Exercise Prescription and Programming - Designing Cardiorespiratory Exercise Programs

Benefits of Cardiorespiratory Endurance

• ACSM guidelines
• Prescribing and monitoring Intensity
• Building a session
• Case Studies

Terminology

• Cardiorespiratory vs. Cardiovascular vs. Aerobic
• Physical activity for health vs. fitness
• Lower intensity (than guidelines) may still reduce the risk of certain diseases

Physiological Changes Induced by Cardiorespiratory Endurance Training

• Increases:
  • Cardiorespiratory System:
    • Heart size and volume
    • Blood volume and total hemoglobin
    • Stroke volume (rest and exercise)
    • Cardiac Output-maximum
    • $VO_{2max}$
    • Oxygen extraction from blood
    • Lung volumes
  • Musculoskeletal System:
    • Mitochondria (number and size)
    • Myoglobin stores
    • Triglyceride stores
    • Oxidative phosphorylation
  • Other Systems:
    • Strength of connective tissues
    • Heat acclimatization
    • High-density lipoprotein cholesterol
• Decreases:
  • Cardiorespiratory System:
    • Resting heart rate
    • Submaximal exercise heart rate
    • Blood pressure (if high)
  • Other Systems:
    • Body weight (if overweight)
    • Body fat
    • Total cholesterol
    • Low-density lipoprotein cholesterol

ACSM Guidelines for Healthy Adults (Cardiorespiratory Exercise)

• Intensity:
  • 64/74% - 94% HRmax
  • 40/50% - 89% $VO_2$R or HRR
  • 12-16 RPE
• Frequency: 3-5 days/week
• Duration: 20-60 minutes of continuous activity (10 min bouts accumulated)
• Mode: large muscle groups, maintained continuously, rhythmic and aerobic in nature (e.g., walking, running, cycling, rowing).

Evidence for Guidelines

• Frequency 3-5/week
  • Over 10 citations supplied in ACSM literature
  • Hickson et al. (1981)
    • 12 subjects trained 40 min/d, 6 d/wk (cycling/running)
    • After 10 wk, they continued to train either 4 d/wk or 2 d/wk for an additional 15 wk.
    • Intensity and duration for the additional 15 wk remained the same as on the tenth week of training.
    • Increase in $VO_{2max}$ in response to 10 weeks of training was 25% when measured during bicycle testing and 20% when measured during treadmill testing.
    • $VO_{2max}$ in the 4 d/wk and 2 d/wk groups remained the same for the next 15 weeks

Frequency - In Practice

• Dependent on fitness status, goals, and mode.
  • < 5 METS functional capacity - daily (multiple) sessions
  • > 5 METS functional capacity - 3 - 5 sessions/week
• Alternate days to reduce injury risk.
• Weekend warriors?

Weekend Warrior Physical Activity Pattern & Mortality Risk (O'Donovan et al., 2017)

• All-Cause Mortality:
  • Inactive: No moderate- or vigorous-intensity physical activities
  • Insufficiently active: < 150 min/wk in moderate-intensity physical activity and < 75 min/wk in vigorous-intensity physical activity
  • Regularly active: 150 min/wk in moderate-intensity physical activity or 75 min/wk in vigorous-intensity physical activity from >=3 sessions
  • Weekend warrior: 150 min/wk in moderate-intensity physical activity or 75 min/wk in vigorous-intensity physical activity from 1 or 2 sessions
  • Weekend warrior and other leisure time physical activity patterns characterized by 1 or 2 sessions per week may be sufficient to reduce all-cause, cardiovascular disease, and cancer mortality risks.
• Cardiovascular Disease
• Cancer Mortality

Evidence for Guidelines

• Duration 20-60 (10 min accumulated)
  • Over 20 citations supplied in ACSM literature
  • Hartung et al. (1977)
    • 29 subjects trained for 6 weeks at 75% of maximum heart rate.
    • Training durations were 5 min (N = 10), 15 min (N = 10) and 25 min (N = 9) with over 80% of the training sessions consisting of monitored treadmill walking on a grade.
    • The improvements in treadmill time were 7.7%, 14.7% and 20.2% for the three training groups, all significant.
    • Improvement in the 25 min group was significantly greater than the control and 5 min groups, but not the 15 min group.
    • The same differences were noted when estimated maximal oxygen uptake changes were analyzed.

Duration - In Practice

• What does a weekly schedule look like?
• What is the current activity level/ base fitness like?
• Something is better than nothing!
• Evidence?
  • Light exercise done for half the required time improved aerobic capacity in sedentary women
  • 10 x 3min bouts reduced serum cholesterol

Duration

• Time constraints of client
• Adjust intensity
• 20 - 60 minutes of continuous or intermittent (minimum 10 minute bouts) accumulated throughout the day
• Healthy individuals may sustain exercise at 60 - 85% $VO_2$max for 20 - 30 minutes.
• Poorly conditioned individuals may only be able to exercise at low intensity (40% $VO_2$max) for 10 minutes (need to perform multiple sessions/day).
• Alternative prescription technique is to use the caloric cost of exercise (ACSM recommends caloric thresholds of 150 - 300 Kcal per session or 800 - 900 Kcal per week
• Or Pedometer counts? 7000? 10 000?
• Appropriate combination of duration and intensity so that the individual adequately stresses the cardiorespiratory system without overexertion
• Improvement stage - increase every 2-3 weeks

Evidence for Guidelines Intensity

• 64/74% - 94% HRmax or
• 40/50% - 89% $VO_2$R or HRR or
• 12-16 RPE
• Over 20 citations supplied in ACSM literature
• Eg. Gossard et al. (1986)
  • 21 trained at low intensity (42-60% $VO_2$max)
  • 23 trained at high intensity (63-81% $VO_2$max)
  • 20 controls
  • Caloric expenditure was kept constant between high and low groups
  • Low intensity increased $VO_2$max by 8%
  • High intensity increased $VO_2$max by 16%

Evidence for Guidelines Frequency and Intensity

• Duncan et al (2005): 4 walking groups:
  • a) moderate intensity/low frequency
  • b) moderate intensity/ high frequency
  • c) hard intensity/ low frequency
  • d) hard intensity/ high frequency
• Outcomes at 6 and 24 months showed significantly improved cardiorespiratory fitness in groups b, c, d
• Group D showed greatest increase in cardiorespiratory fitness as well as HDL-C markers and total cholesterol-HDL-C ratio compared to control group (physician advice only).
• Exercise prescribed at either hard intensity or high frequency produced sig. long-term improvements in cardiorespiratory fitness.
• The combination of hard intensity plus high frequency exercise may provide additional benefits, including larger fitness changes and improved lipid profiles.

$VO_2$R and HRR (Heart Rate Reserve)

• $VO<em>2$R is the difference between $VO</em>2$max and resting $VO_2$
• HRR is the difference between HRmax and resting HR
• Percent values of $VO_2$R and HRR are approximately equal

$VO_2$R/HRR vs HRmax

• Small but systematic differences between $VO<em>2$R/HRR and HRmax because the %HRmax method represents about 55 - 70% $VO</em>2$max
• Either method can be used
• In the end, it is only a guide

Intensity

• Should first take into account duration
• Range is intentionally broad
• For most individuals 70 - 80% HRmax or 60 - 80% of $VO_2$R or HRR
• Untrained and older individuals (30-39% HRR)
• Younger and aerobically fit individuals (60-89% HRR)
• Different methods of prescribing intensity
  • 40 - 50% HRR/VO2R 64 - 74% HRmax (Low-fit)
  • 85% HRR/VO2R 94% HRmax (Physically Active)

Intensity Category Method to Prescribe and Monitor Intensity

• Very light: < 57 (% of HRmax), < 37 (% of $\dot{V}O<em>2$max), < 30 (% of HRR or % of $\dot{V}O</em>2$R), <2.0 (METS), Below (Ventilatory / Lactate Threshold), Able to sing (Talk/Sing Test), < 9 (RPE)
• Light: 57-63 (% of HRmax), 37-45 (% of $\dot{V}O<em>2$max), 30-39 (% of HRR or % of $\dot{V}O</em>2$R), 2.4-4.7 (METS), Able to sing (Talk/Sing Test), 9-11 (RPE)
• Moderate: 64-76 (% of HRmax), 46-63 (% of $\dot{V}O<em>2$max), 40-59 (% of HRR or % of $\dot{V}O</em>2$R), 4.8-7.1 (METS), Able to talk but unable to sing (Talk/Sing Test), 12-13 (RPE)
• Vigorous: 77-95 (% of HRmax), 64-90 (% of $\dot{V}O<em>2$max), 60-89 (% of HRR or % of $\dot{V}O</em>2$R), 7.2-10.1 (METS), Above (Ventilatory / Lactate Threshold), No comfortable talking (Talk/Sing Test), 14-17 (RPE)
• High: 80-100 (% of HRmax), 70-100 (% of $\dot{V}O<em>2$max), 65-100 (% of HRR or % of $\dot{V}O</em>2$R), 10.2- 11.3 (METS), Very difficult to talk (Talk/Sing Test), 17-18 (RPE)
• Supra-maximal: N/A (% of HRmax), ≥ 100 (% of $\dot{V}O<em>2$max), N/A (% of HRR or % of $\dot{V}O</em>2$R), > 11.3 (METS), Unable to talk (Talk/Sing Test), ≥ 18 (RPE)

Intensity Prescription Using HR

• First, you need HRmax
  • Best to determine max HR during a max test
  • Estimate using age (variance is around 10 - 12 bpm) + specialised regression equation
• Once you have HRmax - three methods to prescribe intensity
  • Direct method (medication)
  • Percent of HRmax
  • HRR method

Intensity Prescription using HR

1. Direct method
   • plot measured HR against measured $VO_2$ or exercise intensity or RPE (if available)
2. Percent of HRmax
   • straight percentage of measured or estimated HRmax
3. Heart Rate Reserve
   • Resting heart rate is subtracted from maximal heart rate then you calculate the heart rate range then add resting HR back to get the target range e.g.
     • HR max = 180, HR rest = 60
     • HRR = 120,
     • Training HR range = 60 - 80%
     • Low Target HR = $(0.6)120$ + HR rest = 132 bpm
     • High Target HR = $(0.8)120$ + HR rest = 156 bpm

• For both heart rate-based approaches, for longer durations, cardiovascular drift will likely increase heart rate when exercising at the same work rate. Therefore work rate may need to be decreased to keep the heart rate on target, or in the target zone

Intensity Prescription using MET’s

• If you are able to assess/estimate the client’s functional cardiorespiratory capacity ($VO_2$max)
• MET’s (as a % of $VO_2$max)
  • If a person's $VO_2$max = 35 mL/kg/min = 10 METs
  • Training intensity of 60 - 80% = 6 - 8 METs
• Once a MET level is identified, a corresponding work rate may be calculated through the use of tables

Intensity Prescription by $VO_2$

• As a % of $VO_2$R
  • Target $VO<em>2$ = (intensity) ($VO</em>2$max - $VO<em>2$rest) + $VO</em>2$rest
  • Target = $(0.65) (35 - 3.5) + 3.5 = (0.65) (31.5) +3.5 = 24.0$
  • Target = $(0.80) (35 - 3.5) + 3.5 = (0.80) (31.5) +3.5 = 28.7$
  • Target $VO_2$ = 24 - 29 mL/kg/min (6.9 - 8.3 METs)

Intensity Prescription Using Metabolic Equations

• Most Accurate
• Cycle Ergometry
  • $1.74 \times (work rate \times 6.12/kg \text{ of body weight}) + 3.5$
  • 150-750 kpm/min
• Treadmill walking and running
  • $speed \times (0.17 + (grade \times 0.79) + 3.5$
• Stepping
  • $3.5 + (0.2 \times steps/min) + (1.33 \times (1.8 \times step height \times steps/min))$
  • 12-30 steps/min
  • Metabolic equations for the estimation of $\dot{V} O_2$ (mL/kg/min) during cycle ergometry, treadmill walking and running, and stepping
    • cwork rate in Watts
    • dspeed in m/min where 1km/h = 16.7 m/min
    • egrade in % expressed as a decimal
    • fstep height in m

Limitation in Using MET’s or Metabolic Calculations

• Variable on skill (economy of movement)
• No consideration for the environment

Intensity Prescription using RPE

• Considered an adjunct to monitoring HR as it may not consistently translate to the same intensity on other modes
• Good for people with HR palpation problems
• Aim for an RPE of between 12 - 16 (using Borg scale)
• There are two commonly used RPE scales for aerobic exercise: the Borg 6–20 scale and the Borg category ratio (CR)-10 scale. There are no current recommendations regarding use of one scale in preference to another. The 6-20 scale was chosen as a simple way to estimate heart rate. Multiplying the Borg score by 10 gives an approximate heart rate for a particular aerobic activity (e.g. resting heart rate of 60 bpm (=6) and maximal heart rate of 200 bpm (=20) for a 20 year old).

Talk Test

• Can you carry on a conversation with your exercise partner? Moderate intensity exercise
• Can you only talk in short phrases, or not at all? Or talk but not sing? High intensity exercise

Methods to Monitor Exercise Intensity

Intensity - In Practice

• Most complex factor
• Level should be selected based on:
  • Client goals
  • Individual’s capacity
  • Preference
  • Health risks
  • Willingness to monitor intensity
  • Duration of activity
• Can be recommended, measured, and monitored in several ways

Other Considerations

• Some individuals prefer to exercise at a certain end of the intensity range
  • E.g., Older individuals – low end (min for improvements?)
• Individual’s perception of effort will vary for different modes (when exercising at the same HR)

Building a Session

1. Warm-up: ~ 10 minutes (moderate aerobic activity and stretches)
2. Conditioning/aerobic activity: ~ 20 – 60 minutes
3. Cool-down: ~ 10 minutes (diminishing intensity aerobic activity and stretches)

Interval Training

• Aerobic exercise interval training involves alternating periods of usually higher intensity exercise with light recovery exercise or no exercise between intervals
• Two of the more common approaches are high-intensity interval training (HIIT) and sprint interval training (SIT).
• HIIT may be further divided into high and low volume HIIT based on the total duration of the high-intensity intervals. Any protocol with a total high-intensity duration < 15 minutes (e.g. 10 x 1 -minute) is low volume HIIT
• A common high volume HIIT protocol is the 4 x 4 approach that consists of four 4 -minute high-intensity intervals separated by 3 minutes of recovery at a light intensity. This results in 16 minutes of high-intensity exercise and is therefore considered high volume HIIT.

Interval Training Evidence

• Nybo et al, 2010, MSSE- High intensity training versus traditional exercise interventions for promoting health
  • 5x2min @95% 1min rest between vs 60min at 80%
  • Although total training time was less than 1/3 other groups, increase in $Vo_2$max was superior
  • No changes in metabolic fitness (fat ox), muscle mass, body comp
• This is one example- this literature has exploded in the last 10 years

7 Elements Can Be Modified

• Work Intensity
• Recovery Intensity
• Work Modality
• Number of Intervals
• Work Duration
• Recovery Duration
• Session Duration

Rate of Progression

• Months 1 2 3

• Initial fitness level

• Overload

• Injury, illness

• Initial – first 2 weeks – “start low and go slow” - low-level activity (40 - 60 % HRR)

• Improvement - progression becomes more rapid (50 - 85% HRR), every 2-3 weeks

• Maintenance - group 2 and 3 exercises?

Modes of Aerobic (Cardiorespiratory Endurance) Exercises to Improve Physical Fitness

Training Progression for the Sedentary Low-Risk Participants

Continuous vs. Discontinuous

• Continuous
  • Maintenance of exercise intensity
  • Less demanding, more enjoyable
  • May not provide optimal performance benefit for athletes
• Discontinuous
  • Repeated bouts of low to high intensity with rest periods
  • May be necessary for those competing
  • saves time - more work in a given period of time
    Dropout rate ?
    short bouts of exercise may be preferred when prescribing exercise to obese adults:
    Jakicic et al (1995) showed similar changes in cardiorespiratory fitness but enhanced weight loss when comparing short bouts (10mins multiple times daily) to long bouts (one 20- 40 min bout daily). There was a trend for greater weight loss and adherence in the SB group over a 20-week period.

Aerobic (Cardiovascular Endurance) Exercise

Putting Parts Together…

Client Interview

• Past exercise experiences
• Specific health goals
• Time constraints
• Equipment needs
• Personal reasons for exercising
• Test results/health appraisal
• Injuries/Obesity or overweight?
• Clear, measurable, concise goals

PBL Activity – Case Study

• Male, 38 years, normal ranges for BMI, waist circumference, blood pressure. Visually you would classify him as an ectomorph. Screening and medical history revealed he recently had a “medical”, with no issues mentioned by his doctor. Doctor said he was in “A1 health”. Fitness assessment showed below-normal levels for strength. One of his goals is to improve his strength. His exercise history reveals little to no experience with resistance training.
• Questions to consider:
  • In his first session, how many resistance exercises would you prescribe?
  • How many sets of each?
  • How many reps in each set?
  • What would the exercises be, and what order would you put them in?
  • How could you set the intensity?
  • Would you do anything different in the second session?
  • How often would you be asking him to do resistance training?
  • For a four-week prescription, what factors would you be considering?
  • During the first few sessions, what would you be concentrating on?

PBL Activity – Case Study

• Female, 20 years, normal ranges for BMI, waist circumference, blood pressure. Screening and medical history reveals no apparent concerns. Fitness assessment shows average strength scores. She is on the border of getting into the Queensland Water Polo Team but needs to “get stronger in the water”. Her exercise history reveals she has been given a few “weights programs” but never really enjoyed them and therefore only stayed on them for a few weeks.
• What would be some of the features that you would have in her program?

PBL Activity – Case Study

• Female, 35 years old, two young children (4 and 7 years old). Used to be an elite pole vaulter but stopped training 15 years ago and has not done much physical activity since. She is a high school teacher. Her goal is to lose weight and be healthy and a good role model for her children.
• What extra questions do you want to ask her before you write her a program?
• What will you prescribe for the cardiorespiratory component of her program?