BIomech Final

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BIomech Final
2012-04-30 06:00:26

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  1. why is the shoulder most complex joint?
    it has 5 articulations: glenohumoral peeps dont rehab scap, sternoclav (doesnt dis and clav breaks first), acromioclavic, coracoclavic, scapulothorac.
  2. baseball pitch what joint actions take place at shoulder and elbow? is there any torque at these locations?
    what causes injury?
    • elbow ext, horizontal abduction, adduction
    • elbow and shoulder torque
    • overuse and bad mechanics!
  3. what kind of pull up is the hardest/easiest in terms of torque and why?
    anlge of pull?
    • palms towards face is the easiest because this position has the least amount of torque small angle
    • palms away at shoulder length is the hardest because the angle is the greatest, 90+ and at 90 the elbow has the greatest amount of force... the elbow is in line with the angle of pull for 1 and 2, not three: also scap mms come into play for three
  4. during abduction what kind of force is at the joint?
    what is pulling with rotator cuff?
    when is max shear force on gh?
    • compressive and some shear
    • the deltoid ligament pulls with the rotator cuff
    • max shear on gh is at 60 degrees
  5. what kind of forcs act on the shoulder and elbow during a push up?
    what push up is the hardest and why?
    peak forces on elbow can reach % bw?
    • shear forces
    • wide cause the moment arm is moving farther away
    • 45%
  6. what kind of stress on the elbow does pitching do?
    when is largest compressive force at elbow produced?
    • valgus stress
    • during full extension
  7. what are the differences between flex and ext of the elbow?
    • tri has to create more force to extend then bi to flex..why?
    • tricep attachment is closer to the elbow joints axis of rotation resulting in the moment arm being shorter!
    • tri mms produce more force to have equal torque
  8. where are the rotator mms located?
    • anterior: subscapularis
    • superior: supraspinatus
    • posterior: teres minor and infraspinatus
  9. scapulohumoral rhythm consists of what kinds of movements?
    • during the initial thirty degrees of shoulder elevation the gh will abduct the shoulder and then during the remaining degrees of shoulder flexion the scapula will rotate downward.
    • 2:1 ratio gh to scapulathoracic movement
  10. which scap mms are stabilizers during crutch walking?
    what are recommended shoulder positions for those that are working at desk?
    • depressors
    • 20 abduction and 25 flexion
  11. what mms are used in baseball throw!?
    • lats for decel
    • teres minor and infraspinatus for decel!