adv ex phys exam 1

energy transfer system depends on

intensity, duration and fitness status

immediate energy

ATP-PC

short term energy

anaerobic glycolysis

long term energy

aerobic glycolysis

ATP-PC

lasts less than 10 seconds of max intensity

100m dash, 25m swim etc.

energy comes from intramuscular phosphates

anaerobic glycolysis

resynthesis of the high energy phosphates without oxygen (creates lacate)

done by stored muscle glycogen breakdown

60-180 s duration

at light to moderate exercise intensity, blood lactate formation

is equal to lactate disappearance

at light to moderate exercise intensity, oxygen consumption

is equal to energy demands

lactate is used during anaerobic glycolysis to

generate energy from hydrogen oxidation

an untrained indiviudal will produce lacate

at a faster rate than someone trained

trained individual will also have a stronger buffering system

blood lacate thershold

typically at about 50-55% of VO2 max

above this lactate production exceeds lactate use

at lactate threshold there is a

decrease in intramuscular oxygen

more reliance on glycolysis activation of fast twitch fibers

reduces lactate removal

lactate dehydrogenase in the fast twitch muscle fibers favors

conversion of pyruvate to lactate

used in sprint activities

lacate can be used as a fuel source (the cori cycle)

buffering systems (H+ removal)

helps with greater lactate turnover at any level of physical activity

determined by muscle fiber type and blood flow responsiveness

training can cause adaptations for less lactate production

lacate producing capacity

the most lactate is produced at maximal physical activity

trained sprint-power athletes have 20-30% higher lactate production

• more trained = more lactate

increased muscle glycogen stores that come with training allow for greater lactate conversion (phosphofructokinase)

aerobic system (aerobic glycolysis)

activities lasting more than 3 min

produces the most ATP

uses glucose and fatty acid catabolism

oxygen consumption will rise exponentially during first 3-4 min and then steady state is reached

long term endurance exercise adaptations

angiogenesis

increase in size and number of mitochondria

increased enzyme concentration

at steady state exercise

there is a balance between energy required and energy produces

high use of central circulation to deliver oxygen to muscle

high capacity of action muscles to use that oxygen

at steady state exercise can continue indefinitely but is limited by

fluid loss

electrolyte depletion

external and internal temp

use of liver and muscle glycogen stores

high energy phosphates at the start of physial activity

will generate about 3-4 L of oxygen dept (will be repaid at the end of exercise, EPOC)

endurance trained O2 debt

smaller O2 deby

reach steady state more rapidly and hold it longer

faster aerobic kinetic response to consume more O2

anaerobic component of energy transfer is smaller

increase in overall cardiac output

angiogenesis and more mitochondria

athletes will a larger O2 debt are

sprint- power athletes

cardiac patients

older populations

untrained individuals

fast twitch muscle fibers

type 2 fibers

lots of force with a short duration

fast contraction speed

used during all out efforts

type 2a muscle fibers

higher aerobic capacity

type 2x fibers

produce lots of power

slow twitch muscle fibers

type 1 fibers

generate power mostly through aerobic systems

slower contraction speed

larger size and number of mitochondria

produce lots of ATP slowly over long periods

fatigue with glycogen depletion

athletes of different types of sports will

have a different concentration of each muscle fiber

oxygen consumption during recovery

after light activity VO2 recovery will follow logarithmic curve, decreasing about 50% every 30s until reaching baseline

at higher intensities, VO2 recovery takes longer to return to pre exercise level

EPOC

total VO2 in recovery - the total VO2 theoretically consumed at rest during activity and recovery

the amount of oxygen needed to return body to homeostasis

O2 uptake during recovery will always exceed resting value

fast phase of EPOC

most of O2 recovery

slow phase of EPOC

return to baseline of

• blood lactate levels (cori cycle)

• body temp

• hormone levels

the rest of O2 debt is paid off

two phases of O2 debt

alactic O2 debt (without lacate)

lactic acid blood oxygen debt

what types of physical activity produce little lactate

steady rate aerobic activity and brief 5-10 all out efforts

active recovery

‘cooling down’

submaximal effort with large muscle groups

light muscle activity to decrease muscle cramps and stiffness

helps with lactate removal and overall recovery

passive recovery

person usually lies down

total inactivity reduces the resting energy requirements

frees oxygen to fuel the resting energy levels

massage, cold showers, consuming cold liquids

what happens during recovery

resynthesis of high energy phosphates

replenishment of blood oxygen

return to baseline of bodily fluids

muscle myoglobin

after non steady state exercise

working at 30-40 % of vo2 max will accerlateate recovery

interval training is used to

increase high intensity workload with the production of lactate

balance fatigue and recovery

10s work 5s rest is most like continuous work without the lacate build up

direct calorimetry

measured by heat

rate of heat production by cells and tissues defines rate of energy metabolism

usually done in a chamber that is airtight and environment controlled

change in water temperature directly relates to the persons energy metabolism

indirect calorimetry

measured by gas

measurement of oxygen consumption during physical activity

changes in O2% and CO2% are compared to the ambient air

doubly labeled water technique

gold standard for energy expenditure measurement but very expensive

someone drinks water with more H+ and O and sweat, urine and pulmonary water vapor are tested

measured CO2 production

tracks how water and CO2 flow in and out of the body during macro nutrient oxidation

respiratory quotient

tells us that fuel source is being broken down

the ratio of metabolic as exchange measured at the lungs

• different amounts of CO2 are produced depending on what is being metabolized

this is an aerobic measure

RQ of CHO

value close to 1

RQ of fat

value close to 0.7

RQ of protein

value close to 0.82

metabolism of protein is not simple like CHO and FAs

nitrogen and sulfur are excreted in the urine, sweat and feces

RQ disadvantages

it is not possible to determine protein contributions to RQ

exercise will influence CO2 values (hyperventilation during anaerobic exercise and overall metabolism during aerobic exercise)

RER and RQ

essentially the same thing, but at high intensity RER must be used because Co2 output is greater than 1

CO2 elimination increases during

hyperventilation

• when breathing increases to a higher rate than metabolic demands

• this creates a RER over 1 which does not reflect macronutrient oxidation

RER rises above one because

of sodium bicarbonate and increased pulmonary Co2 release

this duffering adds extra non metabolic-created Co2 into expired air

low RER values occur when

the cells and the bodily fluids retain CO2 to replenish bicarb stores that buffered the accumulating lactate

BMR

minimum level of energy to sustain vital functions in the waking state

the energy required to live

measured in a fasting state

why is BMR measured fasted

to avoid increases in metabolism from digestion, absorption and assimilation of ingestive nutrients

BMR is measured by

VO2 over at least a 10 minute period

RMR contributes what % to TEE

60-75 %

PA contributes what % to TEE

15-30%

TEF contributes what % to TEE

10%

BMR is always

slightly higher than RMR

what influences BMR

gender, age, overall body size and FFM

hormone status, body temp, health/ fitness status

metabolic size concept

EE is expressed via body surface area

the larger the person the more EE

what does it mean to index BMR and RMR

to divide by lean mass so people of different body sizes can be compared

BMR falls with

age

lower for women after puberty

what does PA do it RMR

increase it and it will change body comp

BMR are normal if

they are within 10% higher or lower of normal value

the liver and the brain

contribute the most to RMR and require the most oxygen

what are the 5 things that affect TDEE

PA, thermogenesis from food, metabolism of food, climate and pregnancy

what exercises burn the most calories

large muscle, continuous, rhythmic activities

• fast walking, running, uphill hiking, cycling, swimming

obligatory thermogenesis

heat from food breakdown

energy required to digest, absorb, assimilate food nutrients

facultative thermogenesis

sympathetic stimulus from eating

relates to activation of the sympathetic nervous system and its stimulating influence on metabolic rate

diet induced thermogenesis

heat/ caloric expenditure from eating food

pure carbs have a low thermogenic effect, pure fat and protein have a high one

weight and TEF

overweight individuals have a blunted TEF

this contributes to higher body fat accumulation

endurance athletes and TEF

they may have a lower TEF due to caloric sparing adaptations to conserve energy and glycogen during longer periods of PA

exercise metabolism and food

breakfast will increase RM by 10%

performing Pa after a meal will produce a larger EE

what happens to RMR in a tropical climate

decreases by 5-20%

PA performed in a warm climate= 5% increase in VO2

what happens to RMR in the cold

will increase both at rest and during PA

• depends on fat mass and clothing

  • shivering will increase metabolic rate up to 5x

RMR and pregnancy

HR and VO2 increase due to weight gain with weight bearing PA (no change in weight supported)

PA is classified by

intensity and duration

METS

metabolic energy equivalents

unit of oxygen consumption over a time duration

1 MET is

3.5 mL * kg-1 * min-1 (corrected for body mass)

every kg of body weight is burning 3.5 ml of O2 per min

5 kcal is needed to consume 1 L of oxygen

VO2 and heart rate have a ___ relationship

linear relationship

until about 80% of VO2 max where after that is anaerobic PA

what influences HR and VO2 relationship

temperature, emotion, previous food intake, body position during PA, muscle groups used, continuous or discontinuous PA, dynamic or static PA

gross EE includes cals expended during

both rest and activity

net EE is

exact EE of the activity itself not inducing rest or RER

mechanical efficiency

energy needed to produce work

the more work someone can do with expending less energy the better

measured by vertical work (physics) and EE (represented as total VO2)

RQ is used to determine kcal number

movement economy

oxygen needed to produce work

during steady state exercise VO2 mirrors EE

• someone with greater movement economy will use less oxygen during running, swimming, cycling

what kind of muscle fibers have been show to correlate with better movement economy

slow twitch