Midterm Flashcards
Exercise
requires planned, structured and repetitive movement
Physical activity
movement produced by skeletal muscles requires energy expenditure
New category of movement
Nonexercised activity thermogenesis
Energy expenditure doing everyday activities not exercise ex. carrying groceries
Systems involved in exercise
Nervous, skeletal, cardiovascular, lungs, neuroendocrine/metabolism
Service organs (muscle-centric view)
Permit continued exercise
Facilitate allostasis (feedforward adjustment)
Steps
Less than 5,000 steps - Sedentary lifestyle
5,000-7,499 - Low active
7,500-9,999 - somewhat active
10,000-12,499 - active
More than 12,500 - highly active
3 factors determine our health and longevity
environment, behaviour and genetics
Primary cause of death in 20th century
Progress in medical fields
infectious diseases (life expectancy 47 years)
infectious disease to chronic diseases
Dimensions of wellness
social, physical, spiritual, environment, mental, emotional, occupational
Leading risk factors of death are related to lifestyle choices (big five)
Smoking, high blood pressure, high body mass index, physical inactivity, high blood sugar
In the last century
diet includes much worse things, we have become increasingly sedentary and change in social interaction (online)
Sedentary death syndrome (SeDS)
Hypokinetic diseases
Death attributed to lack of PA
Illness related to lack of PA
PA decreases
mortality rates, there is a drop in diseases
Current recommendation for physical activity
150 minutes of Modern intensity or 75 minutes of vigorous intensity
Women have a reduced risk of
Cardiovascular disease before menopause
Life long endurance athletes have a higher
Vo2 even as they grow older and it helps you stay active for longer before deteriorating
170 - 242min moderate intensity or 90-128min vigorous activity per week decreases
Chance of cardiovascular disease
Extreme Extreme physical activity can result in “Extreme exercise hypothesis”
U- shaped association - association between CVD and exercise
Committed exercisers have been shown to
-Maintain youthful hearts
-reduce arterial stiffness
- reduce central blood pressure
Additional benefits of PA
-Important for muscle, bone and joint health (doesn’t help lungs)
-Improves mood, cognitive function, creativity
-Increase blood flow to brain
-Facilitates removal of metabolites (prevent alzheimers and dementia)
-Release of the protein brain-derived neurotrophic factor
-Increased excitatory neurotransmitters
-Significant association between physical fitness and academic achievement
Sitting for too long effects
Solution
even individuals who exercise 5 times/week for 30 minutes/ session
stand and move every 30 minutes of inactivity (5 minute break for every 30 minutes)
Light PA
Moderate PA
Vigorous PA
(uses less than 150 calories/day)
(uses 150 calories/day or 1000 calories/week)
(requires more than 6 METs energy per day)
Skill Related Fitness
fitness components important for success in skillful activities and athletic events
Health Related Fitness
able to perform activities of daily living without undue fatigue
Why is it hard to change?
-Our behaviours based on core values and personal nature
-We resist change that is not immediately rewarded, even if it provides great future reward
What triggers desire to change?
No pressure
Solution? - receive instant gratification for action and people’s feelings addressed
Two types of external obstacles to healthy behaviour
Physical and social obstacles in the environment
Anchor points
social norms that individuals use as a reference when considering a new behaviour, could be stopping you from exercising
Environmental influence on physical activity
work and leisure time (increased sitting and screen time), community design, school and community policy (insurance plans)
Environmental influence on diet and nutrition
food quality and abundance, dining out
Motivation and confidence chart
need 7 in both to be ready to start new goal
Personal values and behaviour
And what they are shaped by
values are core beliefs and ideals, govern priorities and behaviour - established by education, shaped by role models and examples
Planned to automatic habits in basal ganglia
Dopamine has many functions and plays a key role in habit formation
Striatum (largest nucleus in basal ganglia) key role in habit formation and motor control
Change habits by focusing on long-term values
Change in core values overruled instant rewards as we look for long-term gratification
Prefrontal cortex (PFC) reminds us
who we are
puts brake on impulsive behaviour
serotonin abundant in PFC (confidence, delayed gratification)
Locus of control (what we perceive we have control over)
Internal - you have control over your life
External - what happens is due to change, environment or unrelated to your behavior
This is part of what prevents people from taking action
Barriers to change
complexity, procrastination, gratification, lack of core values, preconditioned beliefs (mom says no run), risk complacency (if I get fat later who cares)
Behaviour change theories
Learning theories (increased knowledge of obesity)
problem-solving model
social cognitive theory
relapse prevention model
humanistic theory of change
(first meet basic needs, then start taking steps toward best version of yourself)
Transtheoretical Model of change
Precontemplation, contemplation, preparation, action, maintenance, termination/adoption
People manage weight by using 2 sources of feedback that can be misleading
BMI and the way clothing fits
Why does body composition matter?
-Establishes risk for early illness and death
-Does not depend only on body weight to determine if someone is fat or skinny
-Helps us identify changes that decrease fat and increasing lean body mass
-Helps identify weight-related changes
Obesity and BMI
Obesity - excessive amount of fat related to body weight
BMI - weight (kg)/ height(m)2
Android vs gynoid obesity
Android obesity - fat stored in trunk or abdominal area (men usually)
Gynoid obesity - fat stored around the hips and thighs (women usually)
True or false, developing countries have a lower obesity rate
True
Body composition - two component model assumptions
Whole body = fat and fat-free body component
densities of various tissues are the same (not true)
everyone’s densities of bones and stuff are the same (not true)
Individuals are measured compared to the reference body
FFB density depends on age, sex, ethnicity, physical activity and BF%
Multicomponent models
Eliminate error of estimation
Measure water and mineral percentage
Method for developing population specific
Takes into account differences
Essential fat
Storage fat
Essential fat - needed for normal physiological function (men 3%, women 12% needed)
Storage fat - stored in adipose tissue (subcutaneous fat (under skin), visceral fat (around organ)
Functions of storage fat
stores calories, release hormones that control metabolism, body heat, acts as padding against physical trauma
Subcutaneous fat vs visceral fat
Subcutaneous fat - releases beneficial hormones, suppresses appetite, burning stored fat and increasing insulin sensitivity
Visceral fat (increases risk of disease more than subcutaneous) - also known as intra-abdominal fat, metabolizes into fatty acids more often than subcutaneous fat
Techniques to assess body composition
Skinfold thickness, bioelectrical impedance, dual-energy x-ray absorptiometry
Skin fold thickness
Assumptions
indirect measurement of subcutaneous body fat
SKF good measure of subcutaneous fat
distribution of subcutaneous and internal fat is similar for all of the same sex (assuming subcutaneous and visceral is same percentage) ex. 1/3
Sum of SKF from multiple sites is used to estimate rest of body
Bioelectrical Impedance Analysis
Noninvasive
Sensors applied to body, electrical pulse sent through
Fat tissue is a worse conductor than lean tissue (tissues either intefere or conduct electrical currents)
Total body water volume inversely related to resistance of currents
Dual-Energy x-ray Absorptiometry
Best method to estimate the mineral contribution of FFB
Shows different densities of bone, fat, lean tissue
Fasting increases accuracy
Minimal client participation
No pregnant women
Gold standard for visceral adipose tissue assessment
Energy balance
energy intake = energy expenditure
Positive: weight gain
Negative: weight loss
Kilocalorie (kcal)
unit of heat energy
Resting metabolic rate (RMR) is the largest contributor to
total energy expenditure (TEE)
Obligatory thermogenesis vs facultative thermogenesis
normal digesting food vs something such as shivering
Preliminary steps to weight loss
set body weight goal, assess kcal intake, assess kcal expenditure
Learn the equation for figuring out how much weight to lose - lecture 5
Weight loss program design
-3,500 kcal deficit needed to lose 1 pound
-500 to 1,000 kcal/day deficit
-Calorie restriction and exercise combo
-Exercise: conserve FFM
-Collaborate with a nutritionist to ensure adequate nutrient intake
-Monitor body composition
Exercise prescription for weight loss
Frequency: daily
Intensity: moderate, duration is more important
Time: Greater than 60 minutes
Type: aerobic for weight loss, but use resistance training to prevent weight regain and preserve FFM
How many minutes of exercise are needed to prevent weight gain
250 min/week
Sarcolemma and endomysium =
same thing
Connective tissues in muscles
Epimysium (on top), perimysium (between) and endomysium (inside)
Learn muscle structure
Hierarchy of muscle structure
Myofibril > sarcomeres>myofilaments>actin and myosin
How does a muscle contract?
Excitation-contraction coupling, cross-bridge cycling and sliding filament theory
Excitation-contraction coupling
- Ach released at pre-synaptic terminal to post synaptic receptor
- Action potential along sarcolemma (ATP)
- AP in t tubule leads to calcium release from Sarcoplasmic Reticulum
- Calcium goes to cross-bridge cycling step (ATP - SERCA pumps put calcium back in sarcoplasmic reticulum)
Cross-bridge cycle
- ADP bound myosin head is ready to bind to actin
- Calcium bind to troponin exposing binding sites for myosin
- Bound myosin binds to actin and does a power stroke
- ADP is releases and new ATP molecule binds to the myosin head
- Actin and myosin detach
- ATP is hydrolyzed and is now ADP again
ATP is very important so muscles can relax
Sliding filament theory
myosin slides past actin while lengths stay the same
Isometric
Concentric
Eccentric
no movement (some actin-myosin overlap)
ex. Bicep curl - muscle shortening (sliding movement allows myosin to be overlapped by actin)
muscles lengthening (pulls actin away from myosin, sarcomeres get pulled from each other)
Force-length relationship
“optimal” length - maximized active force because you have the ideal relationship between actin and myosin
The force-frequency relationship
Lower stimulation frequency = lower force
Force-velocity relationship
High force = slow muscle shortening
Small force = faster shortening
Power-velocity relationship (P=FxV)
Inverted U-shaped
Certain velocities where you can generate the most force and power
Max power = about ⅓ of velocity max
Why do we study fatigue?
-Exercise tolerance
-Occupational health/safety
-Optimize performance
-Clinical treatments
-Injury risk
Fatigue vs fatigability
Perceived fatigability vs performance fatigability
Fatigue is used to describe a symptom in a range of chronic diseases and disorders
Perceived fatigability - subjective (mood motivation)
Performance fatigability - objective (exercise-induced fatigue)
Definition of neuromuscular fatigue
a failure to maintain a required submaximal (sustained force)
An exercise-induced decline in maximal force or power production
Motor unit
-Makes up functional unit of movements
-Consists of an alpha motorneuron and all the muscle fibers it innervates
-Different muscle fiber to motor unit ratio ex 1:5 or 1:800
-All or none principle: all of the muscle fibers innervated in a motor neuron are stimulated to contract
FF
FR
S
Henneman’s size principle
FF - type 2x fibre
FR - typa 2a fibre
S - type 1 fibre
motor units recruited from smallest to largest
Muscle wisdom
sustained isometric contraction = increasing fatigue
Muscle wisdom theory proposed that slowing the firing frequency of recruited motor units could serve to minimize fatigue
Central vs peripheral fatigue
Fatigue before neuromuscular junction vs fatigue after neuromuscular junction
Mechanisms of peripheral fatigue
Decreased ATP levels, inhibition in the pre and post-synaptic areas, inadequate ach release, slow actin-myosin detachment, slow ca2+ re-uptake, lowered CA2+ availability (decreased release)
Mechanisms of central fatigue
Your central nervous system gets signals from your peripheral system telling it if it is fatigued
Fentanyl decreased the signals as if they weren’t sending the afferents to say they were tired
Mechanisms: Factors affecting cortical drive, factors affecting spinal drive, afferent feedback
Interpolated twitch technique (ITT)
Electrical signal causes nerve to fire and find maximal voluntary contraction and voluntary activation
Calculating VA (voluntary activation)
Calculating VA (central fatigue) requires both Super imposed twitch and resting twitch
Central and peripheral fatigue summary
MVC force = capacity of central nervous system and muscled
Large SIT = decreased CNS drive muscles
Decreased VA = increased central fatigue
Small RT = decrease muscles to produce force
Decreased RT = increased peripheral fatigue
Effect of exercise intensity-duration
Neuromuscular fatigue is dependent on exercise intensity and duration
Lower intensities/longer durations = increased central fatigue
Higher intensities/shorter durations = increased peripheral fatigue
Factors affecting fatigue
perceived fatigability and performance fatigability
Resistance exercise can help prevent and be good for
Muscle loss, chronic diseases, rehabilitation, physiological problems
Types of resistance training
Static (isometric) ex. dead hangs or planks
Dynamic (isotonic) ex. bicep curl
Variable external resistance training ex. assisted pull ups
Muscle strength
Submaximal force
Maximum force output of a muscle or muscle group
Percentage of the one RM or multiple RM that someone could lift
Training principles
Individuality
Specificity
Reversibility
Genetics, cellular growth rate, metabolism, cardio. High responders vs low responders
Mode, intensity, duration, muscle group ex. a swimmer vs a cyclist
Use it or lose it
Progressive overloading
Muscle is loaded beyond the load it is normally used (frequency, load, volume - 5 reps instead of 7, duration of rest)
Load-Adaptation-load-adaptation
Sarcopenia
What factors contribute to this
Loss of skeletal muscle mass that occurs with biological aging
Muscle loss specifically increases the risk for glucose intolerance
Hormones, get less active as you age, usually you eat less when you are elderly, decrease in motor units and fibres
Reversing muscle loss
12 -20 exercise sets of 2-3 days/week can increase muscle mass in adults
Resistance training Recharges resting metabolism
-muscle protein turnover
-more energy at rest (more tissue means more calories being burned)
Resistance training reduces body fat
-manages obesity
-reduces intra-abdominal fat
Visceral fat gain in premenopausal women over a 2 year study period (7% resistance-trained vs 21% untrained)
Resistance training increases bone mineral density
Sarcopenia is associated with bone loss (osteopenia)
Resistance training can prevent or reverse 1% of bone loss per year
Building blocks of resistance training
Volume on bottom (foundation)
Intensity and mode in middle
repetitions, rest, sets, duration on top
