GAIT

Gait :

Walking is the simple act of falling forward and catching oneself.

One foot is always in contact with the ground , and within a cycle , there are two periods of single leg support and two periods of double leg support.

During running there is a period of time during which neither foot is in contact with the ground , a period called ''double float'' .

GAIT CYCLE : 

The gait cycle is the time interval or sequence of motions occuring between two consecutive initial contactsof the same foot.

The gait cycle consists of two phases for each foot :

STANCE PHASE - which makes up 60% to 65% of the walking cycle.

SWING PHASE - which makes upto 35% to 40% of the walking cycle.

In addition , there are two periods of double support and one period of single leg - stance during the gait cycle.

As the velocity of the cycle increases the cycle length or stride length decreases.

For eg; In jogging , the gait cycle is 70% of the walking cycle and in running , the gait cycle is 60% that of walking.

gait velocity decreases with age.

STAGES OF STANCE PHASE:

1. INITIAL CONTACT (HEEL STRIKE)
2. LOAD RESPONSE (FOOT FLAT)
3. MIDSTANCE (SINGLE LEG-STANCE)
4. TERMINAL STANCE (HEEL OFF)
5. PRE SWING (TOE OFF)

Initial contact is the weight loading or weight acceptance period of stance leg. It is 10% of the gait cycle because both feet are in contact with the floor , it is  a period of double support or double leg stance.

The load response and midstance consists of single support or single leg stance , it consists of 40% of the gait cycle.

The stance leg must be able to hold the weight of the body , and the body must be able to balance on one leg.

The terminal stance and preswing makes the weight unloading period , it consists if next 10% of the gait cycle , during this period the stance leg is unloading the body weight to the contralateral limb and preparing the leg for the swing phase.

STAGES OF SWING PHASE:

1. INITIAL SWING (ACCELERATION)
2. MIDSWING
3. DECELERATION

Acceleration is when the foot is lifted off the floor , during normal gait, rapid knee flexion and ankle dorsiflexionoccur to allow the swing limb to accelerate forward.

The midswing instant occurs when the swing leg is adjacent to the weight bearing leg which is in midstance.

During the deceleration the swinging leg slows down in preparation for initial contact with the floor.

ABNORMAL GAIT :

1. ANTALGIC GAIT (PAINFUL) : result of injury to the pelvis , hip , knee , ankle , or foot. The stance phase on the affected leg is shorter than that on the non affected leg because the patient attempts to remove weight from the affected leg.
2. ARTHROGENIC (STIFF HIP OR KNEE) GAIT :results from stiffness , laxity or deformity and it may be painful or pain free. circumducted gait due to stiffness. The patient with this gait lifts the entire leg higher than normal to clear the ground because of a stiff hip or knee.
3. ATAXIC GAIT : If the patient has poor sensation or lacks muscle coordination , there is tendency toward poor balance and a broad base , movements are also exaggerated in this , the resulting gait is irregular , jerky and weaving.
4. EQUINUS GAIT (TOE WALKING) : upward bending motion of the ankle joint is limited , it can occur in one or both feet .
5. PARKINSONIAN GAIT : shuffling or short rapid steps , patient may lean forward and walk progressively faster and unable to stop.
6. SCISSORS GAIT : result of spastic paralysis of the hip adductor muscles.
7. TRENDELENBURG GAIT