Lab Exam 1 Flashcards by Deleted Deleted

What is EMG

Electromyography

The electrical current measured when an action potential passes along a muscle fiber towards the surface of the skin

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What does emg activity represent

The traveling of an action potential

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How does emg relate to muscle contraction

EMG and the electromyogram shows the recording of the electrical events of muscle contraction

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What is the 2 raw responses

Amplitude - recruitment of motor units

Frequency - firing of motor units

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What is the integrated response

Amplitude + frequency = recruitment and firing of the motor units

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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

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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

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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

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What does local muscle fatigue precede

What depletes first

(MAX EFFORT OVER TIME)

Neural fatigue

ATP + CP
Then neurotransmitters

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How do we know when neural fatigue is starting to kick in

When there is a significant drop in EMG

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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

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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

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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

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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

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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

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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

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Endurance athletes have more

Sprinting athletes have more

ST Muscle

FT muscle

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How do you work out % of FT

[(Pre - Post / Pre) / 0.009] - 5.2

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Work (kgm) =

Force (kg) x distance (m)

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Anaerobic power =

What does it measure

Rev. at 5 secs - rev at 0 secs x workload x 6

Measures the development of phospagen metabolism

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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

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Fatigue index =

Percentage of anaerobic power

[(kgm/first 5 secs - kgm/last 5 secs) / (kgm / first 5 secs)] x 100

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Body weight =

lbs / 2.2

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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

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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

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