How to Build a 12 Week Half Marathon Training Plan

A 12 week half marathon training plan is a common program for intermediate to experienced runners. More than likely, this demographic has a well-established base. They regularly do speedwork and maintain moderate to high mileage. Since their musculoskeletal systems are so well adapted to the biomechanical demands of running, less time needs to be spent adapting to running 13.1 miles. These runners can cover the distance – so the focus shifts to how to run faster over the half marathon.

Runners doing their first half marathon or returning from injury may want to spend longer preparing for a race. (Not sure how long you should train for a race? This article delves into all of the considerations.)

Can I Train for a Half Marathon in 12 Weeks? It Depends

This article does not provide a general 12 week half marathon plan. Instead, this article gives you a guide on how to create an individualized half marathon training plan for 12 weeks. You will learn what to include in each phase of the plan, how to adjust strength training, how to taper, and more.

This will empower you to build a plan that fits seamlessly into your busy schedule and maximizes your chances of success, while also equipping you with the knowledge needed to design a safe training plan that will help you effectively prepare for your race.

Weeks 1-4: Increase Training Load 

Most likely, you are coming off of a base-building phase. You have probably been building mileage and doing some general-fitness workouts. Intentionally, you were not doing peak mileage or very intense workouts. The first four-week phase of a 12 week half marathon training plan will build a bridge from base building to more demanding training. 

The first four weeks are not the time for workouts at your goal race pace. Instead, you want to focus on a variety of workouts to improve all aspects of fitness. In the first four weeks, you should include some interval runs and some threshold runs. 

If you are injury-prone, you do want to be cautious about increasing both mileage and intensity. Choose one variable to priortize during this phase. If you focused on mileage in base building, you may want to introduce more intensity during this time. If you came off of a speed phase or have low mileage, you may want to build mileage. 

Sample Workouts: 

• 8-10 x 2 minutes at critical velocity/1-1.5 min recovery jog
• 12-14 x 1 minute hard/1 minute recovery jog
• 2-3 x 10 minutes threshold (2-3 min recovery jog)
• 6-8 x 1K at threshold (1 min recovery jog)

Weeks 5-10: Specific Training

Your mileage may not increase significantly during this time. However, your training intensity will increase. During this time, training intensity distribution will likely reach 20% of your workouts moderate to hard. Typically, this is one to two hard workouts per week, including some long runs with workouts built in. The remainder of your runs are still easy. (This episode of the Tread Lightly podcast address how to apply 80/20 running to your training!)

Long runs are a staple feature in this phase of half marathon training. For an intermediate to experienced runner, long run duration will range from 12-16 miles. Some long runs will still be easy, while others will have intensity built into them. Progression long runs, long runs with fartleks, and goal pace intervals in long runs are some long run workouts you will see in a half marathon training plan. In my coaching approach, I generally alternate between easy-pace long runs and long run workouts. 

This training phase is when you will do longer intervals (often at critical velocity or threshold), longer tempo runs, and some long run workouts. You are not strictly training at half marathon goal pace. (Some workouts will be at half marathon goal pace, just not all!) However, you are working intensities closer to half marathon effort. Very high-intensity intervals are less of a priority in this phase, especially since they are very fatiguing. You will still include strides during this time to maintain quick turnover. (Read here for more on what workouts to include in a half marathon training plan.)

At three weeks out from the race, you will do an overload week – a deliberate push before the taper. An overload week includes the hardest workouts of your training cycle. These workouts may include long tempo runs or goal pace repeats within a long run. It is vital to build in extra recovery around these workouts. 

Sample workouts:

• 3-4 x 2 miles at half marathon effort, with 4-5 min recovery jog (in a long run)
• 5-6 mile continuous tempo at half marathon pace
• 4-5 x 1 mile at 10K effort
• 6 x 5 minutes at threshold effort, followed by 6 x 30 seconds fast
• 15 minutes at threshold, 3-4 min recovery jog, 5 x 1-minute at critical velocity, 3-4 min recovery jog, 15 minutes at threshold

Weeks 11: Taper

The half marathon taper lasts approximately 10-14 days leading up to the race. The exact duration of the taper depends on your response. If you tend to feel sluggish and flat on race day, you may have tapered too much. If you feel fatigued on race day, you may need more taper. 

As you reduce volume, you still want to maintain intensity. Don’t stop doing workouts yet! You will want to scale back the time at intensity. Workouts in the taper are designed to maintain fitness without significant recovery demands. During this time, most workouts will be at or around race pace. For example, if your peak workout was a 10K run at half marathon effort, scale back to 2 x 2 miles at half marathon pace. 

For more on how to taper for a half marathon, read this article. 

Week 12: Race Week

The final week of a 12 week half marathon training plan is focused on feeling sharp for the race. At this point, you are not gaining any fitness from your runs.

 In this week, the volume of your runs (not counting the race) is approximately 40-50% of your previous volume. Think about this volume on a daily level. So, if you regularly ran 8 miles on a Monday, you only run about 4 miles. 

Your final pre-race workout is generally 4-5 days before your half marathon. Unlike older approaches, you want to avoid any anaerobic work during this time. The week of a half marathon is not the time for 400-meter repeats. Instead, opt for a short tempo run (or tempo intervals) at half marathon pace. A goal pace workout allows you to practice race effort one last time, without excessive stress on the body. 

On the day before your race, you may opt to rest entirely or do a shakeout run. A shakeout run is a short run – generally just about 10-20 minutes. Advanced runners may include a short set of gentle strides as part of their shakeout. A shakeout run is generally recommended if you feel flat coming off of a complete rest day. If you prefer, you can rest completely the day before. 

More Advice for Your 12-Week Half Marathon Training

Cutback Weeks

Cutback weeks are a staple in a well-developed training plan. A cutback week encourages recovery on a mesocycle scale. Depending on your response, you reduce either volume or intensity (or both) by about 15-20% for one week, before continuing on with the plan. This temporary reduction encourages recovery and allows you to keep building without being in a state of non-functional over-reaching. 

The exact frequency of a cutback week depends on your injury risk and training response. Athletes with higher injury risk or more life stress may need more frequent cutback weeks (every 3-4 weeks). Athletes with lower risk and less stress may go longer between cutback weeks (4-5 weeks). However, every runner needs them – you gain no advantage by skipping a cutback week. 

Strength Training

Should you include strength training during a 12 week half marathon plan? 

If you’re a novice at lifting (or took a long break), it is not appropriate to start a lifting program during your half marathon training. However, if you are adapted to a lifting program, you can continue it throughout the training plan. 

Lifting will follow an inverse trajectory compared to running. In the first phase (weeks 1-4), your lifts may not look much different. Many athletes can handle two lifts, including lower body exercises, in this time. 

In the second phase (weeks 5-10), you may start scaling back your lifts. The goal is to maintain strength, not build. The number of sets may decrease. You may choose to reduce or maintain weight instead of progressively overloading. You will want to priortize your recovery in this time. If you feel fatigued from your run, shorten or skip your lift. (Here’s how to schedule lifting around your runs.)

When you start tapering for the half marathon, you will want to start tapering your lifting. You may choose to reduce to one lift per week with lower sets/reps/weights. You can also entirely remove lifting during this time. Some evidence, such as this 2020 study in Sports, suggests that even four weeks off of lifting maintains the benefits for runners. If in doubt, err on the side of caution with lifting during the taper. 

No matter what, you do not want to lift during race week. There are no benefits – only the risk of fatigued, tired legs on race day.

What Happens If You Miss Some Runs?

Very rarely is a training plan completed exactly as planned. Unplanned rest days are a part of training. More often than not, it is beneficial to skip a run or two when sick or potentially injured. You may also miss a run due to life demands or travel. 

If you miss fewer than five days’ worth of runs, simply pick up the plan as is. Do not attempt to make up runs! Trying to squeeze in missed workouts alters the training density of a plan. 

If you miss more than five days, you will want to adjust the plan. Scale back the mileage by 50-75% for the same amount of time you missed. You can keep doing workouts, but adjust them to ensure they progress appropriately from the last workout you completed. 

Is a Tune-up Race Helpful or Necessary?

Some runners enjoy tune-up races in half marathon training. A tune-up race offers the benefits of assessing fitness, practicing nutrition, and training the central nervous system to tolerate discomfort. 

In a 12 week half marathon training plan, a tune-up race can be scheduled for approximately 4-6 weeks out from the race. A tune-up race is typically shorter than the goal race distance. For a half marathon, the 10K provides the best assessment of fitness. You can also race a 5K race as a tune-up race. 

However, a tune-up race is not a necessity. You can train for a half marathon without one! In some scenarios, I will have an athlete do a 30-minute time trial to assess their fitness. This time trial provides similar benefits of learning how to tolerate discomfort – and doubles as a productive mid-week workout.

Rock Your 12 Week Marathon Training Plan

A well-structured 12-week half marathon training plan is key to achieving your race day goals. By gradually increasing your training load, incorporating a variety of workouts, and strategically tapering, you can optimize your performance while minimizing the risk of injury. Remember to prioritize recovery, listen to your body, and adjust the plan as needed.

Important Reminders

• A 12 week half marathon plan should be tailored to your goals! Even two runners with similar finish times may have different training plans.
• Always rest at the first sign of illness or injury.
• Follow a sound pacing strategy for your half marathon race.
• Priortize nutrition, including a one-day carb load, your pre-race meal, and intra-race fueling plan.

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