Mm contraction but no movement - expressed as MVC or % MVC - intact muscle/real life

- muscle contraction that produces tension to move joint - Concentric/Eccentric -intact muscle/real life

- reflects the isometric force for a given muscle length - from contractile elements

- Maximal Voluntary contraction - measure static contractions

Muscle Strengthening Physiology Flashcards by Chaeli Greco

Resistive Exercise

any active exercise where muscular contraction is resisted

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Hypotnoicity vs Hypertonicity

decreased tone, flaccidity

- increased tone, rigidity

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Strength

-maximum force that can be exerted by a Mm contraction

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Amount of ATP needed to produce a given tension is less for ____

eccentric contractions than concentric contractions

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Max tension you can get from a muscle is _____>_____>_____

-eccentric>isometric>concentric

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Active Insufficiency

-decreased ability of a Mm to produce or maintain active tension because agonist is too short

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Goal of Resistive Ex’s

increase strength, endurance &/or power

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Tone

-Muscle’s resistance to passive ROM

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Isometric Contraction

(muscle fiber contraction)

cross bridge cycling without sliding of actin & myosin
laboratory with fiber ends fixed

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You can create max tension during _____ contractions

-eccentric

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Static Contraction

Mm contraction but no movement

expressed as MVC or % MVC
intact muscle/real life

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Dynamic Contraction

muscle contraction that produces tension to move joint
Concentric/Eccentric

-intact muscle/real life

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Isokinematic Contraction

movement of a joint with a constant angular velocity

- intact/real life

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Active tension

reflects the isometric force for a given muscle length

- from contractile elements

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The smaller the motor unit:

the lower the recruitment threshold

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Passive Tension

-tension due to stretching of passive elastic elements
-non contractile connective tissue
(epimysium, perimysium, endomysium, sarcolemma)

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Length-Tension Curve based on:

testing of isometric strength in a lab setting

- muscle detached

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3 Types of Muscle Contraction

laboratory setting

isometric
isotonic
isokinetic

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MVC

Maximal Voluntary contraction

- measure static contractions

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Isotonic Contraction

(muscle fiber contraction)
-tension generated by fiber is constant throughout the ROM

-lab/muscle removed

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Isokinetic Contraction

muscle fiber contraction
type of dynamic contraction where velocity is kept constant

-lab

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Types of Muscle Contraction

real-life

Static
Isokinematic
Dynamic (concentric/eccentric)

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Intact Mm Strength depends on:

number of cross bridges
length of moment arm
passive restraints of antagonist
normal length

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2 Types of Dynamic Contraction

concentric

- eccentric

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Hypertrophy

increased individual fiber size due to increased # of actin/myosin

Eccentric Contraction

-Contraction where ends of muscle move apart

Concentric

-Contraction of muscle where ends move towards each other

1 RM

- 1 repetition max | - max amount of weight that can be lifted through the entire ROM using proper technique one time

Larger Motor Unit=

- greater tension | - higher recruitment threshold

General factors affecting Mm contraction strength

- diameter of Mm - # of fibers per motor unit - # motor units firing - length of muscle when stimulated - type of contraction elicited

Hyperplasia

incr # of fibers

Endurance

-ability to perform low intensity reps over prolonged time

Stength-Shortening Cycle of Plyometrics

-rapid, powerful concentric contraction right after a preloaded eccentric contraction

Passive Insufficiency

limitation of movement caused by passive tension because antagonist is too short

Motor units are recruited _____

from smallest to largest

Force-Velocity Curve for Concentric Contraction

- increased velocity=decreased tension generated | - lighter load=faster it can be moved

Power is increased by

- doing same amount of work in shorter time | - doing more work in same time

Motor Unit

an alpha motor neuron and all the fibers it innervates | -larger motor unit=increased strength

Force-Time Relationship

- relates the load the muscle is going to lift & the time span between Mm excitation & the onset of Mm shortening - takes longer to generate enough force to lift heavy objects

Total Tension=

Active tension + passive tension

Length-Tension Curve

-each Mm in body has an optimal length to create a maximal tension

Motor units recruited from _____

smallest to largest

Jean's Mantra

- you can hold more than you can lift | - you can lower more than you can hold

3 Fiber Types

I, IIa, IIx

Type I Fiber

- tonic - Red - Slow twitch/Slow oxidative - aerobic

Type IIx Fiber

- Phasic - white - fast twitch/fast glycolytic - anaerobic

Relaxation Time I: IIx:

I: slow IIx: fast

Threshold to Stimulate I: IIx:

I: Low IIx: high

Fatigue I: IIx:

I: Slow IIx: Fast

Shortening Velocity I: IIx:

I: Slow IIx: Fast

Anaerobic Activity I: IIx:

I: Low IIx: High

Lactate Production I: IIx:

I: Low IIx: High

Capillary Density I: IIx:

I: High IIx: Low

Mitochondria I: IIx:

I: High IIx: Low

Oxidative Enzymes I: IIx:

I: high IIx: low

Myoglobin I: IIx:

I: high IIx: low

Neuron Size I: IIx:

I: small IIx: large

Aerobic Capacity I: IIx:

I: High IIx: Low

Triglyceride Storage I: IIx:

I: high IIx: low

Phosphocreatine Stores I: IIx:

I: low IIx: high

Specific factors affecting muscle contraction strength

- how often fiber stimulated | - length of sarcomere when stimulated

Force-Velocity Curve of Eccentric Contraction

- incr velocity=increased tension generated (to a point) | - heavier load=faster it can be moved (to a point)

Effect of 2-joint Mm on length and tension

-active and passive insufficiency

Power

rate of doing work power=F (d/t)=w/t

As load ____ (____) power increases; after a point ______

- increases - (up to 30-50% max load) - load becomes to heavy to move quickly

Initial increase in strength due to

- neural changes | - becaues learning & increased corrdination and # and rate of motor unit firing

Tearing occurs at ____% of resting length

200%

Glycolytic Enzymes I: IIx:

I: low IIx: high

Tension I: IIx:

I: small IIx: large

glycogen stores I: IIx:

I: low IIx: high

Fiber Diameter I: IIx:

I: small IIx: large

ATPase Levels I: IIx:

I: low IIx: high

3 Factors affectign speed of Mm contraction

- force velocity curve - force-time relationship - type of muscle fiber

7 Muscle Changes

1. hypertrophy 2. hyperplasia 3. conversion of fiber types (Controversial) 4. vascular changes 5. metabolic changes 6. connective tissue changes 7. bone changes