Gait: Exam 4

Gait cycle

The activity that occurs between the time the heel of one extremity touches the floor and when that same foot again touches the floor. Example: Right heel strike to right heel strike

Stride length

The distance covered in one gait cycle, defined as the distance between heel strike of one leg and its subsequent heel strike. Example: Distance measured from right heel strike to right heel strike.

Stance phase

The period when the foot is in contact with the ground, representing 60% of the gait cycle.

Swing phase

The period when the foot is NOT in contact with the ground, which begins when the foot leaves the ground and ends when the heel of the same foot touches the ground, representing 40% of the gait cycle

Double support:

The phase when both feet are in contact with the ground simultaneously, occurring between the heel-off and toe-off phases of one limb and the heel strike and foot flat phase of the opposite side. Represents approximately 10% of the gait cycle.

Nonsupport

The time during which neither foot is in contact with the ground, occurring typically in activities such as running or jumping, and does not occur during basic walking.

Single support

The phase where only one foot is in contact with the ground. Two periods of single support exist: when the right foot is on the ground and when the left foot is on the ground. Each single support period takes up approximately 40% of the gait cycle

Step

The phrase concerning the equal times for right and left steps, encompassing the period of double support, single support, stance phase, and swing phase.

Step length:

The distance between heel strike of one limb and heel strike of the other limb. It is noted that while walking speed varies, the step percentage remains equal for each limb.

Cadence

The number of steps taken per minute. This varies widely based on walking speed, e.g., 70 steps per minute for slow walking, up to 130 for fast walking

Phases of Gait

Swing Phase: Foot not in contact with the floor.

Stance Phase: Foot in contact with the floor.

Step: One swing + one stance (in one limb).

Stride: Two steps = one right + one left (in two limbs).

Cadence: Number of steps per minute, indicating walking speed.

Double limb support: Both feet in contact with the floor simultaneously

Posture and Trunk Rotation During Gait

• The step length should be equal in both distance and time.

• Arms should swing opposite to the leg in motion.

• The trunk rotates forward as the limb transitions through the swing phase, with arm movement in opposition to the trunk rotation.

• The head must remain erect, shoulders level, and the trunk in extension throughout the gait process.

Traditional Terms

Focus on specific points in time during the gait cycle

Rancho Los Amigos Terms

Focus on distinct periods in the movement

Heel Strike (Traditional)

Heel contact with ground

Foot flat (Traditional)

Plantar surface of the foot contacts ground

Midstance (Traditional)

Point at which the body passes over the weight bearing limb

Heel-off (Traditional)

Heel leaves the ground, while ball of the foot and toes remain in contact with the ground

Toe-off (Traditional)

Toe is leaving ground, ending stance phase

Acceleration (Traditional)

From when the toes leave the ground until the foot is directly under the body

Midswing (Traditional)

When the non-weightbearing limb is directly under the body

Deceleration (Traditional)

When the limb is slowing down in preparation for heel strike

Initial contact is same as what?

Heel strike

Loading response (Ranchos Los Amigos)

Period from just after initial contact until the opposite foot leaves the ground

Midstance (Rancho Los Amigos)

Period from when the opposite foot leaves the ground until body is directly over weight bearing limb

Terminal Stance (Rancho Los Amigos)

From midstance to initial contact of the opposite foot

Preswing (Rancho Los Amigos)

From initial contact of the opposite limb to just before the toes leave the ground

Initial Swing (Rancho Los Amigos)

From when the toes leave the ground until maximum knee flexion of the same limb

Midswing (Rancho Los Amigos)

Just after maximum knee flexion until the tibia is in a vertical position

Terminal Swing (Rancho Los Amigos)

From the vertical position of the tibia to just prior to initial contact

Stance Phase: Heel Strike

• Marks the beginning of the stance phase as the heel contacts the ground.

• Ankle remains in a neutral position (neither dorsiflexion nor plantar flexion), and the knee begins to flex.

• Trunk rotates towards the opposite side with the opposite arm moving forward.

• The same-side shoulder may hyperextend as body weight begins to shift onto the stance leg.

Stance Phase Heel Strike: Muscle Activity

• Ankle dorsiflexors activate to maintain ankle in a neutral position.

• Quadriceps engage concentrically but switch to eccentric contraction to control knee flexion.

• Hip flexors exhibit activity while hip extensors begin to contract to prevent excessive hip flexion.

• Erector spinae muscles maintain trunk stability against flexion forces

Stance Phase: Foot Flat

• Entire foot retains contact with the ground post-heel strike.

• Ankle transitions into plantar flexion while dorsiflexors work eccentrically to prevent foot slap.

• The knee flexes and the hip advances into extension, with continued weight transfer onto the stance limb

Stance Phase: Midstance

• This point represents when the body shifts over the weight-bearing foot.

• The ankle may enter slight dorsiflexion, with plantar flexors establishing a contraction to manage the leg's rate of movement over the ankle.

• The knee and hip progressively extend while arms are in shoulder extension parallel to the body.

• The trunk holds a neutral rotation displaying a peak elevation within the gait cycle during this single support period

Stance Phase: Heel-Off

• The heel lifts off the ground signaling the transition into the push-off phase.

• The ankle transitions from dorsiflexion into plantar flexion, with plantar flexors active in facilitating body movement forward.

• The knee approaches full extension, the hip reaches hyperextension, while the trunk begins to rotate towards the same side

Stance Phase Toe-Off

• Occurs directly before, and encompasses the moment, the toes leave the ground.

• This marks the conclusion of the stance phase and the onset of the swing phase.

• Characterized by plantar flexion of the ankle, while the knee and hip begin to flex

Components of swing phase

1. Acceleration

2. Midswing

3. Deceleration

(40% of gait cycle)

Swing Phase: Acceleration

The limb trails the body while moving to catch up, involving active dorsiflexion of the ankle alongside continued flexion of the knee and hip

Swing Phase: Midswing

• The ankle achieved a neutral position due to the antagonistic action of the dorsiflexors.

• The knee is at its maximum flexion (~60°), functioning to shorten the limb for foot clearance during the swing

Swing Phase: Deceleration

• The dorsiflexors maintain the ankle in a neutral position to prepare for heel strike, while the knee extends.

• Hamstring muscles contract eccentrically to slow the forward swing movement of the leg

Center of gravity Displacement includes:

1. Vertical Displacement

2. Horizontal Displacement

3. Width of walking Base

4. Lateral Pelvic Tilt

Vertical Displacement

The normal amount of COG Vertical Displacement is approximately 2 inches, being highest at midstance and lowest at heel strike

Horizontal Displacement

COG experiences side-to-side displacement as body weight shifts during single support, being most pronounced at midstance.

Width of Walking Base

• During walking, feet are typically positioned 2-4 inches apart.

• Lines can be drawn through the midpoints of heel contact between successive steps

Lateral Pelvic Tilt

• This tilt occurs during the toe-off phase when weight is lifted off the limb, leading to a drop on the non-weight-bearing side.

• Limitation of the lateral pelvic tilt is maintained by hip abductors on the opposite side and the erector spinae muscles on the same side.

Muscles Working to Minimize Lateral Pelvic Tilt

• Hip abductors

• Erector spinae muscles

Range of Motion Requirements for normal gait

• Hip Flexion: 0 – 30°

• Hip Extension: 0 – 20°

• Knee Flexion: 0 – 60°

• Knee Extension: 0°

• Ankle Dorsiflexion: 0 – 10°

• Ankle Plantar flexion: 0 – 20°

Hip Movement During Gait

• Flexes during pre-swing phase and extends during stance phase.

• Adducts during weight-bearing (stance phase) to stabilize pelvis. Eccentric activity of abductors prevents excessive adduction.

• Abducts during non-weight-bearing (swing phase) and rotates medially during most of the stance phase, laterally during swing.

Knee Movement During Gait

• Achieves near full extension at heel strike.

• Engages into flexion by a few degrees at foot flat.

• On set of extension during toe-off and flexes again during pre-swing to ensure foot clearance

Ankle Movement During Gait

The neutral position occurs at heel strike, transitions into plantar flexion for foot flat, then shifts to dorsiflexion during stance, plantarflexes for toe-off, dorsiflexes in early swing to clear the foot, and returns to a neutral position at heel strike

Pelvis Movement During Gait

Rotates forward and downward on the swing side as the leg prepares for weight-bearing.

Arms and Torso Movement During Gait

The arms act in opposition to the legs: as the right foot advances, the left arm moves forward, and vice versa.

Muscle Actions During Gait

• Hip flexors initiate swing.

• Hip extensors & hamstrings decelerate at the swing's conclusion.

• Knee extensors contract eccentrically at heel strike to prevent knee buckling.

• Dorsiflexors keep toes off the ground during swing, and prevent foot slap at heel strike. They also eccentrically contract to slow down plantar flexion.

• Plantar flexors contract during push-off stages

Additional Factors Influencing Gait

• Vertical rise and fall of COG is nearly 2 inches.

• There may be lateral swaying of approximately 2 inches.

• Speed control of the lower leg is necessary during swing to avoid a foot slap into extension; in patients with impaired hip flexors, trunk use compensates

Gluteus Maximus Gait

Characterized by a quick posterior shift of the trunk at heel strike, with the hip kept extended during stance. This is often referred to as “rocking horse gait.”

Gluteus Medius Gait (Trendelenburg gait)

The trunk shifts towards the affected side during stance; if the left gluteus medius is weak, the pelvis drops on the right side when the right leg leaves the ground.

Quadriceps Weakness

This leads to several compensatory strategies; when solely weak, hip extensors and triceps surae help to extend the knee at heel strike

Hamstring Weakness

Results in excessive knee hyperextension during the stance phase (genu recurvatum), and a failure to decelerate knee forward swinging leads to a sudden snap into extension.

Ankle Dorsiflexors Weakness

“Foot slap” occurs as they fail to control the descent; “foot drop” or “steppage gait” may result during swing, characterized by excessive knee flexion and toe strike instead of heel strike.

Waddling Gait

Common in muscular dystrophies, where body balance and swing necessitate the entire body to pivot forward, often characterized by hip resting on the iliofemoral ligament.

Hip Flexion Contracture:

Limits the extension during midstance and poses difficulty in push off phases, creating compensatory mechanisms such as anterior pelvic tilt and lumbar lordosis

Tight Hip Adductors

Results in “scissor gait” where the affected leg crosses the midline and other limbs must perform circumduction to prevent tripping

Knee Flexion Contracture

Creates early heel rise at push-off, with shortened step length on the unaffected side

Knee Fusion

The fixed position of the limb results in circumducted gait where the leg remains abducted throughout the gait cycle

Triceps Surae Contracture

Depending on severity, can lead to steppage gait, where excessive knee lift occurs during the swing phase.

Ankle Fusion

This involves subtalar and transtarsal joint fusion; stride length is shortened and difficulties arise when walking on uneven surfaces.

Hemiplegic Gait

Shows alterations depending on the level of spasticity or flaccidity, leading to body weight shifting chiefly towards the uninvolved side, a limited reciprocal arm swing, and a circumduction movement during swing.

Ataxic Gait

Resulting from balance disruption, produces a wide base of support with jerky, uneven movements and difficulty moving in a straight line.

Parkinsonian Gait

Characterized by diminished movements, with a common flexed posture of lower extremities, reduced stride length, shuffling gait, and festinating steps

Crouch Gait:

Typically noted with bilateral leg involvement expressing excessive lumbar lordosis, anterior pelvic tilt with hip flexion, knee flexion, and exaggerated arm swing.

Antalgic Gait

Occurs when pain is present in any lower extremity joint, typically resulting in shortened stance phases and rapid steps on the uninvolved side

Hip Flexors

Function: Acceleration of swing

Abnormalities if weak/painful: Backward lurch indicating failure to initiate swing, often seen in hemiplegic patients

Hip Abductors

Function: Stabilizes pelvis in stance

Abnormalities if weak/painful: Ipsilateral lurch (Trendelenburg) or contralateral drop of the hip

Hip Extensors

Function: Stabilizes pelvis during stance

Abnormalities if weak/painful: Trunk lean posteriors, may require a quick step on the contralateral limb

Hamstrings

Function: Deceleration of swing

Abnormalities if weak/painful: May cause overshoot at the end of swing, leading to slam into extension or genu recurvatum

Quadriceps

Function: Shock absorption at heel strike

Abnormalities if weak/painful: Forward lurch during stance; may lock knee during stance causing hyperextension

Ankle PF & Toe Flexors

Function: Propel during push-off

Abnormalities if weak/painful: Failure of push-off leading to small steps or slow speed

Ankle DF & Toe Extensors

Function: Control foot slap, clear toes for swing

Abnormalities if weak/painful: Leads to steppage or toe-heel gaits caused by weak dorsiflexors