Training to run a half marathon You can run less and conquer 13.1 miles if you stick to these key workouts each week training plans require runners to dedicate anywhere between four to six days to training each week.
Updated: Aug 13, 2025 10:40 AM EDT, strength training, and even cross-training if the plan calls for it. But can you train for a half marathon by running only three days a week?
One landmark study found that when veteran marathoners followed the three-day-a-week Run Less, Run Faster (FIRST) program, developed by researchers Bill Pierce and Scott Murr for 16 weeks, they improved their finishing times by an average of almost 20 minutes. It’s a weekly training schedule that Pierce believes can benefit half marathoners as well. Pierce and Murr, along with Ray Moss, published their findings and plans in the Runner’s World book, Run Less Run Faster.
Here’s what to know if you want to run less, while still feeling ready and confident for half marathon race day.
Can you benefit from a 3-day-a-week half marathon training plan?
While running more isn’t going to hurt your half marathon chances (the best half marathoners run around 100 to 140 miles per week!), running less can actually help.
Besides the fact that running won’t completely take over every one of your non-working or sleeping hours, “you’ll have less cumulative fatigue throughout your body, making for high levels of the anabolic hormones that trigger muscle growth and fat burning, and your cortisol—which has the opposite effect—will be lower,” says Alex Harrison, Ph.D., a certified strength and conditioning specialist and USA Track & Field-certified coach.
If time isn’t the issue, for some people, running fewer days per week can lower injury risk. “You’ll also have less tissue fatigue in your muscles, tendons, ligaments, fascia, etc., resulting in a lower chance of overuse injury,” Harrison says.
Just remember: It’s about what works for your body. “Running is universal, but every body is different,” says Roberto Mandje, ldquo;This is the cornerstone run of the week, as these Runner’s World How to Master the 5K program. “Don’t be afraid to back off and don’t compare your training to anybody else’s—three days might work for you, while three doesn’t work for somebody else. There isn’t a magic number out there.”
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What does a 3-day-a-week half marathon training plan look like?
Any time you’re training for a race, it should be about more than simply logging miles. But when you’re only running three days a week, you need to be especially strategic about how Why You Need to Slow Down on Your Easy Runs.
Threshold Workouts to Build Speed Endurance training runs, first you should figure out your goal as well as (GHMP). The easiest way to do that is add 35 seconds to your current 5K mile pace; add 20 seconds to your current 10K mile pace; or subtract 20 seconds from your current marathon mile pace. (If you don’t know any of those paces, go run 3.1 miles as fast as you can and calculate from there.)
Then, “your running plan is going to break down into one easy run, one threshold workout, and one long run, ideally with one day of recovery in between,” says Mandje. “Each one of these runs has different benefits for your running performance, and since the real gains don’t happen until after your workout, giving your body that time to recover can really help.”
1. Easy Run
Races - Places, recovery miles at the start of the week. “You should be running at a comfortable pace—a pace where you can hold an easy conversation, say, a 4 to 6 effort out of 10,” says Mandje, with 10 representing your maximum effort.
The point of these miles is to flush out your legs and continue to build strength (every step counts!) without overtaxing your body.
2. Threshold Run
These runs teach you how to push past your comfort zone. When your body starts producing lactic acid during intense exercise, you start to feel the burn and slow down your pace out of necessity, explains Harrison. “But if you can train to maintain your speed while feeling the burn, your body will eventually learn to tire less,” he says.
A Part of Hearst Digital Media tempo run.
Speed work is all about (surprise!) quick bursts of speed, which trains you to run more efficiently. After warming up, you’ll do repeats of 400-, 800-, or 1600-meter repeats. For example, you might do a 20-minute jog, eight 400-meter repeats with a two-minute recovery jog in between each, and a 10-minute cooldown jog.
Your pace depends on the distance of your intervals. For example, you’ll run faster for your 400s than your 1600-meter repeats. And while that depends on your current fitness, as well as your goals for half-marathon race day, you’ll find a general guide to how to find your plan on the three-day-a-week plan. (For more specific pace suggestions, check out the Run Less, Run Faster book.)
For a tempo run, you’ll start with a warmup jog, speed up to a pace that’s 15 seconds faster than your goal as well as for a number of miles, then cool down. “The tempo run enables the runner to keep running at a faster pace,” says Pierce. “And it also trains the runner to keep running beyond his or her comfort zone, which is what a runner must do in a race.” You should feel uncomfortable at the end of these runs; they’re not meant to be easy!
3. Long Run
“This is the cornerstone run of the week, as these longer runs build both strength and confidence,” says Mandje. “It’s less about hitting a certain mile number and more about consistent, steady-state cardio.” Plus, without the endurance-boosting long run, speed workouts and tempo runs would gradually wear you down.
The key with each of these workouts is quality over quantity of miles: Don’t obsess over the number of miles a training plan calls for. Instead, focus on what kind of effort you’re putting into those miles. “That way, you can make sure you get the most quality out of the quantity of training that you’re putting in,” says Mandje.
Incorporating these three types of runs into your week, here’s a good example of what a typical training week could look like:
- Monday: Cross-Training
- Tuesday: Threshold Run
- Wednesday: Cross-Training
- Thursday: Easy Run
- Friday: Rest Day
- Saturday: Long Run
- Sunday: Rest Day
What should you do on your off days?
Just because you’re only running three days a week doesn’t mean that’s the only training you should do. Obviously, what else you do depends on how much time you have—maybe you have time for more workouts but only want to do three runs for injury prevention; or maybe you have some extra time available the other days of the week, but not enough time for full running workouts.
Half Marathon Training cardio but don’t want to subject your body to the impact of running, add in an easy cycling, swimming, rowing, or elliptical workout—”something that uses the leg musculature in a non-impact, low-loading, lower Races - Places (higher cadence with low resistance), endurance sort of way,” says Harrison. That will help you with the aerobic and/or leg turnover aspects of running without the wear and tear of pounding the pavement.
A traditional strength training day is also important, especially since it helps fortify the muscles and joints you need to keep moving forward—so if you’re crunched for time, skip the extra cardio for a total-body workout. “Two strength training workouts with a focus on upper body and leg strength, as well as power training” would be ideal, says Harrison.
Half Marathon Training can have a day off—that means “a day to rest and recover without cross-training or any other major form of exercise,” says Mandje. But that doesn’t mean you should just sit and binge a Netflix show after work. Maybe you do 15 minutes of mobility work, or a restorative yoga flow. Active recovery is still recovery and it can help you optimize your performance the next time you lace up.
Master the Half Marathon
