Kinesiology Chapter 12: Stance & Gait

What is the upright locomotion in the particular manner of moving on foot (whether you're walking, running, or jogging) called?

Gait

What level is gait performed at?

Subconscious Level

Compared to four legged animals what are humans considered?

Bipedal

When do humans gain the ability to stand and walk?

1st Year of Life

Moving from one place to another is called what?

Locomotion

This type of locomotion is used clinically, with or without assistive devices.

Ambulation

Defined as an alignment of body segments.

Posture

Movement and posture are what?

Interrelated

Postural control requires what?

Multiple systems interaction such as vestibular, proprioceptive, and visual.

What are the muscles that support upright posture?

Antigravity Muscles

Posture is assessed using this reference to assure all body segments are aligned in gravity.

Plumb Line

Muscles are required to maintain...

Upright Posture

If the line of gravity falls on the concavity of the spinal curves in sagittal plane, then what is required to offset this?

Trunk extensor activity

Where does the line of gravity in posture pass? Examples?

Passes either anterior or posterior to joint axis.

In the knee the line of gravity is located anteriorly to the joint but in the hip it is located posteriorly. It also always falls on the concave side of the vertebrae.

Line of Gravity goes through the following...

Mastoid Process of the Skull -> Shoulder Joint -> Hip Joint -> Knee Joint -> Ankle Joint

In order to maintain a standing position what is required?

The body's high Center of Gravity (COG) must be maintained over a small Base of Support (BOS).

Is the body stationary when standing in place? Why?

Nope

Organ functions like respiration and cardiac contractions which cause small motions.

The body constantly making small motions and reestablishing equilibrium is known as?

Postural Sway

How does the body sway?

In an anterior-posterior and lateral-medial direction.

Where does postural sway primarily occur?

At the ankle

What is the postural control strategy that is initiated at the ankle and feet called when anterior posterior sway is occurring?

Ankle Strategy

What is the preferred postural control strategy when the challenge is small/slow?

Ankle Strategy

What is the postural control strategy that comes from the hip, pelvis and trunk called?

Hip Strategy

What is the preferred postural control strategy when challenge is large/fast?

Hip Strategy

What postural control strategy does the body use when very large and rapid changes occur?

Stepping Strategy

What strategy involves taking a step in order to regain balance and prevent falling?

Stepping Strategy

Gait is synonymous with what word?

Ambulation

Are gait and locomotion different?

Yes, because locomotion is any type of movement from what place to another. Ex: driving.

What is the manner of style of walking?

Gait

What is gait's most fundamental unit?

Gait Cycle

This is the time from when the heel of one foot touches the ground to the time it touches the ground again.

Gait Cycle

Gait Cycle is also known as?

Stride

What two phases is the gait cycle divided into?

Stance and Swing

At normal walking speed, gait cycle lasts how long?

1 Second

During the gait cycle how many periods are there of double limb support?

2 Periods

In the gait cycle what percentage is stance? What percentage is swing?

Stance = 60%; Swing = 40%

According to the RLA terminology system for gait how many subsystems are there for the stance phase and swing phase?

Stance Phase - 5

Swing Phase - 3

What are the 5 subdivisions of stance?

Initial Contact (IC)

Loading Response

Midstance

Terminal Stance

Preswing

Imagine you're about to walk, and you move your right foot forward first....What is happening in initial contact phase?

The right heel has hit the floor in order to initiate the step forward. (Weight Acceptance)

What is happening during loading response?

The entire right foot is flat on the floor, your left foot is on its tippy toes and the body is ready to push the left leg forward. (Weight Acceptance)

What happens during midstance?

The center of gravity is over the right leg (which is flat on the floor) and the other foot is off the ground swinging forward. (Single Limb Support)

What happens during terminal stance?

Now IC is happening with the left foot! so you're tippy toeing on the right, and the heel is getting ready to go down on the left. (Single Limb Support)

What happens during preswing?

Right foot leaves the ground. (Limb Advancement)

In the picture from the powerpoint the stance phase goes like this...

Heelstrike ->Footflat -> Midstance -> Push Off

In the picture from the powerpoint the swing phase goes like this...

Acceleration -> Midswing -> Deceleration

What are the 3 swing subdivisions?

Initial Swing

Mid-Swing

Terminal Swing

What does initial swing involve?

The right foot (that took the first step) now begins to swing forward in order to give some force and acceleration. (Limb Advancement)

What does the midswing involve?

Tibia is perpendicular to the floor in the middle of the swing. (Limb Advancement)

What does terminal swing involve?

The right leg begins to make initial heel contact on the floor to begin the process all over again. (Limb Advancement)

What are the 3 functional tasks of gait?

Weight Acceptance

Single Limb Support

Limb Advancement

Out of the 3 functional tasks what is the swing phase concerned with?

Limb Advancement

Out of the 3 functional tasks what is the stance phase concerned with?

All 3!

Weight Acceptance in initial contact and loading response.

Single Limb Support at midstance and terminal stance.

Limb Advancement: Preswing.

What are spatial characteristics of gait?

Variables which are easily visible by looking at feet as they make a walking pattern.

What are the 4 spatial characteristics of gait?

Step Length

Stride Length

Step Width

Angle of Progression

What is the distance between the initial contact of one foot to the initial contact of the other foot?

Step Length

(Spatial Characteristic)

What is the distance between initial contact of one foot and initial contact of the same foot again?

Stride Length

(Spatial Characteristic)

What is the horizontal distance between the two feet?

Step Width

(Spatial Characteristic)

What is the angle formed between the line of progression in a straight line and a line that bisects the foot at the heel's midpoint and runs between the 2nd and 3rd toes?

Angle of Progression

(Spatial Characteristic)

What are the 3 temporal characteristics of gait?

Velocity

Step Duration

Cadence

What are temporal characteristics of gait?

Anything that has to do with time.

What is the distance covered over a unit of time?

Velocity

(Temporal Characteristic)

What is the number of steps completed per unit of time, usually given in steps per minute?

Cadence

(Temporal Characteristic)

Step Duration?

amount of time foot contact w ground

The best plane to measure gait because the motions are the largest and easiest to track...

Sagittal Plane

What happens in the sagittal plane kinematically?

Two vertical oscillations of the body's COM follow a smooth sinusoidal curve. (Basically a smooth movement).

Flexion/Extension of Hip, Knee and Ankle at the Sagittal Plane

When is the smooth sinusoidal curve highest? Lowest?

The curve is highest at mid-stance; Lowest at double limb support

Vertical displacement of the COM during the sagittal gait phase ranges from...

2-5 cm (depends on speed/stride length)

How much does the hip joint move in the sagittal plane in a single gait cycle?

40° excursion throughout cycle

At the initial contact phase how much flexion occurs at the hip in the sagittal plane?

25-30°

How much hyperextension occurs at the hip during the terminal stance in the sagittal plane?

10°

During the gait cycle how many cycles of flexion and extension does the knee go through in the sagittal plane?

Two cycles

In the sagittal plane, how much flexion occurs during initial contact at the knee?

3-5° of flexion after which further flexion occurs

In the sagittal plane, how much flexion occurs during the end of the loading phase at the knee?

End of loading phase knee is flexed 15-20°

What happens to the knee at terminal stance in the sagittal plane?

Knee moves towards extension reaching full extension at terminal stance

In the sagittal plane, what happens to the knee during preswing and midswing?

Knee begins to flex (35-40°) during pre-swing and reaches a maximum of 60-65° during mid-swing.

How many times does the ankle/foot plantarflex and dorsiflex during one gait cycle?

Twice

During initial contact, what position is the ankle in?

Near neutral dorsiflex/plantarflex

What happens at the ankle/foot during the loading response?

It rapidly plantarflexes.

What happens to the ankle during midstance?

Tibia moves over fixed foot into dorsiflexion. Maximum DF (10°) is achieved just prior to Heel Rise

What happens to the ankle/foot at terminal stance?

Plantarflexion occurs to assist advancement

What happens to the ankle/foot from terminal stance to swing?

Ankle moves from a plantarflexed position to dorsiflexion.

What does dorsiflexion (at the ankle/foot) during swing aid in?

Aids in 'clearing' limb

How much extension must occur at the 1st MTP joint by the end of preswing?

55-60°

Why does the body move laterally in the frontal plane?

To maintain COM over BOS

When does maximum lateral displacement occur? How much to the left/right?

During unilateral stance.

2 cm to left and right

When does maximum lateral and vertical displacements occur?

At the same time of the gait cycle.

In the frontal plane, how does the pelvis tilt during gait? How about during a unilateral stance?

Tilts laterally about 8° on each side.

During unilateral stance, pelvis drops 8°on the swing side.

How do these changes at the pelvis in the frontal plane effect the body?

The pelvis drop places hip abductors on stretch on stance side. (Improved length tension advantage).

Raises COM of swing leg to assist clearing.

In the frontal plane, how are pelvic and hip motions related?

They are directly inter-related.

At initial contact, how much does the hip adduct during gait?

Hip is adducted 10°; Adducts an additional 5°.

What happens to the hip from midstance to terminal stance in the frontal plane?

Hip becomes neutral

What happens to the hip in the frontal plane during swing?

Hip abducts 5°

What happens to the knee in the frontal plane during gait?

Little to no motion of the knee in this plane.

What happens at the pelvis in the transverse plane during gait?

Protraction moves anterior pelvis forward.

If one pelvis protracts, the other retracts.

How much does the pelvis protract in the transverse plane during gait?

Pelvis rotates forward or protracts 4° on swing side and likewise 4° of retraction on stance side (8° total)

When does maximum protraction of the pelvis occur during gait?

Initial Contact

What is muscle activity like during gait?

Muscle activity characterized by 'bursts'. Energy expenditure kept minimal.

When does peak muscle activity of gait occur? Meaning fewer muscles work when?

Peak during Stance; so less during swing

In swing what do muscles work to control?

Momentum

During the 1st half of swing what do muscles work as? How about the 2nd half?

1st half of swing - muscles act as accelerators

2nd half of swing - muscles act as decelerators