P and O

Gait cycle and biomechanics

Phases of the gait cycle, events and the biomechanics of walking

11 questions 1 source pages

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Q1What are the phases of the gait cycle and their proportions?▸

Q2Describe the loading response (1st rocker) of the gait cycle.▸

From initial contact until elevation of the opposite limb; 0-10%
Hip abductors eccentric contraction prevents pelvic tilt
Knee flexes 15-20 degrees to minimize upward movement of CoG
Quadriceps and tibialis anterior eccentric contraction; double limb stance

Q3Describe midstance (2nd rocker) of the gait cycle.▸

Elevation of opposite limb until both ankles aligned in coronal plane; 10-30%
Single limb support; CoG progresses from posterior to anterior
Eccentric gastrocnemius balances tibial progression (plantarflexion-knee extension couple)
Hip extensors concentric contraction

Q4Describe terminal stance (3rd rocker) and preswing.▸

Supporting heel rises until the opposite heel touches the ground; 30-50%
Concentric gastrosoleus contraction
Tibialis posterior inverts the subtalar joint and locks the transverse tarsal joints - rigid lever arm
Preswing: acceleration, CoG in front of hip, knee flexes for clearance/propulsion

Q5Describe the swing phase of the gait cycle.▸

Initial swing: elevation of limb to point of maximal knee flexion - active concentric hip flexor contraction
Mid swing: from knee flexion to point where tibia is vertical - momentum of advancing tibia; HF, KE, ADF
Terminal swing: tibia vertical to just prior to initial contact - deceleration by hamstrings; HF, KE, ADF
Forward momentum provided by the hip flexors in initial swing

Q6How does running differ from walking in the gait cycle?▸

Q7Define stride length and step length.▸

Stride length: distance travelled between consecutive initial contacts of the same foot
Step length: distance between initial contacts of alternating feet

Q8What are Gage's prerequisites for efficient gait and give an example of each?▸

Q9Differentiate antalgic, short limb, Trendelenburg and gluteus maximus lurch gaits.▸

Antalgic: trunk leans away from the painful side (opposite for hip), decreased stance on affected limb, longer stance on unaffected limb
Short limb: pelvis tilts to the affected side (hip hiking), Foot may supinate to compensate, normal side hip/knee flex; equal proportion of stance and swing
Trendelenburg: pelvis drops to the normal side from abductor weakness, trunk shift to painful side brings CG back to middle
Glut max lurch: trunk leans backwards as the hip cannot be locked in extension

Q10How does antalgic gait differ for hip versus knee pain?▸

Knee/ankle pain: trunk leans away from the painful side in the coronal plane
Hip pain: patient leans towards the side of pain to reduce the joint reaction force
Knee pain: quadriceps avoidance mechanism - toe walking and decreased knee flexion to reduce tension on the knee capsule

Q11What movements of the pelvis, knee, ankle and centre of gravity occur during the gait cycle?▸

Pelvis: 4 degrees medial rotation and 4 degrees drop on the swing side to lengthen the limb; lateral displacement shifts COG over the stance limb
Knee: flexion 15 degrees at heel strike lowers COG and absorbs shock; extends as the ankle plantarflexes and foot supinates
Ankle: plantarflexion at heel strike and first part of stance
COG: 5cm anterior to S2 in standing; highest at midstance, lowest at double limb support; 5cm horizontal displacement in an adult male step

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