A&P Module 10
Isotonic
(True Story) After the stalemate, the stronger person wins (Mr. Harris). When Mr. Harris stops taking it easy and begins to produce more force than Mr. Mirabito, the contraction is now:
mechanical advantage
A lever is a simple machine which creates __________ ___________ for the body, so work may be done.
A rigid structure that moves on a fixed point called the fulcrum
A lever is defined as which of the following?
excitability
Ability of a muscle fiber to respond rapidly to electrical or chemical signals
isometric contractions
Active muscle contraction without changing the muscle length. ex: "Stalemate" during an arm wrestling match
Mechanical Advantage
Allows you to use a simple machine to multiple your raw output of force *Use the ratio of output to input
isometric
An elderly patient at a physical rehabilitation clinic is trying to perform an exercise where they push against a wall as hard as they can without bending their elbows. What type of contraction are they performing?
Does not change length because the contractile force is equal to the resistive force
An isometric muscle action is a muscle action in which the muscle:
concentric contraction
Assuming a light load, which of the following will happen the fastest?
Elasticity
Capacity of muscle to return to its normal resting length after a stretch
Extensibility
Capacity of muscle to stretch to normal resting length and beyond after contraction
the relationship between force and velocity is inverse
During a concentric muscle action,
increases
During an eccentric contraction as the force of an object (weight) increases the speed of the contraction _________.
the relationship between force and velocity is direct
During an eccentric muscle action,
concentric and eccentric
During which type of muscle contraction(s) does the muscle length change?
lever system
FA = effort force (muscle) (applied force) FR = resistance force (gravity or load) (force resisting the lever's rotation) Fulcrum - joint
how levers work
FR= force resisting the lever's rotation MRF= moment arm of the resistive force MAF= moment arm of the applied force FA= force applied to the lever
Type IIB muscle fibers
Fastest twitch time Most easily fatigued
The ability to move a joint through a full range of motion
Flexibility is defined as:
More motor units are involved in a contraction.
Generally, muscle force is greater when which of the following occur?
isotonic contractions
Generation of muscle force with constant muscle tension and change in muscle length. -types: concentric & eccentric
it is hydrolyzed and releases a phosphate group and breaking a high-energy bond
How does ATP produce energy?
128lb
How much torque (in-lbs.) would be generated by a wrench that is 8 inches long, with an effort of 16 lbs of force?
growth (muscle adaptation)
Hypertrophy: enlargement of muscle fiber cross-sectional area following training• -Involves: --Actin and myosin synthesis --Titin and nebulin synthesis --Increase in number of myofibrils in muscle fiber
isotonic contraction
If a muscle is attempting to shorten, but due to a large resistance force, is stretched, which of the following contraction type is occurring?
isotonic.
If a person attempts to pick up a 5 lbs stone and they produce 6 lbs of applied force with their muscle which of the following would occur?
Isotonic.
If the force of a muscle is greater than the resistance force of an object, which type of contraction would occur?
isotonic
If the force of a muscle is greater than the resistance force of an object, which type of contraction would occur?
Sitting too much because it causes atrophy of muscle fibers
In an apparently healthy person, which kinds of activities should be avoided to prevent a decline in muscular health?
Type I, Type IIa, Type IIb
In what order are muscle fiber types recruited?
Fiber size is small.-Type I Mitochondria and capillary density is high.-Type I Color is red/white.-Type IIa Fatigue resistance is intermediate/low-Type IIa Color is white and fiber size is large-Type IIb Power output is high-Type IIb
Match the following muscle fiber characteristic with its associated muscle fiber type:
Red in color-Type I Endurance-Type I Intermediate force production-Type IIA Fast contraction speed-Type IIA White in color-Type IIB Large in size-Type IIB
Match the muscle fiber characteristics with the correct type of muscle fiber:
concentric
Mr. Harris is moving a box of textbooks out of his office. What type of contraction is being performed as Mr. Harris successfully lifts the box?
less, isotonic, eccentric
Mr. Harris is setting down a box of new anatomy models for lab. As he lowers the box, his muscles are producing _______ force than the weight of the box. This allows him to lower the box to the ground thus performing a type of _______contraction called an _____contraction.
isometric
Mr. Mirabito challenges Mr. Harris to an arm wrestling match. At first the match is close. The force output from Mr. Harris and Mr. Mirabito is the same and no movement occurs. What type of contraction is occurring during this stalemate?
torque
Multiplying force using a lever -Torque = Force x Moment arm distance -Can be Tresistance or Teffort τ= FA x MAF τ= FR x MRF
agonist
Muscle/muscle group most directly involved in movement
synergist
Muscles that stabilize the body during movement but are not responsible for the movement
antagonist
Opposing muscle group; slows down limbs during fast movement
anaerobic training muscle adaptations
Regular anaerobic training improves muscle strength, power, hypertrophy, endurance, motor skills and coordination -Exercise less than 10 seconds: uses energy from creatine phosphate system -Longer, repeated exercise: uses energy from glycolytic system -Progressive overload: gradual adaptation to increased stress on muscles from exercise
biochemistry (muscle adaptation)
Resistance/sprint training: -Increased cytoplasmic density -Increased sarcoplasmic reticulum and T-tubule density -Increased calcium release Anaerobic training: -Decreased blood and muscle pH
a)Increasing its size b)Facilitating fiber type transitions c)Enhancing its biochemical and ultra-structural components
Skeletal muscle adapts to anaerobic training primarily by:
Type I.
Someone that is able to run a relatively fast marathon likely has a high percentage of which type of muscle fiber?
a)Reduced risk of disease b)Improved emotional and social wellness c)Increased life expectancy
The benefits of exercise include which of the following? Select all that apply.
Moment Arm of Resistance Force
The distance between the resistance force (load) and the fulcrum is known as the:
true
The fixed point which a lever revolves around is known as a fulcrum.
neural control
The frequency of action potential generation in a motor neuron •Frequency increases when more force is required
agonist.
The primary muscles that work together to bring about a movement are called ________.
inverse
The relationship between force and velocity during a concentric contraction is __________.
true
True or False: There is always overlap between actin and myosin.
Perform the powerstroke
What does ATP allow myosin heads to do?
They turn into fat and connective tissue
What happens to muscles that are not activated on a regular basis (months or years)?
Capacity of muscle to return to its normal resting length after a stretch
What is the definition of elasticity?
cardiac and skeletal
What type of muscles are striated? Select all that apply.
Running fast Lifting relatively heavy weight Jumping
What types of activities can be done to prevent atrophy of skeletal muscles, and specifically, type II fibers?
isotonic
When a concentric contraction occurs and the muscle shortens, which type of muscle contraction is occuring?
eccentric contraction
When a muscle lengthens as it contracts, this is known as a:
isotonic concentric
When a person stands up out of a chair, the agonist muscles involved include the quadriceps, gluteals, and hamstrings, which are contracting in which type of muscle action? Select all that apply.
isotonic and concentric
When a person stands up out of a chair, the agonist muscles involved include the quadriceps, gluteals, and hamstrings, which are contracting in which type of muscle action? Select all that apply.
Force of resistance Moment arm of resistance force
When calculating the torque of resistance, what 2 variable are multiplied together?
Moment arm length Force
When calculating torque, what 2 variables do you multiply?
third class lever
Which class of lever, by definition will have a longer moment arm of resistance (MRF)?
T = Force x Moment arm
Which of the following correctly identifies the equation for torque?
Decreased actin and myosin synthesis
Which of the following does not describe a muscle adaptation to exercise?
Excitability
Which of the following functional characteristics of muscle is shared with nervous tissue?
fulcrum force
Which of the following is NOT a component of a lever system?
Elbow flexion with a biceps curl
Which of the following is an example of a third-class lever?
Type I Type IIA Type IIB
Which of the following muscle fiber types would be recruited for jumping on a trampoline? Select all that apply.
Type I
Which of the following muscle fiber types would be recruited for sitting?
Fulcrum - Applied Force - Resistance Force Resistance Force - Applied Force - Fulcrum
Which of the following places the components of a lever in the correct order for a 3rd class lever? (may or may not be more than one answer)
-Transformation within muscle fiber subtypes has been demonstrated. -Type I to Type II transitions¸ and vice versa¸ appear less probable. -Even if fiber types do not change¸ every person can improve in aerobic endurance¸ strength¸ and power.
Which of the following statement(s) is/are true regarding altering characteristics of muscle fiber types? Select all that apply.
second-class
Which type of lever provides the greatest mechanical advantage?
Breast-Fast-twitch Leg/neck-Slow-twitch
With this example and muscle color types in mind, what parts of a chicken are fast-twitch and which parts are slow-twitch?
a46 in-lbs. b50 in-lbs. c47 in-lbs. d100 in-lbs.
You are trying to take apart an Ikea desk to move back home for the summer. You are attempt to get out a screw from the desk. If the resistance torque of the screw is 45 in-lbs., which of the following effort torques would cause the screw to be dislodged? (check all that apply)
first class lever
applied and resistant forces on opposite sides of the fulcrum fulcrum in the middle
Distribution of Type I versus Type II muscle
depends on the demands on that particular muscle.
Functional characteristics of skeletal muscle
excitability, contractility, extensibility, elasticity
Type II muscle fibers
fast twitch inefficient fatigue easily low aerobic capacity produce force more rapidly
third class lever
force is applied between the resistance and the fulcrum
progressive overload
gradual adaptation to increased stress on muscles from exercise
three specific muscle adaptations
growth, fiber type transition and biochemistry
plasticity
muscle's ability to constantly adapt to stretching.
insertion
muscle's distal attachment
origin
muscle's proximal attachment
first class lever
neck rotation is an example of?
second class lever
resistance lies between (in the middle of) the applied force and the fulcrum
Type I muscle fibers
slow twitch efficient resistant to fatigue high capacity for aerobic energy supply produce force less rapidly
smooth
what type of muscles produce the most force per fiber size
fiber recruitment
which and how many motor units are involved in a muscle contraction -Type I fibers are recruited first for any given movement -Type II fibers are recruited second, if needed
Calf raise is a 2nd class lever The moment arm of the applied force is longer than the moment arm of the resistance force
why can you calf raise your body weight, but can't bicep curl your body weight?
To increase the length of the moment arm of applied force More mechanical advantage
why would applying an effort force (applied force) to the far end of the lever generate the maximum amount of torque?
joints create levers
•A lever is a simple machine •Bones, muscle, and joints constitute a lever system
contractility
•Ability of muscle to shorten and produce tension at its ends •Pulls on tendons
concentric contractions (isotonic)
•Contractile force is greater than external load •Muscle shortens ex: elbow flexion (lifting barbell)
eccentric contractions (isotonic)
•Contractile force is less than external load •Muscle lengthens ex: elbow extension
aerobic training muscle adaptations
•Increased aerobic capacity of skeletal muscle •Increased maximal aerobic power •Increased size of Type I muscle fibers due to their increased recruitment •Increased size and number of capillaries and mitochondria
fiber types (muscle adaptation)
•Type IIb can transition to Type IIa with aerobic endurance or high intensity resistance training •Type I to II transitions (or vice versa) are less likely
