KINE 3050 Biomechanics - Gait

“Normal” Gait is a

series of rhythmical, alternating movements of the trunk and limbs

“Normal” Gait results in

forward progression of the center of gravity

Walking pattern may ________ from individual to individual

differ

Heel Strike (HS) =

initial contact (IC)

Foot flat (FF) =

loading response (LR)

Mid stance (MS) =

mid-stance (MS)

Heel-off (HO) =

terminal stance (TS)

Toe-off (TO) =

pre-swing (PS)

Early Swing (ES) =

Initial Swing (IS)

Mid-Swing (MSw) =

Mid-Swing (MSw)

Late-swing (LS) =

Terminal Swing (TSw)

Gait Terminology Image

The Gait Cycle is the period of time from

one heel strike (initial contact) to the next heel strike (initial contact) of the same limb

In Gait, what are the 2 main phases of walking?

Stance Phase/Weight-Bearing: contact phase (weight on foot)​

Swing Phase/Non-weight Bearing: non-contact (no weight on foot)​

​

Phases of gait cycle image

Gait Cycle Image

The stance phase is approximately ____ of the gait cycle

60%

During the stance phase, it begins when the

heel of one leg strikes the ground and ends when the toe of the same leg lifts off

During the gait cycle, what is included in the stance phase?

The swing phase is approximately _____ of the gait cycle

40%

The swing phase represents the period between a

toe off on one foot and heel contact on the same foot

During the gait cycle, what is included in the swing phase?

What are the 2 basic parameters of motion

Temporal (time) and Distance (spatial)

Temporal (time)

SIngle Limb Support Time

Double Support Time

Cadence

Speed

Distance (spatial)

Stride Length

Step Length

Degree of Toe Out

Single Limb Support Time is the amount of time that was spent

during the period when only one extremity is on the supporting surface

Double Support Time is the amount of time spent with

both feet on the ground during one gait cycle

Double support time is increased in

elder patients and balance disorders

Double Support Time is decreased in

speed of walking increases

Which units best represent the pre-swing phase for calculation?

m/s²

Eccentric Contraction

it lengthens

Concentric Contraction

shorthens

Isometric Contraction

Same length but still generates force/tension

Cadence =

the number of steps per unit time

Normal : 100-115 steps/min

Speed (Velocity) =

Stride Length is the distance between

successive points of heel contact of the same foot

• double the step length (in normal gait)

Step length is the distance between corresponding successive

points of heel contact of the opposite feet

Rt step length = Lt step length (in normal gait)

Degree of Toe Out is the

angle of foot placement

For the degree of toe out, the measured angle is formed by

• each foot’s line of progression

• line intersecting the center of heel and second toe

Degree of Toe Out decreases as the speed of walking

increases

What is the path of center of gravity?

• Midway between the hips​

• A few cm in front of S2​

• Least energy consumption if CG travels in a straight line​

During Gait there is _______ and _________ displacement

vertical ; lateral

During Gait and the path of Center of Gravity, Vertical Displacement is the

• Rhythmic up and down movement​

• Highest point: mid-stance​

• Lowest point: double support​

• Average displacement: 5cm​

• Path: extremely smooth sinusoidal curve​

During Gait and the path of Center of Gravity, Lateral Displacement is the

• Rhythmic side-to-side movement​

• Lateral limit: mid-stance​

• Average displacement: 4cm​

• Path: extremely smooth sinusoidal curve​

​

For Heel Strike to Foot Flat, the foot

pronates at subtalar joint

During Heel Strike to Foot Flat is the only time (stance phase)

normal pronation occurs

• Absorbs shock & adapts foot to uneven surfaces​

• Ground reaction forces peak​

During a Heel Strike to Foot Flat, the leg is

internally rotating

What does Heel Strike to Foot Flat end with?

metatarsal heads contacting ground

What are the determinants of Gait

Six optimizations used to minimize excursion of center of gravity in vertical & horizontal planes​

• Lateral pelvis tilt​

• Knee flexion​

• Knee, ankle, and foot interactions​

• Forward and backward rotation of pelvis​

• Physiological valgus of knee​

the determinants of Gait reduce

energy consumption of ambulation​

A determinant of Gait is Pelvic rotation, this is when there is

forward rotation of pelvis in the horizontal plane about 8 degrees on swing-phase

• Reduces the angle of hip flexion & extension​

• Enables a slightly longer step-length w/o further lowering of CG​

Another determinant of Gait is Pelvic Tilt, this is when there is

a 5 degree dip of swinging side (hip adduction)

• In standing, this dip is a positive Trendelenberg sign​

• Reduces height of apex of the curve of CG​

Another determinant of Gait is Knee Flexion , this is when there is

about a 20 degree dip

• Shortens the leg in the middle of stance phase​

• Reduces the height of the apex of the curve of CG​

Another determinant of Gait is Ankle mechanism , this is when it

• lengthens the leg at heel contact

• smoothens the curve of the CG

• Reduces the lowering of CG

Another determinant of Gait is Physiological Valgus of Knee , this reduces the

base of support

• little lateral motion of pelvis is necessary

When we look at motions that occur at joints, how do they occur with respect to a plane

parallel

Running Gait requires greater

balance, muscle strength, and ROM than normal walking

What are the differences between running and walking gait

reduced base support and absence of double support

Running gait needs more coordination and strength which means the muscle

must generate higher energy bout to raise head, arms and trunk higher

Running Gait is divided into

Flight Phase and Support Phase

During running gate, the flight phase is between

toe-off and next foot contact

During running gate, the support phase are the

early stance, mid-stance, and late stance

The most noticeable difference in individual muscle function between walking and running was observed in

SOL

• generating a different distribution of body segment power between the two gait modes

During walking gait, SOL action absorbed power from

the leg in early stance to toe-off

• trunk (generating energy directly to the trunk in late stance)

• Power delivered to the trunk primarily in the horizontal direction to provide forward propulsion

During running gait, SOL is initially absorbed much power

from both the leg and trunk

• SOL generated positive power to both the leg and the trunk (mid-late stance)

• Power delivered to the trunk primarily in the vertical direction to provide support

Stair Gait is the

ascending and descending stairs is a basic body movement required for ADL

Stair Gait involves which phases

stance and swing phase

During Stair Gait , the stance phase is ____

64%

• weight acceptance

• pull up

• foward continuance

During stair gait, the swing phase is _____

36%

• foot clearance

• foot placement