44 Cards in this Set
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What is BMI? What is an advantage and disadvantage of using it?
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BMI- Body mass index
weight (in kg)/height (m^2)
Disadvantage: It is not a calculation of percent body fat. Athletes are often miscalculated as overweight.
Advantage: easy to calculate, rough estimate of body mass
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Body Composition
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Used to describe the percent of muscle, bone, and fat in the body
-Some body fat is essential
-4% in men
-10% in women
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Does the site of body fat storage matter? Which type is more associated with heart risks?
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Abdominal fat or upper body fat (apple)- higher risk for metabolic or cardiovascular disease
Gluteofemoral or lower body fat (pear)- lower risk for heart disease
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Ways to measure body fat composition: Waist-Hip
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Measure waist and hip
Too high=men>1.0 and women>.8
Cheap and easy but not that accurate
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Bioelectrical Impedence
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Resistance to electrical current (fat=terrible conductor)
Strengths: fast equipment not expensive
Limitations: no food/drink 4 hrs before, no exercise 12 hrs before. Error: 3-4%
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Plethysmography (BOD POD)
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Air displacement, can do it to anyone
Problems: expensive, air flow in room disrupts machine.
$30,000
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Skinfolds
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Somewhat accurate
Cheap $250
Error is 3-4%
Can't tell fat
Tester must be trained
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Underwater Weighing
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Used to be the most accurate method
Problems: difficult to test
Air in lungs is problem
Anxiety/personal hygiene
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Dual Energy X Ray Absorptiometry (DEXA)
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Can assess distribution on fat or pattern
Radiation low 1/50th chest ray
Fully dressed
Problem: >100,000
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How many kilocalories of excess energy theoretically equal one pound of fat gain?
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3500 kcals=1 lb of fat
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What are the three main components of energy expenditure?
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Resting metabolic rate
Thermogenesis
Physical Activity
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How is energy balance measured by the body? Where is the sensory? Where is the target? How does the sensor communicate with the target?
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Measured by body sensors
Sensors are located in the brain (hypothalamus)
Target is body fat
Sensors communicate with the hormone leptin
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What hormone functions as the "energy sensor"? Would you expect the levels of that hormone to be high or low in obese people?
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Leptin, levels are high in obese people. They become desensitized to the hormone.
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Looking at the diagram of responses to weight gain and weight loss, which one of these is the system most sensitive to?
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Energy deficit as people become desensitized to leptin when there is a surplus
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Why does the hormonal response from weight loss tend to cause people to regain the weight?
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When you lose weight, leptin reacts and sends out the signal that you are hungry. Ghrelin is produced by the stomach and creates the feeling that you are hungry
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Who is included in the National Weight Control Registry?
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A list of people who lost 20+ lbs and kept it off for at least a year. There are around 6000 people registered.
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How much physical activity is recommended by the people in the National Weight Control Registry?
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About an hour a day
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Describe the three ways that exercise can contribute to weight loss maintenance?
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a)direct effect of exercise: energy expenditure. 400-800kcal/hr (moderate intensity)
b)Post exercise metabolism. Increase in metabolic rate
c)RMPR elevated after exercise 2-24 hrs depending on intensity and duration (Increase in muscle mass=increase in RMR)
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Does exercise make you hungry? If so, how?
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Exercise often suppresses appetite. Exercise stress as well as exercise in heat increase suppression. Exception is swimming (water removes heat)
Could be related to vertical motion (disturbance of ghrelin)
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Why is exercise as a weight management tool often more effective in men than in women?
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Women tend to replace kcals burned more effectively. Women have a higher body fat percentage for reproductive reasons so they tend to hold on to fat more than men.
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How do fat-burning dietary supplements (in theory) help control body weight and body fat?
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A) Thermogenesis leads to increase in metabolic rate
-Usually contains caffeine and something else to compliment caffeine
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What happens in the "flight or fight response"? How long does it last? What about ephedra and ephedrine?
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Ephedra mimics the hormone adrenaline which instigates "flight or fight"
-blood pressure goes up, heart rate goes up
-breakdown of glycogen to glucose, triglycerides to fatty acids
-epinephrine doesnt last long (10 minutes)
-ephedrine mimics epinephrine but lasts much longer (hrs)
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Where does ephedra come from? What is made of and what is it supposed to do?
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-Ephedra comes from Ma Huang ( a plant in the northern hemisphere)
-Ephedra is a mix of ephedrine and psuedoephedrine
-Increase energy, burn fat, lose weight, and elevate mood
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What combination of factors is most commonly associated with ephedra-related illness?
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ephedra, caffeine, and exercise
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What is the physiological cause of ephedra related illness?
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-elevated blood pressure
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What are the physiological responses to ADD/ADHD medications like adderall?
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Increased "noise" in the pyramidal neurons of the prefrontal cortex
-increased heart rate
-faster breathing
-high blood pressure
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Connection between muscles, muscle fibers, myofibrils, actin, and myosin.
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muscles are made up of muscle fibers which are made of myofibril that are made up of actin and myosin. Electrical stimulus by a motor neuron causes sacromeres to shorten and produce force.
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What are the major characteristics that distinguish Type I, Type IIA, Type IIB muscle fibers?
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Type I: small in diameter, slow twitch fibers, low glycogen and cp, many mitochondria, fatigue resistant
Type IIA: Fast contraction, increase in glycogen and creatine phosphate, variable in mitochondria, less fatigue resistant than type I
Type IIB- high in glycogen, CP, low in mitochond…
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What one factor determines if a muscle is type I, type IIA, or type IIB
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Type of training
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What is the definition of hypertrophy? Are type I or type II fibers more prone to hypertrophy?
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Increase in the size of the muscle due to increase in cell size
-type II fibers more prone as they are used for high force production
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What is hyperlasia? Does it occur in humans?
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The increase in muscle due to an increase in the reproduction rate of its cells. (Does the number of muscle fibers change?)
-In some animals (i.e., cats) but no hyperplasia in adult humans as muscles grow by adding protein.
-However, fibers can split as they get larger in order to maint…
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Muscle fibers may split as they grow. How is that beneficial to the muscle?
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-Allows the muscle to get larger while maintaining surface area
-Allows access to oxygen and nutrients
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What are the three main factors that cause muscle hypertrophy?
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1. nutritional
2. hormonal
3. stress
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What kind of energy balance is required to gain muscle?
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-An energy surplus (Ein>Eout)
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How do bodybuilders gain muscle without gaining fat?
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-right energy surplus (300kcal/day)
-hard resistance training
-Cardiovascular training
-manipulate hormonal level (supplements, drugs, etc)
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What are steroid hormones made from? Where in the cell do they act?
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Synthesized from cholesterol
Fat soluble and act directly on DNA---> synthesize new proteins
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What are anabolic effects? What are androgenic effects?
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-Anabolic: muscle building
-Androgenic- giving masculine characteristics
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What two molecules can testosterone be converted into by the body?
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DHT and estradiol
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Differences between oral and injectable steroids?
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ORAL:
-broken down faster
-taken more often and in larger quantities
-Often methylated---> avoid breakdown in the liver
INJECTABLE:
-longer lasting effects
-dosages are much lower and less often
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What are prohormones? How are they supposed to work?
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raw materials to use own enzyme to create testosterone
Allows the body to create anabolic steroids naturally rather than using a prescription
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What is the general consensus regarding the conversion of andro products to and the effects on muscle mass and strength?
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Not fully proven, some say there is no effect on strength and others say there is.
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How does using anabolic steroid or prohormone products cause a DECREASE in the bodies ownnatural production of testosterone?
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When using anabolic agents, high androgen levels lower natural production of testosterone
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Does timing of protein intake affect muscle mass?
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Yes, consuming protein before and after a workout is more effective for improving muscle mass. 0-2 hrs after workout most effective
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Does consuming whey protein increase muscle mass? What is the possible mechanism?
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Possibly, quicker absorption of protein leads to more amino acids available for use
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KIN 110: EXAM 3