Sub 4.20 Marathon Goal - How Do I Get There?

by Mark
(UK (Brighton))

Hi, I'm 39 and have been running for nearly 2 years. I have a half marathon and a marathon coming up in the next three months and am looking to beat my PB.

My 5k pb is 25.07, 10k pb 53.03, half 1.58.04 and marathon 5.07 (calf problem at 21km, was on schedule for a 4.40).

I am 5ft 7in my weight is 13st 7pound and I'm big-built.

I run 25-30 miles a week including 13m - 15m run at the weekends with a bit of mountain biking in between runs.

Can you give me some advice on running sub-9 min miles comfortably.

My first 3 miles are always my worst and in a half marathon miles 8,9 and 10 I can usually run at around 8.30 but slow to 9s there after.

I can run comfortable at 9.30 but would love to run the same at 9s. Any advice would be great. Many thanks.

Answer by Dominique:
Hi there,
Thanks for your question about improving your personal records on both the half and the full marathon.

First thing I did was plug in your results in the Race Conversion Calculator.

It's a useful tool to work out if your racing times are well aligned.

So, what I did was plug in your 5k time, then compare the expected 10k and half marathon times with your real times.

Based on your 5k time your expected 10k time is more than 30 seconds lower than your 53.03 PB and your expected half marathon time is about 2.5 minutes lower than your 1.58.04 PB.

Based on your 10k time, your expected half marathon time is a minute faster (1.57).

Additionally, your 4.20 sub-marathon goal as suggested by the title of your post appears to be within your abilities given your 5k, 10k and half marathon performances.

Your racing times are close, but not fully aligned? Why is this? And why will it be tough for you to hit sub-4.20, despite your performance in other races?

The answer? Your base, your basic stamina is not yet developed fully enough. You have got the basic speed, but can't maintain it for long enough. You are getting there, it's not at all bad. But your aerobic base needs to become stronger. That's the absolute key to marathon success.

And the only way to solve it is by doing a lot of long runs and easy runs.

As I indicate in my marathon training tips the main component of a successful marathon is the long run, with the mid-week mid-long run being a close second.

I'd encourage you to make your weekend long run progressively longer (make sure to hit 20 miles a few times) and also schedule in a mid-week long run of at least 90 minutes in length. You can build up to this, doesn't need to be from next week onwards ...!

In order to make the weekend long run easier you could turn it into a walk/run in which you run at least 70% of the time. You still get much of the benefits of covering the distance and it makes the recovery easier.

The weekly longer long run and the mid-week long run together will do wonders for your stamina.

They will help improve your times in all distances. But the differences will be most noticeable in your half marathon and marathon performances.

In addition, I would encourage you to make sure you use a variety of training speeds in your workouts. Many people just have one speed when it comes to their running training. You can improve your performance by doing some tempo running in addition to your easy, steady-state base running.

Tempo runs help you improve your lactic acid threshold, which in turn, will help make you a faster runner.

I hope this helps.
Kind regards,

Join in and write your own page! It's easy to do. How? Simply click here to return to Marathon Training Questions.

Like this page:

Share this page:

Like this site:

[?] Subscribe To This Site

follow us in feedly
Add to My Yahoo!


  • Beginner Running Tips

    Are you a beginning runner? Then this is your best starting point. Many tips and running programs on offer, dedicated to you.

  • Running for Weight Loss

    Aiming to lose a few pounds? Get into the Running for Weight Loss section for tips and advice.

  • Running Training

    The Running Training section of the site has got the most articles. It is constantly getting updated with new tips and information. A must-visit if you are serious about improving your running performance.

  • 5k Running Tips

    The 5k is a great distance to run and train for. The great thing is that you can do it quite often and see big improvements.

  • 10k Running Tips

    The 10k is a real challenge. You need to run fast for an uncomfortably long time! Check out this section if you are strong of mind and legs!

  • Marathon Running Tips

    The marathon is a massive challenge. Proper training is so important! Make sure to check out this section if you have got your mind set on the marathon!

What's New?

  1. 8 Essential Distance Running Tips for Beginners

    New to distance running and looking for guidance? Look no further! On this page I have compiled 8 essential distance running tips for beginners that will get you off to a flying start!

    Read more

  2. Best Running Tips :: 10k Running Program for Beginners - A 12 Week Training Program for Your First 10k

    Check out the perfect 12-week 10k running program for beginners. This training program is guaranteed to get you ready for your first 10 k race!

    Read more

  3. What is the Right Running Technique?

    I have started using your Beginner Running Program 3 and I have a question about my running technique. I've never run before. I read on many running

    Read more

  4. 70 Years Old - Want to Start Running

    I am 70 years of age. Started on one of your beginner programs am now in Week 2. Really excited at the prospect of getting to run a 5k. I play golf

    Read more

  5. Five Tips for Running the Mile

    Want to improve your mile time? Here are some tips for running the mile that should help make you faster.

    Read more