Week 3 Flashcards
Muscles and Biomechanical Principles
Mass
Quantity of matter in an object
The more mass, the more resistance to change.
What motor neurons cause the muscle to contract?
A. Alpha Motor Neurons
B. Beta Motor Neurons
C. Delta Motor Neurons
D. Epsilon Motor Neurons
A. Alpha Motor Neurons
Third Law of Motion
The law of Action-Reaction
For every action there is an equal and opposite reaction.
Forces always come in pairs
Ex.) Force of a book on table, exerted downward, force of table on book, upward.
Muscle Fiber
Surrounded by a plasma membrane called the sarcolemma
Composed of many fibrils, which give the cell its striated appearance
Epimysium
Sheath of fibrous elastic tissue surrounding a muscle
True/False
Muscular endurance is maintained better that muscle strength or power.
True
Vector
A force with direction and magnitude
Myofibril
The function of the myofibril is to perform muscle contraction via the sliding-filament model
Velocity
The rate of change of position (combine speed with direction of motion.
Will need more speed to adjust when change of position happens.
Endurance
The ability to maintain a force over time or for a set number of contractions or repetitions.
Low intensity, sustained muscle contractions over long periods of time, which are required for ADLs.
Contractility
The ability to produce tension between the ends of two bones to produce a pull, as when muscle contracts
Gravity
Force that attracts the body toward the center of the earth.
Need to know for manual muscle testing.
Inertia
An object’s resistance to a change in its state of motion or rest
Momentum
The product of mass and velocity
Friction
A force that resists the relative motion of two surfaces
- Internal and External Friction*
- Important when trying to simplify or increase the complexity of movement*
Functional Strength
The use of the muscles in a smooth, coordinated manner during functional and real-world tasks and activity.
Second Law of Motion
The acceleration of an object is directly proportional to the force acting on it and is inversely proportional to its mass.
The direction of the acceleration is in the direction of the applied force.
What is a gravity eliminated position?
Laying on side to perform a motion
Horizontal Plane
Strength Testing (Assessment of client)
Endomysium
meaning within the muscle; a wispy layer of areolar CT that sheaths each individual myocyte (muscle fiber or muscle cell)
Contains capillaries and nerves
Torque
Rotation of an object around an axis
Torque will cause an angular acceleration of a body around an axis of rotation.
Fascia
Band or sheet of connective tissue, primarily collagen, beneath the skin that attaches stabilizes, encloses, and separates muscles and other internal organs
True/False
As individuals age there are declines in muscle mass, muscle fiber size and number and decreases in connective tissue and fat.
False
As individuals age there are declines in muscle mass, muscle fiber size and number and INCREASES in connective tissue and fat.
Fascicles
The bundle of muscle fibers
4 General Characteristics of Skeletal Muscles
Contractility
Irritability (Excitability)
Extensibility (Distensibility)
Elasticity
Irritability or Excitability
The ability of the muscle to respond to stimuli and transmit impulses
What factors influence strength?
A. Age
B. Gender
C. Diet
D. Exercise
E. Both A & B.
F. Both A & C.
E. Both A & B.
Force
An influence that causes an object to undergo a certain change
Internal and External Forces
Extensibility or Distensibility
It can be lengthened or stretched by a force outside the muscle (PROM)
Sarcomeres
The basic contractile unit of the muscle
Dark bands are made up of myosin proteins and the light thin bands are actin proteins.
4 General Characteristics of Skeletal Muscles
Contractility
Irritability (Excitability)
Extensibility (Distensibility)
Elasticity
Newton’s Laws of Motion
First Law of Inertia
An object at rest tends to stay at rest, while an object in motion tends to stay in motion.
- Force will cause an object to move, stop, or change direction–this can be an internal or external force.*
- Explanation of mobility and stability.*
Strength
The force of torque produced by a muscle during maximal voluntary contraction based on the demands placed on the muscle.
Directly related to the amount of tension a muscle can produce.
Elasticity
The ability of a muscle to recoil
What are the different types of contractile fibers?
Type I Tonic (slow) Fibers
Type II A (fast) Fibers
Type II B Fibers
What muscle fibers are used to help you sit up?
Type I Tonic (slow) fibers
Someone who is bedridden would have these types of muscles atrophy.
Type I Tonic (slow) fibers
Type I Tonic (slow) Fibers
Antigravity-postural muscles
Red slow twitch fibers, oxidative
Slower to fatigue, good endurance
Atrophy quickly upon injury as they require O2 for metabolism
Sustained Activities
Good Capillary Supply; less build up of lactate and metabolic waste
Type II A: Fast Fibers
Fast-Twitch
Oxidative and Glycolic
Fast conduction rates
Aerobic and anaerobic muscle activities
Fast but fatigue rapidly
Intermittent rounds of high intensity workouts
Type II B Fibers: Big and Powerful
Phasic
White, fast twitch, glycolic
Anaerobic because of less capillary supply (glucose is metabolized)
Short bursts of energy for quick postural changes or skilled movements; faster contractions
Fatigue more quickly
Become week due to pathology, more affected by immobilization and disuse
Lifting heavy weight
Isotonic Muscle Contractions
When a muscle changes length by either shortening or elongating
What type of contraction is the bicep performing?
- *Concentric Contraction**
- Isotonic Muscle Contraction*
Internal force produced by the muscle is greater than the external force or resistance.
Produces a shortening of the muscle
- *Eccentric Contraction**
- Isotonic Muscle Contraction*
Produces the lengthening of the muscle as a whole because the internal force produced by the muscle is less than the external force or resistance.
Breaking action to motion
True/False
Lowering is an exercise for those not strong enough to use the muscle for concentric contraction.
True
Isometric Contraction
Muscles act in a restraining or holding action.
Tension is equal to the resistance it is to overcome
No change in the external muscle length, no motion
Shunt Muscles
Tend to have the line of pull along a bone so the muscle tends to pull two bones together, muscle is a stabilizer.
Spurt muscles overcome and produce movements throughout a wide .
Spurt muscles overcome inertia and produce rapid movements throughout a wide ROM.
Which is a Spurt Muscle and which is a Shunt Muscle?
What are the four roles of muscles?
Agonist
Antagonist
Synergist
Fixator
Agonist
Movement is the muscle(s) that provides the major force to complete the movement
“Prime Movers”
Ex.) In the bicep curl which produces flexion at the elbow, the biceps muscle is the agonist.
Antagonist
Movement refers to the muscles that oppose the agonist.
The antagonist typically relaxes so as not to impede the agonist.
Ex.) During elbow flexion where the biceps the agonist, the triceps muscle is the antagonist
Synergist
Movement is the muscle(s) that stabilizes a joint around which movement is occurring, which in turn helps the agonist function
Ex.) In the bicep curl the synergist muscles are the brachioradialis and brachialis which assist the biceps to create the movement and stabilize the elbow joint.
Fixator
Movement is the muscle(s) that stabilizes the origin of the agonist and the joint that the origin spans (moves over) in order to help the agonist function more effectively.
Ex.) The bicep curl this would be the rotator cuff muscles, the ‘guardians of the shoulder joint’
The majority of fixator muscles are found working around the hip and shoulder joints
Manual Muscle Testing (MMT)
The examiner provides resistance to a muscle GROUP.
Grades the level of strength in a muscle or muscle group
MS and Parkinson’s Disease are examples of…
Hypertonicity
Dislocation is an example of…
Hypotonicity
Clients you might not use Manual Muscle Testing (MMT) on…
Clients with Hyper or Hypotonicity
Dislocations
Cardiovascular and Pulmonary Diagnosis
Osteoporosis and Bone Metastatic Cancer
In Manual Muscle Testing (MMT), the muscle is usually tested in the position of optimum length so force can be generated.
In Manual Muscle Testing (MMT), the muscle is usually tested in the midpoint position of optimum length so maximum force can be generated.
What are the 7 steps in the Manual Muscle Testing (MMT) procedure?
- Explain what you’re doing with the client, what you are examining.
- Place the client into the described test position.
- Provide stabilization as specified in the test procedure.
- Tell the client to hold their position and “don’t let me move you”
- Apply resistance slowly and for 4-5 sec watching for signs of exertion or pain
- Palpate the contracting muscle
- Determine muscle grade and record results and observations
How would I place a client in an antigravity position?
Depends on what I am testing for
What do Dynamometers and Pinch Meter measure?
Dynamometers measure grip strength
Pinch Meter measures pinch strength
Take 3 measurements and average
