How Long Should My Running Training Cycles Be?

BY Matt Fitzgerald

Matt Fitzgerald breaks down how long you should train for your next race.  He examines training cycle lengths, and what factors you should consider when planning your next cycle.

If I asked you to run your best possible 5K race, how much time would you request to train? What if I asked you to run your best 10K? How much time would you need for that? And your best half-marathon? Marathon?

Deciding how long one ought to train for peak performance at a given road racing distance is one of the most basic decisions in running, and yet it does not get a lot of attention. The training plans that runners find in magazines and books and online have certain typical durations that vary by race distance, but the rationales for these durations are seldom explained. Thus it is unclear to the curious runner whether these typical durations are optimal (and if so, are they optimal for everyone?) or if their lengths merely represent conformity to convention.

24, The Magic Number

Among the few running experts who have explicitly addressed the matter of optimal training duration is Jack Daniels. In his seminal book, Daniels’ Running Formula, Daniels identifies 24 weeks as the ideal training duration for all race distances and for runners of all levels, with some exceptions. All of the training plans in the book, for races ranging in length from 1500 meters to the marathon, are 24 weeks in length.

Although Daniels does not explicitly explain why he considers the 24-week duration ideal, one can deduce from his overall explanation of his training system that it simply takes 24 weeks to work through all four phases of his periodization method, but no longer.  It follows from this deduction that if you have already completed the first part of this training process, or something resembling it, then you don’t need a full 24 weeks to prepare for peak performance at a given race distance. For example, each of Daniels’ plans begins with a six-week aerobic base-building phase. If you already have a solid aerobic base before you decide to train for a specific race, then you can skip this phase and devote only 18 weeks or thereabouts to building toward peak fitness.

Not only is 24 weeks enough time to cultivate peak fitness for any race, but it’s also approximately the maximum amount of time one can train progressively without burning out. Reaching lifetime peak fitness takes years, and this multiyear process must be broken into individual cycles separated by brief periods of regeneration in which some fitness is intentionally lost. A runner who attempts to continue improving his or her fitness indefinitely, even from a low starting level, is likely to find that burnout occurs after 24 weeks or so.

Jack Daniels’ approach is not the only approach to determining how long runners train for specific events. For example, Brad Hudson, who coaches two-time Olympian Dathan Ritzenhein among others, uses a nonlinear periodization approach that mixes the various types of training together more than Daniels’ system does. Hudson believes in maintaining a high level of aerobic fitness and speed year-round in his runners, so that they require little time at all sharpen up for peak performance. His marathoners typically devote only 12 weeks to focused preparation for their big races.

Be Fit, Be Ready

The higher your starting fitness level is—in other words, the closer you are to peak fitness when you begin focused training for a peak race—the more you risk burning out before your race if you plan a longer training cycle. Hudson’s runners would likely become overtrained if they trained longer than 12 weeks for a marathon, so fit are they at all times, and in fact Hudson blames an over-long training cycle for Ritzenhein’s poor performance in his debut marathon.

You can intentionally delay a peak when necessary to avoid overtraining, however, by holding yourself back in your workouts until you reach a point where you can ramp up steadily without a high risk of burnout. Suppose, for example, that you are 15 weeks away from peak marathon fitness when you decide to run a marathon that’s 20 weeks away. In this case you could train relatively lightly for the next five weeks and perhaps focus on types of training that will make your body more resilient when you begin ramping up 15 weeks out from race day.

Naturally, this sort of calculation works best when you are able to accurately judge how close you are to peak fitness, in terms of training time. This ability comes with experience, but nobody perfects it. There are simply wild guesses and informed guesses. In the end the best you can do is commit to a schedule that seems sensible and make adjustments as you go. It’s always easier to slow the pace of your ramp-up to prevent burn out than to accelerate it to hasten a peak that seems to slow in coming.

To cite a personal example, this year my coach and I created a 23-week training plan to prepare me for the Boston Marathon. All went well for the first 16 weeks, but then I started to show signs of burnout. So I cut back my training spontaneously to give my body a chance to regenerate, then resumed my ramp-up in the last four weeks. The Boston Marathon is just days away as I write this and I feel great.

One might assume that it does not take as long to develop peak fitness for shorter running events than it does for longer running events. This is true to some degree for runners who are beginning the training process at a low level of running mileage. A runner who currently trains just 12 miles a week can achieve peak fitness for a 5K sooner than he can for a marathon, because his endurance is very far away from the level needed for optimal marathon performance. But in fact it takes almost as much time for the relatively untrained runner to hone the speed and aerobic capacity needed for optimal performance in the 5K as it takes to develop the endurance needed for optimal performance in a marathon. Runners usually allow enough time to train for marathons because they simply can’t finish otherwise, whereas they just as often do not allow enough time to train for shorter races because merely covering the distance is no problem and it’s harder to appreciate how long it takes to fully develop speed and aerobic capacity.

Give yourself 20 weeks or so to peak for your next 5K (not counting any tune-up races you may choose to do along the way) and see what a difference it makes!

Trainingpeaks Author Matt Fitzgerald
About Matt Fitzgerald

Matt Fitzgerald is a journalist, author, coach and runner specializing in the topics of health, fitness, nutrition, and endurance sports training (read more about Matt on his blog). Matt uses TrainingPeaks to train, coach and deliver pre-built training plans for runners including training plans built specifically to be used with a Garmin Forerunner. View Matt’s 80/20 running plans here and his 80/20 triathlon plans here.

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