Chapter 2: Defining and Measuring Energy Flashcards
Bioenergetics
Process of converting food into biologically useful forms of energy
Energy
Ability for perform work
Force Production
The generation of tension by contracting muscles
Potential energy
Stored energy
Kinetic Energy
Energy of motion
Endergonic
Chemical reactions that store energy
Exergonic
Chemical reactions that release energy
Adenosine Triphosphate (ATP)
A chemical compound that provides most of the energy to the cells
Sliding Filament Theory
the actin (thin) filaments of muscle fibres slide past the myosin (thick) filaments during muscle contraction, while the two groups of filaments remain at relatively constant length
First Law of Thermodynamics
“conservation of energy”
Adenosine diphosphate (ADP)
a chemical compound formed by the breakdown of ATP to release energy
ATP concentrations in Muscles
- does not drop below 20-30%
- muscles fatigue and protects against ATP depletion
Rephosphorylation
establishing a chemical phosphate bond, as in ADP reestablishing a third phosphate bond to become ATP
Direct calorimetry
a scientific method of determining energy content of food or energy expenditure by measuring changes in thermal or heat energy
calorimeter
a device that measure energy content of food or energy expenditure , “bomb”
indirect calorimetry
a scientific method of determining energy expenditure by measuring changes in oxygen consumption and/or carbon dioxide production
Resting Metabolic Rate (RMR)
the amount of energy per unit time required by the body to maintain a nonactive but alert state
The Doubly Labeled Water (DLW)
the indirect (O2 in and CO2 out) determination of energy expenditure over much longer periods of time usually 1-3 weeks and allows subjects to participate in normal activities
Components of Energy Expenditure
resting metabolic: 70%
physical activity: 20%
thermic effect of food: 10%
Joule
SI unit of measure for energy
Basal metabolic rate (BMR)
measure of the amount of energy per unit of time necessary to keep the body alive at complete rest
Total Energy Expenditure (TEE)
the amount of energy that is required by the body, typically determined over the course of a 24 hour day
Formulas for resting metabolic rate
- Mifflin-St. Jeor Equation: healthy caucausion, sedentary adults
- Cunningham: RMR=500+22 (FFM/fat-free mass) better for athletes
- Simplified formula: men: 1 kcal per kilogram of body weight per hour
women: .9 kcal per kilogram of body weight per hour
* to convert weight to pounds divde by 2.2 lb/kg
Metabolic equivalent (MET)
Level of energy expenditure equal to that measured at rest. 1 MET = 3.5 ml/kg/min of oxygen consumption
