KINS304 Exam #4

Hindfoot (rear-foot)

Hindfoot (rear-foot)

-talus

-calcaneus

Midfoot

-navicular

-cuboid

-3 cuneiforms

Forefoot

5 metatarsals, 14 phalanges

The 3 arches of the foot

-medial longitudinal

-lateral longitudinal

-transverse

Functions of the foot

-support body weight

-adapt to uneven surfaces

-absorb shock

Gait analysis

the study of human locomotion used to assess posture and coordination during movement

Gait cycle

the sequence of events between one foot strike and the subsequent foot strike of the same limb

Stance phase (support phase)

-foot is in contact with the ground and weight bearing

-60% of gait cycle

Swing phase

-foot is suspended in air and non-weight bearing

-40% of gait cycle

When walking, we have periods of…

double support

What are the five elements of the stance phase?

1. initial contact (heel-strike): when foot touches ground

2. loading response: weight transfers onto supporting limb; joints begin to absorb shock

3. midstance: body is directly over the support limb; joints are stacked

4. terminal stance: body moves forward to prepare for weight transfer; “falling forward”

5. pre-swing (toe-off): limb begins to unload as weight is transferred and accepted by the opposite limb

What are the three elements of the swing phase?

1. initial swing: foot comes off floor and femur advances forward

2. mid swing: foot clears the ground as the thigh advances forward

3. terminal swing: lower extremity prepares to contact the ground again

What happens to the stance and swing phases when running?

they switch so…

60% swing phase and 40% stance phase

What is added as we run?

a flight phase

Is only one foot or are both feet in contact with the ground when running?

only one foot

Step

distance between the points of contact of contralateral (opposite) feet

Stride

distance between ipsilateral (same) points of contact

What is a healthy gait (stride)?

about 1 second to complete stride

Which of Newtons Laws can be applied with gait?

Newtons Third Law: with every action there is an equal and opposite directed reaction

How can ground reaction forces identify gait issues?

-see how force changes between different activities

-see how different strike patterns impact forces

-see how footwear impacts forces

-see how size/weight impacts forces

Heel strike

heel lands first, followed by the forefoot

Midfoot strike

heel and ball of foot land simultaneously

Forefoot strike

ball of foot lands first, followed by the heel

Which strike pattern of the foot is best for reduced injury?

not enough research to back up evidence and answer questions

Compression

due to body weight and gravity

Hip compression

-bears up to 3-4x body weight while walking stance phase

-7x body weight during running

Knee compression

-bears about 3x body weight during walking

-4x body weight during stair climbing

Ankle/foot compression

-about equal in body weight during walking

-about 2-3x body weight during running

Compressive forces on joints increase or decrease as body weight and activity speed increase?

increase

Tension

due to passive eccentric loading

What does tension during the stance phase result in?

results in stored energy which is then used during the push-off/toe-off phases of walking and running

The use of stored energy reduces the…

metabolic energy cost during gait

Anatomical factors impacting human gait

-Q-angle

-Coxa varus and Coxa valga

-Genu valgum and Genu varum

-arch height

Other factors impacting human gait

-ROM

-strength

-motor function and control

-balance and stability

-previous injury

What will happen if one or more factors is compromised?

other joints will begin to compensate for the injured joint

Gait change after lateral ankle sprain

-chronic ankle instability

• increased ankle inversion at initial contact

• lateral foot loading during support phases

• hip adduction during swing phase

-increased peak ankle plantarflexion moment (rotational force)

-decreased knee flexion moment during toe-off

Gait change after ACL injury

-limb differences between surgical and healthy limb

• decreased knee flexion

• decreased tibial internal rotation

• decreased knee flexion moment

• decreased adduction moment

-decreased knee flexion angle, decreased knee flexion and adduction moments

-knee flexion and adduction moments differences present up to 5 years after surgery

Trendelenburg Gait

-weakness in and/or instability to control hip abductors

-gluteus medius/minimus

-causes the contralateral (opposite) hip to drop

Steppage gait (foot drop)

-paralysis of the ankle dorsiflexors

-increase hip flexion to clear the ground

Slap gait

-weakness of ankle dorsiflexors causing the foot to slap during eccentric contraction

-typically creates audible sound

What can we do for anatomy/alignment issues?

-braces

-orthotics

-corrective devices

What can we do for prevention and rehabilitation?

-increase ROM and flexibility

-increase strength

-increase motor function/coordination

What equipment can we analyze to help gait?

-footwear

• goal is to decrease impulse and aid in shock absorption

6 steps to a kinematic analysis

1. Ask questions

2. Optimal perspective

3. Optimal viewing distance

4. Number of trials

5. Attire and environment

   1. Video camera

Cerebrum

controls conscious thought and intellectual function, memory storage and processing

Cerebellum

coordinates motor patterns, responsible for balance and coordination

Brain Stem

responsible for autonomic functions (breathing, heart rate, body temperature, organ function, sensory information, etc)

The spine has how many bones?

33

Functions of the spine

-protect spinal cord

-support body weight

-muscle attachments

-enables motion in 3 cardinal planes

Spinal curvatures aid in…

shock absorption

Primary curvatures

thoracic and sacral regions; present at birth

Secondary curvatures

cervical and lumbar regions; develop as we support our body weight

Scoliosis

lateral curvature of spine

Kyphosis

increased thoracic curvature

Lordosis

increased lumbar curvature

What vertebrae has the largest ROM?

cervical

What vertebrae has limited ROM?

thoracic

Increased size helps withstand and reduce stress in what vertebrae?

lumbarI

In lumbar, as surface area increases, what decreases?

stress

Stress

distribution of force within a body

Compression

pressing/squeezing force directed axially

Tension

pulling/stretching force directed axially

Bending

asymmetric loading that produces compression on one side and tension on the other side

Shear

force directed parallel or tangent to a surface

Torsion

twisting force around the longitudinal axis

Combined

simultaneous action of 2+ types of loading and is the most common type of loading

What are the cushions of the spine?

intervertebral discs

What type of mechanical loads does the spine go through?

-Standing and daily activities= axial compression

-During flexion, extension, and lateral bending= compression and tension

-Rotation: shear stress

What are the facet joints of the spine?

-assist in load bearing, and help resist compressive loads, shear forces, and rotational torsion

-increased load during hyperextension

Where is most stress placed on in the spine?

L4-S1 discs and facet joints

What is the primary load affecting the spine?

compression

What significantly increases the load on the lumbar spine?

sitting, slouching, bending, lateral flexion, and rotation

Deformation

change in shapeq

What is the yield point in the load-deformation curve?

point where deformation is permenant

What is the elastic region on the load-deformation curve?

temporary deformation

What is the plastic region on the load-deformation curve?

the point of no return for deformation

Over time, our tissues lose…

elasticity

Acute loading

-application of a single force of sufficient magnitude to cause injury to a biological tissue

-macrotrauma: high load, low frequency

Repetitive loading

-repeated application of a subacute load that is usually of relatively low magnitude

-microtrauma: low load, high frequency

Examples of acute loading

-concussions

-dislocations

-spinal injury

-strains

-sprains

-dislocations

Examples of repetitive loading

-disc herniations

-low back pain

-parkinsons and alzheimers

-stress fractures

Spondy

repetitive hyperextension of the spine

Disc herniations

protrusion of the nucleus pulposus from the annulus fibrosus

What are some common causes of disc herniations?

-disc generation

-poor mechanics

-repetitive flexion and/or twisting

Common culprits of low back pain

-poor mechanics

-muscular weakness

-overweight/obesity

What Newtons Law corresponds with traumatic brain injuries?

Newtons First Law: a body in motion will stay in motion unless acted upon by an external force

Momentum

influenced by mass, velocity, and direction of the bodies involved

Impulse

must consider the magnitude and timing of the force

Impact

large force over a small time interval

Concussion

“trauma-induced alteration in mental status that may or may not involve loss of consciousness”

Physical symptoms of a concussion

-nausea

-vomiting

-headache

-light/noise sensitivity

Cognitive symptoms of a concussion

-confusion

-amnesia

-difficulty remembering

-difficulty concentrating

Emotional and behavioral symptoms of a concussion

-irritability

-sadness

-nervousness/anxiety

-opposite of normal mood

-change in sleep patterns

Prevention for concussions

-education

-proper form and coaching

-activity tracking and modification

-neck strengthening

What are the motions at the knee joint?

-flexion

-extension

-internal rotation

-external rotation

What does the patella do for the knee?

-increases the mechanical effectiveness of the quads by changing the line of pull and increasing the lever arm

-increases contact area between structures

• reduces friction

• decreases pressure/stress

Menisci are the ___ of the knee

shock absorbers

Menisci aid in…

proprioception

Ligaments enhance the ___ of the knee joint

stability

What are the two collateral ligaments?

Lateral Collateral and Medial Collateral