Final Exam Flashcards
what can body composition assessment be used for?
to quantify changes in muscle mass and body mineral density as a result of physical training or malnutrition
what can body composition allow us to estimate?
if an individual is at risk for obesity (which is linked to type 2 diabetes, hypertension, hyperlipidemia, and certain types of cancer)
what can obesity cause?
disc degeneration, low back pain, joint injury, osteoarthritis, and limitations to an individual’s ability to independently engage in activities of daily living.
sarcopenia
age-related loss of muscle
osteopenia
bone density is nearing the at risk category
osteoporosis
low bone density, can be modified with diet and lifestyle
cause of osteo-sarcopenia?
Combination of low bone denisty, low muscle mass, high body fat.
Can be caused by diet (calcium, not anything to fuel body)
outcomes of osteo-sarcopenia?
Increase risk of falls and bone fractures, increase in body fat %, reduction in overall physical capacity
anthropometry
measurement of the human body (height, weight, circumferences, skinfolds)
body fat percentage
Percentage of total body weight that is composed of fat
BF % = (fat weight/body weight)*100
fat-free mass
mass of the non-fat tissue (more than just skeletal muscle)
fat mass
mass of the fat tissue
body composition models: direct
chemical analysis of a cadaver
body composition models: indirect
Methods derived from the direct method
*Hydrostatic weighing, CT and MRI scans, air displacement, DEXA scans
doubly indirect
Methods derived from an indirect method
Subject to greater measurement error
*Skinfolds, bioelectrical impedance, near-infrared interactance
what is BMI used for?
to assess an individual’s mass relative to height
can be used to determine CVD risk
BMI advantages
Quick
Easy to do
Collect a lot of information with limited resources
Can send out self-reports to collect data
BMI disadvantages
Doesn’t tell you what your body is
Doesn’t tell you what is fat, bone, or muscle
Not useful for athletes
waist-hip ratio
A ratio measurement of the circumferences of the waist to that of the hip
It is an indicator of body fat distribution, which can be used to predict disease risk
*Visceral obesity increases the risk for developing hypertension, type 2 diabetes, hyperlipidemia, metabolic syndrome, and CVD.
calculating waist-hip ratio
The circumference of the waist (above the iliac crest) divided by the circumference of the hips (buttocks/hips measure) and is used to identify individuals with higher amounts of abdominal fat.
Take the average of two measurements (must be within 5mm of each other)
Feet together, deep breath in, take measurement at end exhalation
waist-hip health risk for men
very higk for young men when WHR is >0.95
waist-hip health risk for women
very high for young women when WHR is >0.86
measurement: waist
Measured around the smallest part of the waist (usually about 1 inch above the umbilicus)
management: hip
Measured around the largest part of the buttocks
waist- hip advantages
quick, easy, inexpensive
waist-hip disadvantages
does not differentiate between fat and non-fat tissue
thigh circumference
Represents muscle mass
Small thigh circumference may be indicative of low muscle mass & glucose intolerance (if you remove the influence of BMI and waist circumference) and heart disease
densitometry & hydrostatic weighing
Whole-body density using the ratio of body mass to body volume
The limiting factor in the measurement of body density is the accuracy of the body volume measurement because body mass is measured simply as body weight.
hydrostatic weighing advantages & disadvantages
the “criterion method” for body composition assessment
advantages: Accurate body fat % data
disadvantages:
Two compartment model (nothing about bones)
Some people are not comfortable with being in water
Might get a falsely high body fat percentage (breathing out air before going underwater, may not breathe out air completely), make yourself as heavy as possible by breathing everything out
hydrostatic weighing
Body fat contributes to buoyancy because the assumed density of fat is less than water
To conduct a hydrostatic weighing test, you must know the following:
Residual volume (RV)
Density of the water
Volume of gas trapped in the GI system
Dry body weight
Body weight when fully submerged in water
Subject:
Wear a tight-fitting bathing suit that does not trap air
Remove all jewelry
Use bathroom before
plethysmography
Measured by air rather than water displacement
Uses a dual-chamber plethysmograph that measures body volume by changes in pressure in a closed chamber
This technology is now well established and generally reduces the anxiety associated with the technique of hydrodensitometry
air displacement (BodPod)
Measures body volume by air displacement (rather than water like UWW)
Quick, comfortable, noninvasive
Expensive
air displacement (BodPod) pre-test instructions
Subject must wear a tight-fitting swim suit and swim cap
All hair must fit into swim cap
i.e. can alter volume
No food, drink, exercise 2 hr prior to testing
Remove jewelry, eyeglasses
Ask subject to void prior to the test
Skinfold analysis has two assumptions:
The amount of subcutaneous fat is directly proportional to the amount of body fat
1/3 of total fat is located subcutaneously (this varies with sex, age, and ethnicity)
skinfolds advantages
Easy
Inexpensive
Measurement of body composition
skinfolds disadvantages
Takes a lot of practice on different body sizes and proficiency to get good on it
bioelectrical impedence
Assumes that fat-free tissue in the body is proportional to the electrical current and hydration of the body
A small electrical current is sent through the body and the speed (or impedance) to that current is measured
BIA estimates total body water and uses equations for percent body fat
who might bioelectrical impedance not be appropriate for?
Amputees, overly obese individuals, people who have muscular disorders, people who are overly/dehydrated
DEXA
Dual Energy X-Ray Absorptiometry
The DEXA scan is based on a 3C model of total body mineral stores, fat-free mass, and fat mass
Highly correlates with hydrostatic weighing
DEXA advantages
Safe (low radiation dose)
Quick
Minimal subject cooperation
DEXA disadvantages
Expensive
Assumes constant hydration
Some people may be too large to fit on the machine
general considerations for interpreting and body fat percent
When interpreting, consider that:
*There are no universal standards for percent body fat that have been established and accepted.
*All methods of measurement are indirect, so error needs to be considered.
Body fat percent standards:
*National standards exist for BMI and waist circumference.
body fat distribution: android obesity
Male-pattern obesity
Apple shape
Excessive storage of fat in the abdominal and trunk area
Linked with cardiovascular and metabolic diseases
body fat distribution: gynoid obesity
Female-pattern obesity
Pear shape
Excessive storage of fat in the hips and thighs area
Generally accepted weight loss goals are:
1-2 pound/week
goal body weight equation
fat free weight/(1-[Goal % body fat/100])
basal metabolic rate (BMR)
how many calories you expend to keep you alive
metabolic rate in supine position, 12-18 hrs after meal, immediately after waking up in thermoneutral environment
Accounts for 60-75% total calories per day
calculating RMR
- Know the RMR
- Identify amount of calories being consumed
- Calculate how many calories are needed to be expended to create a negative energy balance
For example,
RMR of 1750 kcal/day, consume 2250 kcal/day = 500 kcal stored/day
Therefore, expend a minimum of 500 kcal/day to maintain weight (or whatever goal you have)
For a weight loss of 2 pounds over 1 month???
role of skeletal muscles
This is where fat is actually broken down. Thus, it would make sense to have bigger/stronger muscles:
1: increased RMR
2: workout harder/longer
3: shift reliance to fat
In turn, the cardiovascular exercise is more effective and overall health is improved
goal: prevent weight gain
amount of physical activity:
150-250 min/week of moderate intensity exercise
evidence-supported results:
Stay within 3% of baseline weight
clinically significant weight loss
amount of physical activity:
250-420 min/week of moderate intensity exercise
evidence-supported results:
More than 5% of baseline weight
exercise prescription limitations
Assumptions with diet and energy balance
We calculate energy expenditure from exercise, but what about all other activity?
Calculating target weights
- Does not consider fat vs muscle changes
- It is a predictive equation
VO2 measurements to guide Ex Rx
Metabolic equations may not be as applicable for deconditioned individuals
what contributes to flexibility?
Joint capsule
Muscle and fascia
Tendons and ligaments
Skin
Body type
Age
Physical activity/inactivity
Neurological patterns
static flexibility training
a slow stretch and hold for 10-30 seconds
ballistic (bouncing) flexibility training
uses body momentum to produce the stretch
dynamic flexibility training
slow movements of a muscle with a progressive increase in reach and range of motion
Proprioceptive Neuromuscular Facilitation (PNF) techniques:
combination of isometric contraction and static stretching
flexibility can affect…
Muscles being used/not used
Stiffness
Pain
Loss of range of motion
Posture
Goals
Muscular strength and endurance are linked with:
Bone mass (osteopenia)
Muscle mass (sarcopenia)
Glucose tolerance (Type 2 Diabetes)
The ability to perform activities of daily living (ADL), which is related to perceived quality of life and self-efficacy among other indicators of mental health
Fat free mass and resting metabolic rate (weight management)
Muscular Strength:
Load = 60-70% of 1 RM for 8 – 12 reps
Volume = 8 – 12 reps, 2 – 3 d*wk
Rest = 2 – 3 minutes
Muscular Endurance:
Load = 10 – 15 reps
Volume = moderate to high
Rest = 1 –2 minutes for high reps (15 – 20), less than 1 for moderate (10 – 15)
Health Recommendations:
Resistance Training
2-3 non-consecutive days
8-10 exercises that target all major muscle groups for 8-12 repetitions
Modifying Programs (progression principles, exercise order, free weights & machines, velocity)
Progression Principles: specificity, variation, classical periodization, reverse periodization, undulating periodization
Exercise Order: What influence does this have? Affects the acute expression of muscular strength. Muscle force and power may be potentiated when opposing exercises are performed, force and power may be reduced if the exercises are performed consecutively. Multiple joint exercise performance declines significantly when these exercises are performed later rather than early in a workout.
Free Weights and Machines: What are the differences in physiological demand? Free weights – may result in a pattern of intra and intermuscular coordination that mimics the movement requirements of a specific task
Machines – help stabilize the body and limit movement about specific joints involved in synergisitc force production, demostrated less nerual activation when matched for intensity for most comparisons to free-weight exercises.
Velocity: What influence does this have? The velocity selected shouldcorrespond to the intensity and the intent should be tomaximize the velocity of the CON muscle action
Measures of Isometric Strength
Upper body strength:
Hand grip dynamometer
*Used as an estimate for maximal upper body strength
- maximal hand grip strength for right and left hands (two trials of each)
Lower body strength:
Hand held dynamometer
*Used as an estimate of overall lower body strength, balance, fall risk
*Record maximal quadriceps and hamstrings strength (two trials of each)
Muscle Size
Hypertrophy (larger muscles) vs hyperplasia (increase in amount of muscle fiber cells)
aging process on muscle fibers
Maintain strength until 40s, then a slow decline through mid-50s, followed by a sharp decline.
Loss of fast twitch muscle fibers
Neuromuscular Adaptations (motor unit recruitment, firing rate, sync neutral signals, reduce neural inhibition)
Motor unit recruitment - more nervous system signals to muscle to create more force
Firing rate – increased, more frequency = more force
Sync neural signals – be able to build upon each other to build more force
Reduce neural inhibition – deactivate the opposing muscle groups to allo movement, enable you to apply more force
Variables to Consider for resistance training
Progressive overload: muscles need to be repeatedly stressed in order to further gains
Specificity of training:
*Influenced by a “needs analysis”: how much time do you have, relevant health issues, goals
Periodization: the manipulation of resistance training variables
Prioritization: What is it that you really want to improve?
*Maximal strength, power, endurance, hypertrophy
Resistance training programs can be separated by muscle groups, called what?
splits
within a given training session: training all major muscle groups
Large muscles groups before small muscles groups
Multi-joint before single joint
Rotate upper and lower body exercise and agonist vs antagonist
Important! Avoid muscle imbalances!
within a given training session: training individual muscle groups
Multi-joint before single joint
*If you want to put additional stress on targeted muscle, you can pre-fatigue muscle groups with single joint movement, and then follow with multijoint movement
Perform higher intensity exercises before lower intensity
rest time: strength
3-5 mins for large muscle groups with multi-joint movements in advanced lifters; 1-2 mins for single joint or smaller muscle mass exercises
rest time: endurance
1-2 mins due to the higher repetition range and lower intensity %.
classic periodization
2-4 week microcycles that build in intensity and create a mesocycle
nonlinear periodization
variation within each microcycle; can be as effective as linear periodization.
