Biomechanics Midterm

Use the tail to tail method when ___ vectors

s; substracting; subtract

Use the tip to tail method when ___ vectors

\- adding; add; a

An example of a situation where you would use vector-scalar multiplication is ___

running; run

V \* cos(theta) = V_

x

V \* sin(theta) = V_

y

arctan(Opp/Adj) =

\- theta

T/F: Use absolute values when using trig functions

\- T; True

Is the numerical or graphical method of comparing vectors more accurate?

\- numerical; n

The study of the action of forces on particles and mechanical systems

\- mechanics

An object or group of interacting objects

\- system

Prefix for living organism

\- bio

Application of the principles of mechanics to the study of living organisms

\- Biomechanics

Describes the motion of a system in a temporal spatial context; The form, pattern, or sequencing of movement with respect to time

\- Kinematics

Study of the relationship between the forces acting on a system and the motion of the system

\- Kinetics

Forces causing motion are NOT considered in ___ (kinematics/kinetics)

\- Kinematics

Branch of mechanics dealing with systems in a constant state of motion

\- statics

Branch of mechanics dealing with systems in which acceleration is present

\- dynamics

The Study of Human Movement

\- kinesiology

Stability is generally a ___ motion

\- kinetic

General motion is a combination of ___ and ___ motion

\- Angular, linear; rotational, translational

Linear motion can be ___ or ___

\- curvilinear, rectilinear; c, r

In angular motion, the axis of rotation is oriented ___ to the plane of rotation

\- perpendicular; perp

Most human motion consists of ___ motion

\- g; general

An orthogonal spatial reference frame has ___ axes

3

A perpendicular spatial reference frame has ___ axes

2

A spatial reference frame provides a means of quantifying ___ and ___ in space

\- direction, position

An example where you would not use the center of mass of an object for 1D motion is during a ___

\- race

2D analysis of motion refers to ___ motion

\- planar

In a 2D analysis of motion, you use ___ number(s) to specify position and ___ number(s) to specify orientation

\- 2, 1

How many numbers are needed to describe 1D motion?

\- 1

How many numbers are needed to describe 2D motion?

\- 3

How many numbers are needed to describe 3D motion?

6

In a 3D analysis of motion, you use ___ number(s) to specify position and ___ number(s) to specify orientation

3,3

Spatial reference frames can be either ___ or ___

\- absolute, relative; abs, rel

Relative spatial reference frames are AKA ___ or ___ frames

- Internal, Local

Absolute spatial reference frames are AKA ___ or ___ frames

\- External, Global

Normal equations of motion do NOT apply to ___ spatial reference frames

\- Relative; rel; internal; local

Abduction and adduction occur in the ___ plane

\- frontal; f

Flexion and Extension occur in the ___ plane

\- sagittal; s

Rotation occurs in the ___ plane

\- transverse; t

Planar skills occur in ___ dimensions

2

Multiplanar movements occur in ___ dimensions

3

Minimum number of variables needed to specify the position of a system

\- DF; degrees of freedom

In reality, all joints have ___ degrees of freedom (half are rotational and half are translational)

6

The human body moves via ___ movement

\- rotational; rotation

Despite all joints technically having 6 DF, you typically ignore the 3 associated with ___ movement because of structures supporting the joints

\- translational; translation

Injury occurs if constraint force required is ___ than tissue strength

\- greater

Typically, you ignore DF associated with ___ motion

\- negligible

Vector displacement (velocity, acceleration, or position) is the difference between the ___ vector and ___ vector

\- final, initial; f, i

Compute displacement via vector ___ (Using final and initial positions)

\- subtraction; s; sub

Linear velocity = rate of change of ___

\- position

Location of a point, with respect to origin, within a spatial reference frame

\- position

The kinematics of particles, objects, or systems undergoing linear motion

\- linear kinematics

Do we use relative or absolute position (r) for identifying landmarks in the human body?

\- relative; r

T/F: Position (r) can be either distance (x,y), OR distance at an angle (theta)

\- True; t

Estimate instantaneous velocity/acceleration using the ___

\- central difference method; cdm

If a resultant vector is at an angle that is 10 degrees above horizontal, will the x or y component be larger?

\- x

To find an instantaneous vector on a graph, you need to find the slope of a line that is ___ to that respective point on the curve

- tangent

The steeper the curve on a graph, the ___ (greater/lower) the vector

\- greater; g

When a position vs time graph has no slope, ___ = 0

\- velocity; v

The direction of acceleration is the direction of change in ___

\- velocity; v

Acceleration in line with the direction of motion (the same or opposite direction) changes ___

\- speed

Acceleration perpendicular to the direction of motion changes the ___ of the motion

\- direction

When a velocity vs time graph has no slope, ___ = 0

\- acceleration; a

What are the 3 phases of linear acceleration?

\- braking, propulsive, static

During the propulsive phase of linear acceleration, acceleration and velocity are in the ___ direction, and the magnitude of velocity ___

\- same, increases

During the braking phase of linear acceleration, acceleration and velocity are in ___ directions, and the magnitude of velocity ___

\- opposite, decreases

During the static phase of linear acceleration, acceleration = ___ and velocity is ___

\- 0, constant

If something is slowing down while moving in the negative direction, acceleration will be ___ (positive/negative)

\- p; positive

If a velocity graph has 2 inflexion points, then a position graph will have ___ and an acceleration graph will have ___ inflexion points

\- 1, 3

All points in an object or system move in a circle about a single axis of rotation. All points move through the same angle in the same time

\- angular motion; rotation

1 radian =

\- 180/pi

1 revolution = ___ radians

\- 2 pi

T/F: Radians are dimensionless (have no units)

\- t; true

arc length / radius =

\- radians; rad

In angular kinematics, a positive angle denotes movements in the ___ direction unless stated otherwise

\- counterclockwise

In general, when describing a relative angle, it is in relation to horizontal or vertical. However, you should use ___ when describing parts of the body

\- anatomical position

Absolute angle is AKA the "angle of ___"

\- inclination

Find relative angle by ___ the absolute angles of the segments

\- subtracting; s; sub

Joint angles are ___ (absolute/relative) angles between ___ segments (AKA rotation of the distal segment relative to the proximal segment, or vice versa)

\- relative, adjacent

In general, joint angles are typically ___ while segment angles are typically ___

\- relative, absolute; r, a; rel; abs

Joint angles in 2D: Ab, Ad, Ext, and Flex are the angles between ___ axes

\- longitudinal

Joint angles in 2D: Inward/Outward Rotation uses the angles between either the ___ or ___ axes

\- anterior-posterior, medial-lateral; AP, ML

When computing joint angles, you ___ the absolute angles

\- subtract; s; sub

When computing joint angles, the first step is to set each angle relative to the ___ point

\- same

ROM can be measured as either ___ joint angle, or the difference between the ___ and ___ joint angles

\- max, max, min

A joint exceeding anatomical range results in ___

\- injury

ROM can be used clinically for ___ (seeing how far the joint goes relative to how far it is supposed to go)

\- injury diagnosis; diagnosis

The change in either the absolute OR relative angle of an object between two instants in time

\- angular displacement

T/F: angular displacement depends on the path between orientations

\- F; False

1 Revolution = ___ degrees

\- 360

Rate of change of the angle of an object

\- angular velocity

Using equations such as (⍵ = (Δθ / Δt)), or (V = (Δd / Δt)), results in an ___ vector (between tf and ti)

\- average; mean

In the human body, the PROPULSIVE phase is produced by ___ (concentric/eccentric) contractions of ___ (agonist/antagonist) muscles, and/or external torques in the ___ (same/opposite) direction as the direction of motion

\- concentric, agonist, same; c, agonist, same

In the human body, the BRAKING phase is produced by ___ (concentric/eccentric) contractions of ___ (agonist/antagonist) muscles, and/or external torques in the ___ (same/opposite) direction as the direction of motion

\- eccentric, antagonist, opposite; e, antagonist, opposite

T/F: During the eccentric phase of a bicep curl (weight going down), you recruit the triceps

\- False; F

In the normal convention for human movement, it is generally accepted that ___ (ab/ad), ___ (flex/ext), and ___ (In/Ex Rotation) are positive unless stated otherwise.

\- Flex, Ab, Ex

(Δθ / Δt) =

\- angular velocity; omega

(Δ⍵ / Δt) =

\- angular acceleration; alpha

(Δr / Δt) ...OR... (Δd / Δt) =

\- velocity; v