Kinesiology Unit 3 Exam

Early in life, child needs _-_ months to learn to stand and walk

11-15

Age _-_ resembles adult walking

4-5

Visual gait analysis

easy, doesn't require any tools or equipment, but eyes can't detect high-speed movements. Joint kinematics and forces not measured. Difficult to track improvements without measurements; requires proficient clinical skills.

Video-based analysis

Requires recording device, allows slowing down and replaying of footage to assess motion. Kinematics may be assessed (accuracy depends on camera placement), but doesn't provide force or muscle activity information. Can be used for patient education and pre-post comparisons.

Gait cycle

Beginning of a walking event by one limb and continuing until the event is repeated with the same limb

(i.e. time from heel strike to next ISPILATERAL heel strike)

Stride

one complete gait cycle (right step + left step)

Step

beginning of an event of one limb until the beginning of same event of contralateral limb

Stride length

distance between successive heel contacts of same foot

Step length

distance between successive heel contacts of the two different feet

Step width or BOS

lateral distance between the heel centers of two consecutive foot contacts

Step width decreases as _ increases

cadence

Foot angle

amount of toe-out (~5-7º)

Cadence/Step rate

number of steps per minute
(walking: 110-120 steps/min)

Speed

step rate * step length or distance / time

-usually described in m/sec or mph

For a given limb, stance is _% of gait cycle

60%

For a given limb, swing is _% of gait cycle

40%

Initial contact (heel strike):

when foot touches ground

Loading Response (foot flat)

between initial contact and beginning of other leg swing

Mid stance

when other foot off floor until body directly over stance limb

Terminal stance (heel off)

when heel of stance limb rises to other foot touching ground

Pre-swing (toe off)

when other foot touches ground and stance foot reaches toe off

Initial swing (acceleration)

when stance foot lifts from floor to maximal swing knee flexion

Mid swing (same)

from maximal knee flexion during swing to when tibia perpendicular to ground

Terminal swing (deceleration)

From when tibia perpendicular to floor to when foot touches ground

Functional tasks for each limb during the gait cycle

-Weight acceptance
-Single limb support
-Swing limb advancement

Speed can be increased by increasing

•Step length (A)
•Step rate (B)
•Or both

With faster walking speeds, a smaller percentage of gait cycle is spent in

double-limb support

Pelvis Sagittal Plane Kinematics

5º ant & post pelvic tilt

_ pelvic tilt during double limb support

Posterior

_ pelvic tilt during single-limb support

Anterior

Hip sagittal plane kinematics

30º flexion - 10º extension

Hip flexed ~__º at initial contact

30

As body moves over foot, hip extends to ~__º at toe off

10

Knee sagittal plane kinematics

60º flexion - 0º extension

Ankle sagittal plane kinematics

10º of DF - 20º of PF

At initial contact, knee is flexed _º and it flexes _-_º

5 degrees, 10-15 degrees

_º of knee flexion at toe off and maximal knee flexion (60º) at mid swing

35 degrees

Heel makes contact in slight

plantarflexion

After heel off, ankle PFs to

15-20º

During swing, the ankle

DFs to neutral to clear toes

Pelvis frontal plane kinematics

10-15º pelvis-on-femur hip adduction and abduction

During weight acceptance on Right, Left iliac crest initially _ before elevating (hip abduction)

drops (hip adduction)

STJ frontal plane kinematics at initial contact

Inverts 2-3º

STJ frontal plane kinematics at midstance

Everts to 2º

STJ frontal plane kinematics at toe-off

reverses direction to 6º inversion

Excessive frontal plane movement of the stance hip is

common

Possible reasons for excessive frontal plane movement at the hip

•Weakness of hip abductors --> contralateral hip drop

•Reduced "shortening" of the swing limb ---> contralateral hip hiking

•Limb length difference

During double-limb support, iliac crest of longer limb will be

higher

Initial 1/3 of stance phase generally characterized by

internal rotation of pelvis

Swing phase is primarily

internal rotation

Hip flexion needed for gait

0-30º

Hip extension need for gait

0-10º

Knee flexion needed for gait

0-60º

Knee extension needed for gait

0º

Ankle dorsiflexion needed for gait

0-10º

Ankle plantarflexion needed for gait

0-20º

CoM at lowest and most central position during

middle of double limb support (5 & 55% of gait cycle)

CoM at highest and most lateral position at

mid-stance of each limb (30 & 80% of gait cycle)

Energy expenditure during walking is lowest at

80 m/min (~1.3 m/s or 3 mph)

-which is normal walking speed.

Hip extensors control hip _ (via eccentric or isometric activity) and initiate hip _

flexion, extension

Hip _ control frontal plane pelvis movement

abductors

Hip flexors control hip _ at terminal stance and initiate hip _ in swing

extension, flexion

Knee extensors control knee _ and initiate knee _

flexion, extension.

Ankle dorsiflexors control ankle _ & initiate ankle _

plantarflexion, dorsiflexion

Ankle plantarflexors control ankle _ and initiate ankle _

dorsiflexion, plantarflexion

Ankle supinators (PF/Inv) control ankle _

pronation (especially when excessive pronation occurs)

Ankle pronators (DF/Ev) control ankle _

supination

Key muscle activity during initial contact

-ankle DF
-quads/hamstrings
-hip extensors
-abductors

Key muscle activity during loading response

-ankle DF
-quads
-hip extensors
-ankle PF to control DF
-posterior tibialis to control pronation

key muscle activity during midstance

-ankle PF (ecc)
-quads
-hip extensors
-hip abductors

Key muscle activity during terminal stance

-ankle PF (con)
-hip abductors
-hip flexors to control rate of hip extension

Key muscle activity during pre-swing

-peak ankle PF (con)
-hip flexors

Key muscle activity during initial swing

-ankle DF
-hamstrings to flex knee
-hip flexors

Key muscle activity during midswing

ankle DF

Key muscle activity during terminal swing

-ankle DF
-ankle invertors
-quads/hamstrings
-hip extensors

Peak vertical GRF

120% BW

Peak ant-post GRF

20% BW

Peak med-lat GRF

5% BW

Path of the center of pressure (COP)

-Typically initial contact is on lateral heel so CoP just lateral to midpoint of heel
-moves toward lateral midfoot at midstance
-moves towards medial forefoot under 1st or 2nd MT head during heel-off to toe-off

External torques are resisted by

internal torques

Joint power formula

Net Internal Joint Torque (Nm) * Joint angular velocity (º/s)

Positive power

Energy generation = Concentric muscle activation and release of energy from stretched tissues

Negative power

Energy absorption = Eccentric muscle activation and stretching of passive tissues

During the early part of stance, line of action of GRF is

posterior to ankle and knee and anterior to hip.

Hip extensors are most active in which phases?

the 1st half of stance phase and terminal swing phase

Hip flexors are most active in which phases?

2nd half of stance phase and initial swing phase

Antalgic gait

-limp to avoid pain
-shorter step length and shorter stance phase on involved leg

Ataxic gait

Unsteady, uncoordinated, with wide base of support

Foot slap

weak dorsiflexors, dorsiflexor paralysis

Steppage gait

-Excessive Hip and Knee Flexion to Compensate for Foot Drop

-Weak ankle dorsiflexion may result in foot drop during swing phase requiring excessive knee and hip flexion for the toes to clear the ground as the limb is advanced

Vaulting gait

Vaulting through excessive plantarflexion of the unaffected stance limb is used to compensate for limited functional shortening of affective swing limb like when having a knee braced in full extension

Weak quadriceps gait

•Excessive Anterior Trunk Bending to Compensate for Weak Quadriceps

•Weak quadriceps leading to anterior trunk lean to move the CoM of the body anterior to the axis of rotation of the knee

Genu recurvatum gait

•Knee Hyperextension and Forward Trunk Lean to Compensate for an Ankle Plantar Flexion Contracture (Pes Equinus Deformity)

Weak abductor gait

Hip circumduction gait

•Hip Circumduction During Swing Due to Inadequate Hip, Knee Flexion, Ankle Dorsiflexion

•Swinging leg out to the side compensates for inability to shorten the swing leg

•Elevating the pelvis (hip hiking) is a similar compensation

Crouched gait

•Knee Flexor Contracture Causing a Crouched Gait of the Stance Leg

•To clear the toes during swing, the unaffected contralateral limb must compensate with exaggerated knee and hip flexion

Function of the vertebrae

•Provide stability

•Protects the spinal cord, ventral and dorsal n roots along with exiting spinal n roots.

Costocorporeal joint

head of a rib to pair of costal demifacets

Costotransverse joint

tubercle of rib with costal facet on transverse process of corresponding vertebrae

How many vertebra are there?

33 vertebrae:

•7 cervical
•12 thoracic
•5 lumbar
•5 sacral
•4 coccygeal