Gait

7,730 views

Published on

0 Comments
12 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
7,730
On SlideShare
0
From Embeds
0
Number of Embeds
6
Actions
Shares
0
Downloads
326
Comments
0
Likes
12
Embeds 0
No embeds

No notes for slide

Gait

  1. 1. GAIT JAYANT SHARMA M.S.,D.N.B.,M.N.A.M.S.
  2. 2. DEFINITION Normal Gait = – Series of rhythmical , alternating movements of the trunk & limbs which result in the forward progression of the center of gravity – series of ‘controlled falls’
  3. 3. Gait Cycle –Single sequence of functions by one limb –Begins when reference font contacts the ground –Ends with subsequent floor contact of the same foot
  4. 4. Gait Cycle - Definitions: Step Length = –Distance between corresponding successive points of heel contact of the opposite feet –Rt step length = Lt step length (in normal gait
  5. 5. Stride Length = –Distance between successive points of heel contact of the same foot –Double the step length (in normal gait)
  6. 6. Walking Base = –Side-to-side distance between the line of the two feet –Also known as ‘stride width’
  7. 7. Normal Gait STANCE (60-62% gait cycle) Initial Contact: The moment the foot contacts the ground. Loading Response: Weight is rapidly transferred onto the outstretched limb, the first period of double-limb support. Midstance: The body progresses over a single, stable limb. Terminal Stance: Progression over the stance limb continues. The body moves ahead of the limb and weight is transferred onto the forefoot. Pre-swing: A rapid unloading of the limb occurs as weight is transferred to the contralateral limb, the second period of double-limb support
  8. 8. SWING (38-40% gait cycle) Initial Swing: The thigh begins to advance as the foot comes up off the floor. Mid Swing: The thigh continues to advance as the knee begins to extend, the foot clears the ground. Terminal Swing: The knee extends, the limb prepares to contact the ground.
  9. 9. The contact period - Objective: adapt to terrain, shock absorption, forward progression - 0-10% of gait cycle (HC to FFC) - at HC: hip flexed, knee extended, ankle in neutral (90°), STJ supinated - from HC to FFC: knee flexes, ankle plantarflexes, STJ pronates Muscle activity: - long extensors decelerate plantarflexion - tibialis posterior decelerates pronation - gastrocnemius decelerates internal tibial rotation
  10. 10. Midstance - objective: progression over stationary foot, limb and trunk stability - 10 - 30% of gait cycle (FFC to HO) - knee and hip start to extend - subtalar joint pronation should have ceased (ie. neutral) Muscle activity: - tibialis posterior and soleus start to supinate STJ - peroneus longus stabilizes first ray - triceps surae decelerate forward displacement of tibia, and plantarflex ankle joint
  11. 11. Propulsion - objective: forward progression, foot becomes 'rigid lever' - 30 - 60% of gait cycle (HO to TO) - knee flexes, ankle plantarflexes - subtalar joint rapidly supinates - first ray plantarflexes - 1st MPJ dorsiflexes: toe-off through tip of hallux Muscle activity: - soleus and tibialis posterior assist heel lift - peroneus longus stabilizes first ray - FHL, FHB, AbH, AdH stabilize hallux - EHL dorsiflexes hallux
  12. 12. Swing phase - objective: forward progression, ground clearance - 60-100% of gait cycle - hip continues to flex - knee extends from flexed position - ankle dorsiflexes - STJ slightly pronated at toe-off Muscle activity: - long extensors dorsiflex foot for toe clearance - tibialis anterior dorsiflexes the first ray
  13. 13. The Functional Phases of the Gait Cycle Stance (62%) IC LR Weight Acceptance MS TS Single Limb Support Swing (38%) PSw ISw MSw TSw Swing Limb Advance
  14. 14. Normal Stride Characteristics A. Cadence: steps / timeAdult: approx. 2 steps/sec Females (20 - 69 years old): 121 ∀ 8.5 steps/min Males (20 - 69 years old): 111 ∀ 7.6 steps/min Cadence = – Number of steps per unit time – Normal: 100 – 115 steps/min – Cultural/social variations
  15. 15. Comfortable Walking Speed (CWS) = –Least energy consumption per unit distance –Average= 80 m/min (~ 5 km/h , ~ 3 mph)
  16. 16. –Velocity = Distance covered by the body in unit time Usually measured in m/s Instantaneous velocity varies during the gait cycle Average velocity (m/min) = step length (m) x cadence (steps/min)
  17. 17. Phases: Stance Phase: Swing Phase: reference limb reference limb in contact not in contact with the floor with the floor
  18. 18. Support: (1) Single Support: only one foot in contact with the floor (2) Double Support: both feet in contact with floor
  19. 19. Stance phase: 1. Heel contact: ‘Initial contact’ 2. Foot-flat: ‘Loading response’, initial contact of forefoot w. ground 3. Midstance: greater trochanter in alignment w. vertical bisector of foot 4. Heel-off: ‘Terminal stance’ 5. Toe-off: ‘Pre-swing’
  20. 20. Swing phase: 1. Acceleration: ‘Initial swing’ 2. Midswing: swinging limb overtakes the limb in stance 3. Deceleration: ‘Terminal swing’
  21. 21. Time Frame: A. Stance vs. Swing: Stance phase = 60% of gait cycle Swing phase = 40% B. Single vs. Double support: Single support= 40% of gait cycle Double support= 20%
  22. 22. With increasing walking speeds: Stance phase: decreases Swing phase: increases Double support: decreases Running: By definition: walking without double support Ratio stance/swing reverses Double support disappears. ‘Double swing’ develops
  23. 23. Path of Center of Gravity Center of Gravity (CG): – midway between the hips – Few cm in front of S2 Least energy consumption if CG travels in straight line
  24. 24. Path of Center of Gravity Vertical displacement: Rhythmic up & down movement Highest point: midstance Lowest point: double support Average displacement: 5cm Path: extremely smooth sinusoidal curve
  25. 25. Lateral displacement: Rhythmic side-to-side movement Lateral limit: midstance Average displacement: 5cm Path: extremely smooth sinusoidal curve
  26. 26. Overall displacement: Sum of vertical & horizontal displacement Figure ‘8’ movement of CG as seen from AP view
  27. 27. Determinants of Gait : Six optimizations used to minimize excursion of CG in vertical & horizontal planes Reduce significantly energy consumption of ambulation Classic papers: Sanders, Inman (1953)
  28. 28.  Pelvic rotation: Forward rotation of the pelvis in the horizontal plane approx. 8o on the swing-phase side Reduces the angle of hip flexion & extension Enables a slightly longer step-length w/o further lowering of CG
  29. 29. Pelvic tilt: 5o dip of the swinging side (i.e. hip adduction) In standing, this dip is a positive Trendelenberg sign Reduces the height of the apex of the curve of CG
  30. 30. Knee flexion in stance phase: Approx. 20o dip Shortens the leg in the middle of stance phase Reduces the height of the apex of the curve of CG
  31. 31. Ankle mechanism: Lengthens the leg at heel contact Smoothens the curve of CG Reduces the lowering of CG
  32. 32. Foot mechanism: Lengthens the leg at toe-off as ankle moves from dorsiflexion to plantarflexion Smoothens the curve of CG Reduces the lowering of CG
  33. 33. Lateral displacement of body: The normally narrow width of the walking base minimizes the lateral displacement of CG Reduced muscular energy consumption due to reduced lateral acceleration & deceleration
  34. 34. Gait Analysis – Forces Forces which have the most significant Influence are due to: (1) gravity (2) muscular contraction (3) inertia (4) floor reaction
  35. 35. The force that the foot exerts on the floor due to gravity & inertia is opposed by the ground reaction force Ground reaction force (RF) may be resolved into horizontal (HF) & vertical (VF) components. Understanding joint position & RF leads to understanding of muscle activity during gait
  36. 36. At initial heel-contact: ‘heel transient’ At heel-contact: Ankle: DF Knee: Quad Hip: Glut. Max&Hamstrings
  37. 37. Low muscular demand: – ~ 20-25% max. muscle strength – MMT of ~ 3+
  38. 38. COMMON GAIT ABNORMALITIES A. Antalgic Gait B. Lateral Trunk bending C. Functional Leg-Length Discrepancy D. Increased Walking Base E. Inadequate Dorsiflexion Control F. Excessive Knee Extension
  39. 39. Hip abductor load & hip joint reaction force
  40. 40. Hip abductor load & hip joint reaction force
  41. 41. Swing leg: longer than stance leg 4 common compensations: A. Circumduction B. Hip hiking C. Steppage D. Vaulting Functional Leg-Length Discrepancy
  42. 42. Increased Walking Base Normal walking base: 5-10 cm Common causes: – Deformities Abducted hip Valgus knee – Instability Cerebellar ataxia Proprioception deficits
  43. 43. Inadequate Dorsiflexion Control In stance phase (Heel contact – Foot flat): Foot slap In swing phase (mid-swing): Toe drag Causes: – Weak Tibialis Ant. – Spastic plantarflexors
  44. 44. Excessive knee extension Loss of normal knee flexion during stance phase Knee may go into hyperextension Genu recurvatum: hyperextension deformity of knee Common causes: –Quadriceps weakness (mid-stance) –Quadriceps spasticity (mid-stance) –Knee flexor weakness (end-stance)
  45. 45. Lateral Trunk bending Trendelenberg gait Usually unilateral Bilateral = waddling gait Common causes: A. Painful hip B. Hip abductor weakness C. Leg-length discrepancy D. Abnormal hip joint
  46. 46. Antalgic Gait Gait pattern in which stance phase on affected side is shortened Corresponding increase in stance on unaffected side Common causes: OA, Fx, tendinitis
  47. 47. Velocity: distance/time Adult: 1.4 m/sec Females (20 - 69 years old): 79.3 ∀ 9.5 m/min Males (20 - 69 years old): 82.1 ∀ 10.3 m/min
  48. 48. C. Stride length: right heel strike to right heel strike Adult: 1.5 m Females (20 - 69 years old): 1.32 ∀ .13 m Males (20 - 69 years old): 1.48 ∀ .15 m
  49. 49. Abnormalities during Weight Acceptance: Joint Deviation: Possible Cause Trunk Backward lean: To decrease demand on hip extensors (glut max) Forward lean: Due to increased hip flexion (joint contracture or mm weakness) Lateral Lean: R/L Weak hip abductors Pelvis Contralateral drops: Weak hip abductors on reference limb Ipsilateral drops: Compensation for shortened limb
  50. 50. Hip Excessive flexion: Hip flexion contracture, excessive knee flexion Limited flexion: Weakness of hip flexors, decreased hip flexion Knee Excessive flexion: Knee pain, weak quads, short leg on opposite side Hyperextension: Decreased dorsiflexion, weak quads Extension thrust: Intention to increase limb stability Ankle Forefoot contact: Heel pain, excessive knee flexion, pf contracture Foot flat contact: Dorsiflexion contracture, weak dorsiflexors Foot slap: Weak dorsiflexors Toes Up: Compensation for weak anterior tib
  51. 51. Abnormalities during Single Limb Support: Joint Deviation: Possible Cause Trunk Backward lean: To decrease demand on hip extensors (glut max) Forward lean: Due to increased hip flexion (joint contracture or mm weakness) Lateral Lean: R/L Weak hip abductors
  52. 52. Pelvis Contralateral drops: Weak hip abductors on reference limb Ipsilateral drops: Compensation for shortened limb Anterior Pelvic Tilt: Hip flexion contracture Hip Limited flexion: Weakness of hip flexors, decreased hip flexion Internal Rotation: Weak external rotators, femoral anteversion External Rotation: Retroversion, limited dorsiflexion Abduction: Reference limb longer Adduction: Secondary to contralateral pelvic drop
  53. 53. Knee Excessive flexion: Knee pain, weak quads, short leg on opposite side Hyperextension: Decreased dorsiflexion, weak quads Extension thrust: Intention to increase limb stability Wobbles: Impaired proprioception Varus: Joint instability, bony deformity Valgus: Lateral trunk lean, Joint instability, bony deformity
  54. 54. Ankle Excessive plantarflexion: Weak quads, Impaired proprioception, ankle pain Early heel off: Tight dorsiflexors, Increased pronation: STJ deformity, Toes Up: Compensation for weak anterior tib
  55. 55. Abnormalities during Swing Limb Advance: Joint Deviation: Possible Cause Trunk Backward lean: To decrease demand on hip extensors (glut max) Forward lean: Due to increased hip flexion (joint contracture or mm weakness) Lateral Lean: R/L Weak hip abductors Pelvis Hikes: Clear swing limb Ipsilateral drops: Weak hip abductors on contralateral side Hip Limited flexion: Weakness of hip flexors, decreased hip flexion, hip pain
  56. 56. Knee Limited flexion: Excess hip flexion, knee pain Excess flexion: Knee contracture, weak quads Ankle Excessive plantarflexion: Weak quads, Impaired proprioception, ankle pain Drag: Secondary to limited hip flexion, knee flexion or excess pf Contralateral Vaulting: Compensation for limited flexion of swing or long swing limb Toes Inadequate extension:Limited joint motion, forefoot pain, no heel off Clawed/hammered: Imbalance of long toe extensors and intrinsics, weak pf
  57. 57. Running Gait Variations from walking STANCE (30 - 40%) Foot Strike: Mid-support: Take-off (propulsion) SWING (60 - 70%) Follow through: Forward swing: Foot descent:
  58. 58. list of common overuse injuries associated with poor gait biomechanics: Shin splints Plantar fasciits Iliotibial band syndrome (runners knee) Patella tendonitis (jumpers knee) Patello-femoral knee pain Achilles tendonitis Lower back pain
  59. 59. Shock absorption and energy conservation are important aspects of efficient gait. Altered joint motion or absent muscle forces may increase joint reaction (contact) forces and lead subsequently to additional pathology. In early stance, nearly 60% of one's body weight is loaded abruptly (less than 20 milliseconds) onto the ipsilateral limb. This abrupt impact is attenuated at each of the lower extremity joints. Loading response plantar flexion is passive, substantially restrained by eccentric work of pretibial muscles. The absorptive work by pretibial muscles delays forefoot contact until late in the initial double support period (7-8% GC).
  60. 60. At initial contact, external (ground reaction) forces applied to the contact foot produce a tendency toward knee flexion. Repositioning the knee (recurvatum) increases knee mechanical stability, but at the cost of increased contact forces and shock generation. A balance between knee stability and shock absorption is achieved by eccentric quadriceps contractions during loading response. The impact of loading is minimized at the hip during single support through hip abductor muscle contraction.
  61. 61. Energy conservation Ambulation always is associated with metabolic costs. These costs are relatively minor in normal adults performing free speed level walking. The self-selected walking speed in normal adults closely matches the velocity that minimizes metabolic work.

×