Lab Category: Cardiovascular Training

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.

Intensity Description ​Examples:

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

The purpose of the YMCA cycle test is to estimate a client’s VO₂max (aerobic fitness). This is a sub-maximal, heart rate dependent, fitness assessment. This test involves minimal upper body movement so is ideal for clients needing BP data collected during exercise. It is non-weight bearing (seated) so there is less joint trauma and risk of the client falling. It is also more applicable for measuring performance of cyclists and translates well to those wanting to use cycling in their exercise program. This test has been validated in people aged 15-69, with balance/coordination difficulty and those who prefer cycling over walking/jogging/running.

The YMCA Cycle Ergometer Test is a multi-stage cycle test. The client will complete a minimum of 3 workloads (stages). This includes a warm-up workload (the first stage). This test is designed so that a client’s heart rate is between 110bpm and 85% HRmax for two consecutive workloads; such that, a ‘valid test’ yields two consecutive workloads/stages (not including the warm-up) in this 110bpm – 85% HRmax zone. The closer a client’s heart rate gets to 85% HRmax the more accurate the aerobic fitness prediction. The intensity can continue to increase after the third workload but, for comfort, you can stop your client after two workloads within the 110 bpm and 85% HRmax range.

Similar to the other assessments we have been discussing, the purpose of the Wellness-Fitness Initiative (WFI) treadmill protocol is to estimate a client’s VO₂max. This test, used by several Fire Protection Agencies, is a heart-rate reliant, submaximal, assessment which predicts aerobic fitness. Like all submaximal aerobic fitness predictive tests, this test is known to underestimate VO₂max of highly trained individuals and overestimate aerobic capacity of less fit (most) individuals (Dolezal, Barr, Boland, Smith, Cooper, 2015).

The WFI aerobic fitness assessment is a predetermined prescription of walking/jogging/running speed and treadmill incline; hence, the oxygen cost of the exercise is known. The client should complete the prescription until their heart rate reaches 85% of max. It is important to record the client’s BMI and the time (in minutes) when their HR reaches 85% of their HR max.

A strength of this assessment is that the trainer/client does not have to determine an appropriate workload speed for the client (pre-determined). It is also a more challenging protocol than the George Test so it will accommodate a client with greater aerobic fitness; however, athletes with Excellent levels of fitness may still max-out this test (complete 18 minutes) before reaching 85% of their HR max. Weaknesses include: length of time for clients with VG/E level of fitness, still HR dependent, and the incline can be intimidating for some clients.

It should be noted, the preferred protocol for most people is a single stage protocol. For more athletic clients, remember, watching a client run on the treadmill for 18 minutes is not a good use of time with a client. For some athletes (i.e., cross country runners), wanting a prediction of their VO₂max, a more appropriate test would be the 1.5 mile run field test (will be discussed in class).

Working a client to a point just before they are no longer using oxygen (i.e., 80-85% HRmax for most clients) yields a more accurate prediction of aerobic fitness than being future off from that target. 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:

1. It is known that most client’s do not enjoy maximal fitness and often cannot push themselves to work at a maximal intensity
2. These tests provide an opportunity to observe client’s responses to exercise similar to that which will be prescribed. Having your client jog for 3-5 minutes with you will help you gain insight as to what they will actually do in an exercise prescription.
3. 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.

Prior to any aerobic fitness test, you should complete the pre-screening process with your client, organize the paper work to prepare for the test, explain the purpose of the test, explain the procedure of the test, and ensure your client understands and is comfortable with the instructions.

The Single Stage Jogging Test (George Test) is a jogging test involving a warm-up and one workload. The speed of the treadmill is determined by the client (self-selected). The warm-up speed usually ranges between 2.0 mph and 4.0 mph and the workload speed must range between 4.3 mph and 7.5 mph. Remember, your client must be jogging during the workload for this test.

If your client cannot jog they should be doing a walking protocol. On a similar note, the client should not hang on to the railings during this test – if your client is hanging on you must decide whether this test is appropriate for them or whether you have the speed of the treadmill to high. Conversely, if jogging at 7.5 mph at a 0% incline is not challenging enough for your client to experience vigorous intensity they are better suited for a more challenging test (i.e., the WFI running test which we will cover next week).

Note: lab this week will be done in two parts. Be sure to attend you Demo #1 appointment on either Monday March 2 or Wednesday March 4th (schedule). Also, lab class will take place on Thursday March 5^th, 4-6pm, in room C1052.

The 20m Shuttle Run was developed by Leger and colleagues in 1988. Clients run back and forth continuously on a 20M course until they can no longer maintain the pace. The running pace is set using a tone. The starting pace is 8.5 km/hr and the speed increased 0.5 km/hr each minute. Each stage takes one minute, there are 21 stages in this assessment.

The maximal speed (kilometer/hour) can be used in combination with a client’s age (in years) to estimate VO₂max (ml/kg/min). Many equations have been used to determine a rough estimate of aerobic fitness from the Shuttle Run (we will discuss validity and necessity of this in class).

For example: VO₂max (ml/kg/min) = 31.025 + (3.238 x speed) – (3.248 x age) + 0.1536 (age x speed)

Another example: VO₂max (ml/kg/min) = 25.8 – (6.6 x gender) – (0.2 x body mass) + (3.2 x speed)

(Where, male = 0; female = 1; speed = km; BM = kg; age = years)

There are two type of warnings that a client can be given during the test: cautions (cheating; leaving before the tone, not touching the 20M line) and warnings (not making it to the 2M warning line before the tone). Clients are eliminated from the assessment if they have three cautions at any time in the test. When a client falls behind the pace and doesn’t make it to the warning line before the tone, he/she must complete the 20M shuttle (i.e., run to the 20M line) then pivot and run over the warning line on the other side before the tone sounds. The test is complete for the client when they fall behind the pace of passing a warning line before the tone two times IN A ROW. In other words, the client must miss two consecutive WARNING LINES to be eliminated from the test.

Cautions (C) and warnings (W) should be recorded on a scoring sheet. A client should be notified when he/she is given a caution or warning. Also, on your scoring sheet, record with a check-mark when your client has completed a stage so that you can easily keep track of your client’s progress. Remember, a stage is not considered complete until the client hears the announcement on the recording while he/she is running with the pace.

Steady state (SS) training involves training at a fixed intensity (stable heart rate and oxygen consumption) below the client’s lactate threshold. This type of exercise is generally used for health benefits, to build endurance, for psychological benefits, for active recovery, and for Cardiovascular (CV) training effects.

Untrained clients can see CV training effects with as little as 10-15 minutes of steady state CV training, two or three times a week. As the cardio-respiratory system improves, allowing for greater perfusion of oxygenated blood and removal of metabolic waste, the client will be able to increase the duration of their steady state workouts. Beginner clients should start with this type of training to build a foundation, to increase endurance, to increase maximum oxygen uptake (VO₂max), and to improve their lactate threshold. SS training effectively improves endurance and maximum oxygen uptake in under-trained or moderately trained individuals.  SS training is less effective in increasing VO₂max in well-trained athletes who require higher training intensities for physiological adaptations to occur.

Intermediate and advanced clients will need longer sessions. Intermediate or advanced clients, depending on fitness, will use this training style for 30 to 90+ minutes (i.e., long slow distance exercise [LSD]). The main goals of LSD for these clients include endurance, thermoregulatory function, muscle oxidative capacity, and fat utilization. For reference, when working with a trained endurance athlete, more mileage per week is almost always better – the point of diminishing return appears to be around 60 miles/week.

SS training is done below intensity of what the client is capable of so that the training can be completed for a longer period of time (i.e., to an inverse relationship between intensity and duration). For most clients, this training is done at a moderate intensity, 50-60% HRR, 5-6 RPE (out of 10). Importantly, this pace should be below lactate threshold; the client should be able to hold a steady heart rate (oxygen consumption). Hence, a very untrained client may need to work lower than 50% HRR and a trained client could hold higher than 60% HRR for 30+ minutes. A general rule of thumb is that this type of training is prescribed at an intensity where the client can talk a sentence and not feel the discomfort of metabolic waste accumulating (while their HR is in the training zone).

Following the prescribed warm-up, once target intensity is achieved, the exercise can continue as long as the client is able to maintain their HR within the prescribed zone and as long as energy is available. Once the client’s heart rate begins to increase without an increase in workload, the exercise session is complete.