Human Gait

Gait is the process or components of walking Each person has a unique style Requires balancing on the one leg while the other moves forward and vise versa Movement of trunk and upper limbs

Normal Gait Series of rhythmical , alternating movements of the trunk & limbs which result in the forward progression of the center of gravity

Gait cycle - definition The rhythmic alternating movements of the 2 lower extremities which result in the forward movement of the body. Simply stated, it is the manner in which we walk

Gait cycle

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%

Defining the terms of Gait Stance phase – activity occurring when the foot is in contact with the ground divided in to 5 main components, Heel strike, foot flat, mid stance, heel off &toe off Swing phase - activity occurring when foot is not contact with ground Divided in to 3components accelaration, mid swing & deceleration

Gait Terminology Heel strike (initial contact) : heel contacts the ground Foot flat (loading response) : plantar surface come and touch the ground Mid stance : total plantar surface is in touch with the ground, total body weight passes through

Heel off (Terminal stance) : heel is off the ground, initial contact of the other leg occur Toe off (Pre swing) : fore foot is off the grond, weight is shifted to the other leg

Acceleration (initial swing) : swinging leg begins to move towards the body Mid swing : swinging leg is under the body Deceleration ( terminal swing) : swinging leg is slowing down to start the next heel strike

Analyzing of Gait

Pelvic rotation: Pelvis remains relatively level in the sagittal plane 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

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

Hip joint Heel strike starts with 30 degrees hip flexion and trunk moves foreword over the foot Extend an average of 40 degrees in combination with the lumbar vertebrae

Knee joint Heel strike occurs in extended knee and is immediately followed by 15 degree of knee flexion Stance phase again the knee extends and begins to flex at the heel off The second flexion cycle occurs in swing phase with an average of 70 degrees required to clear the swinging foot from the floor

Ankle joint Heel strike ankle would be in neutral position, and it would rapidly plantar flex for the foot flat and mid stance phases When tibia moves over the fixed foot ankle is about 10 degrees dorsiflexion In the heel off phase plantar flexion of 20 degrees

Determinants of Gait : 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

This points follow a smooth sinusoidal curve with highest level at mid stance and lowest level at double support. Oscillations of the body’s center of gravity ( COG – S2) vary from 2 – 5cm

Muscle work during gait Stance phase Heel strike – Quadriceps muscle before heel strike concentric contraction, at the heel strike eccentric contraction to decelerate the knee flexion Just after the HS calf muscle has a concentric then isometric contraction to stabilize foot in supination

Foot flat – dorsiflexors eccentric contraction Calf muscle eccentric contraction Mid stance & Heel off – Concentric contraction of the peroneus longus and brevis to support the toes Toe off - Rectus femoris provide

Swing phase Vastus medialis, latralis & intermdius has a concentric contraction before heel strike to extend the knee Hip flexors concentric contraction

Gait Parameters Walking velocity Cadence Step length Stride length Single support time Double support time Walking base

Analyzing Gait Should observe gait from both sides and front Pelvic movement Walking base Step length Arm swinging Position of head & trunk

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

Gait of a Child Wide walking base Cadence is high Stride length is shorter Initial contact with flat foot on ground No/little reciprocal arm swinging

Gait of Elderly Most changes occur due to fear of fall Other factors are loose muscle mass, less active, poor hearing & vision Slow walking velocity, more time in stance phase Increased double support time Reduced step length & vertical displacement Wider base

Abnormal Gait Antalgic gait -- limp adopted so as to avoid pain on weight-bearing structures, characterized by a very short stance phase. Propulsive gait -- a stooped, stiff posture with the head and neck bent forward Scissors gait -- legs flexed slightly at the hips and knees like crouching, with the knees and thighs hitting or crossing in a scissors like movement

Spastic gait -- a stiff, foot-dragging walk caused by a long muscle contraction on one side Ataxic gait -- an unsteady, uncoordinated walk, employing a wide base and the feet thrown out

Steppage gait -- foot drop where the foot hangs with the toes pointing down, causing the toes to scrape the ground while walking, requiring someone to lift the leg higher than normal when walking Waddling gait -- a duck-like walk that may appear in childhood or later in life

Festinating gait -- a gait in which the patient involuntarily moves with short, accelerating steps, often on tiptoe, as in parkinsonism

Thank You