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Aerobic
 

Aerobic

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    Aerobic Aerobic Presentation Transcript

    • Assessing Cardiorespiratory Endurance A Fitness Indicator
    • Determination of Fitness Level
      • Everyone possesses some degree of cardiorespiratory endurance (CRE)
      • CRE=a health associated component that relates to the ability of circulatory and respiratory systems to supply fuel during sustained physical activity and to eliminate fatigue products after supplying fuel.
    • VO 2 max
      • VO 2 max is the most commonly used index to assess CRE
      • Definition - The largest amount of oxygen that an individual can utilize during strenuous exercise to complete exhaustion
      • Has become the accepted measure of CRE
    • AEROBIC GLYCOLYSIS AND THE ELECTRON TRANSPORT CHAIN
    • KREBS CYCLE
    • METABOLISM OF FAT
    • OXIDATIVE PHOSPHORYLATION
    • VO 2 max
      • Units
        • liters/minute or ml/minute (absolute)
        • ml/kg/min (relative to body weight)
        • ml/kg of FFM/min (relative to FFM)
      • Range 15 (sedentary with disease) to 75 (young endurance runner) ml/kg/min
      • Women about 10-20% lower than men
    • Methods of Determining VO 2 max
      • Submaximally
      • Maximally
    • GXT
      • Graded Exercise Testing - GXT (incremental increases in workload)
      • General Guidelines
        • measure the subject’s HR and BP and RPE at regular intervals (near the end of each stage [HR, BP, RPE] or every minute [HR])
        • if HR does not reach steady state during the stage extend stage 1 minute
    • GXT
      • General Guidelines
        • All testing begins with a 2-3 min warm-up
        • Cool- down at a low intensity for at least 4 minutes - continue measuring HR, BP and RPE
        • increase intensity in .5-2 MET increments
        • closely observe subject for contraindications
    • Submaximal Assumptions
      • 1. A steady-state HR is obtained for each exercise work rate
      • 2. A maximal HR for a given age is uniform (220-age)
    • Assumptions
      • 3. Mechanical efficiency (ie. VO 2 at a given work rate) is the same for everyone.
        • This may not be true and it has been suggested that submaximal exercise testing underestimates VO 2max in the untrained and overestimates in the trained
    • Submaximal Assumptions
      • 4. There is a linear relationship between HR and Workload
      • 5. HR will vary depending on fitness level between subjects at any given workload
    • Age vs. HR
    • Submaximal Protocols
      • Oxygen consumption for any given WL does not vary between subjects
      • The slope of the line is about the same for any two given subjects
      • The rate of increase in O2 consumption with increasing WL does not vary between subjects
    • EXERCISE INTENSITY AND OXYGEN UPTAKE
    • Submax Protocols
      • HR does vary between subjects
      • rate of increase in HR depends on fitness level
      • The more fit you are the lower your HR at any given WL
      • An untrained person will reach their HR max at a lower WL vs. a trained person of the same age.
    • HEART RATE AND INTENSITY
    • HEART RATE AND TRAINING
    • HR vs. Workload
    • HEART RATE, VO 2 , AND INCREASING WORK .
    • HR vs. WL and VO 2
    • Submaximal Protocols
      • 1. YMCA - bike
      • 2. Astrand Rhyming – bike
      • 3. ACSM - bike
      • 4. Bruce Protocol - treadmill
      • 5. McCardles Step Test
    • YMCA
      • Multi-stage protocol
      • 3-4 consecutive 3 minute stages
      • HR between 110-150 bpm (the HR range at which the relationship between VO 2 and WL is most linear)
    • YMCA Procedures
      • 1. Adjust seat height (legs nearly straight when extended - 5º bend)
      • 2. Measure pre-exercise BP and HR with subject seated on bike
      • 3. Pedal at 50 rpm (if using a metronome - 100x/minute)
      • 4. Warm-up, zero resistance for 2-3 minute
    • YMCA Protocol
      • 5. Stage 1
        • .5 kp for 3 minutes
        • at every stage measure BP at 2.0 min (more often if hypertensive)
        • at every stage measure HR during last half of minutes 2 and 3
        • if HR at 2 and 3 minutes differ by more than 6 bpm extend the stage for 1 min
    • YMCA Protocol
      • 6. Stage 2
        • Workload in this stage and successive stages depends on HR during stage 1 (p 75 guidelines)
      • 7. Continue test until HR recorded at two successive WL are between 110 and 150 bpm (for many this occurs during 2nd and 3rd WL)
    • YMCA Protocol
      • 8. Note that if HR is greater than 110 at end of 1st stage then only one more stage is necessary
      • 9. At completion of test reduce resistance to .5kp and allow subject to pedal for at least 4 minutes or until HR falls below 100 bpm and BP stabilizes.
    • YMCA Protocol
      • 10. The HR measured during the last minute of each stage is plotted against workload.
      • 11. The line generated from the plotted points is extrapolated to the age-predicted HR max
      • 12. A perpendicular line is dropped to the x-axis to estimate the work rate this person would achieve if taken to max.
    •  
    • ACSM Bike Test
      • 1. 2-3 minute warm-up
      • 2. Take HR twice during each stage (3 minute stages) and RPE/BP once (similar to YMCA)
      • 3. If HRs are greater than 110, steady state should be reached (HRs within 6bpm) before increasing the workload
    • ACSM
      • Protocol A B C (kgm/min)
      • Stage 1 150 150 300
      • Stage 2 300 300 600
      • Stage 3 450 600 900
      • Stage 4 600 900 1200
    • ACSM
      • Protocol Selection
      • BW Very Active
      • (kg) No Yes
      • <73 A A
      • 74-90 A B
      • >91 B C
        • *very active is defined as aerobic exercise 20 minutes, 3 days/week
    • ACSM
      • 5. Terminate test when HR reaches 85% of age-predicted max HR or 70% of HR reserve
      • 6. Recovery at workload equal to the 1 st stage or less for at least 4 minutes with HR, BP, and RPE monitored.
    • ACSM
      • Plot HRs from last two stages to determine VO2max much like YMCA.
    • Astrand Rhyming
      • Single-stage test (VO2 max is determined using 1 submaximal data point-HR)
      • Duration of test is 6 minutes
    • Astrand Rhyming
      • 1. Adjust seat height (legs nearly straight when extended - 5º bend)
      • 2. Measure pre-exercise BP and HR with subject seated on bike
      • 3. Pedal at 50 rpm (if using a metronome - 100x/minute)
      • 4. Warm-up, zero resistance for 2-3 minute
    • Astrand Rhyming
      • 5. Pedal rate is 50 rpm
      • 6. Determine Workload
        • unconditioned males - 300 or 600 kgm/min
        • conditioned males - 600 or 900 kgm/min
        • unconditioned females - 300-450 kgm/min
        • conditioned females - 450 or 600 kgm/min
      • 7. 6 minute test
    • Astrand Rhyming
      • 8. At end of 2nd minute of pedaling take HR (BP at 1.25-1.5 min)
        • want the HR to be between 125-170bpm
        • if less than 125 increase resistance by 1 kp for men and 1/2 kp for women
        • if greater than 170 bpm decrease resistance by 1 kp
        • continue to monitor HR every minute until HR exceeds 125
    • Astrand Rhyming
      • 9. At the end of the 5th and 6th minute take HR and average the two values (make sure values are within + 6bpm to assure a steady state HR was obtained)
      • 10. BP at 4:30 and 5:30
      • 11. Reduce resistance and cool-down for 4 minutes.
    • Astrand Rhyming
      • 10. Determine VO 2 from nomogram (p. 73 guidelines, p.69 Heyward)
      • 11. Age-correction factor (p. 74 guidelines, p.72 heyward)
      • 12. Convert to relative value
    • Treadmill Tests
      • Bruce Protocol
      • Balke
      • Ellestad
      • Others……….
    • Treadmill Protocols
      • Bruce and Ellestad
        • larger increments
        • use on younger and/or more physically active
      • Balke-Ware
        • smaller increments (1MET/stage or lower)
        • use on older, deconditioned, and/or diseased subjects
    • Treadmill Protocol
      • Single-stage (using one data point) even though we may have more than one stage
      • May need to have a long accustomization period and explanation of procedures before beginning
    • Bruce Treadmill Protocol
      • 1. Measure resting BP and HR while standing on the belt of the treadmill
      • 2. Ask subject to straddle the belt while starting treadmill at 1.7 mph and 0% grade
      • 3. Ask subject to begin walking and when comfortable release handrails
      • 4. This is a warm-up and should continue until subject is comfortable
    • Bruce Treadmill Protocol
      • 5. Stage 1
        • Increase grade to 10%
        • 3 minutes long
        • Measure HR at end of each minute and BP at end of each stage
    • Bruce Treadmill Protocol
      • 6. The objective is to reach a steady state HR between 115 and 155 bpm (usually occurs during the first 6 minutes of exercise or by the end of the 2nd stage) – Page 98 guidelines
      • 7. Once subject reaches proper HR terminate the test at the end of that stage
    • Bruce Treadmill Protocol
      • 8. Reduce treadmill speed to 1.7mph and 5% grade and cool-down for 4 minutes.
      • 9. VO2 is estimated from the last minute of a fully completed stage
    • Treadmill Protocol
      • 10. Calculate VO 2 from the gender specific equations
      • Males
        • VO 2 =SM VO2 [(HR max -61)/(HR SM -61)]
      • Females
        • VO 2 =SM VO2 [(HR max -72)/(HR SM -72)]
        • SM VO2 = submaximal VO 2 from table or ACSM equations
        • HR SM = submax HR from test
    • Modified Bruce Protocol
      • Start at 1.7 mph, 0% grade or at 1.7 mph and 5% grade (used on diseased and elderly populations)
    • Treadmill Protocol
      • Protocols should be individualized
      • Test time should ideally be 8-12min
      • Increments of 10-15 W/min or 1-3%/min grade can be used for the elderly
    • McCardle’s Step Test
      • Bench ht. = 41.25 cm
      • Step Rate = 24 step/min (metronome = 96) for men and 22 step/min (metronome=88) for women
      • 3 minutes of stepping
      • Record HR from the first 15seconds after the stepping has stopped
    • McCardle
      • Men
        • VO 2 = 111.33 - (0.42 x HRrec)
      • Women
        • VO 2 = 65.81 - (0.1847 x HRrec)
        • value is ml/kg/min
    • Maximal Testing
      • Assumption: The subject was highly motivated and gave a maximal effort.
    • Max Testing
      • Laboratory Tests
      • 1. Open Circuit Indirect Calorimetry
      • 2. Cycle
      • 3. Treadmill (Bruce)
    • Maximal Protocols
      • Field Tests
      • 4. 12 minute run
      • 5. 1.5 mile run
      • 6. Rockport Walking Test
    • Measuring Energy Costs of Exercise
      • Direct calorimetry —measures the body's heat production to calculate energy expenditure.
      • Indirect calorimetry —calculates energy expenditure from the respiratory exchange ratio (RER) of CO 2 and O 2 .
    • A CALORIMETRIC CHAMBER
    • Open Circuit Indirect Calorimetry (Gas Analysis)
    • Respiratory Exchange Ratio
      • The ratio between CO 2 released (VCO 2 ) and oxygen consumed (VO 2 )
      • RER = VCO 2 /VO 2
      • The RER value at rest is usually 0.78 to 0.80
    • RER
      • Value ranges from .7-1.0
      • 0.7 mainly uses fats as an energy source
      • 1.0 mainly uses carbohydrates as an energy source
      • Can exceed 1.0 during heavy non-steady state, maximal exercise, or when nervous due to hyperventilation (increased CO2)
    • KCALS
      • (RER + 4) x (Liters of O 2 consumed per minute) = kcal/minute
      • For example:
        • RER determined from gas analysis = .75
        • 4 + .75 = 4.75
        • L of O 2 per minute = 3 liters
        • 4.75 x 3 = 14.25 kcal/min
        • If exercised for 30 minutes = 427.5 kcals
    • Cycle to Max
      • 15 W/min protocol
      • VO 2males =10.51 (power in W) + 6.35 (BW in kg) - 10.49 (age in y) + 519.3
      • VO 2females =9.39 (power in W) + 7.7 (BW in kg) - 5.88 (age in y) + 136.7
      • values are in ml/min - divide by BW in kg
    • Treadmill to Max (Bruce)
      • VO 2 = 14.8 - 1.379 (time in min) + 0.451 (time 2 ) - 0.012 (time 3 )
      • While holding handrail
      • VO 2 = 2.282 (time in min) + 8.545
    • Population-specific Equations
      • P. 61 Heyward
      • Active vs. Sedentary, Gender specific, Cardiac patients
    • 12 minute run
    • 12 minute run
      • The further you can run in 12 minutes the higher your VO 2max
    • 1.5 mile run/Rockport Walking
    • 1.5 Mile Run/1 Mile Walk
      • The faster you can run 1.5 miles or walk 1 mile the higher your VO 2max
    • Field Tests
      • 12 min run
        • VO 2 = 3.126 (meters in 12 min) - 11.3
      • 1.5 mile run
        • VO 2 = 3.5 + 483/(time in minutes)
      • Rockport Walking Test (1 mile walk)
        • VO 2 = 132.853 - 0.1692 (BW in kg) - 0.3877 (age in y) + 6.315 (gender) - 3.2649 (time in min) - 0.1565 (HR)
        • 0 for female; 1 for male; HR at end of walk
    • Normal Responses to GXT
      • 1. Systolic BP increases in direct proportion to increasing WL
      • 2. HR increases linearly with WL
      • 3. Diastolic BP changes very little
      • 4. Shortened QT Interval
      • 5. Reduced R-wave amplitude
      • 6. Positive upslope of ST segment
    • Abnormal responses to GXT
      • 1. ST segment depression
      • 2. Increased R-wave amplitude
      • 3. V-tach
      • 4. Multiform PVC’s
      • 5. Failure of HR to rise with WL
      • 6. Failure of systolic to rise
      • 7. Systolic and diastolic greater than 250 or 120
    • Test Termination
      • 1. Have reached a pre-determined endpoint
      • Absolute
      • 1. Suspicion of myocardial infarction
      • 2. Moderate to severe angina
      • 3. Drop in Systolic BP with increasing Workload (>20)
    • Absolute
      • 4. Arrhythmias
      • 5. Pale or cold and clammy skin
      • 6. Severe shortness of breath
      • 7. Dizzy, blurred vision, or confusion
      • 8. Patient requests stop
      • 9. V-tach or multiform PVC’s
      • 10. ST segment depression
    • Absolute
      • 11. Excessive rise in BP (systolic >250; diastolic >120)
      • 12. Failure of HR to increase
    • Relative
      • 1. ECG changes from baseline
      • 2. Chest pain that is increasing
      • 3. Wheezing
      • 4. Leg cramps
      • 5. High Systolic/Diastolic
      • 6. Less serious arrhythmias
      • 7. Less severe shortness of breath
    • Advantages of Submaximal Testing
      • 1. Safer
      • 2. Controlled pace (motivation not a factor)
      • 3. Not population specific (no pacing advantage)
      • 4. Quick assessment
      • 5. Cost effective
    • Advantages of Submaximal Testing
      • 6. Don’t need highly trained personnel
      • 7. Can do mass testing
      • 8. No physician supervision required (if symptom and disease free)
    • Disadvantages of Submaximal Testing
      • 1. VO 2 max is not directly measured (error rate of 10-20%)
      • 2. Don’t get a measure of true maximal HR
        • estimates of max HR using 220-age can vary by + 15 bpm for individuals of the same age
    • Advantages and Disadvantages of a Maximal Test
      • Advantages
      • 1. More accurate
      • Disadvantages
      • 1. Motivation is a factor
      • 2. More risk involved
      • 3. Time
      • 4. Cost of equipment (if using metabolic cart)
    • Walking/Running vs. Cycling/Stepping
      • Walking/Running are the most natural forms of locomotion (most Americans are unaccustomed to cycling
      • In general, subjects reach higher VO2max values during treadmill tests
      • Treadmill are more expensive than cycles
      • Treadmill is less portable
    • Walking/Running vs. Cycling/Stepping
      • Body weight has a much smaller effect on cycle ergometry versus treadmills
      • Treadmill more dangerous (greater risk of a fall
      • Measurement of HR is more difficult on a treadmill and while stepping