Lab Exam 1 Flashcards
What is EMG
Electromyography
The electrical current measured when an action potential passes along a muscle fiber towards the surface of the skin
What does emg activity represent
The traveling of an action potential
How does emg relate to muscle contraction
EMG and the electromyogram shows the recording of the electrical events of muscle contraction
What is the 2 raw responses
Amplitude - recruitment of motor units
Frequency - firing of motor units
What is the integrated response
Amplitude + frequency = recruitment and firing of the motor units
Motor unit recruitment we start with
Then
Then
Why do we recruit different motor units
SO
Then FOG
Then FG
As force goes up we have to recruit more motor units
When will a person produce a higher emg recording
Why
(PEOPLE USING SUB MAX FORCE)
When they use more of their max force
Because their workload is higher
What muscle fibers do we start off by using
What happens when fatigue kicks in
(MAX EFFORT OVER TIME)
All (SO, FOG, FG)
FG drops out
FOG then drops out
SO remains
What does local muscle fatigue precede
What depletes first
(MAX EFFORT OVER TIME)
Neural fatigue
ATP + CP
Then neurotransmitters
How do we know when neural fatigue is starting to kick in
When there is a significant drop in EMG
During sub max effort what happens to EMG as time increases
SUB MAX ACROSS TIME
Increase in EMG reponse
Because of the recruitment of FG and FOG fiber types as well as the slope of the integrated EMG combined with EMG activity of slow twitch motor units
Force production relationships:
Cross sectional area
Motor units/fiber type
Speed of movement
Greater area = greater force production
Greater FT muscle fibers = greater force production
Increase in speed = decrease in force production - because recruitment of ST motor units decreases
What is Isokinetic strength
Characteristics….
Has… To keep constant…
Higher torquel force for people with more FT muscle (assuming same area of muscle)
Involves maximal overload throughout the entire range of motion
Constant speed of movement as muscle contracts
Movement is in direction of force vector
Force is greater than resistance
Accomodating resistance gives a constant predetermined speed
What happens during a single effort contraction
Slow speed
Recruits ST and FT units
Individuals who have more FT will create a greater force production
FG > FOG > SO
Peak contractions at various speeds what will we see between the two individuals
Both will show decline in force production as speed increases
The individual with more FT muscle will show less decline = thicker axon and more intramuscular stores of myosin ATPase
At high speeds recruitment of SO ceases
FG>FOG>SO
Repeated contractions at constant speed will see that the individual will experience
As time goes on the individual with more ST muscle will show less of a decline in force production because More ST muscle = more myoglobin, mitochondria and oxidative enzymes = more ATP recycled
SO>FOG>FG
Endurance athletes have more
Sprinting athletes have more
ST Muscle
FT muscle
How do you work out % of FT
[(Pre - Post / Pre) / 0.009] - 5.2
Work (kgm) =
Force (kg) x distance (m)
Anaerobic power =
What does it measure
Rev. at 5 secs - rev at 0 secs x workload x 6
Measures the development of phospagen metabolism
Anaerobic capacity (kgm/30secs) =
What does it measure
Rev. at 30 seconds - Rev. at 0 secs x workload x 6
Measures the development of phosphagen and anaerobic glycolysis
Fatigue index =
Percentage of anaerobic power
[(kgm/first 5 secs - kgm/last 5 secs) / (kgm / first 5 secs)] x 100
Body weight =
lbs / 2.2
Workload =
What does it measure
(0.075 kp x Bw (kg)) = ______ kg of resistance to the nearest 0.25 kp
Measures the oxidative capacity of muscle by finding the percent decline in the work of first/last 5 secs
Sprinter tend to have a ____ work indices because ______
Higher
They have more FT muscle
A person with more lean muscle body weight will score _____ than a person with the same weight who has ____ distribution of fat
Higher
Higher
An individual with a high distribution of _____ should score high in all 3 work indices since they have _____ strength but _____ endurance
FT muscle (sprinter)
Higher
Less
** Body weight _____ effect the test results, it _____ used to determine the _______**
Does not
only is
Optimal pedaling resistance
What metabolic calculations are calculated by the computer
Oxygen uptake rate (VO2)
Carbon dioxide production rate (VCO2)
How do you convert VO2 ml/min into VO2 L/min =
What athletes does it better represent
(VO2 ml/min) / 1000ml
Better represents athletes whos body weight is supported e.g. swimmers
How do you converted VCO2 ml/min into VCO2 L/min
What athletes does it better represent
(VCO2 ml/min) / 1000 ml
Better represents athletes whos body weight is supported e.g. swimmers
RER or R value =
VCO2 / VO2
Carbon dioxide produced / oxygen consumed
** Once you have the _____ then use the chart***
R value
Kcal/min =
How do we find Kcal of CHO and fat usage
(Kcal/L of VO2) x VO2 L/min
Use chart to find Kcal of CHO and Kcal of Fat usage
VO2 in ml/kg/min =
What athletes does it better represent
(VO2 L/m x 1000) / BW (kg)
Better represents VO2 Max in athletes who carry own body weight
MET =
VO2 ml/kg/min = 3.5ml/kg/min
1 MET =
It is the _____
Known as _____
3.5 ml/kg/min of VO2
The oxygen needed to sustain body functions at rest
Resting metabolic rate
P - wave =
Depolarisation and contraction of atriums
QRS =
Depolarisation of ventricles
Atriums are repolarising and relaxing
T - wave =
Ventricles relax and repolarise
How do we measure max heart rate in:
Leg
Arm
Water based
220 - age
207 - age
208 - age
What two arteries can we monitor palpations
Radial or carotid artery
Left arm contains
Lead (I) = positive or negative
Left foot contains
What is the charge in both arms
Lead (II) = positive
(Right arm negative)
Lead (III) = positive
(Left arm negative)
AVR is located in
Charge is
Right arm
Negative
AVL is located in
Charge is
Left arm
Negative
AVF is located in
Charge is
Left foot
Positive
What does V5 pick up
Picks up 80% of abnormalities
Where can there be positive QRS complexes be found
Leads: 2 , 3 AVF V4 V5 V6
Where can there be negative QRS complexes be found
AVR
AVL
V1
V2
Where can QRS complexes be either or positive or negative
Lead 1
V3
Depolarisation of the heart occurs where
Down and slightly left from the SA node
Pathway of electrical current in heart from nodes
SA node
AV node
Purkinji fibres
What is a normal resting heart rate between
60-100 bpm
What is tachycardia
> 100 bpm
What is bradycardia
< 60 bpm
Can be athletes or untrained
What is the speed at standard paper
25mm/second
25 X 60 seconds = 1500 mm/min
1500 X 10 cardiac cycles = 15000 mm/10 cardiac cycles
Each small square is how many mm or seconds
Each big square is how many mm or seconds
1mm or 0.04 secs
5mm or 0.2 secs
Premature ventricular contractions can be distinguished by
No P wave
Pause after PVC
Wider than 3mm
Ischemia can be distinguished by
Why is this
Inverted T wave
Lack of blood flow to cardiac tissue
Ventricular flutter can be distinguished by
Smooth wave
Twitches at 200-300 bpm
Ventricular fibrillation can be distinguished by
Twitches at 300-500 bpm
A lot of messy lines
ST elevation can be distinguished by
What is it usually resulted by
Enlarged Q wave = due acute recent injury - will never go away
ST elevation = fresh infarction
Multifilament pvc can be distinguished by
No P waves
No T waves
They all look different
Significant Q waves are distinguished by
When there was a previous myocardial infarction
1mm wide Q wave
1/3 of total height of QRS is present in the Q wave
V1 is
Negative
V2 is
Negative
V3
Positive or negative
V4 is
Positive
V5 is
Positive
V6 is
Positive
Lead 1 is
LA
Positive or negative
Lead 2 is
LL
Positive
Lead 3 is
LL
Positive
AVR is
RA
Negative
AVL is
LA
Negative
AVF is
LL
Positive
ST motor units have
Greater capillarisation
Higher intramuscular myoglobin, mitochondria and oxidative enzymes
FT motor units have
Thicker axon
Myelinated axon
More intramuscular myosin ATPase
What does training do to heart rate
Decreases resting heart rate
Decreases sub max heart rate
No effect on max heart rate
What is the normal range for systolic blood pressure
What is considered mild hyper tension
What is considered major coronary heart disease risk factor
What is considered a relative contraindication to exercise testing
100-140 mm Hg
140-160 mm Hg
=> 160 mm Hg
> 200 mm Hg
What is the normal range for diastolic blood pressure
What is the range considered to be coronary heart disease
What is the relative contraindication to exercise testing
60-90 mm Hg
> = 90 mm Hg
120 mm Hg
What values of systolic and diastolic blood pressure should we stop a test
Greater than:
250 mm Hg systolic
120 mm Hg diastolic
drops in blood pressure of 20 mm Hg or more
Failure of increase in systolic blood pressure with increasing workloads
Long term training has what effect on individuals with normal blood pressure
Minimal effect on resting blood pressure
What happens to the R wave if depolarisation moves towards the positive electrodes
What happens if it moves away from the positive electrodes
Makes the R wave positive
Makes the R wave negative
What is the auscultatory gap
Happens more commonly in…
A gap between the high pressure sounds and the sounds that occur when the pressure is reduced
Hypertensive patients
Systolic blood pressure is
Pressure in the artists during contraction of ventricle
What does the Kortocoff sound like during systolic
Clear
Sharp
Tapping sounds
Gradually increase
Systolic pressure _______ during exercise
Increases
Diastolic pressure is…
Pressure in arteries during relaxation of the ventricles
The Kortocoff sound of diastolic is
Sound disappears at rest
Muffled sound during exercise
Diastolic pressure ________ during exercise
Remains low
Training can lower blood pressure in
Hypertensive patients
Training has no/minimal effect on resting blood pressure in
Normotensive patients
Oxygen deficit is
The time period during exercise when the level of oxygen uptake rate is below what is necessary to supply all the ATP that is required for exercise
Steady state is
When can you reach steady state
The time period during exercise when a physiological function like vo2 remains at a relatively constant rate
Oxygen demand = oxygen supply
During low intensity exercise
+/- 2 ml/kg/min oxygen uptake rate
What is oxygen debt
Payback of the oxygen deficit that occurred prior in exercise
The amount of oxygen consumed during recovery from exercise above that is ordinarily consumed at rest in the same time period
Why is oxygen debt greater than deficit (3)
1) Oxygen uptake rate is driven up in order to dissipate heat by circulation to the surface of the skin
2) Thyroxin and catecholamines remain active during recovery to keep stimulation of metabolic pathways - VO2 is increased by this
3) There is an increased oxygen a lactic phase needed to replenish the phosphagen stores and remove lactate by oxidation - cardiac and respiratory muscle needs oxygen to meet this need during recovery
Alactacid phase of oxygen debt occurs within the….
This phase allows for the….
1st 2 mins of recovery
Replenishment of phosphagens
Lactacid phase of oxygen debt occurs in order to…
Removal of lactate by oxidation that was produced during oxygen deficit
What are the inherent pacemaker rates of the
Atria
AV node
Ventricles
75 bpm
60 bpm
30-40 bpm
Ventricular asystole is
Flatline
The maximum tension a muscle can generate is due to…
The amount of Actin and myosin binding
The speed of a muscle is controlled by
The thickness of the axon
And
Stores of myosin ATPase
The ability of muscle to continue to contract and maintain force production over extended periods is based on
Regeneration of ATP
