Human Movement Midterm1

  1. Translation
    how bones move against one another
  2. center of gravity
    the point around which all masses are equally distributed
  3. axis of rotation
    a fixed point around which a lever rotates
  4. osteokinematics
    position and movement in the cardinal planes
  5. A muslce is most flexible when...
    when it is the most lax/short
  6. What forces we are concerned with therapeutically?
    • Gravity
    • Muscles
    • Externally applied resistance (splint, cast)
    • Friction (hospital socks)
  7. Degree of stability depends on...
    Size, Weight, Height, Location

    • Size of base of support
    • Weight of the body
    • Height of COG above BOS (for ex. someone on stilts COG has moved up and is further from BOS)
    • Location of COG

  8. Moment Arm
    The shortest perpendicular distance between an AOR and the action line.

    -muscles operate on SHORT moment arms because their insertions are close to the joint axis!
  9. Qualities of a 2nd class lever
    Can carry a larger amount of weight for a short distance at a low speed
  10. Qualities of a 3rd class lever
    Can carry less weight for a long distance at a fast speed.
  11. Biomechanics
    using physics to study how forces interact within the body
  12. Synarthroses
    • non-synovial joint
    • Fibrous/Cartilaginous connective tissue
    • EX: skull, spinous processses, tibia + fibula, sternocostal joint
  13. Diarthrodial
    • synovial joint
    • Articular cartilage
    • -joint capsule, synovial membrane, synovial fluid, ligaments, blood vessels, nerves
  14. Periarticular Connective Tissue
    • Dense
    • Articular
    • Fibrocartilage
    • **do not regenerate or have a good blood supply**
  15. Dense CT
    • outer layer of joint capsule
    • makes up ligaments and tendons
  16. Articular Cartilage
    found at the end of the bones that form synovial joints
  17. Fibrocartilage
    • tightly woven
    • ex: intervertebral disks
  18. Uniaxial Joints
    • 1 degree of freedom
    • Hinge- elbow, PIPs, DIPs (proximal interphalangeal)
    • Pivot- skull on the atlas
  19. Biaxial
    • 2 degrees of freedom
    • Saddle- CMC (carpometacarpal) where you have 'arthritis'
    • Condyloid- MCP (metacarpal phalangeal) "no soup for you"
  20. Triaxial
    • 3 degrees of freedom
    • Ball & Socket- hip, shoulder
  21. 2 basic categories of joints, most joints are a version of these:
    • Ovoid
    • Saddle
  22. when Convex moves on Concave...
    the joint surface moves in the opposite direction
  23. when Concave moves on Convex...
    the joint surface moves in the same direction
  24. Joints can be in 'Action' or in 'Position'.  If I were to extend my arm, the action would be extension, but if I paused my arm, the position would be flexion.
  25. Why are joints vulnerable?
    • bad blood supply
    • -poor recovery potential
    • load bearing
    • TRAUMA: acute, overuse, inactivity!
    • -we need to move to produce synovial fluid, joints depend on motion!
  26. Name the 5 layers within a muscle
    • Fasciculus
    • Muscle Fiber
    • Myofibril
    • Myofilament
    • Sarcomere
  27. The contractile unit of a muscle/unit of tension is:
  28. What filaments slide past one another int he Sarcomere and how do they interact?
    • Actin (thin) & Myosin (think)
    • The myosin head attaches to the actin and forms a crossbridge (Oxygen + ATP are required for the motion of the myosin head)
  29. What is a crossbridge
    • Necessary for contraction!
    • A crossbridge is formed when the myosin head attaches to actin
  30. When a patient has COPD, they are weak, why?
    They have low oxygen which is needed for muscle contraction/formation of crossbridges.  They are forming fewer crossbridges and are therefore weaker.
  31. What is the ideal resting length of a muscle?
    • When the most crossbridges are formed-thus the greatest force with contraction!
    • the middle 3rd is where this occurs-most overlap of myosin and actin
  32. A motor unit is made up of:
    • neuron, axon, muscle fiber
    • Neuromuscular Junction
  33. Motor unit capabilities vary according to:
    • Size of cell body
    • Type of muscle fiber
    • Diameter of axon
    • Number of music fibers innervated
  34. Why are the muscle fibers innervated by a single axon not usually located next to one another?
    • so that if one axon dies, others can take over it's duties
    • smooth muscle movements
  35. The magnitude of a muscle contraction can be altered by:
    • Increasing/decreasing
    • --the number of motor units activated
    • --frequency of firing
  36. Why are smaller motor units selected first by the nervous system?
    • require less energy
    • generate less tension
    • ALSO, we base it on:
    • Previous experience-i know how heavy my book is
    • Nature of task-I can SEE that a marble weighs less than a boulder
    • Mechanical advantage-of the joint
  37. Contraction Types:

    • Concentric: internal force wins, shortening
    • Isometric: no lengthening or shortening
    • Eccentric: external force wine, lengthening
  38. What is an agonist, antagonist, synergist?
    • Agonist: prime mover
    • Antagonist: opposite direction
    • Synergist: assists, stabalizes
  39. What are the characteristics of a Fusiform muscle fiber organization?
    • parallel fibers that pull in the same direction
    • favor distance!
  40. What are the characteristics of a Pennate muscle fiber organization?
    • Fibers run diagonally
    • greator force! (less distance)
  41. Compare Fast vs. Slow Twitch fibers
    • Fast Twitch
    • -fast contraction time
    • -fatigue easily (1-5 mins)
    • -large motor neuron
    • -greater force
    • ex: Sprinting

    • Slow Twitch
    • -slow contraction time
    • -resistant to fatigue (hours!)
    • -small motor neuron
    • -small force generation
    • EX: long distance running, posture

  42. Active tension decreases when...
    • the muscle is fully contracted or fully elongated aka sarcomere is too long or short.
    • why? It's hard to hold this position for too long,
  43. Passive tension is..
    • passive stretch, used in walking (achiles)
    • why use passive tension? it does not require energy
  44. Examples of Active & Passive tension in Tenodesis
    • Flexion (duck): active are wrist flexors, passive are finger extendors
    • Extension: active are wrist extensors, passive are finger flexors
  45. Muscle function is affected by:
    • Number + Type of muscle fibers
    • Diameter of axon
    • Number + Frequency of motor unit firing

    • N + T
    • D
    • N + F
  46. What can inactivity and aging do to muscles?
    • Inactivity: degradation of proteins, decreased slow-twitch fibers REHAB FOCUS: low intensity, long duration
    • Aging: loss of muscle tissue, decreased nerve activation. REHAB FOCUS: balanced, resistive exercise
Card Set
Human Movement Midterm1
human movement