Quiz #7 Flashcards
The description of angular motion without regard to its cause
angular kinematics
All parts on the object of interest move through the same angle, but do not undergo the same linear displacement
angular
Two lines that intersect at a vertex
- vertex (axis, joint)
angle
Types of angular motion in human movement
- about an axis through a joint
- about the center of mass
- about an external axis
Types of angular motion in human movement
- Each assumes that the axis is _
- Often only have an instantaneous _ _ _
- stationary
- center of rotation
Angular kinematics units of measurement
- Revolution (rev)
- Degree (deg)
- Radian (rad)
1 deg = _ of a revolution
1/360
Unit is dimensionless
radian
Angular kinematics types of angles
- absolute angles (segment angles)
- relative angles (joint angles)
Describes the orientation of a segment in space
- in the body, reported with respect to a right horizontal at the distal end of the segment
- counterclockwise (ccw) is positive
absolute angle
Theta = tan^-1 ((Yproximal - Ydistal) / (Xproximal - Xdistal))
absolute angle
Describes the orientation of a joint in space
- Reported as the acute angle
- Counterclockwise (ccw) is positive
Relative angle
May be computed using:
- Law of cosines
- Biomechanical (using segment angles)
relative angle
May be computed by knowing the coordinates of the proximal and distal end of the segment
absolute angle
Relative angle
- assumes anatomical = 0 degrees
- provides the amount of movement from anatomical position
Segment angles (biomechanical angle)
Relative angle: using biomechanical angles (segment angles)
- Hip
- Theta hip = _
Theta hip = Theta thigh - Theta trunk
Relative angle: using biomechanical angles (segment angles)
- Hip
- if Theta hip = 0 then thigh and trunk are _
aligned
Relative angle: using biomechanical angles (segment angles)
- Hip
- if Theta hip > 0 then hip is _
flexed
Relative angle: using biomechanical angles (segment angles)
- Hip
- if Theta hip < 0 then hip is _
extended
Relative angle: using biomechanical angles (segment angles)
- Hip
- In walking Theta hip oscillates _ _ _
- In running Theta hip oscillates _ _ _
- 20 deg about 0
- 35 deg about 0
Relative angle: using biomechanical angles (segment angles)
- Knee
- Theta knee = _
Theta knee = Theta thigh - Theta shank
Relative angle: using biomechanical angles (segment angles)
- Knee
- If Theta knee = 0 then thigh and shank are _
aligned
Relative angle: using biomechanical angles (segment angles)
- Knee
- If Theta knee > 0 then knee is _
flexed
Relative angle: using biomechanical angles (segment angles)
- Knee
- If Theta knee < 0 then knee is _
extended (hyperextended)
Relative angle: using biomechanical angles (segment angles)
- Knee
- If Theta knee decreases the knee is -
extending
Relative angle: using biomechanical angles (segment angles)
- Knee
- In walking Theta knee oscillates _
- In running Theta knee oscillates _
- 0-50 deg
- 0-80 deg
Relative angle: using biomechanical angles (segment angles)
- Ankle
- Theta ankle = _
Theta ankle = Theta foot - Theta shank - 90
Relative angle: using biomechanical angles (segment angles)
- Ankle
- If Theta ankle = 0 then shank and foot are _
perpendicular
Relative angle: using biomechanical angles (segment angles)
- Ankle
- If Theta ankle > 0 then ankle is _
dorsiflexed
Relative angle: using biomechanical angles (segment angles)
- Ankle
- If Theta ankle < 0 then ankle is _
plantarflexed
Relative angle: using biomechanical angles (segment angles)
- Ankle
- In walking Theta ankle oscillates _ _ _
- In running Theta ankle oscillates _ _ _
- 20 deg about 0
- 35 deg about 0
Relative angle: using biomechanical angles (segment angles)
- Rearfoot angle (motion of subtalar joint in frontal plane)
- Theta RF = _
Theta RF = Theta shank - Theta calcaneus
Relative angle: using biomechanical angles (segment angles)
- Rearfoot angle (motion of subtalar joint in frontal plane)
- If Theta RF = 0 then shank and calcaneus are _
neutral
Relative angle: using biomechanical angles (segment angles)
- Rearfoot angle (motion of subtalar joint in frontal plane)
- If Theta RF > 0 then the rearfoot is _
inverted
Relative angle: using biomechanical angles (segment angles)
- Rearfoot angle (motion of subtalar joint in frontal plane)
- If Theta RF < 0 then the rearfoot is _
everted
Relative angle: using biomechanical angles (segment angles)
- Rearfoot angle (motion of subtalar joint in frontal plane)
- During gait the value generally at contact is _ and moves toward neutral and possible _
- After midstance it moves toward _
- inverted (+), everted (-)
- inverted (+)
Relative angle
- assumes anatomical = 180 deg
- provides body position
Law of cosines
Theta = cos^-1 ((a^2 - b^2 - c^2) / (-2bc))
law of cosines
Know how to do absolute angle using tangent calculation
Tan^-1 ((Yp - Yd) / (Xp-Xd))
Know how to do relative angle using biomechanical calculations
- Theta hip = Theta thigh - Theta trunk
- Theta knee = Theta thigh - Theta shank
- Theta ankle = Theta foot - Theta shank - 90
- Theta RF = Theta shank - Theta calcaneus
- Angular distance
- Angular displacement
- Angular speed
- Angular velocity
- Angular acceleration
Kinematic descriptors
The study of the cause of motion in which all points on the object of interest move through the same displacement in the same time
Linear kinetics
The study of linear forces
linear kinetics
Linear kinetics:
Important from a _ perspective
- Helps identify why injuries occur and how to prevent them
- Helps direct conditioning, training & rehabilitation programs
biomechanical
Any interaction between two objects that causes or has the potential to cause an acceleration
Force
Measured in Newtons (N) = Kg m/s^2
Force
Properties of _
- magnitude
- direction
- point of application
- line of action
force
Linear kinetics:
Governed by three basic laws (Principi, sir Isaac Newton, 1687)
- first law - law of inertia
- second law - a = ZF / m, ZF = ma
- third law - action - reaction
Linear kinetics:
Types of forces
- non contact
- contact
Linear Kinetics:
Types of forces
- Non contact = _
gravity
The force of gravity is inversely proportional to the square of the distance between attracting objects and proportional to the product of their masses
law of gravitation
Fg = (Gm1m2)/r^2
- G = _
universal gravitational constant = 6.67*10^-11 Nm^2/kg^2
Linear kinetics:
Types of forces
- Direct interaction of two or more objects
- Ground reaction forces, external forces, friction, fluid, resistance, joint reaction, inertial forces, muscle forces, elastic forces
contact
