CHAPTER 4 Flashcards
What is energy?
capacity to do work aka mechanical energy
Is work=force x d mechanical energy?
yes
Is power = work/time mechanical energy?
yes
What is mechanical energy?
muscle contraction
What is chemical energy?
glucose and ATP
What is energy expenditure equation?
energy/time in kj or kcal/unit
calorie
Energy needed to raise the temperature of 1 g water 1oC.
Calorie
expressed on food labels
Joule
energy required to move a mass of 1 g at a velocity of 1 m/s.
1 cal = ______ Joules
4.186
1 kilocalories = ____ kilojoules
4.186
Is energy lost when converted from one form to another? Give example
no
CHO and fat combustion cause muscle contraction and rest goes to heat energy
Joule provides what kind of energy
mechanical
Energy efficiency: chemical or mechanical energy?
BOTH
Energy efficiancy
% of total work
20% is what we use for human work
remaining 80% as heat (homeostasis)
Gross efficiency
ratio of total work to energy expended
GE=work/energy expended X 100%
For GE: as exercise intensity increases, energy expended __________(increases /decreases). ultimately, GE gets bigger or smaller?
energy expended decreases, so your GE will increase
Net efficiency
baseline is the energy expended at rest to resolve GE getting bigger
NE = work accomplished / (energy expended-resting energy ependiture) X 100%
Work efficiency
another way to calculate baseline where baseline is the energy cost of unloaded work
WE = work accomplished/ (energy expended-energy expended in unloading condition) X 100%
Delta efficiency
change in energy expenditure relative to the change in actual work accomplished per minute
DE: delta work accomplished/delta energy expended X 100%
Atwater factors for CHO, fat and protein
CHO=4kcal/g
Fat=9kcal/g
Protein=4kcal/g
Coefficient of digestibility for CHO, fat and protein
Carb 97%
Fat 95%
Protein 92%
Does fibre increase or decrease digestibility?
Fibre decreases digestibility
Energy content for fat depends on
structure of FA and TAG
Energy content for protein depends on
type of protein and ntirogen content
If theres nitrogen in protein, does it give more energy or less energy?
less,
nitrogen DOES NOT PROVIDE energy