Upper Extremities Parts Shoulder Girdle Shoulder Joint Elbow
Upper Extremities Parts Ø Shoulder Girdle Ø Shoulder Joint Ø Elbow Joint Ø Radioulnar Joint Ø Wrist Joint
Muscle Contribution to Joint Ø Stronger Muscles = More Joint Stability Ø Angles of Pull influence Joint Stability Ø Stabilizing Angles = < 90 angle of pull Ø Dislocating Angles = > 90 angle of pull
Shoulder Girdle Ø Involved in Reaching/Grasping Motions Ø Designed for Mobility Ø Unstable joint Ø Strength of Muscles VERY important
Shoulder Joint ü Involved in a wide variety of motions ü Designed for Mobility, Unstable joint ü Rotator Cuff & Deltoids = small angle pull ü Wheel-Axle Mechanism
Overarm Throw Pattern Ø “cocking action” = extreme lateral rotation Ø rapid medial rotation and protraction Ø Strengthen Medial Rotators BOTH Concentrically and Eccentrically
Elbow Joint Ø Only Flexion and Extension Ø Stable joint due to bony structure Ø Muscle arrangement = stabilizing effect
How to Strengthen Elbow Extensors üElbow Extensions with shoulder flexed figure 2. 5 e on page 61 üShoulder Hyperextensions with elbow extended figure 2. 5 d 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. 5 j on pg 62
Radioulnar Joint Ø Unstable due to weak bony arrangement Ø Pronate = turn inward [medial] away from anatomical position Ø Supinate = turn outward [lateral] back toward anatomical position figure 5. 12 left side of picture pronated page 185 right side of picture
Wrist Joint Ø 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 Ø CTS - Carpal Tunnel Syndrome Ø see Force guidelines per task on page 189
Hip Joint Ø Medial rotation involved in kick, throw & strike Ø Wheel-Axle - figure 6. 5 and 6. 6 [page 197] A: medial rotation B: lateral hip
Hip Joint Ø Bending/Stooping = increase FA resistive Ø to achieve equilibrium, hip extensors must provide high Tension/Force [hams, back] FIG 9 -30 page 296 “Basic Biomechanics” 4 th 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
ANKLE JOINT Ø Bony arrangement = stability Ø Ligaments play major role in stability Ø flexion = dorsiflexion Ø extension = plantar flexion FIG 6. 13 page
SUBTALAR JOINT Ø allows foot to navigate uneven surfaces Ø inversion (sole in) and eversion (sole out) Ø inversion with plantar flexion Ø eversion with dorsiflexion FIG 6. 15 page 209 Inversion during Plantar Flexion
Muscles of Ankle & Foot Ø Strength important on all sides Ø Muscular imbalance = misalignment Ø misalignment = line of g eccentric to joints Ø weak dorsiflexors may cause shin splints Ø overdeveloped inversion/plantar flexion muscles = prone to lateral ankle sprains
Stretching Achilles Tendon Ø Preventative measure for shin splints Ø Achilles tendon = extension of both gastrocnemius and soleus muscles Ø 2 dorsiflexion stretches: 1. with knee extended 2. with knee flexed
Plantar Fasciitis Ø Overuse Syndrome injury Ø overload of stress at insertion of plantar surface fascia on calcaneous Ø chronic therapy involves: 1. Strengthen plantar & dorsiflexors 2. Increase ROM in dorsiflexion see page 210 re Kibler et al study
Walking LOCOMOTION Running ü Long support phase [65%] ü Shorter support phase ü always support phase ü non-support phase ü F vertical = 3 x body wt
Ideal Alignments: LEG Ø Lower extremities like columns supporting a roof Ø Ideally as vertically aligned and as straight as possible to support the forces from above FIG 6. 19 page 213
Ideal Alignments: FOOT FIG 6. 20 page 214 a is Ideal
Leg Length Inequities Ø Anatomical - due to bone structure Ø Functional - due to tilted pelvis Ø Environmental - due to uneven ground
Femoral ü Femur rotated medial ü medial facing patella ü frequent in FEMALES ü treatment: 1. Strengthen lateral hip rotators 2. Stretch medial hip TORSION Tibial ü Tibia rotated lateral ü lateral facing patella ü frequent in MALES ü treatment: - muscular balance in all 3 hamstrings must be developed
VARUS INWARD angle from proximal to distal Ø lateral stress is proximal Ø medial stress is distal Ø
VALGUS OUTWARD angle from proximal to distal Ø medial stress is proximal Ø lateral stress is distal Ø
Key Features of Good Shoes ü Heel well cushioned ü Heel Counter firm ü Arch Support firm ü Sole Width reasonable for stability ü Forefoot flexible & cushioned ü Toe Box with reasonable room ü Traction, Durability, Permeability
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