How much mileage is enough?

BY JASON R. KARP, PhD

Irecently finished reading ScottThorpe's How to Think LikeEinstein. The book's theme isthat you have to break rules inorder to solve difficult questions.According to Thorpe, Einstein

discovered the theory of relativityby seeing past rules other scientiststhought were unbreakable.

One of the "rules" of distance run-ning is that athletes must run a lot ofmiles. Indeed, most runners link theirfitness level to the number of milesthey run, assuming that more is better.A friend of mine who almost made theU.S. Olympic Team in the 1,500 metersran 100 miles each week. Frankly, Ithought he was nuts. And I began to

wonder: Is it really necessary to run100 miles per week to train for a four-minute race?

As legendary coach Arthur Lydiardso ardently claimed, lots of aerobic run-ning forms the basis of any distancetraining program. Whether athletes aretraining for the mile or the marathon, itall starts with mileage. That's becauseendurance training stimulates manyphysiological, biochemical, and molec-ular adaptations. All these adaptationscan be thought of as the body's attemptto cope with the demands placed on itby running every day.

For example, endurance trainingstimulates more fuel (glycogen) to bestored in an athlete's muscles, increases

the use of intramuscular fat at the samespeed to spare glycogen, and improvesblood vessels' oxygen-carrying capa-bility by increasing the number of redblood cells and hemoglobin. It createsa greater capillary network for a morerapid diffusion of oxygen into the mus-cles, and through the complex activationof gene expression, increases mitochon-drial density and the number of aerobicenzymes, which in turn increases anathlete's aerobic metabolic capacity. Thelink between an increase in mitochon-drial enzyme activity and an increase inthe mitochondria's capacity to consumeoxygen has provided much insight intothe adaptability of skeletal muscle.

Generally speaking, the greater the

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demand, the greater the adaptations.Although many scientists have acknowl-edged that there is an upper limit tothe volume of training that will causefurther adaptations, research has notyet documented at what point theseadaptations stop occurring in responseto demand. In other words, how muchmileage is enough?

The answer depends on a number offactors, including athletes' genetically-determined propensity to continuallyadapt to greater amounts of runningand the amount of running they canphysically and psychologically handle."It's very hard to say how much mileageis ideal to maximize the various cellularadaptations that take place as a func-tion of time spent running," says JackDaniels, PhD, Head Distance Coach atthe Center for High Altitude Trainingat Northern Arizona University andauthor of Daniels' Running Formula."The best answer might be to do asmuch as you can without losing interestor getting sick or injured."

While most runners and coachesbelieve that more running equals great-er success, Daniels cautions about itspotential to dissuade potential distancerunners. "We may be going overboardwith the mileage thing in running, espe-cially for youngsters," he says. "We maylose too many potential runners if westart stressing mileage when they are inmiddle school or even high school."

EFFECT OF TRAINING VOLUME ONPHYSIOLOGY AND PERFORMANCEAs coaches, we all know that the bet-ter our athletes get, the harder it is forthem to improve. Unfortunately, noneof the adaptations associated with train-ing continue indefinitely.

Much of the research on biochemicaladaptations to endurance training hasbeen done on animals. For example, themitochondrial enzyme content of ratshas been shown to reach its maximumadaptation by running 60 minutes perday five days per week.

A 1998 study published in theEuropean Journal of Physiology onhorses training for 34 weeks found thatincreases in muscle fiber area and thenumber of capillaries per fiber plateauedafter 16 weeks of training. After thefirst 16 weeks, the horses were dividedinto two groups: a control group andan overload training group that trainedwith higher mileage.

Both groups increased mitochondrial

volume and VO2 max with the increasedmileage over the next 18 weeks, but therewas no difference in those variables or inmuscle fiber area and capillarizationafter 34 weeks, despite the two-folddifference in training volume betweengroups over the final 18 weeks. Clearly,there is a limit to muscles' adaptive

percent of the difference in VO2 maxbetween runners.

Another study published in theEuropean Journal of Applied Physiologyand Occupational Physiology found thatrunners training more than 62 miles perweek ran significantly faster in racesranging from 10K to 90K, compared

While most runners and coaches agreethat training volume is important, train-ing intensity is even more importantin improving fitness and performance,especially in highly trained runners.

response to training.Obviously, the more untrained your

athletes, the more they can expect toimprove by increasing their mileage.For example, a 1992 study published inthe Journal of Applied Physiology foundthat weekly mileage ranging from fiveto 75 miles per week explained 86.5

to those who ran less than 62 miles perweek. While it is likely, and even prob-able, that running more mileage leadsto a higher VO2 max and faster racetimes, we cannot conclude cause andeffect from cross-sectional studies com-paring separate groups of runners. It'slikely that genetically-gifted runners

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after mile

SHOULD THEY RUN MORE?Current Mileage< 30 miles

30-60 miles

60-70 miles

> 70 miles

AdviceChances are your athletes will get faster by running more, possibly up to 60to 70 miles per week, assuming they can physically handle it. Have themrun the same mileage for two to three weeks, back off for one week torecover and adapt, then increase their mileage slightly (three to five moremiles per week) to begin a new cycle.

At the low end of this range, chances are your athletes will get faster byrunning more. At the high end of this range, they may get faster by runningmore, assuming they can physically handle it and have the genetic ability tocontinue adapting. Have them run the same mileage for two to three weeks,back off for one week to recover and adapt, then increase their mileageslightly (five more miles per week) to begin a new cycle. If they have moreexperience at this mileage range, you can increase their mileage for two tothree weeks (five more miles per week) before backing off for a recovery week.

Only increase your athletes' mileage past this point if their prior training andracing experience gives you reason to believe that they will continue toimprove with more mileage. If their performances haven't plateaued at 70miles per week, there's no reason to increase their mileage to 80.

Running more than 70 miles per week may improve economy, but alsocomes with an increased injury risk. "For the average recreational athlete,75 miles per week is the maximum he or she should attempt to achieve," saysTimothy Noakes, MD, Discovery Health Professor of Exercise and SportsScience at the University of Cape Town in South Africa and author of Lore ofRunning. "Going farther is only of value if you are racing for longer thanthree to four hours. If your athletes are among the lucky ones who areblessed with great genes, they may improve by running more."

who have a high VO2 max are capable ofrunning more miles and faster races.

According to David Costill, PhD,Professor Emeritus of Exercise Scienceat Ball State University and formerDirector of its Human PerformanceLaboratory, physiological changes pla-teau at a modest amount of mileage."When you go from an untrained stateto a trained state, running 30 to 40 milesper week, VO2 max and the measure-ments commonly taken from musclebiopsies increase. But as you move upto about 60 miles per week, things startto plateau," he says. "The exact mileageat which this plateau occurs dependson the individual, but beyond about 60to 70 miles per week, there's not muchchange taking place."

If VO2 max and muscle cellularadaptations plateau at about 70 miles perweek, why do people run much more

than that? "I really have no idea," saysCostill. "People who run 5Ks and lOKsstill need a lot of speed, and when yourun 120 or 130 miles per week, you can'tdo much quality."

HOW MUCH DO ELITE ATHLETES RUN?In 2004, I conducted a study on thetraining characteristics of U.S.Olympic Marathon Trials qualifiers.My findings, which were publishedin the International Journal of SportsPhysiology and Performance, revealedthat the men averaged 90 miles per weekwith a peak mileage of 120, while thewomen averaged 72 miles per week witha peak mileage of 95 during the year oftraining leading up to the trials.

The elite male marathoners (sub2:15) didn't run significantly more thanthe national-class marathoners (2:15-2:22). The elite men averaged 97 miles

per week with a peak mileage of 126,while their national-class counterpartsaveraged 90 miles per week with a peakmileage of 119.

There was, however, a significantdifference in mileage between the worn-ens' performance levels, likely due totheir greater range in performance. Theelite women (sub 2:40) averaged 84 milesper week with a peak mileage of 112,while their national-class counterparts(2:40-2:48) averaged 69 miles per weekwith a peak mileage of 91.

While the faster female marathonersran more, only a quarter of the differ-ence in marathon performance betweenthe women could be explained by theamount of mileage they ran. Mileageaccounted for even less of the differenceamong the men.

Running more doesn't necessar-ily make you faster. Regardless of how

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HOW SHOULD THEY INCREASE THEIR MILEAGE?

Cycle #1

Week 1: 25 milesWeek 2: 25 milesWeek 3: 30 milesWeek 4: 20 miles

Monday Tuesday Wednesday Thursday Friday Saturday Sunday

3 miles353

6665

RestRestRestRest

5564

4453

RestRestRestRest

7785

Cycle #2

Week 1: 55 milesWeek 2: 60 milesWeek 3: 65 milesWeek 4: 43 miles

Monday Tuesday Wednesday Thursday Friday Saturday Sunday

4/5 (am/pm)4/6 (am/pm)4/7 (am/pm)

6

7887

4/6 (am/pm)4/7 (am/pm)5/7 (am/pm)

8

910116

8897

RestRestRestRest

1213149

Once your athletes have reached a significant amount of mileage and/or you feel they are no longergaining any further benefit from increasing their mileage, begin inserting more quality running(e.g., tempo runs, intervals).

much your athletes run, genetics playsa large role in their performance. Arunner with a lot of talent will almostalways outperform a runner with littletalent and a lot of training.

"If you look at the training data ofelite athletes, you find that the opti-mum training volume for the world'sbest athletes lies somewhere between 75and 110 miles per week," says TimothyNoakes, MD, Discovery HealthProfessor of Exercise and Sports Scienceat the University of Cape Town in SouthAfrica and author of Lore of Running."However, the time spent running maybe more important than the mileage, sincea fast runner will run that distance muchquicker than a slow runner. Humansmay have a maximum training volumethey can undertake, and I think it's closeto 75 to 100 miles per week. Your bodysimply can't absorb any more trainingvolume without breaking down."

BEYOND VOz MAX ANDMETABOLISMIf there is little or no improvement inVO2 max and the metabolic profile ofmuscles as athletes run more than 70miles per week, is there any benefit torunning more? Maybe.

Research has shown that runnerswho run high mileage tend to be more

economical, which has led to the sugges-tion among scientists that running morethan 70 miles per week improves runningeconomy (the amount of oxygen usedto maintain a given pace). It is possiblethat, just as repetition of the walkingmovement decreases the jerkiness of atoddler's walk, repetition of the runningmovement has an under-recognized neu-ral component.

With countless repetitions, musclefiber recruitment patterns and possiblyeven the relationship between breathingand stride rhythms are optimized to min-imize the oxygen cost. In other words,practice makes perfect. Additionally,high mileage reduces body weight, whichfurther reduces the oxygen cost. Becauseit is hard to prove cause and effect, it isnot clear whether high mileage runnersbecome more economical by runningmore miles or are innately more eco-nomical and can therefore handle highermileage without getting injured.

Beyond the physiological adaptationsto running lots of miles and their con-tribution to performance, the amount ofmileage that athletes run may ultimate-ly depend on their brains. "The moreimportant explanation is that the brainis critically important in this process andis under-recognized," says Noakes. "Thebrain may optimally adapt to a certain

volume of training, and a lot of our train-ing focus and adaptation may actually beto teach us that we can run the distance.The mental preparation starts long beforeyou go training."

While most runners and coachesagree that training volume is important,training intensity is even more importantin improving fitness and performance,especially in highly trained runners.Research has shown that a high trainingintensity is vital for maximizing cardio-vascular improvement and that VO2 maxand other physiological variables cancontinue to improve with the inclusionof high intensity training.

For example, interval training per-formed at 95 to 100 percent VO2 max isthe most potent stimulus for its improve-ment, and is necessary for furtherimprovement in highly trained runners.Given that training volume will impacttraining intensity, the better questionmay not be how much mileage is neces-sary or enough, but how much mileage istoo much to sacrifice intensity.

As your athletes prepare for their nextrace, how much mileage should they run?If you've read this far, you know the answeris not an easy one. (For guidance, see"Should They Run More?" on the preced-ing page and "How Should They IncreaseTheir Mileage?" at the top of this page.)

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A runner with alot of talent willalmost alwaysoutperform arunner with lit-tle talent and alot of training.

The best way to determine how muchyour athletes should run is to slowly andsystematically increase their mileage frommonth to month and year to year, tak-ing care to note how they respond to thetraining stimulus. And remember thatmore is not always better. Like Einstein,sometimes you have to break the rules. *

Jason R. Karp has a PhD in exercisephysiology, and is director and coachof REVO2LT Running Team. His writinghas appeared in numerous internationalrunning, coaching, and fitness maga-zines and scientific journals. He hascoached high school and college crosscountry and track and field, and current-ly coaches athletes of all levels throughRunCoachJason.com.

LYDIARD REVISITED

New Zealand coach Arthur Lydiard, who passed away in 2005,was best known for his high-mileage approach. Even his middle-distance runners ran 100 miles per week, including Peter Snell,who won gold medals in the 800 and 1,500 meters at the 1960Olympics. But is that amount of mileage necessary? Was Lydiardright, or did his talented athletes run well despite their trainingrather than because of it? Like my friend trying to qualify forthe Olympic Trials, many of today's middle-distance runners runnearly as many miles as marathoners.

While 100 miles per week is probably not necessary for yourathletes to maximize their potential in the mile, a moderateamount of mileage can help. Since any race lasting longer thanabout three minutes relies more on aerobic than on oxygen-independent (anaerobic) metabolism, having a well-trainedaerobic system is still important for the shorter distances.

"Even the 800 meters demands some aerobic power, if for noother reason than to help recover faster during more intensespeedier sessions," says Jack Daniels, PhD, Head Distance Coachat the Center for High Altitude Training at Northern ArizonaUniversity and author of Daniels' Running Formula. "Every racefrom the 800 meters on up is run at some fraction of your VO2max, so improving your VO2 max increases the speed associatedwith any fraction of your VO2 max. A miler needs that aerobicconditioning, and mileage helps a lot in that regard."

Although Lydiard argued that runners should build a solidaerobic base that includes high mileage before progressing tovarious forms of speed work, doing too much training too earlymay have detrimental effects when it's time to peak. A 2000study published in the Journal of Strength and ConditioningResearch found that the preseason training phase (May toAugust) of college cross country teams had the greatest impacton performance during the peak phase (November). Teams thatqualified for the national championships took more rest daysduring the preseason phase and actually ran shorter weeklyruns than teams that did not qualify (11.5 vs. 13.7 miles).

During the competition phase (August to October), therewas no statistical difference in weekly mileage betweenqualifying and non-qualifying teams (72 vs. 63 miles perweek, respectively). Among the qualifiers, the teams that ranmore miles (above 70 miles per week) and ran twice per dayduring the summer months actually ran slower at the nationalchampionships in November than teams that ran less. It'spossible that running too much in the summer makes yourathletes too fatigued to race at their peak in the fall.

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