Gait, it's classification , important facts about Gait

 Gait

It is a term used to describe the style of walking.

Through evolution, man has changed from a quadruped gait to a biped gait. The gait in the animals is more stable, since it walks on all the four limbs and the centre of gravity is in between the fore limbs and hind limbs. 

And the ‘speed’ is also more in animal gait, since the trunk musculature helps the limbs in locomotion. This stability and speed is compromised in human gait because of the two legged gait. The centre of gravity keeps changing and is above the base. 

The gait in each person is different and has a characteristic pattern which helps in the identification of that person. 

GAIT CYCLE

Definition It can be defined as all the activities that occur from heel contact of one foot to the next heel contact of the same foot (alternatively it can be from toe off of one foot to the next toe off of the same foot).

Phases of the gait cycle (Fig.1). 

There are two phases:

1. The stance phase

2. The swing phase.

Stance phase: This comprises 60 per cent of the normal adult gait cycle. It begins with the initial heel contact and ends with the toes coming off the ground.

Swing phase: This forms 40 per cent of the gait cycle in adults. It begins when the concerned foot lifts off the ground and ends when the same foot comes in contact with the ground.

Terminology of the Gait Cycle

Two gait terminologies are described:

1. Traditional terms.

2. Rancho Los Amigos (RLA) terms.

                               

GAIT CYCLE

Stance phase (60%)         Swing phase (40%)

• Heel strike                         Acceleration

• Foot flat.                              Mid-swing

• Mid-stance                          Deceleration

• Heel off

• Toe off

         Double limb support forms only

                20% of the gait cycle

Fig. 1: Phases of the gait cycle

Traditional terms vs RLA terms

Traditional                      RLA

1. Heel Strike                Initial contact

2. Foot Flat                     Loading response

3. Mid-Stance                 Mid-stance

4. Heel off.                       Terminal stance

5. Toe off.                          Pre-swing

6. Acceleration.                Initial swing

7. Midswing.                      Midswing

8. Deceleration.                 Terminal swing

Stance Phase (Fig.2A)

This consists of the first five phases.

a. Heel strike—here, the heel strikes the ground.

b. Foot flat—here, the foot is flat on the ground.

c. Midstance.

d. Heel off—here, the heel is off the ground.

e. Toe off—here, the toes are off the ground.

Swing Phase (Fig.2B)

a. Acceleration—here the leg is in front of the body.

b. Midswing—here the leg continues to swing forward.

c. Deceleration—here the swing slows down and the heel is ready for the strike.

In a normal gait, each leg alternatively goes through a stance phase and a swing phase. Thus, the body is carried forward in normal walking by these rhythmic cycles.

Fig. 2B: Swing phase of gait cycle

Quick facts: What is the percentage of each phase in the gait cycle?

I. Stance phase (60%) II. Swing phase (40%)

a. Heel strike 0-2% a. Acceleration 60-73%

b. Foot flat 0-10% b. Midswing 73-85%

c. Midstance 10-30% c. Deceleration 85-100%

d. Heel off 30-50%

e. Toe off 50-60%

Note

• The swing stance ratio is 0.66.

• Double limb support: Here both the limbs are on the ground for a brief period of time. This constitutes 20 per cent of the gait cycle.

Quick facts: Interesting ‘gait’ facts

• The passenger unit (This represents 70 per cent of the body weight). According to Perry 1992.- It is the head,neck, arms and trunk.

According to Elthman (1954) It is head, arms and trunk (denoted by the acronym—HAT).

This is so called, because they do not directly contribute to the act of walking but ‘go along for the ride,’.

• The locomotor unit This is the functioning system whichis comprised of the pelvis and both the lower limbs.

Note 

The locomotor unit consists of 19 joints:

a. Lumbosacral

b. Both hips

c. Both knees

d. Both ankles

e. Both subtalars

f. Both MTP joints

 Vital facts

1. Single limb support : Here only one foot is in contact with the ground. Forms 80% of the gait cycle.

2. Double limb support: Both limbs are on the ground. Forms the remaining 20% of the gait cycle.

3. Stride length: It is the distance the ‘body’ has travelled in one gait cycle.

Men 4.8 feet

Women 4.2 feet.

 Overall average is 4.6 feet.

4. Step length: It is the distance one foot has travelled during a gait cycle.

Men 2.4 ft feet

Women 2.1 feet, Both (average)—2.3 feet.

5. Cadence: Number of steps taken in a specified time.

Men 111 steps/min, Women: 117 steps/min.

Both 113 steps/min (average).

6. Walking velocity: The speed of walking on a smooth snail surface.

Men 276 ft/min

Women 250 ft/min

Both 262 ft/min (average).