Foster, Carl Ph.D., FACSM; Stanley, Derek M.Ed.; de Koning, Jos J. Ph.D., FACSM; Porcari, John P. Ph.D., FACSM
EVALUATING YOUR CLIENT
In the ideal world, it always is best to have an evaluation before you prescribe exercise, especially in an individual preparing for a really significant challenge like a half marathon. A well-done test measuring maximal oxygen uptake (V˙O2max), with heart rate (HR) and rating of perceived exertion (RPE) responses, and maybe some information about the economy of running, and maybe even blood lactate responses with increasing speed would be really ideal. Even a clinical stress test, although focused on pathology rather than performance, would be useful as it could provide peak exercise capacity and maximal HR (if it’s done well). Unfortunately, these are seldom available. Furthermore, in a healthy exerciser, with no symptoms or risk factors, a clinical stress test is not really justified and performance tests are hard to come by.
However, even though you don’t have laboratory tests on your clients, you can make some pretty good estimates of what they might be able to do based on performance information gathered from a “fun run” and their body mass index (BMI). Indeed, most running coaches individualize their training programs this way, using current performance data. Performance data integrate all the aspects of physiology important to running as effectively as do specific laboratory tests.
The 5-km fun run was done in 29:30. Assuming a pretty accurate course, this is equivalent to a pace of 9:30 per mile (which is 169 m per minute because 1 mile = 1,609 m). You can use well-validated ACSM equations to estimate the oxygen cost of running . It’s better to assume a 1% grade to account for outside conditions). From this, we can estimate the oxygen cost (V˙O2) during the fun run:
ACSM equation for estimating V˙O2 = cost of moving horizontally + cost of moving vertically vertical + resting oxygen uptake
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Then substitute speed (169 m per minute) and grade (0.01) from the fun run:
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This is the average V˙O2 that was used during the fun run. However, in a run of approximately 30 minutes, they weren’t working at V˙O2max but considerably less than V˙O2max. If they “weren’t talking to anyone,” you can assume that they were likely running around the “negative stage” of the “Talk Test” (where you definitely can’t talk comfortably). This is an intensity that approximates several important, and somewhat interchangeable, markers derived from physiological testing, such as the Respiratory Compensation Threshold, the 4-mmol lactate threshold, the maximal lactate steady state, or the critical velocity. The exact value will vary individually, but it’s close enough to say that this intensity also is about 85% of V˙O2max. This allows you to estimate your clients’ V˙O2max; V˙O2max = 38.8/0.85 = 45.6 mL O2/kg per minute. Note that this value is adjusted for their body weight and is the best single measure of the capacity to move oneself around. Think of it as the motor divided by the weight of the chassis of a car. It also will be important to know the absolute value of the V˙O2max (e.g., the motor) because you also are going to recommend that your runner lose a little weight. If we multiply the V˙O2max/kg × the runner’s body weight (e.g., 70 kg), we find that his “motor” is 45.6 × 70 = 3,192 mL/min or 3.192 L/min (for comparison, think of a truck with a 5-L motor). For a person in his early 40s, this is pretty good, as the average “young adult” male has a V˙O2max of 45 mL O2/kg per minute (35 mL O2/kg per minute for women). So, our runner, even though he is a little heavier (BMI = 27) than ideal (BMI <25) has what might be called fairly good talent for endurance activities.
Given his BMI (weight in kilograms divided by height in square meters) of 27 and assuming a body weight of 70 kg (154 lb), then his height is 1.61 m (63.4 inches). Before a race like a half marathon, it would be good to reduce BMI to less than 25 (the upper limit of the ideal range). You could go to the trouble of measuring %fat to get even more accurate, but BMI remarkably is useful for most people. At that point, and assuming no great changes in muscularity, body weight at a BMI of 25 would be 64.8 kg (142 lb). A “motor” of 3.19 L/min in a smaller body that is 12 lb smaller gives him a V˙O2max of 49.2 mL O2/kg per minute (3.19 L/min divided 64.8 kg body weight).
Because he already is exercising regularly, about 100 min/wk at moderate intensity, most of the training effect for V˙O2max has been achieved already. With the addition of some higher-intensity training, he might improve his gross V˙O2max by approximately 5%. So the maximum estimated V˙O2max on race day (e.g., the best-case scenario) (3.19 × 1.05 = 3.349 L/min), with BMI = 25, is 51.7 mL/kg per minute (3.349/64.8). We will use this idealized V˙O2max to calculate his maximal aerobic speed (MAS), the speed at which V˙O2max occurs, and which is sustainable for only 5 to 7 minutes. This will be a very important index when he starts adding some interval training to his program:
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He can’t sustain V˙O2max and MAS for the 2-hour goal of a half marathon. Although elite runners can sustain close to 85% of V˙O2max for the slightly more than 2 hours required for a marathon, a reasonable estimate for a moderately trained runner is that he can sustain 75% of V˙O2max for approximately 2 hours. So, his race V˙O2 is likely to be 51.7 * 0.75 = 38.8 mL O2/kg per minute. Solving the ACSM equations for a racing V˙O2 of 38.8 mL/kg gives:
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So, he is now in the range where a 2-hour time for 13.1 miles is within reach based on a reasonable 5% physiological improvement from training and a reasonably achievable weight loss.
The highest HR he saw during the 5-km fun run is probably pretty close to his maximal HR. We have no way of really knowing what his maximal HR really is, but we know that the prediction equations (e.g., 220 - age) are almost useless for prescribing exercise. Indeed, in certain people, that can be somewhat dangerous, in that they can encourage training at an intensity that is too high. In any case, the terminal HR in a run where “they weren’t talking to anyone” is a pretty good estimate of maximal HR. So, with a “maximal” HR of 175 BPM and a casual resting HR of 65 BPM, they have a HR reserve (HRR) of 110 BPM. For already trained individuals with good exercise capacities, the best evidence regarding an appropriate training window is between 70% to 85% HRR.
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We already know from the casual observations they made of HR in training that they have been training in the range of 130 to 140, which is at the low end of the ACSM-recommended HR during training. We also know that successful endurance athletes tend to do their “easy” or “volume” training below the intensity of the lactate/ventilatory threshold, which typically occurs at approximately 80% of the maximal HR. So 175 * 0.80 = 140.
We also know that successful endurance athletes do their harder (e.g., interval) training at about the point where their breathing and blood lactate really increase rapidly, which is about 90% of maximal HR. So 175 * 0.9 = 158 (or 85% HRR = 159).
Thus, using two completely independent HR prescription methods, we get the idea that longer runs should be done at or just below an HR of 140. Harder runs (e.g., interval training) should be done at an HR at or just above 160. The primary goal of the training program is to increase the maximum distance that they can tolerate. So, being conservative and erring on the side of more distance, approximately 140 probably represents the highest HR they want to achieve.
In other words, the very first thing they have to do is to run more, and more, and more, in pretty much the same way they have been running. If they do nothing other than that, they will survive a half marathon and might not be too far off their goal time. Your first job, then, is to create a schedule that will allow them to increase their training mileage in a sensible way.
Once they gain the ability to run longer, we also want them to be able to run faster and to develop a higher V˙O2max (e.g., a bigger motor) to work with. It doesn’t take much interval training to cause an improvement in V˙O2max and a very noticeable improvement in running performance. The best studies of high-level athletes suggest that they only do about 10% of their training at higher intensity. So, assuming that they will build up to about 30 miles per week of total running (see below), the most higher-intensity training we will get our runner up to is approximately 3 miles per week. We also know that interval runs should be done at about the MAS. Our best estimate of the MAS for our neo-competitor is about 6:58 per mile or 1:45 per lap or 53 seconds per half lap. MAS may ultimately be a little faster than this, as he will have already done more training and will have lost weight before the interval training starts, but we must always keep in mind that we are preparing for a 2-hour race, so absolute speed isn’t particularly important. Furthermore, it’s much better to start conservatively and find out that the runner can comfortably go faster than to be too enthusiastic too early. Too much early enthusiasm just leads to loss of interest or injury. The speed of MAS will be our starting speed for interval runs. The pace will increase naturally as our runner becomes fitter (and lighter), but the progression will be guided by the HR response.
So, with a little thought about our runner’s previous performance data, we can make reasonable estimates of his V˙O2max, or his MAS, and (assuming that he takes his BMI down to <25) that his goal of 2 hours for a 13.1-mile run is within reach.
THE TRAINING PLAN
To keep the risk of injury sufficiently low, it probably is a good idea to keep the number of days of running to four per week. More frequent training (potentially) will yield better results, but it also increases the risk of injury. For the runner who is just beginning a more ambitious training level, it probably is best to err on the side of slightly smaller and slower results if it means a reduction in the risk of injury. If more frequent training is desired, the mode of training should be non-weight bearing (cycling, elliptical, swimming), with the idea that the extra day of training is designed primarily to use energy, so that it’s easier to get his body weight down to the point where his BMI is less than 25. Based on the principle that the best training for running is running (i.e., specificity of exercise), we have designed a 4 days-per-week training plan based only on running. Indeed, research studies have shown that on a minute-versus-minute basis, so-called “cross training” only is 25% to 50% as effective as specific training relative to improving performance.
There is a long-standing rule of thumb in the distance running community called the “rule of threes,” suggesting that you need to be averaging about one third of race distance per day during the 2 months or so before a long race. So, 13.1/3 = 4.4 miles/d × 7 days = 31 miles per week. To make the program simple, we will use 30 miles per week as a round number. To complete longer distances successfully, you have to train longer!
So, our first goal is to get to 30 miles per week.
The second goal is to increase the length of the longest training run(s).
The third goal is to use some interval training to get faster.
As a general principle, longer runs should be done twice per week, with the other two runs reserved for recovery. Later, one of the recovery runs will be used for higher-intensity running, but only after your runner is well along the path to adequate training volume. Also note (Table) that the workload occasionally decreases from one week to the next. This is planned entirely, it’s called periodization and is a well-accepted technique to allow the body to consolidate the adaptations it has made and to give time for some recovery.
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A schematic diagram of how the training load might be increased during the 6 months of training is depicted in Figure 1. With 4 training days per week, it is necessary to run at least 2 days in a row. Indeed, recent research from both Denmark and Australia suggests that training when the legs are a little tired may be more effective than if the legs are recovered fully, so the two longest days will be back to back. Figure 1 is set up assuming that Saturday and Sunday are the back-to-back days. Most people have more time on the weekends. That means that Monday, Wednesday, and Friday will be days off. However, it’s important not to think of them as “off days” but days where they are “preparing to train well” on their “training days.” If your runner’s schedule doesn’t work for Saturday and Sunday, it just requires some common-sense adjustments to his schedule.
The length of the longest run should be increased by about 1 mile per week (assuming that he starts at 3 miles on his longest runs). The second longest run should increase by about a half mile per week, until one long run of 10 miles is achievable after 9 weeks. The other long run of 10 miles should be achieved after 20 weeks). Keeping the two “short days” at 3 miles per day, this will bring the runner to 21 miles per week after 12 weeks (goal 1 almost accomplished) and 30 miles per week after 21 weeks. The pace of running will increase gradually as the runner becomes fitter and loses weight. However, the HR in training should remain around (or just below) 140 and the runner should always pass the “Talk Test” (e.g., be able to converse comfortably) during all of his running at this stage). It’s much more important to go longer than harder. Thus, it’s important to resist the temptation to be overly competitive during training. In fact, the priority at this stage is so much on increasing distance, that even if he has to do some walk-run segments to build up distance, that’s preferable to turning training sessions into races.
In the fourth month we also will introduce some faster training. This can be accomplished by increasing one of the “short” days to about 6 miles (add 1 mile per week from a starting point of 2 to 3 miles on this day) and by adding some interval training to the other “short” day, so that it totals about 3 miles. By the end of the training period, the interval day will have a short warm-up and cooldown and a total of about 3 miles (∼10% of total volume) of interval training.
Notice that the total volume of training will be nearly stable after 4 months. Increases in training load during the last 2 months will be based on increasing intensity.
The higher-intensity training will be mostly about intensity of the MAS, which will result in an HR of about 85% HRR (160 bpm). By this point, the MAS inevitably will be faster than 1:45 per lap, but it’s best to start with this speed and use fairly short intervals of about 53 seconds per half lap on a track. Start by running 1 mile as normal to warm-up, then run approximately 4 times half a lap, with a half-lap recovery interval, and then finally 1 mile to cooldown (3 miles total). The pace for the next runs will be adjusted based on the HR response. If it’s below 160 after the second interval, the pace should be increased. If it’s above 160, then the pace should be moderated (i.e., keep the intensity window narrow (155 to 165). Progressively, the length of the hard segment will increase (Table).
As your runner prepares, it probably is worthwhile to do a fun run or test effort about every 4 to 6 weeks. First, it will be enjoyable for him to see himself getting better week by week and, second, it will help you evaluate his progress. This should be done in place of one of the normal “long runs,” and the goal should be to get a better feeling for how he feels while running at a little harder pace. Test efforts of more than about 10 km (or 6 miles) probably are not necessary. Once 10 km can be run comfortably in a fun run setting, it may be worth trying to run at the goal pace for his upcoming 13.1-mile run to get a feel for how he should feel at the halfway point in the target race. This probably will be slower than what he could do for 10 km at this point, but the goal is to use the fun runs to learn how to manage themselves during the half marathon. This is really critical because the single biggest mistake that almost all runners make during their first longer races is to be too enthusiastic early in the event. Runners need to learn that the effort (e.g., perceived exertion measured on a scale developed by Swedish psychologist Gunnar Borg) should grow progressively during the target race and only approach maximal effort very near the end of the race. This means that they actually will be pretty comfortable at the halfway point (Figure 2). They need to learn that feeling! If they don’t learn it, then the last 3 miles of the half marathon will feel very long. It also is important to keep reinforcing that the correct intensity during a half marathon race is one that will allow comfortable conversation for at least the first 10 miles of the race (e.g., passing the “Talk Test”). Because he will have already done several 10-mile runs in training, it’s important to reinforce that the first 10 miles of the half marathon won’t be a lot faster than the 10-mile training runs, but that they should be able to keep the pressure on, if not slightly increase the pace, during the last 3.1 miles.
During the last week of training, the distance of all efforts should be reduced to 60% to 80% of that accomplished at the peak of training, 2 weeks before the target race. Even if they haven’t built up to the training targets discussed, it’s best to get to race day somewhat rested, rather than feeling worn out from progressive increases in training, so do the “taper” based on what they actually have accomplished 2 weeks out from the target day for the race. In this regard, it is important to use the occasional planned reductions in the training load, periodization, to help them get to race day both fit and well recovered.
On race day, make sure that they are running in shoes, socks, shorts, and shirt that they have used several times before. New “racing clothes” may look good, but something new on race day is much more likely to present a challenge than to boost performance. Similarly, during a 2-hour run, your client probably will want to drink a small amount of a glucose-electrolyte beverage when he runs. It’s not particularly critical because dehydration is unlikely to be an issue during only 2 hours, but because it will be available on the course, most runners can’t resist the opportunity to “fuel up.” Just as with the “racing clothes,” he doesn’t want to try anything new on race day. So, make sure that he has experienced consuming small amounts of glucose-electrolyte beverage as a routine practice during his longer training runs.
Lastly, depending on where he lives, if the weather presents an unexpected hot day and, more particularly, if he isn’t acclimatized to warm weather, you should have discussed a definite plan B. There is nothing worse than trying to accomplish a time goal in a long race in hot weather, particularly, unexpected hot weather. It absolutely is miserable, it almost is never successful, and it is the one time where long-distance running is appreciably dangerous. Your client will be in very good shape, so from a training standpoint, it’s easy to have an alternative race sometime in the next month, just recycle the training program back the appropriate number of weeks. The goal is to succeed in his first race, even if it’s not exactly the race he planned for.
CONDENSED VERSION AND BOTTOM LINE
Increase the volume of training during about the first 5 months of the 6-month buildup period. The eventual weekly volume of training should be about 2.3 times the race distance. For a half marathon, the primary focus of training is on achieving total training volume and performing multiple long runs (up to about 75% of race distance). A secondary focus of training is performing 6 to 8 weeks of 1 × weekly interval training at about the maximal aerobic speed. The training plan should be periodized to allow recovery within the overall structure of the increasing training load.
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© 2014 American College of Sports Medicine.