KINS FINAL EXAM

• Center of Gravity (CG)

  The body's weight is equally balanced in all directions
• Center of Gravity (CG)

  • Summation of all body torques is equal to zero (e.g. yardstick)
• Center of Gravity (CG)

  • An object that has moving segments can change their CG - depends on 1) how massive the moving segment is 2) how far the segment moves from midline
• Stability


  Resistance to the disruption of equilibrium, a resistance to acceleration
• Factors affecting stability

  • Mass; Acceleration = Force/Mass 2) Base of Support - area bound by the outermost regions of contact between a body and support
• Factors affecting stability

  1. Horizontal location of CG 2. Vertical location of CG (e.g. torque)
• Base of Support

  The area bound by the outermost regions of contact between a body and support
• Movements of the Trunk

  • Head and Neck: Cervical flexion and extension, Cervical lateral flexion, Cervical rotation (rotation right (body's right) rotation left (body's left))
  • Trunk: Lumbar flexion and extension, Lumbar lateral flexion, Lumbar rotation: rotation right (body's right) rotation left (body's left)

  
• Rectus abdominis

  1. O: Crest of Pubis, I: Cartilage of 5th, 6th, and 7th ribs and xiphoid process, A: Both sides - lumbar flexion; right side – lateral flexion to right; left side - lateral flexion to left

  
• External oblique abdominal muscle

  1. O: Borders of lower eight ribs at side of chest, dovetailing with the serratus anterior, I: Anterior ½ of crest of ilium, inguinal ligament, crest of pubis, and fascia of rectus abdominis muscle at the lower front, A: Both sides – lumbar flexion; right side – lumbar lateral flexion to the right and rotation to the left; left side – lumbar lateral flexion to the left and rotation to the right

  
• Internal oblique abdominal muscle

  O: Upper ½ of inguinal ligament, anterior 2/3 of crest of ilium and lumbar fascia, I: Costal cartilage of 8th, 9th, and 10th ribs and linea alba, A: Both sides – lumbar flexion; Right side – lumbar lateral flexion and rotation to the right; Left side – lumbar lateral flexion and rotation to the left
• Transversus abdominis

  1. O: Outer 1/3 of inguinal ligament, inner rim of iliac crest, inner surface of cartilage of lower six ribs, lumbar fascia, I: Crest of pubis and iliopectineal line, abdominal aponeurosis to linea alba, A: Forced expiration by pulling abdominal wall inward
• Quadratus lumborum

  1. Posterior inner lip of iliac crest, I: Approximately ½ length of lower border of 12th rib and transverse process of upper four lumbar vertebra, A: *Lateral flexion to side on which it is located, stabilizes and extends the lumbar spine

  
• Spine

  • cervical (7), thoracic (12), lumbar (5)
  • cervical (lordosis)
  • thoracic (kyphosis)
  • lumbar (lordosis)

  
• Intervertebral disk

  Annulus fibrosis: resists tension

  Nucleus pulposus: resists compression
• Erector spinae (iliocostalis, longissimus, spinalis)

  1. Posterior part of the iliac crest, posterior aspect of the sacrum, and lumbar spinous processes, I: posterior ribs, spinous and transverse processes of the cervical and thoracic vertebrae, occipital bone, A: Extension, lateral flexion, and same side rotation of spine and head

  
• Sternocleidomastoid

  1. Manubrium of sternum, medial clavicle, I: mastoid process, A: Both sides – flexion of head and neck; right side – rotation to the left, lateral flexion to the right; left side – rotation to right and lateral flexion to left

  
• Splenius cervicis / capitus

  1. spinous processes of C7-T6, I: mastoid process, occipital bone, and transverse processes of C1-C3, A: Both sides - extension of head & neck; Right side – rotation & lateral flexion to the right; Left side – rotation & lateral flexion to left

  
• Ergonomics

  A systematic and rational means of fitting the work to the person
• Occupational Biomechanics

  The study of the physical interaction of workers with their tools, machines, and materials as to enhance the worker's performance while minimizing the risk of musculoskeletal injury
• The "Happy Spine"

  • cervical (lordosis), thoracic (kyphosis), lumbar (lordosis), Deviations away from the "happy" spine increases intradisc pressure
• Kinetic Link


  Open Sequential Kinetic Link - a skilled movement transferring momentum from one body segment to another

  Typically, the link is a transfer of momentum from larger body segments to smaller ones, such that the smallest body segment becomes the fastest moving link

  The link is aided by timing deceleration and acceleration of segments (inertia)

  example of a open sequential kinetic link: overhand throwing