Introducing basic concepts

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Introducing basic concepts

  1. 1. Introducing basic concepts 1 Richard Baker Professor of Clinical Gait Analysis
  2. 2. Goals • Outline basic concepts that we’ll be using for the rest of the day
  3. 3. Colour Left Right
  4. 4. 4 Cyclic walking
  5. 5. Distance and time
  6. 6. 6 Stride length How far does one foot move each stride
  7. 7. 7 Stride length right stride length = left stride length
  8. 8. 8 Stride length Doesn’t matter which cycle you use
  9. 9. 9 Stride length Doesn’t matter which point on the foot you use
  10. 10. 10 Step length (symmetrical walking) How far is one foot in front of the other
  11. 11. 11 left step length = right step length IF gait symmetrical Step length (symmetrical walking)
  12. 12. 12 stride length =left step length + right step length Step length (symmetrical walking)
  13. 13. 13 Step length Doesn’t matter which cycle you use
  14. 14. 14 Step length Doesn’t matter which point on the foot you use
  15. 15. 15 Step length (asymmetric gait) How far is one foot in front of the other
  16. 16. 16 Step length (asymmetric gait) Left step length ≠ right step length
  17. 17. 17 Step length (asymmetric gait) Stride length = left step length + right step length
  18. 18. 18 Step length (asymmetric gait) Left stride length = right stride length
  19. 19. 19 Step length (asymmetric gait) Doesn’t matter which cycle you use
  20. 20. 20 Step length (asymmetric gait) Doesn’t matter which point on the foot you use
  21. 21. 21 Step width How far are the feet apart?
  22. 22. 22 Step width Not defined separately for left and right
  23. 23. 23 Step width Depends on point of foot chosen
  24. 24. 24 Cadence Strides per minute or steps per minute
  25. 25. 25 Cadence Cadence = 1/stride time
  26. 26. 26 Cadence Cadence ≠ 2/step time
  27. 27. 27 Cadence Not defined separately for left and right
  28. 28. 28 Walking speed Walking speed = stride length / stride time
  29. 29. 29 Walking speed Walking speed = stride length * cadence
  30. 30. Phases
  31. 31. 31 Stance and swing Stance SwingFoot contact Foot contact Foot off
  32. 32. 32 Oppositefootcontact Stance and swing OppositeFootoff Firstdoublesupport Single support Seconddoublesupport Swing Footoff Footcontact Footcontact
  33. 33. According to Perry Loading response Initialcontact Mid-stance Terminal stance Pre-swing Initial swing Mid-swing Terminal swing 0% 2% 10% 30% 50% 60% 73% 87% 100% Timings only applicable for healthy walking
  34. 34. Issues with Perry Loading response Initialcontact Mid-stance Terminal stance Pre-swing Initial swing Mid-swing Terminal swing Initial contact isn’t a phase Loading occurs throughout first single support Mid-stance isn’t in the middle of stance Terminal stance isn’t at the end of stance Pre-swing emphasises continuity of gait cycle Why not pre-stance? Single support and swing are divided into a different number of phases
  35. 35. Adapting Perry Loading Mid-stance Pre-swing Initial swing Mid-swing Terminal swing First double support Single support Pre-stanceSecond double supportEarly Middle Late
  36. 36. Making graphs
  37. 37. 37 75 -15 Flx Ext deg Knee Flexion 75 -15 Flx Ext deg
  38. 38. 38
  39. 39. 39 75 -15 Flx Ext deg Knee Flexion 75 -15 Flx Ext deg
  40. 40. 40
  41. 41. 41 50% rule
  42. 42. Another example Hip Flexion -10 0 10 20 30 40 50 60 FlexExtdeg 20 40 60 80 What is hip flexion in mid-stance on the left (red) side? 5° flexion 30° What is hip flexion on the right (blue) side at the same time as mid-stance on the left (red) side? 30° flexion 50% 5°
  43. 43. Knee Flexion 75 -15 Flx Ext Knee Flexion 75 -15 Flx Ext
  44. 44. Reference data Knee Flexion 75 -15 Flx Ext
  45. 45. Multiple walks Knee Flexion 75 -15 Flx Ext
  46. 46. Different aspect ratios 75 -15 Flx Ext deg 75 -15 Flx Ext deg 75 -15 Flx Ext deg 75 -15 Flx Ext deg 75 -15 Flx Ext deg 75 -15 Flx Ext deg 75 -15 Flx Ext deg 75 -15 Flx Ext deg 75 -15 Flx Ext deg 75 -15 Flx Ext deg All graphs in this course have an aspect ratio of 3:4
  47. 47. Different scaling All graphs in this course have consistent scaling 75 -15 Flx Ext deg 60 0 Flx Ext deg 90 -90 Flx Ext deg 75 -15 Flx Ext deg 60 0 Flx Ext deg 90 -90 Flx Ext deg
  48. 48. Graph arrays (NormBF11 16.c3d) (NormBF11 16.c3d) Pelvic Tilt 60 0 Ant Pst Hip Flexion 70 -20 Flex Ext Knee Flexion 75 -15 Flx Ext Dorsiflexion 30 -30 Dor Pla Pelvic Obliquity 30 -30 Up Dwn Hip Adduction 30 -30 Add Abd Knee Adduction 30 -30 Var Val Ankle Rotation 30 -30 Int Ext Pelvic Rotation 30 -30 For Bak Hip Rotation 30 -30 Int Ext Foot Progression 30 -30 Int Ext Sagittal plane Transverse plane Coronal plane Pelvis Hip Knee Ankle
  49. 49. Graph arrays (NormBF11 16.c3d) (NormBF11 16.c3d) Pelvic Tilt 60 0 Ant Pst Hip Flexion 70 -20 Flex Ext Knee Flexion 75 -15 Flx Ext Dorsiflexion 30 -30 Dor Pla Pelvic Obliquity 30 -30 Up Dwn Hip Adduction 30 -30 Add Abd Knee Adduction 30 -30 Var Val Ankle Rotation 30 -30 Int Ext Pelvic Rotation 30 -30 For Bak Hip Rotation 30 -30 Int Ext Foot Progression 30 -30 Int Ext All graphs will be consistent throughout this course
  50. 50. “missing” graphs (NormBF11 16.c3d) (NormBF11 16.c3d) Pelvic Tilt 60 0 Ant Pst Hip Flexion 70 -20 Flex Ext Knee Flexion 75 -15 Flx Ext Dorsiflexion 30 -30 Dor Pla Pelvic Obliquity 30 -30 Up Dwn Hip Adduction 30 -30 Add Abd Knee Adduction 30 -30 Var Val Ankle Rotation 30 -30 Int Ext Pelvic Rotation 30 -30 For Bak Hip Rotation 30 -30 Int Ext Foot Progression 30 -30 Int Ext
  51. 51. Kinetics Sagittal plane Transverse plane Coronal plane Hip moment Knee moment Ankle moment
  52. 52. Kinetics Joint power
  53. 53. Thanks for listening

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