4-6 Chapter Questions

In a free-body diagram of the human body, where does the weight vector originate and in what direction does it point?

It originates at the center of gravity (COG) and points downward

Is weight always a force?

True

Is force always a weight?

False

The amount of inertia possessed by a body is directly proportional to what?

Mass

What is the opposite of tensile force (tension)?

Compression

An injury resulting from a single large force application is called what?

Acute injury

What is the vector sum of all forces acting on a body called?

Net force

Which type of force acts parallel to a surface?

Shear

Does mass change depending on gravity?

False

How many Newtons equal one pound?

4.448 N (approximately 4.45 N)

How many pounds are in one kilogram?

2.205 lb

What equation solves for mass using force and acceleration?

m = F

What characteristic of a vector represents its magnitude?

Length

Which quantity is calculated the same way as pressure?

Stress

Stress fractures result from which type of loading?

Repetitive loading

What defines volume?

The amount of three-dimensional space occupied by a body

Which statement about stress and surface area is true?

Decreasing the surface area over which a force is distributed increases stress

Regarding a shot put and a softball of equal diameter, what is true?

They have the same volume

A bending force produces what types of stress?

Compression and tension

Draw a free-body diagram of a long jumper under windy conditions. What forces should be included?

Weight (gravity), air resistance (wind), and ground reaction force if still in contact with the ground

When two force vectors are parallel and point in the same direction, how are they combined?

Add them

The articular fibrocartilage partial disc in the knee is called what?

Meniscus

The myotatic reflex is also known as what?

Stretch reflex

A series of quick bouncing stretches is called what?

Ballistic stretching

The carpometacarpal joint at the base of the thumb is what type of joint?

Saddle joint

What connects bone to bone?

Ligaments

What connects muscle to bone?

Tendons

Can damaged articular cartilage usually heal on its own?

False

Can PNF stretching significantly increase ROM after one session?

True

Are third-degree sprains the mildest sprains?

False

What is the most common site for a sprain?

Ankle

Which factor does NOT affect joint range of motion?

Number of proprioceptors present at the joint

PNF stretching is based on responses from which receptors?

Both Golgi tendon organs and muscle spindles

Which joint injuries are accompanied by inflammation?

Sprains, dislocations, and bursitis (all of the above)

Is a goniometer used to directly measure joint range of motion?

True

Which is NOT associated with synarthrodial joints?

Typically weak

Which are examples of articular fibrocartilage?

Menisci and intervertebral discs

What protective tissue covers the articulating surfaces of synovial joints?

Articular cartilage

What lubricates the inside of a synovial joint capsule?

Synovial fluid

What is the ability of a joint to resist abnormal displacement?

Joint stability

What joint position has maximum contact between articulating surfaces?

Close-packed position

What is the angle through which a joint moves called?

Range of motion

Which sensory receptor inhibits tension development in a muscle?

Golgi tendon organ

What is inhibition of the antagonist caused by muscle spindle activation called?

Reciprocal inhibition

What stretching technique involves maintaining a slow sustained stretch?

Static stretching

What stretching technique alternates muscle contraction and relaxation?

PNF stretching

When slowly lowering a backpack, what type of contraction do the elbow flexors perform?

Eccentric

The amount of torque a muscle group can generate measures what?

Muscular strength

When wrist flexion weakens grip strength because the finger flexors are shortened, what is this called?

Active insufficiency

What is electromechanical delay?

The time between receiving the nerve impulse and beginning tension development

An eccentric contraction immediately followed by a concentric contraction is called what?

Stretch-shortening cycle

Where is the series elastic component (SEC) located?

Tendons

What is a motor unit?

A single motor neuron and all the muscle fibers it innervates

Which characteristic does NOT describe a pennate muscle?

Fibers parallel to the long axis

A contraction with no change in muscle length is called what?

Isometric contraction

A muscle directly responsible for producing a movement is called what?

Agonist

What type of muscle acts opposite a flexor?

Extensor

What is the force-velocity relationship?

As load increases, contraction speed decreases

Which component force pulls bones together at a joint?

Stabilizing force

Which fibers have intermediate contraction speed and fatigue resistance?

Fast-twitch oxidative glycolytic (Type IIA) fibers

Which are behavioral properties of muscle?

Extensibility, irritability, and the ability to develop tension

During elbow flexion, which muscle prevents unwanted supination by the biceps?

Neutralizer producing pronation

Atrophy is how bones typically respond to stress.

False

What type of joint is triaxial?

Ball-and-socket joint

A goniometer measures what?

Joint range of motion

Dynamic flexibility is achieved by actively contracting which muscle?

The antagonist

What is stretching produced by a force other than antagonist contraction called?

Passive stretching

Do tendon sheaths contain synovial fluid?

True

Is cortical bone strongest in resisting tensile stress?

False

Do osteoblasts build new bone tissue?

True

What is a bone with high porosity called?

Cancellous (spongy) bone

What is true regarding Osgood-Schlatter disease?

It occurs at the tibial tubercle, is more common in children, and is an epiphyseal injury (all of the above)

Which level of flexibility increases injury risk?

Both low and high flexibility

Is the sternum part of the appendicular skeleton?

False

During the follow-through of a punt, what type of contraction do the quadriceps perform?

Eccentric

Which type of muscle tension acts as a braking mechanism?

Eccentric

Do long-distance female runners have a higher prevalence of secondary amenorrhea?

True

What fracture results from repeated low-magnitude loading?

Stress fracture

Which term is defined as deformation divided by original length?

Strain

Can lifelong high-intensity exercise reduce age-related motor unit loss?

True