Below is a great read on Aerobic training that appeared at:

http://fitnessintuition.com/2009/08/09/five-arguments-for-aerobic-running/

In recent articles, I’ve talked about the training methods of Arthur Lydiard.
The cornerstone of Lydiard-style training is three long runs, typically 10 to 15-miles on Tuesday and Thursday and 22 miles on the weekend, to be run at a medium to high aerobic pace.
Because of my recent four-month layoff due to chronic bronchitis, I’ve been unable to start my Lydiard-style training program, so I can’t write about it from personal experience. But while rooting through some older writings on my computer, I found some stuff on earlier experiments with aerobic training that I think may be worth sharing. Here goes.
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How important is aerobic training? In his wonderful book, Running With the Legends: Training and racing insights from 21 great runners, Michael Sandrock describes how world-class marathoner Priscilla Welch prepared.
(Welch set a world master’s marathon record of 2:26:51 at age 42, in the London Marathon. She won the New York City Marathon the same year.)
Heartrate monitors can help runners properly develop their aerobic base, which Welch [Dave Welch, Priscilla’s husband and coach] considers the most important part of a training program, because it helps the body develop the capacity to burn fats.
“Most runners don’t do that properly at all, and that’s why most of us stay at one level for years on end. One of the things you can do with a heartrate monitor is program the monitor to between 70 and 80 percent of your maximum heartrate, so that it beeps at you when you go out of the range. It’s like having a coach on your arm. The way to do this is to do all your running between 70 and 80 percent of your maximum heartrate, even if it means walking up a hill.”
Welch measures progress through what he calls a “maximum aerobic pace test.”
Calculate 80 percent of your maximum. For Priscilla, that is 145 beats per minute. She’ll go down to the track and run five miles with her heartrate at a steady 145 beats per minute. And we time each mile. What you’re going to notice if you do this test every week or every 10 days or every two weeks is that you’re going to progress if you stay within the zone all the time.
Colleen Cannon, the world’s best female short-course triathlete for several years, followed Dave’s system. One summer Dave gave her a maximum aerobic pace test, which she ran at 8:23 per mile. What that meant was that Cannon was not developed aerobically, even though she was running well at the shorter distances, said [Dave] Welch. “If she had trained to do a half-marathon, she would have bonked for sure. And within 8 weeks, she was down to under 6 minutes per mile from 8:23.”
Dave Welch was saying that by training at 70-80% of max heart rate, we can improve our speed and endurance. If we train, for example, at 75% of maximum during all of our weekday runs, and a little slower on weekend long runs, then we’ll get faster, and we’ll develop endurance at the same time.
Is that cool, or what? After reading Sandrock’s book, I put on the heart-rate monitor and began doing all my runs at 75% of maximum heart rate, except for a once-a-week, 20-minute tempo run at 85-92% of maximum. (I got this figure from Daniels’ Running Formula, by physiologist and coach Jack Daniels, Ph.D.).
Sure enough, my speed slowly but steadily improved as I trained at the same, consistent 75% heart rate. Also, I found that I felt better after my runs; less tired and with an uncann sense of satisfaction, as if the body were communicating its pleasure that I was – finally! – training in harmony with nature’s laws.
Of course, it wasn’t long before I screwed it up by reading books that offered conflicting advice. In Road Racing for Serious Runners: Multispeed Training: 5K to Marathon, Pete Pfitzinger, a well-known runner, coach, and sports physiologist, suggests an aerobic training zone of 60-85% of max. And yet another author, John L. Parker, Jr., in Heart Monitor Training for the Compleat Idiot, suggests doing most runs no faster than 70% of max heart rate by the “Karvonen formula,” which, for me, works out to 78% of MHR calculated as an absolute figure. I also read Phil Maffetone’s book, Training for Endurance, and followed its recommendations rigorously for eight months, without the slightest progress. I suspect Maffetone’s ideas work best for runners who’ve already achieved a very high level of fitness, and/or are overtrained.
I’ll spare you the frustrations of my training over the next two years. Suffice it to say that the concept of a zone raises questions. “Hey, I want to improve as quickly as possible. Exactly how fast should my long and easy runs be? If the “correct” aerobic training zone is 65-80% of MHR, why not do my recovery and long runs at 80%? Surely I’ll improve quicker by training at the fastest aerobic pace. IT’S LOGICAL! Aerobic running is ‘easy’ by actual, scientific definition, so there’s no way I’ll get overtrained.”
Well, okay, but the scientific answer to that is: “Ha-ha.” When reason comes striding confidently along, reality has a way of sticking out its foot. When I tried training at “max aerobic pace,” I quickly became overtrained, and all the joy went out of my running. But when I backed off and trained at 75% again, the feelings of harmony and “rightness” returned.
In the end, I had to concede that I couldn’t plan my training precisely by logic alone. I discovered that there were other “tools” I could turn to, and that they were surprisingly precise.
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To judge by the happy feelings I experienced while running at about 75% of my maximum heart rate, I wondered if it might not be important to listen to the messages of the heart.
Last night, I was re-reading Covert Bailey’s excellent book, Smart Exercise: Burning Fat, Getting Fit. In the chapter titled “The Aerobic Zone,” Bailey discusses the puzzling question of precisely how fast we should run within the “aerobic training zone.”
When we talk about the aerobic zone, 65-80 percent of maximum heart rate, everybody asks, “Where in the zone should I exercise?” Or, “Should my pace be a little on the easy side or a little on the hard side?” As the last chapter showed, you’ll improve most quickly by exercising at the upper end of the zone, around 80 percent. But that doesn’t work for everybody. In recent years, more and more research shows that exercising at the lower level of the aerobic zone is far more beneficial than we used to think.
The advantages of lower level exercise were first noted in older people. A study was done comparing two groups of men averaging seventy years of age. Half ran around a high school track every day at a speed that got their hearts up to 65 percent of maximum. The other half went around the track with their hearts going at about 80 percent of maximum. Both groups were tested periodically to see if they were getting fitter. Were their lungs getting better and their hearts stronger? Were the fatburning enzymes in their muscles increasing? Surprisingly, the researchers found that the men who exercised at 65 percent showed more improvement than the men who exercised at 80 percent. The reason is that at age seventy, your body doesn’t repair itself as fast as it did when you were twenty. When the men who exercised at 80 percent rested, their bodies said, “Do you want us to grow enzymes or repair tissue? We can’t do both.” They needed to rest more or to exercise at a lower level.
Wow, an Old Folks’ Zone. Well, I’m not 70, I’m only 67, and my optimal training pace appears to hover between 75% and 80%. Speaking for myself, I’d rather run at 80%, and rest more, instead of running every day at 65%, which I find is a boring, deadly slog.
How do I know the 75% to 80% range is the “best” pace? Once again, because my heart “tells” me so. At my age, these “optimal” runs must be carefully spaced, and it’s unlikely that I’ll be doing a Lydiard-style weekly 10, 15, and 22 anytime soon.
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I think it’s uncanny, how often the “80%” figure pops up in training lore. Is it the ceiling on most people’s aerobic metabolism? I don’t know. Elite marathoners are able to run aerobically at a much higher percentage of MHR.
The 80% figure occurs in John L. Parker, Jr.’s book, mentioned above. His “70% Karvonen” aerobic training formula works out, for me, to around 78%. In practice, I find that if I’m fit and rested, that pace feels exactly right for most runs.
To calculate 70% MHR by the Karvonen formula, subtract your resting heart rate from your maximum heart rate, multiply the resulting figure by 0.7, then add your resting heart rate. For example, my max and resting heart rates are 175 and 50, so my aerobic ceiling is 175-50 = 125 X .7 = 87.5 + 50 = 137.5, or about 78.6% of my max heart rate, as a simple percentage of MHR.
Being a typical running maniac, I chose to train as close as possible to Parker’s maximum recommended “recovery pace” of 137 beats per minute, or about 78-79% of my MHR. After all, this is well under Pfitzinger’s 85% ceiling. As a 60-year-old, I was training just three days a week and hiking or weight training on three other days — so surely I’d be safe doing “moderate” aerobic running. Alas, the result of this logical, scientifically documented, slyly clever approach was that I stopped improving.
All I can say is: “Thank God for Covert Bailey.” Who is Covert Bailey? He’s yet another exercise physiologist. (They breed like rabbits.) In his books and lectures, Bailey speaks mainly to “ordinary” people, and he does a fine job of describing – and ridiculing – “serious” runners’ manic compulsion to overtrain. Best of all, he suggests common-sense ways to avoid the overtraining syndrome.
Bailey explains overtraining in simple terms. The body says: “I can burn or I can build, but I can’t do both at the same time.” In other words, if you train too hard, long, or often, the body gets behind in its “homework” of rebuilding, and you stop improving. Given the choice between health and fitness, the body always chooses health – every time.
When you train too hard, you feel crabby and the body expresses its discontent by giving you diarrhea, bone-deep weariness, sniffles, and insomnia. It’s telling you – loudly – to back off. Wise runners hear the message.
I had felt extremely good initially while running at 138 beats, and these feelings of well-being tempted me to increase my mileage too fast. Even after I began to feel less than good, I rationalized that I could “tough it out” while my body adapted to the new workload. I wanted to be a high-mileage runner and enjoy racing success! But in the end, I failed to improve, got injured, and became a low-mileage runner with no option to race.
Remembering my initial successes with the heart monitor, I recalled that I’d made excellent progress running at a steady 75% of max heart rate. I now decided to run at 75% max. Once again, I found myself finishing my runs with that uncanny feeling of rightness, as if my body were expressing its delight: “Yes! Now you’re training right!” My average training speed slowly began to rise.
The problem with making a fetish of scientific precision is that training simply isn’t precise. The best scientific training is the least precise. Take John L. Parker, Jr.’s recommendation to train no faster than 70% of MHR per Karvonen. It’s scientific because it simply works – Parker has the evidence of hundreds of success stories to prove it. Something that Parker’s followers routinely experienced is that as their aerobic metabolism developed, speedwork got much harder, because it took running much faster to raise their heart rate to the desired heart rate.
When I came to my senses and stopped letting logic (and emotion and machismo) lead me around by the nose, I realized – well, duh – that 75% to 80% was my best training pace.
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I failed to improve by training near the theoretical maximum aerobic training pace, 80% of MHR. So I decided to do my 20-milers slower, at 75%. On these runs, I carefully monitored my heart rate and found that when I ran even a tiny bit faster than 75% (just 1-3 beats more), I felt a decrease in the uncanny sense of “rightness” and harmony, and I finished my runs feeling a sliver too tired.
The heart monitor tells me when my body is tired. When I’m overtrained or fatigued, my heart rate is faster at a given pace than when I’m fit and rested. When this happens, warning bells go off. The too-fast pace simply feels wrong.
These days, I monitor my heart rate and feelings during the first miles of a run. If running feels like dreary, joyless work, I pack it in or run slower or shorter. I’ve realized that nothing is ever gained by pushing a tired body.
Training is individual. Think about it. The ultimate sports training guidebook is You.
If sports teaches us anything, it’s that the mind and heart, when overheated, can be brutally wrong. “Hey, Peter Mundle ran a 2:35 marathon a week before he turned 40. I’m 39. If I train as hard as Peter did, I can run 2:35!” “Wow, Bob Deines swore by long, slow training. He set a US 50-mile record and finished sixth at Boston. If I run 115 miles per week at 8:00 pace, I can be a champion, too!”
Well. Peter Mundle ran a 4:26 mile at age 40. And Deines’s mile PR was 4:16.1. Both runners had excellent basic speed. Deines described his notion of a “long, slow training run” thus:
“Most of my [daily] runs are about 15 miles in two hours – 8-minute pace or a little under. We cover a fair amount of hills…. On Sunday, I like to get in a longer run, up to three hours, covering up to 24 miles.”
If you covet results like Deines’s, ask yourself: Can you run 15 miles a day, year in, year out, and 24 miles on Sundays, at a bit under 8-minute pace, and race 5Ks and 10Ks frequently? (In an ideal week, Deines ran 114 miles at sub-8:00 pace.)
There’s more than one flavor of aerobic training. If you do most running at just 65% of your maximum heart rate, a speed that most sports physiologists would call “recovery pace,” you’re unlikely to experience noticeable improvement in your racing speed, unless you’re running tremendous mileage and racing short distances often.
The racing results of runners like Deines prove that you can get faster by:
Doing the vast majority of your running at 75-80% of max heart rate
Running high mileage. If you can’t run high mileage, you may be able to improve by, at the very least, running 20 miles or longer at a medium to high aerobic pace once a week, or every other week.
Racing short distances frequently – e.g., a 5K or 10K 1-2 times per month.
Choosing your parents. It doesn’t hurt to have good basic speed.
I haven’t proved these ideas personally, and probably won’t in this life. But I may be able to improve my racing speed by training as Parker, Lydiard, and other aerobic-training gurus advised. By training at a high aerobic pace, I expect my speed will gradually rise at the same heart rate. Perhaps in three years, at 70, I’ll be zooming along at … gosh, 6 minutes per mile. I’ll let you know. Please, have respect – stop laughing.
There are two aerobic paces. First, there’s a slower aerobic training pace that doesn’t improve speed but aids recovery and endurance. Second, there’s a medium to high aerobic pace that improves aerobic systems metabolism, speed, and endurance. Lydiard recommended doing three runs per week at the high aerobic pace, and filling in on the other days at the low pace to build mileage.
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The science of running—”the books”–can give us general guidelines, but they can’t give us precision. Precision comes by jumping off the pier and learning to swim – starting with a plan that calm reason and feeling tells us is worth exploring, and refining it as we find out what our bodies can handle. Lydiard believed that very talented runners could increase their mileage quickly by training as he recommended. But he insisted that they honor their individual differences. A hallmark of Lydiard-style training is that it aims at long-term results: years of gradual development, with two Lydiard-style training cycles per year.
In the end, we really are thrown back on “listening to our own bodies.” The question is: How can we best hear what the body is saying?
Have you ever had a run that felt “just right?” Did you wish that you could recreate that feeling every time? It’s possible, and aerobic metabolism holds the key.
Those “just-right” runs happen when we run “well within ourselves,” at a medium to high aerobic pace, and when we adjust our pace and distance to what our bodies can handle during each run.
There are excellent, scientific (that is, experiential) reasons why runners who develop their aerobic systems are (a) happier, and (b) more apt to achieve racing success. Throughout books by and about Arthur Lydiard, a constant theme is how much his Olympic and world champions enjoyed their training.