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Exercise Physiology > Neuromuscular system and exercise > Flashcards

Neuromuscular system and exercise Flashcards

1
Q

neuromuscular system

A

interaction between our nervous system and skeletal muscle

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2
Q

muscle contraction

A

basis for all human movement

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3
Q

proprioceptors are in the

A

brain

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4
Q

is everything voluntary

A

no because you have reflexes

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5
Q

4 functions of skeletal muscles

A

locomotion
body posture
venous return
thermogenesis

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6
Q

4 characteristics of muscle tissue

A

irritability - ability to receive and respond to stimuli
contractility - ability to respond to stimuli by shortening
extensibility - ability to be lengthened or stretched
elasticity - ability to retrn to resting length after being stretched

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7
Q

how much energy is dissipated as heat?

A

75%

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8
Q

potential travels along

A

cell membrane

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9
Q

how many muscles do we have and percent in genders

A

650

  • 40-45% BW in males
  • 23 - 25% BW in females
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10
Q

fibres

A

cylindrical cells that lie parallel to each other

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11
Q

fibres in small vs big muslces

A

small muscles for precise activities movements may only have 100-300 muscle fibres (Ears and eyes)
large muscles for movement may have 1,000,000 muscles (hamstrings)

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12
Q

fibre length

A

varies from a few mm in eye muscles to 40 cm in large leg muscles

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13
Q

Eepimysium

A

upon - surrounds entire muscle and blends into intramuscular tissue shesaths to form tendons

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14
Q

perimysium

A

around - surrounds a bundle of fibres called a fasciculus

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15
Q

endomysium

A

within - wraps each muscle fibre

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16
Q

sarcolemma

A

polarized cell membrane enclosing fiber’s cellular contents

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17
Q

sarcoplasm

A

contains nuclei that house genes, mitochondria, glycogen and myoglobin

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18
Q

how do you transfer signals

A

polarized

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19
Q

single multinucleated muscle fibre contains

A

myofibrils that lie parallel to the fibre’s long axis

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20
Q

t-tubule

A

continuous with sarcolemma and carries polarization to interior of cell

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21
Q

sarcoplasmic reticulum

A

stores and releases Ca2

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22
Q

myofibril

A

composed of myofilaments (actin and myosin)

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23
Q

cross striation patterns

A

myofibrils -
I band - lighter area
A band - darker area

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24
Q

A band

A

centre of it is the H zone, M band bisets H zone, consists protein structures that supports arrangement of myosin filaments

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25
Q

Z line

A

bisects I band and adheres to sarcolemma to provide structural stability

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26
Q

sarcomere

A

basic repeating unit between two Z lines, comprises the functional unit of muscle fibre

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27
Q

H zone

A

no overlap

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28
Q

I band

A

extends across two sarcomeres

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29
Q

how do the thick and thin filaments overlap?

A

3D space arrangement

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30
Q

3 types of proteins in sarcomere

A

contractile
regulatory
structural

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31
Q

contractile protein

A

actin and myosin

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32
Q

regulatory protein

A

troponin and tropomyosin

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33
Q

structural protein

A

many diff proteins form the cytoskeleton of the sarcomere

- titin - from z disc to M line, resists sarcomere stretch (as its undergoing eccentric muscle contraction)

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34
Q

Ca binds to

A

troponin, changes the tropomyosin and moves off and muscle contractin takes place

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35
Q

thick filaments

A

200-300 myosin molecules

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36
Q

myosin composed of

A

myosin heavy chain - two globular heads and rod like tail

myosin light chain

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37
Q

myosin heads

A

2 heads, each has ATPase and actin binding sites

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38
Q

How many heads do they use with mysoin

A

1 during concentric, not sure what the other one is

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39
Q

what muscle fibres have heavy chain?

A

type 1, 2A/X

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40
Q

myosin light chain

A

regulatory - chains looping - loops around myosin molecules

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41
Q

thin filaments

A

contractile protein actin and regulatory protein

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42
Q

contractile protein actin

A
  • small globular subunits (G actin) combined to form fibrous actin (F actin) - 2 strands of F-actin form an actin filament
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43
Q

regulatory proteins

A

Tropomyosin and troponin

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44
Q

tropomyosin

A

blocks the actin binding sites during resting state

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45
Q

troponin

A

controls the position of the tropomyosin
C- ca binding
I - inhibit binding of actin and myosin
T- binding troponin to tropomyosin

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46
Q

how do muscles shorten

A

sliding filament theory of andrew and hugh hyxley 0 movemnt of actin filament over the myosin filament

  • I band and H zone shorten and may disappear
  • A band remains unchanged
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47
Q

axon potential

A

travel down to the motor end plate

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48
Q

andrew and hugh huxley

A

published their paper and worked indepen

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49
Q

3 steps of contraction of a muslce fibre

A

generation of an AP in a motor neuron (ventral root)
transmission of the AP to the muslce fibre (motor end plate of muscle)
excitation - contraction coupling

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50
Q

cell bodies can be found in

A

spinal cord

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51
Q

dorsal vs ventral root

A

sensory vs ventral root (cell body)

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52
Q

upper motor neuron will

A

activate cell body to send a signal down the ventral motor root to alpha motor neuron (lower motor neuron) down to muscle fibers

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53
Q

muscle fibre is wrapped by

A

endomysium

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54
Q

fascicle is wrapped by

A

PERIMYSIUM

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55
Q

epimysium AKA

A

deep fasica

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56
Q

parts of a tendon (7)

A 
paratendon 
fascicle 
fascicular membrane 
fibril 
subfibril 
microfibril 
tropococollagen
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57
Q

in a somatic nervous system, what sends the muscle to release what to stimulate what?

A

alpha motor neuron releases ACh to target muscle

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58
Q

2 systems in the sutonomic Nervous system and what do they target

A

sympathetic and parasympathetic

- smooth and cardiac muscles and glands

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59
Q

sympathetic activation

A

gives Ach in preganglion fibres to release NE

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60
Q

parasympathetic activation

A

gives ACh in pre ganglion fibres to release ACh

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61
Q

peripheral nervous system is and travels through

A

skin - somatic sensory fibre

cardio vascular - visceral sensory fibre

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62
Q

central nervous system sends

A

sympathetic and parasympathetic motor fibres to the heart, motor fiber of somatic nervous system

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63
Q

resting potential

A

-70mv

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64
Q

depolarization goes up to

A

30

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65
Q

neuron with a dendrite and a cell body would receive fdbk from

A

stimuli or other neurons

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66
Q

where does the motor signla come from

A

ventral horn of spinal cord

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67
Q

what happens when a neuron is excited

A

permeability changes, voltage gated sodium channels goes to the inside and na is moves in and potassium

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68
Q

how to ensure depolarization

A

positive charge will excite the axn hillock which sends an AP down the axon

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69
Q

repolarization

A

voltage gated sodium channels close and potassium rushes out for repolarization

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70
Q

myelinated/shwann cells

A

saltatory conduction which allows it to move faster down to axon terminal

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71
Q

transmission of AP to muscle fibre

A
  • AP travels the length of axon of motor neuron to axon terminal
    at the neuromuscular junction
  • rush of calcium enters the axon terminal to bind to either ionotropic or nicotinic receptors
    -release ACh via exocytosis into the synaptic cleft
  • synaptic cleft and ACh receptors
  • ligand gated cation channels open
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72
Q

more Na than Ca so

A

it can depolarize

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73
Q

What breaks down Ach

A

ACh esterase

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74
Q

what inhibits ACh

A

nerve gas, which stops the regulation of breathing - or botox - stops the release of the contraction - stops the vesicles from releasing ACh

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75
Q

what inhibits ACh

A

nerve gas, which stops the regulation of breathing - or botox - stops the release of the contraction - stops the vesicles from releasing ACh

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76
Q

what inhibits ACh

A

nerve gas, which stops the regulation of breathing - or botox - stops the release of the contraction - stops the vesicles from releasing ACh

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77
Q

once the threshold is reached, what does the ap propagate along?

A

sarcolemma

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78
Q

when does the activation stop

A

When ach is removed

  • diffuse away
  • ACH esterase breaks it into acetic acid and choline which is transported back to axon terminal for resynthesis
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79
Q

excitation contraction coupling

A

sequence of events by which an AP in the sarcolemma initiates the sliding of the myofilaments, resulting in contraction

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80
Q

9 steps of EC coupling

A

transmission of AP along sarcolemma
depolarization of T tubule
- communication between T-tubule and SR (toilet plunger mechanism) where the voltage gated DHP (Dihydropyridine) receptors cause openings of ryanodine receptors and Ca 2 release to enter the sarcoplasm
ca binds to troponin C
conformational change in the troponin complex
tropomyosin shifts 20 degrees off the actin binding site
attachment of myosin head - cross bridge formation
cross bridge cycling - hydrolysis of ATP
reuptake of Ca by sarcoplasmic reticulum - relaxation (tropomyosin moves back up)

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81
Q

in what direction does EC coupling happen?

A

every single direction from the motor end plate

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82
Q

muslce triad

A

two sister cisternae and the T tubule

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83
Q

cross bridging cycle

A

cyclic events necessary for the generation of force or tension within the myosin heads during muscle contraction
- binding, power stroke, dissociation, activation

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84
Q

during a single muslce twitch myosin binds and detaches from actin _____of times

A

thousands

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85
Q

binding

A

cross bridge formation - activated myosin heads binds to actin
ADP and Pi remain bound to myosin

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86
Q

power stroke

A

myosin head swivels, causing displacement of actin filament

ADP and Pi are released from myosin

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87
Q

dissociation

A

detachment

  • ATP binds to myosin
  • actin and myosin dissociate (cross bridges detach)
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88
Q

activation

A

energy from the hydrolysis of ATP used to activate the myosin head
ADP and PI remain bound to myosin

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89
Q

Rigor mortis

A

rigor state - dead and you have no ATP so you cant take them off
hang meat - decompose to get more tender - for the bonds to break

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90
Q

motor unit (2)

A

a motor neuron (alpha 1 or 2) and specific muslce fibres it innervates
- each muscle fibre generally receives input from only 1 motor neuron, a motor neuron may innervate many muscle fibers

91
Q

all muscle fibers innervated in a motor unit have the same

A

attributes

  • alpha 1 - large diameter neurons innervate type 2 muscle fibers
  • alpha 2 - smaller diameter neuron innervates type 1 muscle fibers
92
Q

smaller cell body/dendrites

A

graded potential - collecting whole signal for innervation - move faster and less innervation needed - more excitable for slow twitch (why they go first)

93
Q

skeletal muscle cells can be characterized by their

A

twitch properties

94
Q

slow twitch (5)

A 
contract and relax slowly 
activated by alpha 2 motor neurons 
only one type - type 1 
reply on oxidative metabolism - slow oxidative 
low excitation threshold
95
Q

fast twitch (4)

A

contract and relax quickly
activated by alpha 1 motor neurons
two types - type 2A and 2X
high excitation threshold

96
Q

2A energy source

A

2A - rely on glycolytic and oxidative metabolism - FOG - fast oxidative glycolytic

97
Q

2X

A

2X - rely on glycolytic metabolism - fast glycolytic

98
Q

what determines if a muscle fibre is slow twitch or fast twitch

A

alpha 1 and 2 motor neurons were cross innervated onto slow and fast twitches

  • interconverted
  • contractile properties of muscle fibres depend on the motor neuron that innervates the muscle fibre
99
Q

what does increased speed mean for lower

A

less

100
Q

P=

A

fv

101
Q

2A AKA

A

FOG

102
Q

3 things that the SO muslce has the most of

A

mitochondirial density
capillary density
myoglobin content

103
Q

4 functional aspects that fast twitch muscles lead in

A

twitch/contraction time
relaxation time
force production
faitgability

104
Q

who has the most phosphocreatine stores

A

FOG and FG

105
Q

2 functional aspects that FOG leads in

A

twitch time and relaxation time

106
Q

Who has the highest glycogen store

A

FG

107
Q

who has the highest triglyceride store

A

SO

108
Q

who has the highest myosin ATPase activity and glycolytic enzyme activity

A

FG

109
Q

who has the highest oxidative enzyme activity

A

SO

110
Q

number of muscle fibers /motor neuron relates to

A

muscles particular movement function

111
Q

muscles involved in gross movement patterns - ratios

A

high muslce fibre nerve ration (580 motor neurons for 1,030,000 muslce fibers in gastroc muslce, ratio of 1775

112
Q

muscle involved in more precise movements - ratios

A

low fibre to nerve ration (120 motor neurons controlling 41000 muslce fibers in finger
ratio of 342

113
Q

fiber to nerve ration in eye

A

1:5

114
Q

all or none

A

neural control of muscle contraction - when a motor neuron is stimulated, all the muscle fibers in that motor unit contract to their fullest extent or they do not contract at all

115
Q

muscle biopsy

A

assessment of muscle fiber type

  • removal and analysis of small portion of whole muscle
  • direct measurement of muscle properties
116
Q

histochemistry

A

muscle samples can be classified according to

  • myosin heavy chain gene expression
  • myosin ATPase activity
  • glycolytic enzymes
  • oxidative enzymes
117
Q

slow vs fast muscle biopsy

A

Fast will have a diff pH, diff precipitate

118
Q

how much NS do you need for force and fast twitch

A

a lot

119
Q

immunohistochemistry

A 
classification according myosin heavy chain type 
antibodies for 
- MyHC - I 
- MyHC - IIA 
- MyHC - IIX 
hybrid muscle fibres exist in the middle
120
Q

4 distribution of muslce fiber types

A

fiber types vary within multi function muslces - quads - 50/50
fiber type varies between diff muscles
- soleus - mainly type 1, gastroc, mainly type 2
fiber types varies according to function of muslces - postural muscles are primarity type 1 because they need to be fatigue resistant for many hours of continuous tension
fiber type can vary between the same muscles of 2 diff people - ind diff in muslc fiber -motor unit ratios contribute to variation in skill performance

121
Q

is it training or genetics that determine the distribution of the muscle fibre type?

A

more genetics - you can shift the properties of the muscles but the actual compostion is pre-determined

122
Q

relationship between fast twitch fibers and performance in strength and power sports

A

strong linear

  • type 2 has an intrinsic speed of shortening and tension development ranging from 3-5 times faster than slow twitch fibers
  • activation plays an important role in stop and go or change of pace sports such as baskeball, soccer, tennis etc.
123
Q

fibre composition and VO2 max in athletes

A

strong linear relationship between vo2max and slow twitch fibres
- type 1 fibers are fatigue resistnt and ideally suited for prolonged aerobic exercise

124
Q

is performance solely determined by fiber type?

A

no

125
Q

ranking of animals from the highest fast twitch fibres? (7)

A 
cheetah
pronghorn 
ostrich and rhino 
dog 
cat and sheep 
camal, ussain
pig
126
Q

sex difference in fiber type

A

no diff in the distribution but females have greater type 1 fiber type cross sectional area relative to males

127
Q

muscle strength

A

max force generating capacity of a muscle or muslce group, measured as 1RM - dynamic exercise or maximal voluntary contraction - static exercise
- no time constraint

128
Q

muscle endurance

A

ability of a muscle or muscle group to repeatedly exert a force against a resistance (performed at a percentage of max strength)

129
Q

muscle power

A

max ability to generate force as quickly as possible

130
Q

measurement of muscular function

A

electromyography

131
Q

electromyography (4)

A

the study of muslce function through the analysis of its electric signal

  • sun of AP of active motor units
  • EMG voltage - proportional to the force of a muslce contraction
  • helps to differentiate which muscles are doing the work
132
Q

supported vs unsupported feet during sit ups

A

unsupported will work abdominals more, otherwise rectus femoris

133
Q

isokinetic dynamometer machines (4)

A

allows the velocity of the limb movement to be kept constant throughout a contraction
- provides accurate measures of torque (rotational force) and power while the sped of the contraction is kept constant
- can be configured to test the limbs in the upper and lower body
- rate and speed varies at diff angle, eliminate speed by fixing it to see the contraction force (force transducers)
$5000

134
Q

lab and field methods for musclular function (2)

A

dynamometers
constant - resistance equipment
- dynamic constant external resistance
- prediction of 1RM

135
Q

risk with free weights

A

injury, so you use lower weight to estimate the percentage of 1RM

136
Q

field tests of muscular function (2)

A

calisthenic activities - situps, curlups, pushups, pullups, flexed arm hangs
vertical jump/standing broad jump
- more than once for muscle endurance
- jump test for power.

137
Q

why is it important to measure muscle function (5)

A 
determine muscle weakness or imbalance (delay muscle fatigue) 
guide rehabilitation 
exercise prescription 
selection of exercise 
research tool
138
Q

contraction

A

tension producing process of the contractile elements within a muslce

139
Q

3 types of muslce fibre contractions

A 
isometric - same measure 
isotonic - same tone 
- concentric - shortening 
- eccentric - lengthening 
isokinetic - same speed 
- concentric - shortening
- eccentric - lengthening
140
Q

3 types of whole muscle contractions

A 
static 
dynamic -
- concentric - shortening 
- eccentric - lengthening 
isokinematic  (dynamic) 
- concentric - shortening 
- eccentric - lengthening
141
Q

isotonic vs isokinetic

A

essentially the same thing

142
Q

downhill skiing is eccentric

A

as youre generating force youre expanding your muscles -

143
Q

isometric contraction

A

a muslce fibre contraction that does not results in a length change in muscle fibre - but changes the tone - sarcomere length changes as it goes into elastic components like tendons, it is generating a force but no greater than the external force

144
Q

static contraction

A

a whole muscle contraction that produces an increase in muslce tension but does not cause meaningful limb displacement or joint displacement and therefore does not result in movement of the skeleton

145
Q

isotonic contraction

A

a mucle fibre contraction in which the tension generated by the muslce fibre is constant through the ROM
- does not actually occur with whole muslce due to changes in joint angles (shortening at a constant velocity)

146
Q

dynamic contraction

A

a whole muslce contraction in which the force exerted varies as the muscle shortens to accomodate change in muscle length and/orjoint angle throughout the ROM while moving a constant external load

  • concentric - shortening under tension
  • eccentric - lengthening of muscle under tension
147
Q

force produced and joint angle

A

goes through a ROM, optimal force at some point

148
Q

isokinetic dynamometer purpose

A

although the velocity of movement varies with joint angle in an intact human muscle contraction, the velocity of contraction can be held constant with a isokinetic dynamometer

149
Q

isokinetic contraction

A

a muslce fibre contraction in which the velocity of the contraction is kept constant - tension and velocity

150
Q

isokinematic contraction

A

a whole muscle contraction in which the rate of limb displacement or joint rotation is held constant with the use of specialized equipment - concentric and eccentric

151
Q

isokinetic/isokinematic function

A

acceleration or deceleration

152
Q

isometric/static function

A

fixation

153
Q

neural activation - rate coding

A

(temporal summation)

  • increased frequency of motor unit discharge
  • repetitive stimuli that reach a muscle before it relaxes
154
Q

latent period

A

excitation contraction coupling so Ca can go back to SR for relaxation - more and more Ca will come out

155
Q

fused tetanus

A

no relaxation between

156
Q

where does tentanus not happen

A

heart

157
Q

neural activation - number coding

A

spatial sumation

  • increase the number of motor units recruited
  • henneman’s size principle - a small motor neuron will fire before a large motor neuron
158
Q

firing order of 3 diff muscle fibres

A

SO, FOG, FG
FOG and FG are responsible for the majority of the force production during fast velocity and maximal voluntary contractions (MVC)
- permits orderly recruitment of specific motor units to produce a smoorh muslce action, allows the CNS to fine tune skeletal muscle activity to meet motor task demands

159
Q

single motor units fires to

A

produce a relatively smooth and summated contraction - coordinated muscle contractions that overlap

160
Q

length tension relationship

A

lab setting - zap and see how much they contract
max tension at resting muscle length due to optimal cross-bridge formation
frank-starling - increases the stretch and decreases the force generation

161
Q

length tension relationship is defeated under what law

A

frank starling

162
Q

when the muscle is shorter, why is it bad for tension production

A

actin starts to overlap and hides some actin binding sites, myosin hits the z line and no contraction can happen

163
Q

when the muscle is longer, why is it bad for tension production

A

because myosin heads no longer interact with the actin filaments

164
Q

tension angle relationships (3)

A

muscle tension is influenced by biomechanical aspects of the joint i.e. joint angle
muscle tension will reach a max at some point over the ROM in a joint and the peak tension will vary depending on the joint
due to lever arm mechanics and the angle of pull that a muslce group can exert for that joint movement - greatest force production is not solely based on optimal overlap of myofilaments

165
Q

tension angle relationship of diff joints

A

every joint has its own angle
knee - high angle has more force (leg extension - 120 degress for highest)
elbow flexion -in the middle

166
Q

how to test tension angle relationship

A

fix the velocity

167
Q

training implications for tension angle relationships

A

train at the joint angle required for sport

168
Q

force velocity relationship

A

muscle tension varies with the velocity of movement
- velocity is inversely related to force
isometric contractions produce the greatest tnesion
- fast concentric movements produce less tension than slow contractions

169
Q

why do faster concentric movements produce less tension than slow contractions

A

faster the muslce movement, less time for optimal MU recruitment

170
Q

more FT motor units

A

generate greater torque for a given velocity

171
Q

why hollow bats

A

lighter so you can move it faster, but you cant move it as far

172
Q

muslces can shorten fastest when the load is

A

the lightest

173
Q

eccentric contractions are done with

A

skiers and ultramarathoners so training will increase force -

174
Q

force velocity relationship

A

eccentric muscle force increases with an increase in velocity

175
Q

possible explanations of force velocity relationship

A

2nd myosin head
decreased rate of cross bridge detachments (increase % of cross bridges remain attached) leading to greater force production
titin protein stiffness increases during eccentric contraction

176
Q

eccentric muslce force is associated with

A

delayed onset muscle soreness

177
Q

power velocity relationship

A

muslce power increases with an increase in concentric movement velocity then decreases at approximately 50% of max shortening velocity

178
Q

why does power increase initialy

A

force reduction drops slower than time

179
Q

muscle with the greatest percentage of FT/MU

A

great power/strength output at any given velocity

180
Q

static

A

zero power

181
Q

if force and time are both decreasing

A

increase in power, initially power is dropping slower than time

182
Q

peak torque generated by a muscle decreases when

A

velocities of movements increases regardless of fiber type distribution

183
Q

elasticity force relationship

A

a muslce will generate more force if it has been stretched immediately prior to contraction
stretching (eccentric contraction) stores elastic energy in the connective tissue, which is released upon concenric shortening, contributing to greater force production

184
Q

what kind of contraction provides the greatest force

A

eccentric dynamic contraction

185
Q

plyomentric exercise

A

eccentric conraction is immediately followed by a concentric contraction

186
Q

eccentic causes

A

more damage to the muscles and more intensive training

187
Q

eccentic causes

A

more damage to the muscles and more intensive training

188
Q

peak torque is generated by

A

a muscle decrease in angle with increased velocity of movement regardless of fiber type.

189
Q

fatigue for FOG

A

lots of force so it decreases quickly

190
Q

mechanisms of peripheral fatigue

A

ions: H, K, Na, Ca, Pi,
Phosphagen depletion
glycogen depletion
reactive oxygen species

191
Q

central fatigue

A

pain in brain -

192
Q

seperation between CNS and PNS

A

all the way till before the junction, then junction on

193
Q

muscle pain is sensed by

A

nociceptors - type of sensory nerve cell and relayed to the sensory cortex

194
Q

immediate/short term pain

A

nocicepors are activated by ions (H, K)
stretch due to swelling
subsides relatively quickly during recovery (restoration of pH occurs quite rapidly)

195
Q

pain receptor center in the brain

A

thalamus

196
Q

muslce lactate recovery time

A

30-60 min

197
Q

blood lactate recovery time

A

60 min

198
Q

muslce H recovery time

A

12-20 mins

199
Q

blood H recovery time

A

30-60 min

200
Q

what happens when pain signals are received

A

opioids/endophins 0 encephalins (endogenous) to hyperpolarize so more trigger is needed

201
Q

what happens when pain signals are received

A

opioids/endophins 0 encephalins (endogenous) to hyperpolarize so more trigger is needed

202
Q

central fatigue

A

neural fatigue
any exercise induced reduction in maximal voluntary contraction forces that is not accompanied by the same reduction in maximal evocable force

203
Q

how can you measure central fatigue

A

percentage voluntary muscle activation can be calculated using the super imposed twitch method. this involves applying a supramaximal nerve stimulus to a muscle that is already under maxial voluntary contraction. twitch response is compared to a control, resting twitch
a reduction in voluntary muscle activation indivates CN fatigue

204
Q

formula for % voluntary activation

A

1-superimposed twitch/control twitch x100

205
Q

pre vs post ultramarathon

A

pre - voluntary muscle activation is close to 100% - super imposed twitch is very small
post - % muslce activaiton is reduced sinificantly after prolonged exercise indicating central fatigue
failure of the superimposed twitch to stimulate maximal force development also indicateds peripheral fatigue

206
Q

delayed onset muscle soreness

A

1-4 days - muscle tenderness, prolonged soreness to touch, mechanical stiffness that does not subside after exercise

207
Q

cause of DOMS

A

muslce, small blood vessel and connective tissue damge caused by high mechanical stress in muslce, tearing of sarcomeres and muslce tendon - eccentric - tearing myosin off the actin binding sites

208
Q

DOMS activation of nocireceptors (2)

A

inflammatory molecules - release of chemical mediators - (prostaglandins, free radicals, histamines, bradykinin, proteolytic enzymes) that continue to stimulate free nerve endings that prolong the sensation of soreness
muscle edema/swellig and spasms/cramps, disruption of Ca - ischemia

209
Q

is pH/lactic acid a component of DOMS

A

no because H cleasr quickly

210
Q

steps of DOMS (6)

A

structural damage in sarcomere cytoskeleton
intracellular Ca increases
degradation of Z discs and regulatory proteins
change in tissue osmolarity and inflammation which increases WBC
swelling in inflammation (local ischemia) which causes pain

211
Q

DOMS is most intense with

A

eccentric form of muscular contraction (heavy weights, plyometrics, downhill running) and unaccustomed forms of exercise

212
Q

how long does it last

A

appears after 8 hours, peaking over 24-48 hours and subsides after 4 days

213
Q

how to measure the extent of muslce membrane damage

A

indirectly meausred by the release of muslce componenets into the blood stream - creatine, kinase, LDH, myoglobin, troponin

214
Q

damage to heart muscle

A

cardiac muscle has blood supply during diastole, during exercise, adenosine increases coronary flow of artery blood, which decreases the Q and HR

215
Q

demands of heat increases

A

HR, SV, TPR -> SBP, RPP, VO2

216
Q

What does chronic endurance training do?

A

increases VO2 max and a-vo2 diff by increasing eccentric hypertrophy (SV)
increased capillarization
increased blood volume

217
Q

rhabdomyolosis

A

breakdown of muslce tissue that leads to the release of muslce fibre contents (i.e. myoglobin) into the bloodstream causing impairment of kidney function

  • rare but usually affects ppl who are detrained and perform large volumes of eccentric muslce contractions
  • travels to the proximal tubules and form precipitates
218
Q

how to prevent DOMS with exercise

A

repeated bout effect - one bout of eccentric exercise can induce adaptations that reduce DOMS with the next bout - adaptation occurs such as fiber size, flexibility hrought the ROM) that helps to reduce DOMS, does not fully eliminate doms

219
Q

3 potential mechanisms of preventing DOMS with exercise

A

neural theory - redistribution of contractile stress over a larger number of motor units
connective tissue theory - remodelling of the cytoskeleton and/ot increased intramuscular connective tissue
cellular theory - an increase in the number of sarcomeres connected in the series thus reducing sarcomere stretch/strain during a repeated bout

220
Q

potential strategies of treating DOMS with meds

A

leucine - nonsteodal anti inflammatory agents vit I, branched chain AA supplement, and adequate warmup/cool down

221
Q

is there evidence that compression, massage, stretching, icing, ultrasound, or antioxidants suppress doms?

A

no

222
Q

diff in gender on muscle function

A

differences in absolute strength between males and females arise at puberty- increased muscle mass and larger fiber size (testosterone)
- overall no inherent diff in muscle function between the two

223
Q

sarcopenia

A

loss of muscle (fibre) as a natural part of aging process
- still same % of SO, FOG, FG
- SO maintain their ___ better than FOG and FG
cannot be prevented but can be slowed down

Exercise Physiology (17 decks)

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