PHTY100 Lecture Notes - Lecture 10: Trendelenburg Gait, Human Musculoskeletal System, Ground Reaction Force
Gait
•Gait: refers to the manner or style of walking
•Gait cycle: a fundamental unit to describe the gait during ambulation. This occurs from the time
when the heel of one foot strikes the ground to the time at which the heel of the same foot
contacts the ground again
•Stride length: the interval between 2 sequential initial floor contacts from the same limb
•Step length: the interval between an initial contact from one foot to the initial contact of the other
foot
•Stance phase: the entire period during which the foot is on the ground
•Swing phase: the time the foot is in the air
•Initial contact: the instant the foot makes contact with the ground. (Previously be referred to as
heel strike)
•Loading response: body weight transfer from initial contact through until the opposite limb is lifted
for swing
•Mid stance: initial phase of single leg support where momentum moves mass over forefoot
•Terminal Stance Phase: completes single leg support. Body weight moves ahead of forefoot
•Pre-Swing Phase: final phase of stance, represents functional commitment to initiating forward
motion prior to swing phase
•Initial Swing Phase: the lift off of the foot from the floor
•Mid Swing Phase: middle area of swing when foot is opposite the stance foo
•Terminal swing phase: last phase of swing in preparation for initial contact
•Heel strike: the onset of stance made by the contact of the heel onto the ground
•Toe off: the lift off of the big toe from contact point on the ground
•GRF: (ground reaction force): the force exerted by the ground on a body in contact with it
10.1 Define and describe the stance and swing phases of the human gait cycle
10.2 Describe the range of motion of the lower limb joints during normal gait
Hip:
•Ranges from 30d flexion to 20d extension (total range 50d)
•Hip motion allows pelvis and trunk to remain erect whilst body weight moves over supporting foot
Knee:
•Ranges from approx. 60d flexion to 0d extension (total range 55d to 60d)
•Key to stance stability
•Reduces the length of the swinging limb and hence facilitates foot clearance in swing phase
Ankle:
•Ranges from 20d plantarflexion to 5d dorsiflexion (total range 25d)
•Plantarflexion reduces impact of heel contact at loading response
•Dorsiflexion through mid-stance to terminal stance facilitates advancement of body weight over
foot
•Plantarflexion prepares limb for swing phase by transforming extended knee into freely flexing
joint
•Dorsiflexion during swing allows for foot clearance
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Document Summary
Gait: gait: refers to the manner or style of walking, gait cycle: a fundamental unit to describe the gait during ambulation. 10. 1 de ne and describe the stance and swing phases of the human gait cycle. 10. 2 describe the range of motion of the lower limb joints during normal gait. Hip: ranges from 30d exion to 20d extension (total range 50d, hip motion allows pelvis and trunk to remain erect whilst body weight moves over supporting foot. 60d exion to 0d extension (total range 55d to 60d: key to stance stability, reduces the length of the swinging limb and hence facilitates foot clearance in swing phase. 10. 3 describe the lower limb muscle activity and the roles of individual muscles during normal gait. Vertical movements of c of g: approximately 3 to 5 cm in amplitude, highest point is at mid stance, lowest point is at double support.
