How Long Should You Train for a Race?

You signed up for a race – and the next step is to think about training for that race. How long should you train for a marathon, half marathon, or other distance race? 

These timelines are all for goal races: races where you are aiming for peak performance (intermediate/experienced runners) or looking to cover the distance for the first time (beginner). If you are running regularly and want to jump into a 10K, for example, you can do so on short notice. 

How Long Should You Train for a Race?
Training for an Ultra Marathon (50K and Beyond)?

Similar to the marathon distance, it depends on your base. Most ultra runners will spend 16-20 weeks specifically preparing for a race, regardless off their base. Take your time to build up to the distance, as injury risk is higher in the 50K distance and beyond. 

How Long Should You Train for a Marathon?

Marathon training can last anywhere from 12 weeks to 18 weeks for a sub-elite to recreational runner level. 

  • 12-14 weeks: If you have maintained a multi-faceted base, including a weekly workout, strides, a long run of approximately 2 hours, and weekly mileage upward of 40 mpw, you can spend 12-14 weeks training specifically for a marathon. Runners who do high mileage (70+ mpw) will do best with shorter cycles to avoid burnout.
  • 14-16 weeks: If you are just coming off another post-race recovery phase or have a well-developed base, 14-16 week is sufficient. 
  • 16-18 weeks: The most common timeframe for marathon training is 16-18 weeks and for good reason. If you have a well-developed base, you can pursue significant time goal and want to maximize adaptations. If you don’t have a robust base, this allow ample time to safely build up. Busy athletes (even those who fall into the other categories) also do well with a 16-18 week schedule, since it permits more alterations (missing a long run, for example). 
  • 18-20 weeks: This is ideal for beginners or those coming off a hiatus who do not have a well-established base. 

Even beginners should limit their marathon training cycle to 20 weeks or fewer. Why? From a psychological perspective, anything longer than eighteen weeks risks falling off of the plan. Mental burnout can be very real when you focus on something for longer than 20 weeks. If you are a beginner and have more than eighteen weeks before your marathon, spend time increasing your weekly and improving your running economy first.  

How Long Should You Train for a Half Marathon?
  • 6-8 weeks: Intermediate to advanced runners with a robust multi-faceted can pull off a shorter half marathon training cycle. This assumes you are already doing a variety of workouts including tempo runs, hills or fartleks, and long runs. 
  • 9-12 weeks: If you need more time to introduce hard workouts or increase your long runs, this is the ideal range for you. Athletes desiring a huge improvement should also aim for a cycle of this length. 
  • 12-14 weeks: Beginners and low mileage runners, particularly if you are currently not completing long runs. 
Training Cycle Length for a 5K or 10K
  • 6-8 weeks: If you are currently training consistently, sustaining 20+ mpw, and doing a variety of runs, you do not need long to sharpen up fitness for a 5K or 10K race.
  • 9-12 weeks: This works well if you are coming back from injury, postpartum, or any period where you have not run much or done any harder workouts. Alternatively, experienced athletes prioritizing a 5K or 10K as their goal race of the season may spend 8-12 weeks in dedicated training. 
  • 12+ weeks: If you are doing a couch to 5K or couch to 10K program, take your time! Give yourself weeks of training to allow for your body to adapt to the increased stress of running long distances. 
Why Spend So Long Training for a Race?
  • Adaptation:
    Adaptation is the goal of training. You apply a stress (the runs), allow time for recovery (sleep and rest days), and as a result, your fitness adapts to a higher level than your baseline. Adaptation can take up to 2 weeks for any single workout. After approximately 6-8 weeks, you will start to notice improvements. By the end of a 3-4 month training cycle, you will likely have adapted enough for significant performance improvements. 
    However, this adaptation is not this clear, linear process. It is messy, with everything from epigenetics to non-training life stress coming into play. Too long of a training cycle, and you may actually lose some adaptations as your body becomes overstressed. Too short, and you may miss out on enough adaptations to elicit peak performance.  When I coach an athlete, their external factors (stress, sleep, etc) are taken into account. When I can coach an athlete for more than one cycle, I then account observations about their adaptation to different stimuli when creating a training cycle. 
  • Progressive Overload: Progressive overload is a common term in fitness programming: you gradually increase a training stimuli overtime. An example of this is gradually increasing long run mileage over a 16 week marathon cycle. A training cycle should be long enough to allow for progressive overload. Sure, you could train for a marathon by going 8 miles -> 10 miles -> 12 miles – > 14 miles – > 16 miles – > 18 miles -> 20 miles, race, but the risks outweigh the rewards. Just because you can, doesn’t mean you should. 
  • Long-term Growth: Short training cycles with rapid increases exponentially increase the risk of injury. On the other end of the spectrum, training cycles over 18-20 weeks increase risk of burnout and make an athlete likely to plateau. Neither are conducive to long-term growth. Find a happy medium where you thrive. 
An Important Note:

Especially if you are in a longer training cycle, training will go through different phases. Generally speaking, you will start out building mileage and working on broad fitness, then introduce more race-specific workouts (roughly 6-8 weeks out from the race), followed by a tapering/sharpening phase. 

You do not want to spend an entire marathon cycle, for example, working on only marathon specific workouts. If you did, the result would be a loss of supporting systems that still are necessary in the marathon, such as fast-twitch muscle fiber recruitment, running economy, and lactate clearance. 

What to Do Before Training for a Race?

Do you have more than extra time before you need to start training for your goal race? Use that time to your advantage!

If you are running lower mileage, build your aerobic base. If you are inconsistent with your running or run fewer than 20 miles per week, your best bet is to increase your weekly mileage. Build cautiously over several weeks (here’s how to safely increase mileage). You do not have to make a sharp increase; even building your base from 20 to 30 miles per week will significantly contribute to aerobic development. 

If you often train for long distances (half marathon and beyond), develop speed. One of the most important workouts for long-term athlete growth, according to research? Short intervals. Long-distance runners can lose their economy and speed if they train for too many consecutive marathon cycles. Short intervals (30 seconds to 3 minutes) improve leg speed and are highly beneficial to long-distance runners (when properly programmed). 
If you are a trail/ultra runner, work on your hill economy. Many trail and ultra runners are skilled at running slow for long periods of time – but their full potential is hindered by a lack of running economy. Assuming you are doing an ample amount of mileage, spend time before specific training developing your economy. Economy on uphills and economy on downhills directly correlate, so spend time doing short repeats (30 sec to 3 minutes) on both.

Are you preparing for a race, whether it’s your first 5K or a goal marathon or 50K? I use evidence-based methods combined with practical knowledge from coaching over 200 runners to their goals. Learn more about my coaching services or purchase a downloadable training plan!

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8 Responses

  1. Very interesting description of the adaptation process, Laura.
    It’s such a delicate balance and so easy to make mistakes.
    I like that you include non-running factors as well – after all, we are humans and not machines.

  2. Thanks for your tips. I used to train for 12 weeks for each half. Now that my base is 10 miles I feel ready and just add 11 then 12 then taper.

    I trained for 16 weeks for my one and only marathon. It worked out well.

  3. I like to have a good 10-12 weeks to train for a half. I am an injury prone runner and it really helps me to have a significant base before adding on the miles. Now I just need to hold onto it until races come back

  4. This is great info! For most of my marathons I’ve trained for 16 weeks. I agree its so beneficial for long distance runners to work on speed. That has been one of my goals over the last year without any races to train for.

  5. As always, great advice. I tend to err on the side of longer training because it makes me feel more confident, but I know that mileage does vary.

  6. Great tips and a good reminder for me that it’s almost time to start marathon training. October sounds so far away but, since I feel like I’ve been in base-building mode for an entire year, I’ll need to get going on it soon.

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