Lecture #3 (Kinematics & Kinetics)

Question 1

True or false:

Sport activities are static in nature.

Answer 1

False

Question 2

In the scheme of biomechanics, what is under the static heading?

Answer 2

Equilibrium, line of gravity, and center of mass

Question 3

In the scheme of biomechanics, what is under the dynamic heading?

Answer 3

Kinematics and Kinetics

Question 4

In the scheme of biomechanics, what falls under the kinematics heading?

Answer 4

Linear or angular displacement, velocity, & acceleration

Question 5

In the scheme of biomechanics, what falls under the kinetics heading?

Answer 5

Force, impulse, momentum, work, energy, power, mass, joint torque, moment of intertia, etc.

Question 6

What are the three things that can influence movement in the body?

Answer 6

Sensory, motor, and biomechanical factors (other factors are present as well such as friction, velocity, momentum, inertia, impulse, etc.)

Question 7

When you move, what moves outside your center of gravity and what tries to catch up?

Answer 7

When you move, your line of gravity (LOG) moves outside your COG, and your base of support (BOS) tries to keep up—i.e. when you’re running

Question 8

What is a state of stability in which motion is restricted or prevented?

Answer 8

Fixation (think of walls, floors, etc.)

Question 9

True or false:

Muscles can only provide motion at its distal end.

Answer 9

False–this is because the muscle can fixate one end and then move either its proximal or distal attachment.

Question 10

What is the description of motion without regard for the forces producing the motion?

Answer 10

Kinematics

Question 11

What are the two types of motion?

Answer 11

Linear (translation) and angular (rotary)

Question 12

What type of motion does our joints utilize?

Answer 12

Angular (rotary)

Question 13

What are the two types of linear motion?

Answer 13

Curvilinear= all points move the same distance
Rectilinear= all points move in a straight line

Question 14

What is angular movement?

Answer 14

Movement around a fixed point (center of rotation/axis) in a curved path

Question 15

True or false:
Each point during an angular movement moves through the same angle and same distance from the fixed point, but the different points move different distances in the same amount of time.

Answer 15

True–think of elbow flexion. When you flex your elbow, the angle of you arm is the same; however, your wrist moves a greater distance than your forearm.

Question 16

What is the length of the path that an object moves?

Answer 16

Distance traveled

Question 17

What is the straight line distance between a starting and ending point?

Answer 17

Displacement

Question 18

What is the rate of motion? How is this typically averaged?

Answer 18

Speed–typically distance/time such as mph

Question 19

What is the rate of motion in a specific direction? How is this measured?

Answer 19

Velocity–displacement/time

Question 20

What is the rate of change of velocity?

Answer 20

Acceleration

Question 21

What is a real-world example of the distance between speed and velocity?

Answer 21

Map Quest would utilize speed–the distance you travel is averaged out over time (that’s how you get your time of travel). A radar gun would utilize velocity because it is measuring the speed of something in a instantaneous moment.

Question 22

True or false:

Motion direction is always an indication of acceleration direction.

Answer 22

False–it is not always indicative of acceleration direction. Think of slowing down, the acceleration is opposite to the direction that is being traveled.

Question 23

What is a projetile?

Answer 23

An object that is given velocity

Question 24

What is kinetics?

Answer 24

Forces that cause linear motion (such as work, energy, and power)

Question 25

What is Newton’s First Law?

Answer 25

Law of Inertia: a body remains at rest or in uniform motion until an outside force acts on it.

Question 26

What is the conservation of momentum?

Answer 26

A product of mass and velocity–this is why it’s easier to run and jump rather than standing and jumping because your body is already moving

Question 27

What is Newton’s Second Law?

Answer 27

Linear acceleration of an object is directly proportional to the force causing it—the acceleration occurs in the same direction in which the force was applied, and inversely proportional to the mass of the object

Question 28

What is impulse?

Answer 28

Force over time–its what is used to change momentum

Question 29

What is Newton’s Third Law?

Answer 29

For every action there is an equal and opposite reaction

Question 30

True or false:

Forces occurs in pairs.

Answer 30

True–that’s how we get opposite forces (think of gravity–there is always a reactive force in the opposite direction to keep us from falling)

Question 31

True or false:

A kinesiological evaluation is primarily qualitative?

Answer 31

True

Question 32

What are the 3 components of a kinesiological evaluation?

Answer 32

1) Describing skill/breaking it down into its elements
2) Evaluating the performance of the skill (determing whether and how related anatomical and mechanical principles have been violated)
3) Prescribing corrections based on appropriate identification of causes

Question 33

When correcting a something due to a kinesiological evaluation, what is the term for correcting the motion before injury? After injury?

Answer 33

Before= prevention
After= rehab

Question 34

During the kinesiological analysis of a skill, it is important to note the primary purpose of the skill as one of four things:

Answer 34

Speed, speed & accuracy (most sports), accuracy, or form

Question 35

True or false:
Most sport skills have both a simultaneous (segments move as one) and sequential (segments move in orderly fashion) nature of motion.

Answer 35

True

Question 36

During a kinesiological analysis (specifically the mechanical analysis), what is the underlying mechanics when the person: regains stability/attain mobility? An example?

Answer 36

Balance–jump stop or track start

Question 37

During a kinesiological analysis (specifically the mechanical analysis), what is the underlying mechanics when the person: travels? An example?

Answer 37

Locomotion–walking, running, skipping, etc.

Question 38

During a kinesiological analysis (specifically the mechanical analysis), what is the underlying mechanics when the person: height, range, & accuracy? An example?

Answer 38

Projection–Pole vault, long jump, or throwing

Question 39

During a kinesiological analysis (specifically the mechanical analysis), what is the underlying mechanics when the person: objects or resistance? An example?

Answer 39

Manipulation–Weightlifting or throwing

Question 40

During a kinesiological analysis (specifically the mechanical analysis), what is the underlying mechanics when the person: uses speed, power, and force? An example?

Answer 40

Maximun Effort–sprinting, power lifting, and blocking

Question 41

When an athlete has a valgus collapse, what do we focus on rehabing and strengthening?

Answer 41

Hip abductors, hamstrings, and hip external rotators

Question 42

What is weakness of a muscle because it is too long (stretched) to create peak force?

Answer 42

Passive insufficiency

Question 43

What is weakness of a muscle because it is too short to create peak force?

Answer 43

Active insufficiency

Question 44

What occurs when the muscle has the highest amount of cross-bridge formation?

Answer 44

Ideal resting length