Training

How Frequently Should You Run?

Rate and Magnitude of Response: The Nautilus North Study

How often should you run?  What is the optimal training frequency?  Most runners, at some point in their running careers, contemplate this question.  The answer to the question depends upon who you ask and what particular training philosophy they follow.  Conventional training wisdom suggests running more frequently results in better performance.  In line with this philosophy, then, conventional training advice is to gradually increase training frequency until you are running 6-7 days per week.  Conversely, Power Running suggests that there is no one training frequency that is right for all or most people and that less frequent training is better for runners with average genetic talents.  But, how do you go about figuring out who is right?

Not surprising, athletes and coaches in other sports face the exact same dilemma of determining optimum training frequency.  In strength training, for example, it’s not uncommon to see the top champions training six days per week.  On the other hand, other programs suggest training as infrequently as twice per week.  That’s a pretty big difference – 6 days a week vs. 2 days per week.  Again, how do you go about figuring out which program is right?

John Little, a monthly columnist for Ironman magazine, inventor of the Max Contraction Training method and the author of over 30 books on bodybuilding, martial arts, history, and philosophy, wondered the same thing.  To answer the question he conducted a research study at the Nautilus North Strength & Fitness Centre in Bracebridge, Ontario, Canada, a study focused on answering questions about just how much and how fast bodybuilders can gain muscle mass.  Dubbed “The Nautilus North Study”, the results were published in the November 2005 issue of Ironman magazine. (1)

This is a running site so why am I discussing a muscle building article from a bodybuilding magazine?  The reason is that the data revealed during The Nautilus North Study speaks directly to the running community.  In fact, the data from this study is important for all athletes to understand, as it illustrates some critically important training principles.  Let’s take a look at it.

Research

11 strength training experienced subjects were recruited for this study.  These individuals had strength training histories that ranged from six months to 20 years and were described as being “fairly well developed in terms of their genetic potentials for mass and strength”.  Since the subjects were not beginners nor were they regaining previously held muscle the researcher believed that, “…any gains – if they were genuine lean tissue, a.k.a. real muscle – would be noteworthy.”

Accurately measuring body composition in the past has not always been easy, convenient, and accurate.  Scientists have employed several different methods over the years with some methods being more accurate but less convenient and others being more convenient and easy but less accurate.  Underwater weighing was the acknowledged gold standard for determining body composition for many years.  It was the most accurate method available, with an error of less than about 2%, but, unfortunately, was not widely available.  In recent years a new method has been introduced – the Bod Pod capsule – which operates on the same principle as underwater weighing, but measures displaced air instead of water.  The Bod Pod is not only quick (under 5 minutes) but accurate to plus or minus 2%, making it of similar accuracy as underwater weighting. 

In practical terms, using the Bod Pod researchers can determine within .1 of a pound if a subject is gaining or losing lean or fat and whether a particular training and recovery protocol is producing lean tissue.  Even better, the Bod Pod capsule allows researchers to determine exactly to the day when the gain or loss in lean tissue or fat occurs.  Luckily, a Bod Pod capsule was available to the researchers for the Nautilus North study.

All subjects were pre-tested to establish their baseline body composition.  Following pre-testing all 11 subjects trained just once and then their body composition was tracked every day for 14 days.  The single workout was a high intensity type program designed to increase both strength and muscle mass.  The subjects were instructed to abstain from additional resistance training for the remainder of the study period.

Results

The subjects gained an average of 3.27 pounds of muscle from the single workout.  It took an average of 6.5 days for the gains in lean tissue to fully manifest.  The largest increase in lean tissue was 9.3 lbs by one subject while the smallest increase was 1.5 lbs by one subject.  The fastest increase in lean tissue was 1 day by two subjects while the longest time to fully realize lean tissue increases was 11 days by one subject.  Averaging the middle nine subjects by dropping the high and low in each category reveals an average lean tissue increase of 2.8 pounds and an average of 6.6 days to fully manifest.  The results are shown in table 1.

Table 1:  Individual, average, and range of changes in lean tissue and days to peak lean for 11 subjects.

Discussion

What are we to make of this study?  There are two very important things to learn from this study.  First, note the wide range of changes in lean tissue in response to the single workout.  One subject gained more than 9 lbs from a single workout, while 3 subjects gained less than 2 lbs from the exact same workout.  That is a range of 620%.  What does this mean to you?  It means there is a broad range of response – the magnitude of response is very large – within the human species.  In running terms, if two runners conducted the exact same running workout, it’s possible that one will improve significantly from that workout and one won’t.

Admittedly, this is a strength training workout focused on building lean tissue.  Does the lesson here – the large differences in magnitude of response across the human species – apply to runners too?  Absolutely!  Other studies have found a range of response in aerobic capacity of 58% - 100%. (2, 3)  The range is not as great as that found in the above study, but the lesson still applies.  There is a very broad range of response.  Some individuals improve a lot, some improve a little, and everyone else is in the middle between the two extremes.  Can you get fast?  Perhaps.  If, however, after several years of training you aren’t fast despite consistent, hard training then it’s likely not due to inadequate training but to your body’s natural, limited response to training.

As important as the first lesson is another, more important, lesson is found in the above study.  Most runners won’t argue much if you suggest people have different levels of inborn talent and that, consequently, some will run faster than other and some will improve more than others.  However, you will likely get a LOT of objections if you suggest that there is a broad range of optimal training frequency.  In fact, I believe I get more argument on this one point than all other training points combined. 

The second, most important, lesson is this – there is a broad range in rate of adaptation to training.  Some will adapt very quickly to training.  Some will take a very long time to adapt.  Everyone else falls in between these two extremes.  Note that the range of response was from 1 day to 11 days, a huge 11 fold difference.  Several individuals had completely absorbed and responded to the training in just 1 day.  On the opposite extreme, one individual took 11 days to fully realize the improvements to the workout and two individuals took 10 days to fully adapt.  What a huge range in rate of response! 

Typically the argument presented to me is that since elites are the fastest runners on earth that their training program is obviously the best.  Elites are known to train daily, often training twice per day, running 100+ miles per week.  This is interpreted to mean that generally running more frequently and higher mileage is the best training method, hence the reason conventional wisdom typically recommends increasing training frequency to 6-7 days per week over time for all runners.  This study indicates otherwise.  This study shows us that people adapt to training at widely different rates.  If you were an individual who recovered in 1 day, would there be any benefit to you in training once every 11 days?  If you were an individual who required 11 days to fully recover and improve from a workout, what would happen if you decided to train every day?  The researchers made this exact same point when they wrote,

“Knowing how soon a mass increase shows up tells you exactly how often you should train.  If, for instance, a gain in mass took two weeks to be produced, what would be the point of training more than once every two weeks?  All that would do is postpone or preempt the growth process.  If, however, the gains showed up in 24 hours, then waiting two weeks could possibly delay the gains.”

Here’s the main point – there is no 1 training frequency that works for everyone.  Instead there is a broad range of optimum training frequency, much broader than most realize or acknowledge.  Trying to train too frequently will likely result in sub-optimal performance and may end in overtraining and injury.  Don’t base your training frequency on how often someone else is training.  You must find your own optimum training frequency, despite how often anyone else trains.

What this study doesn’t teach us

It may be tempting to dismiss or ignore the results of this study because it is a strength training study and not a running study.  While the specifics of this study –rate and magnitude of adaptation to a strength workout – are not directly transferable to running, the major lessons are completely applicable.  There is no doubt that there is both a broad range in magnitude of response to training (a fact confirmed by other studies) and a broad range in rate of adaptation.  This study, more than any other I’m aware of, emphasizes the huge range in how long it takes to fully adapt to a workout.

That being said, there are things this study doesn’t teach us.  First, while it took an average of 6.6 days for subjects to fully adapt in this study, it does not follow that it will also take 6 days to fully adapt to a running workout.  This study doesn’t say that it will take 6 days to fully adapt to a running workout.  In fact, this study doesn’t give us any idea of how long it may take to adapt to a running workout.  Remember the big picture though – there is a broad range in how long it takes to adapt – and don’t focus on the exact number of days it took in this study.  The major point to learn is that there is a broad range in rate of response to a running workout, just like there is a broad range of response in this study.  More research will be required for us to determine what the range in rate of response is for runners, but in the meantime the important thing to learn is that there IS a range in rate of response.

Next, this study used a high intensity workout.  While we now know how long it takes, on average, to recover from a high intensity strength workout, it doesn’t tell us how long it takes to adapt to an easier workout.  Or a longer workout.  Or another type of workout.  Again, the intricate details of this study don’t directly transfer to runners and other athletes, but the major principle does.  The major principle is that there is a broad range of response to a workout, but what that range is for any individual workout is not revealed.  I suggest that harder and longer workouts take longer to recover from than shorter and easier workouts, but this study doesn’t address this particular point.

Finally, this study doesn’t definitively tell us if rate of adaptation increases with training but it indicates that it does not.  Is it possible that people’s rate and magnitude of response changes with training?  It is commonly suggested by runners that they recover faster as they get into better shape.  While this is possible, this study indicates otherwise.  The subjects in this study were experienced strength trainees with up to 20 years training experience and who were training regularly prior to participating in this study.  They were not beginners.  Despite their experience, a broad range in rate of response was clearly evident, suggesting that rate of recovery had not increased significantly as fitness improved.  I suggest that people’s rate of adaptation does NOT improve significantly with training, but despite my above observation, we can’t prove or disprove this point from the data in this study.

Summary

Rate and magnitude of response to a single strength training workout was studied in 11 experienced subjects.  Rate of response ranged from 1 – 11 days, with an average of 6.5 days, and magnitude of response ranged from 1.5 – 9.3 lbs, with an average of 3.2 lbs.  The two major lessons to be learned from this study are that the rate and magnitude of adaptation in the human species is very large, much larger than many realize or acknowledge.  Some people improve a lot, some improve very little.  Some people improve very rapidly – fully adapting to training in just 1 day – while others take many days to realize the benefits of a workout. 

How frequently should you run?  This study doesn't definitively answer this question.  However, it does provide a major principle that must be considered by each individual as they seek to answer the question.  This principle is that there is no 1 training frequency that works for everyone.  In fact, there is not even a small range of optimal training frequency.  Instead, this study teaches us that there is a broad range in the rate at which people adapt to training.  Training too frequently or infrequently results in sub-optimal performance, with too frequent training likely resulting in overtraining and/or injury.  Each person must find their own individual optimal training frequency, despite what the optimal training frequency of any other person may be.  Finally, this study suggests, but does not prove, that rate of response does not increase with improvements in fitness.

Reference:

1.  Little, John. The Nautilus North Study - Determining Optimal Training Frequency: Is it possible to add 100 pounds of muscle in one  year?  Ironman, Vol 64, #11, pgs 100-122.

2.  How Much Can You Improve - Part 1

3.  How Much Can You Improve - Part 3