sprains

Stretching Achilles Tendon

Preventative measure for shin splints

Achilles tendon = extension of both gastrocnemius and soleus muscles

2 dorsiflexion stretches:1. with knee extended2. with knee flexed

Plantar Fasciitis

Overuse Syndrome injury

overload of stress at insertion of plantar surface fascia on calcaneous

chronic therapy involves:1. Strengthen plantar & dorsiflexors2. Increase ROM in dorsiflexion

see page 210 re Kibler et al study

LOCOMOTION Walking Running

Long support phase [65%]

always support phase

Shorter support phase

non-support phase

F vertical = 3 x body wt

Ideal Alignments: LEG

Lower extremities like columns supporting a roof

Ideally as vertically aligned and as straight as possible to support the forces from above

FIG 6.19page 213

Ideal Alignments: FOOT

FIG 6.20page 214

a is Ideal FIG 6.21

Leg Length Inequities

Anatomical - due to bone structure

Functional - due to tilted pelvis

Environmental - due to uneven ground

TORSION Femoral Tibial

Femur rotated medialmedial facing patella frequent in FEMALES treatment:1. Strengthen lateral hip

rotators2. Stretch medial hip

rotators

Tibia rotated laterallateral facing patellafrequent in MALEStreatment: - muscular balance in all

3 hamstrings must be developed

VARUS INWARD angle INWARD angle from proximal to from proximal to distaldistal

lateral stress is lateral stress is proximalproximal

medial stress is medial stress is distal distal

VALGUS OUTWARD angle OUTWARD angle from proximal to from proximal to distaldistal

medial stress is medial stress is proximalproximal

lateral stress is lateral stress is distaldistal

Key Features of Good Shoes

Heel well cushionedHeel Counter firmArch Support firmSole Width reasonable for stabilityForefoot flexible & cushionedToe Box with reasonable roomTraction, Durability, Permeability