You Be the Coach: How fast can Allison run in the half marathon?

One of the most difficult questions for any coach to answer is: how fast can I run in my upcoming race? 


Just think about all of the questions that your coach will ask:

  • How long do you have to train?
  • What’s your current mileage?
  • What’s your current personal best – and how long ago was it?
  • Is the course hilly or exposed to wind?
  • What will the temperature be?
  • Have you been doing race-specific workouts?
  • Is your long run “good enough” – and what is it like relative to what you usually do?
  • Have you been running consistently for 20 years or inconsistently for 1 year?

As you can imagine, my typical answer is: uhm, I’m not sure! In episode 6 of Q&A with Coach, I answered a similar question and dubbed it the most difficult ever submitted to the show.

Still, educated guesses about finish times are possible – and fun. Some of my favorite memories are hanging out with my college track teammates, predicting what we would run in our upcoming races.

And now it’s your turn to be the coach.

Today is another “You Be the Coach” opportunity. I’ve realized that as Strength Running grows (guys, there are over 25,000 subscribers – that’s huge!), the real strength of SR is its community. That’s YOU.

Collectively, we can accomplish more. Together, we can improve at a faster rate. There’s strength in numbers.

So let’s dive into this complex question. I’m pumped to hear your thoughts.

How fast can Allison run?

A few weeks ago, Allison sent me an email with a tough question:

Hi Jason,

I am a 29 year old female and I’m training for my first half-marathon. I was training for it last year, blew my knee out and strained a ligament, and was on crutches for a week. Then I took a very long break from running and now the knee is in great shape. I just don’t want to hurt it again.

I started training for the half-marathon about 6 weeks ago, and I have two more months until the race. I know it’s not much time. Right now I’m increasing my distance. My longest run in the week is 12k, next week it will be 15k, and I’ll cap it at 18k.

I noticed when increasing my distance I was able to maintain my pace. It’s at 8:40 per mile right now. But I’ve never trained for a half marathon. My 5k PR is 21:00 and in peak fitness, I could run a 10k at the same pace, I just can’t get faster on shorter distances, which leads me to think I can keep, or even speed up my pace in half marathon training.

So back to my training question: do you think it’s a realistic goal to maintain, or even speed up, my pace as I increase from 12k to 21k, in the next two months? Or, is that not how the body works?

There’s a lot going on in Allison’s question:

  • we know her age
  • the fact that this is her first half
  • she’s healthy, but not training as much as before
  • we know her 5k PR
  • her current “easy” pace

So, what do you think?

In the comments below, tell Allison what you think of her situation. Can she run 8:40 pace for the half marathon in two months?

More importantly, explain WHY and what she can do between now and the race to help her run this pace (or faster). What should her long run progression look like? Should she do any faster workouts?

Leave your reply in the comments below. Later this week I’ll chime in and give my answer, too!

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  1. She has a good pace already, my guess is when she runs the 1/2 marathon she will do it at a faster pace versus training. The adrenalin is high during a race versus training runs.

    • Laura Thomas says:

      Personally, I would be careful doing too much training in the next 2 months. I would go up to 18k as slowly as possible (+~1 mile per week) and do just a little speed training (one time per week – and just do maybe 4 sprint intervals to start and to up to 8-10 by the week prior to the race). Also, (really) warm up for 10 minutes of jogging when doing intervals. And you can probably run a long cool down afterwards – example: 10 min warm up, 4-8 intervals (flat or hills) and then cool down with a 20-30 minute jog. You don’t need a lot of speed training for a half marathon, but I believe it can help your speed anyway. You just don’t want to get hurt, so don’t overdo it. And if you can get up to 10-12 miles prior to the race that would be good. I worked up to 13 mile runs prior to my half because I don’t run a lot of longer distances and it took me months to get there – I did two of those on the 2 weekends prior to my race. I came in 3rd in my AG (1st half marathon ever and it was in ice, snow, wind and rain)!

  2. Rodney Mickle says:

    There are other variables that I would want to know like weekly mileage and length of long runs before I would want to give a more certain assessment. Given the variable presented in her question I would say its not likely that she has enough time to safely extensively develop her fitness to maintain that pace. Maybe she could doing some intensive development if her base fitness can support her doing interval work like 3k-5k repeats at goal pace. The risk with that is that her knee may not be strong enough to be able to sustain the intensity of that work and that could put her at risk for some overuse injury.

    I would be more comfortable having her aim for completing the race instead of setting up a time goal. May set a goal pace for the 1/2 marathon after she’s completed one and has enough time to properly prepare for it.

  3. Jacob Simpson says:

    I predict Allison finishes in 1hr 45min. Three things come to mind when considering how fast Allison can run her half-marathon:

    1. Aerobic Fitness
    2. Similarity of Training Courses vs. Race Course
    3. Long Run Progression

    Aerobic Fitness – The half-marathon is about 90% aerobic, much more so than the 5K. Allison will need to keep this in mind when starting out of the gate. Many first-time long distance runners will start out too fast because they feel great, only to bonk at mile 11 or 12. Her 5K PR suggests that her finishing speed is great, so the trick will be to rein herself in early in the race and run a good negative split.

    Similarity of Courses – If Allison’s training courses are significantly different than what she will encounter on race day, she could be lulling herself into a sense of false security. The closer her training course approximates what she will face on race day (ascents, terrain, etc), the more her mind and body will be prepared to tackle the course.

    Long Run Progression – Since this is her first half and because of her prior knee injury, she should err on the side of caution when increasing her long runs. With two months to go, she may actually be a little ahead of where she should be. Maybe this week she should keep her distance the same but push the pace a little (maybe 8:30). If that feels comfortable, add 2K the next week and keep the 8:30 pace. Add 2K each week until you get to 20K, which should put her about 2 weeks out from her race. She then has one more week to play with the pace and then taper down.

  4. I think 1:45 would be very attainable but challenging.
    Because she seems to not slow when going longer but has trouble or going faster at shorter distance I feel her endurance is where it need to be. I would have her do 400s and 800s at slightly faster then current 5k pace and and have her do her long runs with a 4-8 mile race pace or slightly faster 7:45-8:00 pace in the middle or just do them as a stand alone workout. She needs confidence and speed she will do well.

  5. 8:00/mile would get her a 1:44:48 half and should be very doable for her. She’s run 5K at 6:46 pace and said she was able to maintain that pace for a 10K as well, so her endurance seems good. Besides all that, race day adrenaline should kick in, as another commented. Two months isn’t a lot of time and I don’t know anything about the course for her upcoming half – is it on flat roads or hilly with some trail running? BTW, 1:45 is my goal for my next half too – I did my first one (a hilly one) last fall in 1:56 and, with a 5K PR of 22:55, I’m not nearly as fast as she is at those shorter distances. But, I’m 52, not 29. 🙂

  6. Allison should be less concerned with finishing the half marathon at an 8:40 pace than running at a comfortable pace throughout the entire distance. Remember it’s her first marathon so there is really no need to be concerned with a certain pace. Intervals once a week, 6 milers twice a week and the longer runs on weekends should give her adequate preparation for a good race at the end of two months.

  7. I would suggest firstly measuring heart rate as soon as she gets up in the morning, then performing a bike ride continuously (stationary bike would be better) for the same length of time she estimates the race to last – if she plans the route on a running website/map creator, she can acertain gradients and adjust difficulties for these intervals. Distance on the bike is not the concern, only duration. Finally, evaluate the pain, swelling and overall aftermath. Then sleep on it. In the morning, measure her heart rate again – if it has increased above 10bom, I would say a slower pace, knocking 5-10mins at least; however, if there is little or no change, that pace would be optimal. Knee injuries are not to be taken lightly, even with such fast lower distance speeds. I would estimate 1:50, depending on the course.

  8. Thanks so much for the feedback everyone. Unfortunately I have a major setback: I strained my hamstring! I’m off running for about a week, and probably need another week off. Just before the injury I got down to running 10k at closer to an 8:00/mile minute pace, so I was feeling really confident about moving forward.

    The area where I live and train is very hilly, much hillier than the actual race terrain, and I think the hills got my hamstring! I think I have much more endurance than I realized at the onset of this process, but man, I never expected that so much of training is about not over training.

    So now, the new goal is (1) rest, which is actually agonizing because all I think about is how much I want to run, and (2) think about a new plan for how I can start training again in a way where I won’t hurt anything else, or further–>a major priority.

  9. Not knowing what kind of strength training you might already be doing, I highly recommend heeding Jason’s strength training tips and techniques as a great way to minimize risk of future injury and build a strong running body. I will also recommend “Build Your Running Body” by Melissa Breyer/Pete Magill/Thomas Schwartz and “Ready to Run” by Dr. Kelly Starett, both excellent books that give you loads and loads of great info on fortifying your body to allow it to stand up to the stresses that come with running.

  10. Great article.

    Great question.

    From what it is worth, here is my response:

    What’s the rush? From the tone of the email, I get the feeling there is a sense of urgency.

    I would not increase pace at the same time as increasing mileage, especially when coming back from an injury. It might be better to run in a 10K race first and see how the leg feels, then progress up in distance.

    It might help thinking 1 or 2 years into the future and asking herself where she wants to be in 2016 and 2017. That will take the focus of the here and now. Safer and smarter that way.

    Work with time, not against time.


  11. Jonathan Sensenig says:

    You’ll find great differences that exist in completing that of 13.1 miles and your previous distances. It is primarily a mental think but you may consider breaking up the race into smaller efforts. I would add 10% to your expected time and then see how you feel once you’ve completed at least half. Here’s to good surprises.


  12. I would suggest Allison do some strength training this will help her endurance for the 1/2 marathon. She should also do intervals of run walk, which will increase her pace and keep her from possible injury. Being that this is Allison’s first 1/2 marathon I would suggest she focuses on finishing the race instead of her pace. The next 1/2 she does she can then look at pace and finishing time.

  13. Robert stamm says:

    Allison could definitely do 8:40 miles for 13.1. Look at it. She is young… She obviously has enough speed to run sub 1:45 based on her 5 k pr. I think she could do sub 1:45, maybe lower. What will make it happen is three fold: increase her total miles and the length of her long runs to 12-15 miles. This will obviously break the 10% increase In miles per week increase rule, But with good strength training, flexibility work and foam rolling she could do it. Second she needs to have some mid distance tempo runs at 7:30 to 8:00 ish pace of 2-5 miles. Assuming she is in relative good shape and not any injuries the tempo runs should be doable. And third she could try to some fast finish on some of her long runs on the last 1-3 miles. Regardless she needs to increase miles as much as her body can handle, vary the pace with some more intense tempo or interval work on the track and go longer to improve endurance. I don’t think she needs to focus on to much intense speed work…. Strides on 2-3 of her runs per week should do it and some hill work. Good luck Allison. Rooting for you.

    • Fantastic advice Robert.

    • Thanks for this, Robert. Since Allison didn’t provide her weekly mileage (as far as I can tell), would you suggest a “goal mileage” for half-marathon prep when you’re aiming for sub-1:45?

      As far as Allison’s story, I can definitely relate. From my limited experience, though, the structural fitness and mental ability needed for the last 5 km of a fast half-marathon is incredibly taxing … so long runs have to be the key. I’m training for my first half, and the hardest part is putting in the miles when your legs feel like lead. On my long runs I burn out around 15 km — not from cardio, but from muscle tightness and soreness. Any recommendations for getting over that hump?

      • Trent, that issue you’re experiencing around 15km is because that distance is challenging for you. You need to continue running that distance and increase gradually. It’s your endurance (i.e., cardio) that needs improving.

  14. I would recommend a goal time of 1:45:00. With a good training plan, she could easily be faster then that. But being her first, coming off an injury, I would not recommend pushing any more then 1:45.

  15. Between 1:45 and 1:50 now but I think she could ultimately target a 1:30 with consistent, smart training. Successful endurance running requires long term commitment.

  16. Katherine Suski says:

    After her knee injury, I’m not sure if having a specific time is realistic. Actually finishing is more important. On long runs she should have been trying to get in as much distance as she can and not worry so much about time. Two other days a week is when she should be worrying about her pace. One day some sort of intervals or mile repeats and a couple days later do a tempo run at race pace. She could also be doing 4-6 100 meter strides several times a week to help increase her leg turnover. Also, I’m not sure if she has enough base to try to run a solid pace from 12K to 21K when her longest run was only 18K. Maybe, though because she’s been hitting strong times in her workouts.

    • When is it ever a good idea to say “get in as much distance as you can” during a long run?

      If she is not worrying about a specific time, why suggest TWO fast workouts per week?

      And since when is Tempo pace the same as race pace?

      Why recommend intervals or mile repeats without a target pace and recovery?