Preparing for your spring marathon: insights from coach-researcher Simon de Waal

Simon de Waal, Senior Lecturer in Sport and Exercise Sciences at University of Gloucestershire, provides important advice about preparing for a marathon based on his own research and experiences as a long-distance runner and coach:

Spring marathon season is swiftly upon us and with the days growing longer and the weather, hopefully, improving, there’s no time like the present to take stock of training already banked and plan your next few weeks.

Most marathon training plans one can pick up from specialist magazines and websites will be in the region of 16 to 20 weeks long, which puts us roughly in the middle of your training block, with eight weeks left to the TCS London Marathon (26 April 2026), seven weeks to the Adidas Manchester Marathon, and six weeks to the Brighton Marathon (among many, many others).

As an endurance running coach, senior lecturer in sport and exercise science, and PhD in ultra-marathon physiology, I have spent the better part of a decade working with numerous athletes – all looking to achieve their own version of success in the marathon.

This article condenses the learnings I’ve made through this process, so that those runners preparing for a marathon might make the most of their remaining preparation time.

Show me a runner who achieved the goal they set out for their marathon and I’ll show you a happy runner. Your goal doesn’t necessarily need to be a position in the marathon or even a time goal, it could be a process goal relating to the habits you wanted to develop in your training block.

Either way, athletes who attain their goals are much more likely to feel motivated to continue with running and report improved self-efficacy.

Now is the perfect time to realign your goals – you know how much work you’ve put in and you have an accurate mental map of what you’ll be able to put in over the next few weeks.

Remember that your goal needs to consider where you are right now as well as how much time there is left to prepare. And no, this isn’t an excuse to set yourself an ‘easy’ goal – in fact setting challenging, but achievable, goals are best practice.

Many runners fear ‘hitting the wall’ during the marathon – and there are several misnomers as to how or why this happens. ‘Hitting the wall’ is the confluence of many things, but routinely I see runners who don’t build the necessary tissue tolerance in training, start way too hard, or don’t eat enough carbohydrate or drink enough water during the race (sometimes all three of these).

To avoid this happening, you should focus on building your running volume steadily over the next few weeks until you taper. Don’t fall into the comparison trap here – against contrary popular belief, there is no ‘perfect’ long-run distance!

That said, if you want to know how your body is going to respond in mile 20 of the marathon, you may want your training to reflect that. To practise pace management (and avoiding being sucked into the herd), try and incorporate some race pace into your training runs. This will also allow you to practice drinking and eating (carbohydrates, usually in liquid or gel form) at race intensity.

When it comes to drinking and eating, I would again avoid the comparison trap. While your friend might be taking caffeine, sodium bicarbonate, ketones, and beetroot juice before every run, the reality is that these supplements only provide marginal gains and the best thing you can do to avoid hitting ‘the wall’ when it comes to diet is avoid dehydration and hypoglycemia.

Your thirst mechanism is generally a pretty good gauge for how much water your body needs, but for most non-elite runners you’re looking at about 400-800ml per hour. Coupled with this, ‘old school’ recommendations on carbohydrate intake were 30-60g per hour from a single source, but more modern strategies are in the 60-90g per hour (sometimes as high as 120g) from dual sources.

In both cases there is quite a range and it depends ultimately on how long you will be running for, your sweat rates, as well as conditions on the day. This is why it’s so important to practice this during your training – this gives you a chance to test your gut and comfortability within these ranges. It goes without saying that failing to prepare is preparing to fail. Do not assume that you can just rock up on race day and meet the goals you’ve set out without some level of preparation.

If you’ve absorbed anything from these reflections, I hope it’s the fact that now is the time for a steady hand in your preparation. It’s certainly too late to be cramming last-minute training to try and force a race goal.

Good luck with your training at this important stage – remember, the old adage that it’s a marathon not a sprint applies as much now as during the race itself!