Chapter 10 Study Guide

The muscles that are most directly involved in bringing about a movement are called which of the following?

• synergist

• agonist

• antagonist

• moment arm

A lever is defined as which of the following?

• a prime mover

• 
  the agonist

• an eccentric muscle action followed by a quick concentric muscle action

• a rigid structure that moves on a fixed point called the fulcrum

The replacement of type II fibers with fat is termed which of the following?

• sarcopenic obesity

• severe obesity

• rhabdomyolysis

• myostatin inhibition

Muscle hypertrophy is defined as which of the following?

• muscular enlargement from an increase in available energy in the muscle

• increase in the number of muscle fibers via longitudinal fiber splitting

• increase in the cross-sectional area of the existing fibers

• 
  increase in number of connective tissue in the muscle

When a muscle lengthens as it contracts, this is known as a ______.

• 
  concentric contraction

• isometric contraction

• eccentric contraction

• isokinetic contraction

An isometric muscle action is a muscle action in which the muscle ______.

• lengthens because the contractile force is less than the resistive force

• does not change length because the contractile force is equal to the resistive force

• 
  shortens because the contractile force is greater than the resistive force

• 
  does not change because both the agonist and the antagonist are relaxed

Flexibility is defined as ______.

• the ability of a muscle fiber to respond rapidly to a chemical or electrical signal

• the capacity of the muscle to stretch to the normal resting length after contracting

• the ability to move a joint through a full range of motion

• the ability to return to its original resting length after a stretch

Skeletal muscle is made up of ______.

• both type I fibers (slow-twitch) and type II fibers (fast-twitch)

• smooth muscle cells (slow/fast-twitch)

• type III fibers (moderate twitch-oxidative)

• smooth and striated tissues

Which of the following defines muscle fiber recruitment?

• which and how many motor units are involved in a muscle contraction

• the speed at which muscle fibers are activated

• the ‘use it or lose it principle’

• there are specific adaptations to imposed demands

What happens to muscles that are not activated on a regular basis (months or years)?

• They turn into fat and connective tissue.

• 
  They swell.

• They are rested.

• They multiply.