• Science based running training
  • Tailored to you
  • Adapting to your progress
  • Giving you the confidence* to succeed

    *and fitness

JSET is a new approach to endurance training

JSET is a highly personalised running training system which takes the uncertainty out of your racing by using science, rather than guesswork, to plan your training and assess your fitness. By understanding the relationship between average pace, weekly distance and race performance, JSET enables runners to do more of the training they enjoy and gives runners confidence that they’ve got the fitness to achieve their race goal.

When you sign up the JSET algorithm takes data from your recent runs and quantifies your fitness. Then, by knowing the fitness needed to achieve your race goal, it sets out a training plan to allow you to reach your target. Coupled with coaching and extra analysis from Josh Sambrook, an elite marathon runner, JSET has helped athletes across the globe, of a wide variety of abilities and backgrounds, achieve their running goals. From runners who simply want to finish their first marathon to runners aiming to win races, JSET works for everyone.

Get your training plan

By signing up for an online marathon training plan with JSET, you will receive a training plan, personalised according to your goals, past performances, current ability, lifestyle and training preferences. This gives your training a high degree of specificity, so you will not feel like you're following a generic plan.

A JSET marathon training plan can change the way you train. Each week you have a target training 'ring'. Which is simply the training load you need to run in order to achieve your race goal. Each mile you run moves you towards this target, and running faster counts as more of your training load.

It’s up to you to decide how you train. Some people run big distances every day, at a consistent, slow place. But if you’d rather run a coached session with a club that’s fine too – just make sure you run enough each week to meet the training load target. It is this highly individual training that has helped runners of all abilities improve.

If you stick to the JSET training program you can be confident you’ll be fit enough to achieve your race goal. You've got the experience of me, an elite marathon runner, but it's the science behind the unique training program that's the really special thing about JSET.

Learn more about the training

Here's what runners think of JSET

Runners of all abilities, from across the world, have used JSET to break PBs and redefine how they train.

  • This type of program is a major stress reliever. I can structure my training to how my time allows and I don’t have to feel confined by missing a workout

    - Forrest

  • I’ve made more progress with JSET in 3 months than I’ve made [on my own] in years

    - Chris

  • I am in love with my dashboard!

    - Beniam

  • One of the most rewarding and fun running programs that I’ve done in my life! I can’t wait to start training again with Josh for my next race!

    - Rossen

  • The system is so motivational and having Josh there has really helped me stay on track with my training

    - Anna

  • I would highly recommend JSET, the most valuable and focused marathon training I've ever done

    - Gavin

Josh S is the coach behind JSET

Marathon runner, coach and woolly hat enthusiast


I believe almost anyone can be a fast runner if they do the right training. JSET exists because I want to share my training methods. In 2016 I was directed towards the equation that JSET is based on, and by applying it to my training I found I was getting faster and faster. By the end of 2018 I was the fastest U23 in the UK. This isn’t because I’m naturally a fantastic runner – for a long time I was an average runner, finishing as an "also ran" in cross country and marathons.

It was training correctly, in a way that I enjoy, that enabled me to really improve. The JSET training uses the structure of science, combined with the intelligence of a skilled human to generate a training program that allows athletes to achieve more than they thought possible. JSET is different because the science underpinning the program understands exactly what training load your body has experienced, and what race performance that will produce.

My training methods are unusual, but have resulted in significant progress for all kinds of people. Essentially, my own training involves running big weekly distances at an easy pace. At the peak of a training cycle I run over 250km per week. One particularly unusual element of the training is that it doesn’t involve running anywhere near race pace for the vast majority of the training. Find out more about the training style.

And finally, some background about me; I am a graduate of the University of Leeds, with a BSc in Sports Science & Physiology. For my final year project (dissertation) I investigated predicting marathon performance from training variables and previous race performance; this is the work that I now use as the foundation of JSET. I ran my first marathon at the age of 17, and I've run at least one every year since. My current PB is 2h28min, which I ran in the Yorkshire Marathon 2018.

Now, please enjoy this photo of me getting very angry at a mascot. He got in my way just before the finish line, costing me an extra three or four seconds on my 9,510 second marathon time.