1. Gait

2. 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

3. 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

4. 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

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

6. 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

7. Gait Cycle
HS: Heal strike
TO: Toe off

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

9. 1- Heal Strike
The instant at which the heel of the leading extremity strikes the ground

10. 2- Foot Flat
Occurs immediately after heel strike and is the point at which the foot fully contacts the ground

11. 3- Midstance
The point at which the body weight is directly over the supporting lower extremity

12. 4- Heal Off
The point at which the heel of the reference extremity leaves the ground

13. 5- Toe Off
The point at which the only the toe of the reference extremity is touching the ground

14. Swing Phase
Consists of:
Acceleration
Midswing
Deceleration

15. 1- Acceleration
Begins once the toe of the reference extremity has left the ground, it continues until midswing

16. 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

17. 3- Deceleration
Is the point at which the knee is extending in preparation for heel strike

18. 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

19. 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

20. 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

21. 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

22. 5- Stride duration
The amount of time it takes to accomplish one stride
Stride duration = gait cycle duration

23. 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.

24. 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

25. Step vs. Stride

26. 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

27. 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

28. 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

29. 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

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

31.  Study Hard & Good Luck 