Kin 310 Exercise/Work Physiology

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Kin 310Exercise/Work Physiology

• Office hours - HC 2910 (lab)
• F 1030-1120
• or by appointment (ryand_at_sfu.ca)
• class email list
• announcements, questions and responses
• inform me of a preferred email account
• class notes will be posted on the web site in
  power point each week
• can be printed up to six per page
• lecture schedule along with reading assignment on
  web site
• www.sfu.ca/ryand/kin310.htm

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Energy for Exercise and Work

• Brooks p1-10 ch 4
• Astrand ch. 17 p 503-540
• Mcardle, Katch and Katch Appendix D
• Outline
• Introduction to Exercise Physiology
• Course overview
• Energy, work and power
• Calorimetry and the estimation of metabolic rate
• Assessment of workload
• Relative VO2, HR, Hormonal response
• Energy expenditure over workday
• Energy systems, work rest ratio

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Exercise Physiology

• Physiological responses to exercise depend on
• Intensity, Duration, Frequency, Environmental
  circumstances, Diet, Health, Physiological status
• Exercise requires the conversion of chemical into
  mechanical energy
• Principles of bioenergetics control and limit
  performance
• Acquisition and utilization of energy and the
  role of organ systems in supporting these
  processes will be discussed
• Understanding short (acute) and long term
  (chronic) effects of exercise on the human
  machine is important in exercise science and
  health

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Rate Limiting Factor

• What limits performances?
• Proper analysis of a sport or work situation is
  important to identify
• Pathways and metabolic sequences that are used
• The factors which turn the rate of these pathways
  up or down
• The steps that are limiting or slow
• All of this is required to understanding
  function, pathophysiology (disease) and to
  concentrate efforts when training to improve
  performance
• Eg. VO2 fig 1-5
• Limited by cardiovascular system
• Widely used criterion of physical fitness

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Performance

• Stress and Response
• With appropriate stimuli, physiological systems
  respond with increased functional capacity
  (training)
• Overload but not overtrain
• Seyle - General Adaptation Syndrome (GAS)
• Alarm Reaction (shock)
• Resistance Development (adaptation)
• Exhaustion (staleness)
• Principles of Fitness
• Overload
• Specificity
• Reversibility
• Individuality

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Course Overview

• Discussion of the physiological basis of exercise
  and work
• Evaluating Energy and Workload
• Cardiovascular and respiratory compensations and
  capacities
• Limitations and adaptations to training
• Cellular bioenergetics
• Providing ATP to meet demand and recovery
• Fatigue - inability to sustain activity level
• description of fatigue in the CNS, the
  neuromuscular junction and the muscle cell
• Molecular level adaptation
• activity changes the cellular environment -
  stimulating adaptation to better meet demand
• Work place / sport analysis and assessment of
  worker /athlete capacity
• Strength evaluation variables
• Ageing - change in physiological capacities -
  impacts of disease and activity level
• Exercise and the Environment
• Heat and barometric pressure can create
  additional demands on physiological systems

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Energy

• Energy - capacity or ability to perform work -
  joules, calories
• Work - application of a force through a distance
  - joules, calories, Kgm
• Biological work - transport, mechanical and
  chemical work
• Power - amount work performed over a specific
  time (workrate) - Joules/s kgm min-1
• Transformation of energy - forms of energy can
  be converted from one form to another
• chemical energy in food is transformed into
  mechanical energy of movement or other biological
  work
• Biological energy cycle

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Metabolism

• Metabolism - the total of processes occurring ina
  living organism
• Because heat is produced by these processes, the
  metabolic rate can be measured by the rate of
  heat production
• Ultimately, all metabolic processes depend on
  biological oxidation
• Measuring O2 consumption is a good estimate of
  heat production, or metabolic rate
• Energy Transduction
• Photosynthesis
• cell respiration (not ventilation)
• cell work

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Calorimetry

• Calorie - heat energy required to raise one gram
  of water one degree Celcius
• Calorimetry - procedure to measure metabolic rate
• Direct Calorimetry - measurement of heat - very
  difficult
• Indirect Calorimetry - measurement of Oxygen use
  - valid and reliable
• Fig 4-8 Atwater and Rosa
• Determined heat production, oxygen consumption
  and carbon dioxide production simultaneously
• Established relationship between direct and
  indirect methods
• Bomb calorimeter - energy value of food when
  ignited - fig 4-9
• Appendix D - Mcardle, Katch and Katch (on
  resreves)

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Respiratory Quotient

• Table 4.1 - energy per unit oxygen different -
  carbohydrates 6.4 higher
• Respiratory Quotient - Ratio of CO2 produced to
  O2 consumed
• Value obtained gives an indication of the type of
  fuel being used in muscle
• Pure Glucose RQ 1.00
• Pure Fat RQ .70
• Mixed fuel will provide intermediate value
  depending on mix
• Fig 4.10 marathon RQ values
• R value - an estimate of RQ that is measured at
  the mouth
• Must consider non-metabolic sources of CO2 - Fig
  4-14

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Measurement of Metabolic Response

• Evaluation provides info about absolute and
  relative intensity of exercise bout (fig 10.1a)
• absolute VO2 (L/min or ml/Kg/min)
• of VO2 max
• of HR max
• multiples of Metabolic Rate (METs)
• 1kcal/Kg/hour at rest 3.5mlO2/kg/min
• determination of metabolic response allows
  estimation of
• Total energy cost
• Nutritional requirements
• Efficiency calculations
• Estimation of workload indicates metabolic system
  utilization, and the potential for fatigue

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Work Load Assessment

• Assessment of work load in relation to work
  capacity
• variability in capacity
• variability in response
• expression of workload by absolute VO2 alone is
  almost meaningless
• Need work load as of individual max
• Assessment requires the determination of
• individual VO2 max
• VO2 requirement of imposed load
• assessment of muscle groups being utilized, and
  the of their maximum strength -to determine
  fatigue onset

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Assessment

• Maximal aerobic power
• direct - VO2 max test
• estimation - predictive tests
• Assessment of Workload
• measure O2 uptake during work
• Fig 17-2 O2 uptake vs bike/work
• portable devices, rapid analysis of VCO2 and VO2
  - large data base
• field studies - collect expired air
• Douglas bag
• or - use flow meter to determine volume of air,
  and take samples of air for content analysis
• Fig 17-3 commercial fisherman
• subjects often affected - test atypical
• Eg. Breathing through mouth not nose

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Indirect assessment

• Recall linear relationships between HR and VO2,
  VO2 and work rate
• HR may be used to estimate workload - on
  individual basis
• same muscle groups environmental temperature, and
  emotional stress
• Continuously recorded HR
• provides general picture of overall activity
  level during entire day
• along with time activity studies collected by
  observers
• possible to separate different activities with
  respect to HR
• Fig 17-5 - fisherman

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Comparison studies

• Fig 17-6 - strong day - day consistency
• Computer analysis of HR data gives
• mean values, peak values, distribution and HR
  variability
• Fig 17-8 comparison of direct vs indirect
  measurement /- 15
• HR is good estimate of workload when work uses
  large muscle groups
• Fig 17-9 arm vs leg work
• HR is higher in arm work than leg work for the
  same work load.
• O2 uptake for work load must be expressed as
  max of individual
• indicates relative degree of exertion
• HR reserve (HR max - HR rest)
• Circulatory strain is best expressed as a
  percentage of an individuals HR reserve

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Stress of Work

• The total stress imposed on the organism by a
  given work situation (physical or psychological)
  is generally reflected by nervous and hormonal
  stimulation
• Proportional to the degree of stress
• Nervous Response
• Inc sympathetic tone - inc HR
• influence linear relationship
• Eg HR vs workload
• Hormonal response
• total stress reflected by sympathetic response
• Measure ep and/or nor ep with urinary excretion
  or blood samples
• Fig 17-16, 17-17 - Catecholamines - inc with
  standing, cold and emotion
• Also inc with duration and severity of muscular
  exertion

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Energy Expenditure

• Need to establish practical limits for physical
  work loads
• Type of work and work/rest cycles are important
• Large individual differences in physical work
  capacity
• 30 - 40 VO2 max for 8 hour day
• 40 of max strength in repetitive muscular work
  
• restwork ratio of 21
• physiological and psychological responses
  influenced by
• individual max aerobic power
• size of muscle being engaged
• working position
• Static or dynamic work
• intermittent vs continuous activity
• environmental conditions

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Daily Energy Expenditure

• Important for
• calculation of energy needs
• determine physical activity of groups
• role of physical activity in health
• Methodology
• 24 hr recorded HR
• time activity data
• assessment of daily energy intake to maintain
  body weight
• all fairly accurate /- 15
• show large individual variability
• 1300-5000 kcal /day
• Table 17-1, 17-2

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Energy expenditure

• O2 uptake and HR - Table 17.1
• Important for
• Calculation of energy needs
• Determine physical activity of groups
• Role of physical activity in health
• Methodology All fairly accurate /- 15
• 24 hr recorded HR Time activity data (video
  analysis)
• Assessment of daily energy intake to maintain
  body weight
• Wide individual variability in energy output -
  Table 17-1,2
• Occupation
• Leisure activity / Physical activity
• Environmental temp
• Daily rate 1300 - 5000 kcal
• Reg active male 2900 kcal/day
• Reg active female 2100 kcal/day

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Energy Expenditures

• Work expenditures
• Most light work lt 5 kcal /min
• Some physical jobs 7.5 - 10.5 kcal/min
• Permissible limits for daily work 2000-2500 kcal
• Limits are difficult due to individual
  differences in work capacity or fitness
• Individuals will usually self regulate the rest
  pauses
• Peak load is more important than mean energy
  expenditure
• You can attain a higher 8 hour energy expenditure
  if the work is consistent and does not have peak
  loads
• Basal Metabolic rate (BMR) - rate of energy
  metabolism in a resting individual 14-18 hours
  after eating

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Energy Expenditure

• Recreational activities
• McArdle, Katch and Katch
• Appendix C (on reserves)
• Different activities have different energy
  expenditures
• Cycling race 13 kcal/min
• Golf 6 kcal/min
• Skiing uphill fast 21 kcal/min
• Swimming -fast 13 kcal/min
• Running 530 mile 22 kcal/min
• Individuals do activities at different
  intensities
• Must take body weight into account