HK 253 Final Exam

Define Biomechanics

the study of biological systems from a mechanical perspective

List five careers that utilize biomechanics

\-orthopedic surgeons

\-athletic coaches

\-rehab engineers

\-therapists

\-kinesiologists

\-prosthesists

\-orthotists

\-sports equipment designers

\

Statics

the study of bodies at rest

\-moving at constant velocity or not moving

Dynamics

the study of bodies in motion

Kinematics

describing motion, not the cause of motion

\-distance, displacement, velocity, speed, acceleration

Kinetics

study of the causes and forces behind motion

\-force, moment, work, power

Quantitative measures

he jumped 5 meters

qualitative measures

\-he jumped very high

\-the man walked very slowly, leaning to the left, and his gait was asymmetrical

superior

closer to the head

inferior

farther away from the head

proximal

closer to the trunk

distal

away from the trunk

sagittal plane

divides body into right and left halves

frontal plane

splits body into front and back halves

transverse plane

divides body into top and bottom halves

longitudinal axis

\-vertical

\-transverse plane rotation

\-pirouette

antero-posterior axis

\-frontal plane rotation

\-cartwheel

medio-lateral axis

\-sagittal plane rotation

\-somersault

most human movement is a combination of

linear and angular

6 muscle groups

\-hip extensors

\-hip flexors

\-knee flexors

\-knee extensors

\-planterflexors

\-dorsiflexors

shoulder hyperextension

moving from a resting position of the arm to behind the body

Which of the following are transverse plane movements at the shoulder?

both horizontal abduction and medial rotation

Most human movement falls into which category?

general

Nodding the head "yes" occurs in which plane?

sagittal

elbow extension takes place in what plane?

sagittal

which of the following professions regularly use qualitative observations?

teachers, coaches, clinicians

movements in the transverse plane occur around which axis?

longitudinal

what does the word qualitative mean?

pertaining to quality

which of the following is true regarding qualitative analysis?

it does not involved the use of numbers and it can be general or specific

which of the following limb movements occur during "jumping jacks"?

adduction and abduction

Which of the following is not an example of a sagittal plane movement?

lateral flexion

Primarily in which plane does the swinging of a baseball bat occur?

transverse

which of the following motions occur primarily in the frontal plane?

cartwheel

linear motion

\-rectilinear

\-curvilinear

angular motion/rotation

rotating around one point

rectilinear motion

motion along a straight line

curvilinear

motion along a curved line

Sagittal plane movements

\-extension and flexion

\-dorsiflexion and plantar flexion

shoulder flexion

moving the arm from the resting position to in front of the body

shoulder extension

moving the arm from a flexed position to the resting position

shoulder hyperextension

Frontal plane movements

\-abduction and adduction

\-ulnar and radial deviation

\-left and right lateral trunk flexion

\-inversion and eversion

transverse plane movements

\-left/right rotation(head, neck, trunk)

\-forearm pronation/supination

\-medial rotation /lateral rotation of hip

\-horizontal shoulder adduction and abduction

three forms of motion

rectilinear, curvilinear, angular motion

Qualitative analysis

description, adjective, nonnumerical, general or specific

biomechanical research relies heavily on

quantitative

If you are a clinician, and you want to improve a person's gait, and you aren't familiar with the task apart from your own experience, what would you do to obtain the relevant knowledge?

consider both qualitative and quantitative assessments

\-use terminology

Degrees of freedom

1 DOF-movement in one plane

2 DOF-movement in 2 planes

linear/skiing

1 dof in the x axis

angular/knee

1 dof in the y axis

ankle has 2 DOF

1 DOF in the x axis (plantar flexion/dorsiflexion)

1 DOF in the z axis (inversion/eversion)

etch a sketch dof

1 in the x axis and 1 in the y axis

hip has 3 dof

flex/ext

abd/add

ext/int

joints with 3 DOF

hip and shoulder

how many dof at knee

1: flex/ext

how many dof at ankle

2: flex/ext

inv/ev

ipsalteral

refers to the same side

Contralateral

refers to the opposite side

discrete variable

a measure that has a single value

\-step length, gait speed, blood pressure

continuous variable

a measure that is tracked over time, provides a time series

the loco mat therapy robot allows knee flexion and extension. how many DOF is that?

1

hip extension

bring down leg

flexion

brings two body segments closer together

bead on bar

1 dof

BOS

center of mass must stay within base of support to avoid person falling

6 concepts of kinematics

\-linear displacement

\-linear velocity

\-linear acceleration

\-angular displacement

\-angular velocity

\-angular acceleration

distance is

scalar

displacement is

vector

vector

has magnitude and direction

scalar

has magnitude only

\-distance and speed

length is

scalar

speed

The distance an object travels per unit of time

\-will never be negative

velocity

displacement/time

to convert from m/s to mph

multiple by 2

negative value tells you

you're going in a negative direction

speed is the product of

stride frequency and stride length

elite sprinters

greater stride frequencies with average stride length

elite skaters

greater stride frequencies with average stride length

positive acceleration

\-subject is increasing velocity and moving in positive direction

\-subject is decreasing velocity and moving in negative direction

negative acceleration

\-subject is increasing velocity and moving in negative direction

\-subject is decreasing velocity and moving in positive direction

If a dropped ball has a negative acceleration, what does that mean?

it means the ball is accelerating in a negative direction

What are the possible explanations for a negative acceleration?

subject could be decreasing velocity or they could be accelerating in a negative direction

\-ve, +direct

\+ve, -direct

What are the possible explanations for a positive acceleration?

subject could be increasing velocity or they could be accelerating in a positive direction

\+ve, +direct

\-ve, -direct

When displacement reaches a peak, what is velocity?

0 m/s

What has occurring in the displacement when velocity reaches a peak?

when velocity reaches a peak, we have reached the maximum vertical displacement

Toe clearance

minimum toe height during swing

\-indicated likelihood of stubbing foot and tripping

You have collected some gait data. During the swing phase, the foot is moving in a negative direction in the antero-posterior plane. during the mid-swing , the foot velocity is -4 m/s and at heel contact, the foot velocity is at -0.1 m/s

=the foot is decelerating, and the foot acceleration will be positive \*

\-think of subject in book, velocity is negative bc moving in negative direction

\-, -=+

Which of the following is not a kinematic quantity?

force

You have collected some gait data. during the swing phase, the foot is moving in a POSITIVE direction in the ant-posterior plane. during mid-swing the foot velocity is 4 m/s and at heel contact the foot velocity is 0.1 m/s

the foot is decelerating and the foot acceleration will be negative

Linear distance traveled per unit of time describes what?

speed

cart lewis changes his velocity from 8 m/s to 11 m/s. Michael Johnson changes his from 7 m/s to 10 m/s. Who has the greater acceleration?

need more info to answer (no time segment)

A runner's acceleration is -6 m/s, Which of the following describes the motion of the runner?

the runner may be EITHER: decreasing velocity(decelerating) in a positive direction or increasing velocity(accelerating) in a negative direction

Which of the following in a scalar quantity

distance and speed

a car is moving at a velocity of 120 m/s at time\=5 seconds. at time\=15 seconds, the car velocity is 20 m/s. What is the acceleration?

=-10 m/s/s

(120-20/5-14=100/-10)

it takes a swimmer 1 hour to cross one lake that is 0.5 km long. What is the swimmer's acceleration?

it cannot be determined from the info given (need velocity, it isn’t always constant)

\-0.5km/1hr is speed

If velocity is constant, then acceleration is what?

zero

What is the average speed of a cyclist who covers 10 km in 30 mins

20 km/hr

10km/0.5 hr=20

A stick figure is a kinematic description of

\-linear displacement(position of body in space)

\-segment and joint angles

\-with more than one frame, determine velocity

What is greater velocity: 118 m/s or -150 m/s?

-150 m/s

Projectile

bodies projected into the air that are in free fall