Chapter 1 - Measurement of Work, Power, and Energy Expenditure Flashcards
Work
force x distance
Power
(force x distance) / time ; how much work you do per unit time
Ergometry
measurement of work output
Ergometer
device used to measure work in meters (bench step ergometer, cycle ergometer, arm ergometer, and treadmill)
Treadmill
Incline of this machine is expressed in percent grade.
-amount of vertical rise per 100 unites of belt travel. (10% grade means 10 m vertical rise for 100 m of belt travel)
Direct Calorimetry
measurement of heat production as an indication of metabolic rate. ( commonly measured in calories; 1 kilocalorie = 1,000 calories
METs
the resting metabolic rate is for the average population
1 MET = resting metabolic rate
-3.5 ml x kg x min
True of False: Running has twice the slope as walking
True
How does exercise work rate influence exercise efficiency ?
exercise efficiency DECREASES as work rate increases.
Factors that influence exercise efficiency
The efficiency of exercise decreases as the exercise work rate increases. This occurs because the relationship between work rate and energy expenditure is curvilinear.
Factors that influence exercise efficiency
To achieve maximal efficiency at any work rate, there is an optimal speed of movement.
-exercise efficiency is greater in subjects in subjects who possess a high percentage of slow muscle fibers compared to subjects with a high percentage of fast fibers. This occurs because slow muscle fibers are more efficient than fast fibers.
Gender Difference in Running Economy
No difference between sexes at slow speeds.
- at “race pace” speeds, males may be more economical that females but not real differences.
Do different people burn energy at the same rate?
No.
Why is direct calorimetry an insufficient way to measure energy?
It is too expensive and not methodically feasible.
Estimation of metabolic rate via the measurement of O2 consumption
Indirect Calorimetry
running has ____ the slope as walking.
twice (2)
How does an open circuit spirometry determine VO2?
this method of indirect calorimetry measures VO2 by measuring the amount of O2consumed.
what is VO2?
Volume of O2 inspired - volume of O2 expired
What is the measurement of heat production as an indication of metabolic rate?
Direct Calorimetry
How does speed of movement influence exercise efficiency?
there is an optimum speed of movement and any deviation REDUCES efficiency.
How does muscle fiber type influence exercise efficiency?
Higher exercise efficiency in muscles with greater percentage of slow fibers.
What kind of relationship does work rate have with % net efficiency ?
negative linear relationship. (the higher the work rate the lower the % net efficiency.)
What kind of relationship does energy expenditure and work rate have?
positive curvilinear relationship. (higher the work rate there is a positive curvilinear increase in energy expenditure. thus less efficient)
What has a positive linear relationship with work load?
VO2, Epinephrine, Heart Rate, Blood Pressure
