Gait

Gait Gait is a general motion composed of translatory progression of the body as a whole, produced by rotatory movements of body segments The head, Arms & Trunk, known as HAT make around 75% of total body weight Each lower extremity is about 10% of total body weight

Gait Gait is more demanding on lower extremities than does static posture. Before one can walk they must be able to balance HAT in a erect standing posture, transfer HAT from one extremity to another, lift one lower extremity off the ground & place it in front of the other extremity in an alternating pattern These activities require coordination, balance, proprioceptive senses, & integrity of the joints & muscles

Phases of Gait Cycle Stance Phase Swing Phase Defined as the period in which some portion of the foot of the reference extremity is in contact with the ground. It extends from the point of initial foot contact of the extremity to the point at which only the toes of the same extremity are in contact with the ground. Swing Phase Defined as the period in which the foot of the reference extremity is not in contact with the ground. It extends from the instant that the toe of the reference extremity leaves the ground to just prior to initial contact of the reference extremity

Stance Phase Begins when one extremity contacts the ground Continues as long as the foot is on the ground Make 60% of gait cycle

Swing Phase Extremity does not contact the ground at any time Begins as soon as the toe of the extremity leaves the ground Make 40% of gait cycle

Gait Cycle HS: Heal strike TO: Toe off

Stance Phase Consists of: Heal strike Foot flat Midstance Heal off Toe off

1- Heal Strike The instant at which the heel of the leading extremity strikes the ground

2- Foot Flat Occurs immediately after heel strike and is the point at which the foot fully contacts the ground

3- Midstance The point at which the body weight is directly over the supporting lower extremity

4- Heal Off The point at which the heel of the reference extremity leaves the ground

5- Toe Off The point at which the only the toe of the reference extremity is touching the ground

Swing Phase Consists of: Acceleration Midswing Deceleration

1- Acceleration Begins once the toe of the reference extremity has left the ground, it continues until midswing

2- Midswing Occurs when the reference extremity passes directly below the body. It encompasses the period immediately following maximum knee flexion & continues until the tibia is in a vertical position

3- Deceleration Is the point at which the knee is extending in preparation for heel strike

Distance & Time Variables Single support time Double support time Stride length Stride duration Step length Step duration Cadence Walking velocity Acceleration Speed Width of base of support Degree of toe out

1- Stance Time 2- Single Support Time It is the amount of time that passes during the stance phase of one extremity in a gait cycle 2- Single Support Time It is the amount of time that passes during the period when only one extremity is on the ground in a gait cycle

3- Double Support Time It is the amount of time that a person spends with both feet on the ground during a gait cycle. It increases in old people & people with balance disorders It decreases as speed of walking increase In a single gait cycle there are 2 period of double limb support It occurs when one lower extremity is beginning its stance phase and the other lower extremity is ending its stance phase

4- Stride Length It is the linear distance from the point of heel strike of the reference extremity to the next heel strike of the same extremity It decrease in old people It increases as speed of gait increases The length of one stride is traveled during one gait cycle

5- Stride duration The amount of time it takes to accomplish one stride Stride duration = gait cycle duration

6- Step Length 7- Step Duration It is the linear distance between two successive points of contact of opposite extremities 7- Step Duration The amount of time spent in a single step When there is weakness of an extremity or pain, step duration may be decreased on the affected side, & increases on the unaffected side.

Step vs. Stride Step: A heal strike of the one lower extremity to a heal strike of the other lower extremity Stride: a stride contains two steps, so it's from the heal strike of one lower extremity to the next heal strike of the same lower extremity

Step vs. Stride

8- Cadence 9- Walking Velocity Is the number of steps taken by a person per unit time 9- Walking Velocity It is the rate linear forward motion of the body Walking velocity = distance walked/time

10- Acceleration It is the rate of change of velocity with respect to time 11- Speed Speed of gait can be slow, free and fast Free speed: a person's normal walking speed

12- Width of Base of Support It is found by measuring the linear distance between the midpoint of the heel of one foot & the same point on the other foot It is necessary for stability, it increases it

13- Degree of Toe Out The angle formed by each foot’s line of progression and a line intersecting the center of the heel & the second toe represents the angle of foot placement

Important ! Study The Table on Page 460 of your “Gait” Note

 Study Hard & Good Luck 