Mechanics of Human Movement Exam 3

Which of the following refers to a movement toward the midline of the body?

Adduction

What is the term for a section that divides the body into top and bottom parts?

Transverse Plane

What anatomical term describes the part of the body that is furthest away from the trunk?

Distal

Which directional term refers to being situated further away from the body's surface?

Deep

What is the anatomical term for the areas of the body closest to the trunk?

Proximal

The area beneath and between the points of contact an object has with the ground is called the:

Base of support

The center of gravity is defined as:

Imaginary point through which the resultant force of gravity acts on an object

The center of mass of an object of uniform shape and density is located:

At the exact center of the object

Which of the following strategies can help increase a person's stability?

Lowering the center of mass

While standing in line to get into a Razorbacks game, you are bumped on the shoulder by someone walking past. Fortunately, you saw them coming so you could brace yourself right before it happened. Which of the following approaches would help you increase your stability?

Lowering the center of mass

In what way can increasing frictional force between the floor and a person's shoes enhance stability?

It provides a greater grip and reduces slippage, improving stability

Which of the following is an example of an absolute angle in human movement?

Angle between the forearm and the floor during a gymnastic routine

For all joints in the human body, flexion is described as a positive angle and extension is described as a negative angle

False

When clinicians measure range of motion at an anatomical joint, they are really measuring:

Angular displacement

Positive angles represent _____ rotation

Counterclockwise

Which of the following statements about torque is true?

Torque is the product of force and moment arm

In which situation is torque maximized when applying a force to a body segment

When the force is applied perpendicular to the segment

What happens to torque when the applied force is doubled while keeping the moment arm constant?

Torque doubles

Moment of force depends on:

Magnitude of the force

Point of force application

Moment arm of the force

Which of the following is a correct unit of torque?

N*m

Sagittal Plane

Divides the body into left and right halves - motion about the medio-lateral axis (flexion/extension)

Frontal Plane

Divides the body into front and back - motion about the anteroposterior axis (abduction/adduction)

Transverse

Divides the body into top and bottom halves (ex: spinning and rotating)

Superior

Towards the head

Inferior

Below another structure

Medial

Towards the midline

Lateral

Away from the midline of the body

Anterior

Front

Posterior

Back

Opposite of Proximal

Distal

Distal

Further from the trunk

Extension

Increasing angle

Adduction

Towards the midline

Abduction

Away from the midline

Inversion

Turning in the medial direction

Most joints in the body are structured for multi-planar movement

True

Standing on your tip toes would put your ankles in...

Plantarflexion

Which anatomical term is a reference term meaning "opposite side of the body"

Contralateral

What is the missing factor that affects stability: Mass, Height of COM, Base of Support, and

Friction

Balance is the ___ of keeping the COM within the base of support to maintain an upright posture

State

At what angular displacement does the arc length and radius have equal magnitude

57.3 degrees

____ angles are measured between two adjacent segments

Relative

If initial angular position is 315 degrees and final position is 390 degrees (rotating CCW), what is the angular displacement?

75 degrees

A calf raise would be considered what lever class

Second-class lever

If an eccentric (or off-center) force causes motion, it will always cause rotation

True

What is the torque if the force applied is 100N and the moment arm is 0.5m

50 Nm

3π/2 =

270°

Angular Kinematics

Kinematics of particles/objects/systems undergoing angular motion - the HOW behind angular motion

How is the body usually analyzed?

As a system of rigid segments that rotate relative to each other around joint centers

An absolute angle is an angle measured relative to

A fixed reference plane

Absolute Angles

Used to analyze the orientation of a segment with respective to a reference point

A relative angle is an angle measured relative to

Two adjacent segments

Relative Angles

Used to measure the orientation of a joint, with 0 representing anatomical position

Moment of force is ____ produced by a force aka _____

Turning effect; Torque

Moment of force is equal to the ____ of the _________ and ______ between the line of action and axis of rotation

product; force; perpendicular distance

To describe torque, you need to know ____ and ________

magnitude; general turning effect (clockwise and counter clockwise)

To increase torque, is it better to increase force or to increase the moment arm? Why?

Moment arm because a longer distance increases the torque

Impulse changes momentum

True

Mass

Kilogram (kg)

Time

Seconds (s)

Length

Meter (m)

Greater Mass, More Friction, Lower COM, Larger BOS

More stability

To increase stability

Widen stance or lower COM

To initiate movement

Purposely reduce stability (stepping forward while walking)

The internal torque balances the external torque

True

Balance

State

Stability

Act

A radian is the angular displacement that results in an arc length ___ the radius

Equal to

Angular Velocity

ω

Angular Displacement

θ

Angular Acceleration

𝛼

π/2

90 degrees

Average Angular Velocity

The rate of change of angular position

If I wanted to complete an analysis of hip and knee angles of a runner, which plane would you chose to observe?

Sagittal Plane

You would have mechanical advantage when...

Effort moment arm is greater than the resistance moment arm