Lab Category: Cardiovascular Training

Interval Training:

Involves alternating high-intensity training and low intensity active recovery. Interval training is very stressful and should not be performed until the client has a firm base of aerobic conditioning (i.e., not a beginner). Interval training is associated with an increased VO₂max and anaerobic metabolism.

Interval Training Examples:

Involves work of approximately 2-5 minutes per interval. The goal is to work toward affording equal amount of time for rest (periods of low-intensity exercise; i.e., work to rest ratio of 1:1). Clients complete 3-8 sets.

This type of training is stressful and should not be done more than three times per week.

*Help your client reach the prescribed intensity with a combination of incline/resistance and speed/cadence*

** Recovery is done at low intensity to allow HR and breathing to recover sufficiently for another interval. Ensure your client is recovered to a point of at least <70% of HRR (or less than their LT) **

Repetition Training (REPS):

A form of interval training to develop speed and endurance. Repetition training involves short bursts of very high-intensity (nearly VO₂max or above VO₂max). The work intervals are between 20-90s with the work:rest ratio varying between 1:3 and 1:5 (or more rest if needed). The physiology adaptions associated with REPS include improved running speed and economy and increased anaerobic metabolism. This type of training is reserved for clients with a firm base of aerobic conditioning and a VERY GOOD level of CV fitness.

Repetition Training (REPS) Examples:

The work intervals last about 20-90 seconds; the work to rest ration varies between 1:3 – 1:5, or more rest if needed. Clients complete 3-8 sets.

This type of training is very stressful and should not be done more than once or twice per week.

• *Help your client reach the prescribed intensity with a combination of incline/resistance and speed/cadence*

** Note, 20s is hard to complete on a treadmill – this is generally done on a field/track.

Other General CV Prescription Reminders:

• Light Intensity Physical Activity results health benefits (despite not often having CV training benefits)
• Exercise intensity is inversely related to duration
• Low and Moderate intensities will improve endurance and maximum oxygen uptake in undertrained or moderately trained individuals but is less effective in well-trained athletes, who require higher training intensities in order for additional physiological adaptations to occur.
• Note, long slow distance training is necessary for endurance athletes, where more mileage per week is almost always better (there is data to suggest a diminishing effect around 60 miles/wk).
• Moderate intensity SS is also good for active recovery, muscular endurance, thermoregulatory function, muscle oxidative capacity, and fat utilization purposes
• Generally, your client is at a VG level of initial fitness before they can tolerate continuous vigorous intensity exercise (i.e., a 20-30-minute tempo exercise bout). Also, your client is at a VG level of initial fitness to be doing repetition training (REPS; anaerobic interval training).
• Pace/temp training can also be done in an intermittent fashion (i.e., intervals) still using a training intensity at about LT but employing a series of intervals with recovery. This allows clients with a moderate fitness base to experience vigorous intensity exercise in a tolerable way.
• Beginner clients should do their CV training on non-consecutive days. Similarly, the introduction of vigorous intensity should happen on non-consecutive days.
• Interval training and repetition training can be an effective way to change body composition, increase fitness, and make exercise fun; however, as a trainer, you have to find an appropriate equipment, intensity, and duration to suit your client. If you are not careful this type of training could cause injury, negative affect, a decrease in exercise adherence, and a decrease in your client’s self-efficacy.

Intensity Description Reminder:

References:

Canadian Society for Exercise Physiology. (2013). Physical Activity Training for Health (CSEP-PATH) Resource Manual. Ottawa, ON: CSEP.

Coburn, J. W., & Moh, H. M. (2012). NSCA’s Essentials of Personal Training. National Strength and Conditioning Association. Human Kinetics: Windsor, ON

Peterson, D. D. & Rittenhouse, M. A. (2019). A Practical Guide to Personal Conditioning. Jones & Bartlett Learning: Burlington MA.

Charts From: Canadian Society for Exercise Physiology. (2013). Physical Activity Training for Health (CSEP-PATH) Resource Manual. Ottawa, ON: CSEP.

A major variable of exercise prescription is intensity. Most clients will require a CV prescription in the moderate and vigorous intensity range; however, clients with initial fitness levels in the ‘poor’ and low-end of ‘fair’ ranges can experience CV improvement working below moderate intensity.

It is important to remember that a CV prescription is based on numerous factors: current ability (i.e., VO₂max, lactate threshold [LT], risk/prescreening), goals, enjoyment, and other aspects of the prescription (i.e., resistance training, week outlook). For example, a general guideline is that continuous vigorous intensity exercise is saved for clients with Very Good or Excellent levels of fitness.

From today’s experience, recognize that working at a given intensity (i.e., moderate/vigorous) will take a different resistance/speed for each client. Also, depending on a client’s lactate threshold (LT), a given intensity (i.e., 75% HRR) will not feel the same or be sustained for as long. LT defines your upper limit in terms of a sustainable pace. After blood lactate starts to accumulate above resting levels, it becomes impossible for the muscles to sustain that pace thereby resulting in fatigue. Importantly, two clients with the same predicted VO₂max will require different exercise intensities due to differences in their LT.

CV exercise intensity can be described in a number of ways (i.e., % of HR max, % of HRR, RPE [10pt. scale], RPE [BORG scale], Talk Test). Predicted maximum heart rate (HR) is often described as 220 minus the client’s age (220-age). Be cautious when using HR based measurement because it is known to be off by 10-15 beats per minute (bpm) or more. Keep in mind that several factors impact HR (i.e., medications, recovery, emotion, environment, stress). Be sure to pair your HR based measurement of intensity with another measurement (i.e., talk test or RPE)

Percent of heart rate reserve (%HRR) is thought to be a better calculation of exercise intensity compared to %HRmax, especially for trained clients, because it takes into account a client’s resting heart rate. Using the %HRR method is also handy because it is thought to be a fine prediction of %VO₂max; hence, using the %HRR equation you can estimate to what % of VO₂max the client is currently working.  The calculation is: HRR = [intensity x (HRmax - HRrest)] + HRrest.

Rate of Perceived Exertion (RPE) is a commonly used method to determine exercise intensity. It is non-threatening for the client to estimate a number on a scale. RPE isn’t influenced by medication; however, is known to be influenced by exercise enjoyment, emotion, stress. Commonly used scales are the 1-10pt. scale and the BORG scale (6-20pts). The BORG scale was originally created to approximately match a 20 year old’s heart rate data (i.e., 200 = age predicted HR max = 20/20 on the scale; 60 = typical resting HR = rest, 6/20 on the scale).

The Talk Test is an easy, non-invasive, method of gathering how hard the exercise session is for the client. A client can talk easily during light intensity exercise (i.e., sing even), a client can talk in short sentences when working at a moderate intensity, can say only a few words in vigorous intensity and cannot talk while engaging in vary hard and maximal effort. A vigorous effort is uncomfortable for a client; whereas, a client feels a moderate effort as purposeful, the client is getting warmer, but moderate effort wouldn’t be associated with discomfort.

The intensities that we are going to experience and describe today are:

1. LIGHT = 30% HRR, maintain for 5 minutes
2. Mid MODERATE = 50% HRR, maintain for 5-10 minutes
3. Low to Mid VIGOROUS = 60-70% HRR, depending on fitness maintain for 5-10 minutes
4. Mid VIGOROUS = 70-​75% HRR, depending on fitness maintain for 5-10 minutes
5. Very Hard to Maximum = > 85% HRR, intensity and duration depends on fitness

Aerobic fitness is the ability of the heart, lungs, and blood vessels to get oxygen to the working muscle. The more efficient your heart, lungs, and blood vessels are at getting oxygen to muscles that need it (to do work) the more aerobically fit you are. Assessing your client’s aerobic fitness is important to build an appropriate CV prescription for the client and to see aerobic fitness change over time (i.e., to see if your prescription is effective). The type of CV training you prescribe to a client (steady state, interval, tempo training, fartlek, circuit) and the intensity you prescribe (light, moderate, vigorous, maximal) are directly related to their initial aerobic fitness; it should be noted that you would also consider your client’s goals, likes/dislikes, limitations, body composition, and experience with your prescription choices.

Working a general population client to maximal intensity is neither necessary nor advised: the risk of injury is high, they will not be able to push themselves hard enough, and they will not enjoy the experience or the pain following the experience. Maximal fitness tests are reserved for clients who are able to work at maximal intensity without injury or psychological losses (i.e., an athlete, superior fitness levels).

Submaximal fitness assessments (stop at 85% of predicted HRmax) are simple, relatively quick, non-invasive tests to determine aerobic fitness using a client’s heart rate to measure exertion of a known workload. Aerobic fitness can be predicted using submaximal fitness assessments because heart rate response to exercise is related to fitness; such that, if the oxygen need for a task is known (standardized) a client’s heart rate response to that workload is predictive of aerobic fitness. There is a linear relationship between Heart Rate (HR) and Oxygen Cost (amount of oxygen needed to complete a task). With this, if your client does anything to alter their HR during the test (i.e., hold on to railing, work harder/less hard than prescribed [signing, flapping arms], caffeine consumption or other exercise prior to the test, physical/mental health on test day) the results will not be valid. Also, if your client is on a beta blocker medication (medications which keep HR artificially low) they are not suitable for tests predicting aerobic fitness using HR.

Keep in mind, submaximal aerobic fitness assessments tend to over predict VO₂max for sedentary clients and under predict VO₂max for highly trained clients. This is due to the standardized protocol of the stopping the test at 85% of HRmax. Stopping the test at 85% of HRmax may actually be a point beyond where a sedentary client is using oxygen. Similarly, a highly trained client may still be working with oxygen beyond 85% of HRmax Working a client to a point just before they are no longer using oxygen yields the most accurate prediction.

Submaximal exercise tests, which are relatively safer and require less time than maximal fitness tests, are also practical in a variety of settings. Other advantages of submaximal exercise testing include:

• It is known that most client’s do not enjoy maximal fitness and often cannot push themselves to work at a maximal intensity
• These tests provide an opportunity to observe client’s responses to exercise similar to that which will be prescribed. Ideally a fitness coach will choose a fitness test similar to the type of training they plan to prescribe so that they can watch the client experience the training modality for a short period of time.
• These tests provide an opportunity to teach client about rate of perceived exertion and intensity of Moderate/Vigorous exercise so that you are on the same page with prescription discussion.