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The marathon advice I wish someone had told me… with Jenny Mannion
Written byEmily Coates
Reviewed byHeeral Patel
Marathons are full of surprises – some thrilling, some painful and some you wish you’d been warned about. ‘Slow runner' Jenny Mannion sets the pace with tips, ‘maranoia’ and why loo roll's a must
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When Jenny Mannion first laced up her running shoes, she wasn’t aiming for a marathon, let alone an ultramarathon. But after a casual 3k run, she did exactly that. “I wanted to commit to something and take on a challenge… so I signed up for an ultramarathon,” she recalls.
What started as a personal test quickly became a passion and, along the way, she learned some valuable (and hard-earned) lessons. In 2023, she founded Runners and Stunners, a women’s running club for slower runners who might not fit into the typical scene. Now, it’s the biggest female run club in London.
A self-proclaimed "slow runner", Jenny shares the lessons she’s learned the hard way, from training smart and avoiding rookie mistakes to race-day survival tactics and the dreaded ‘maranoia’. Whether you're gearing up for your first 5k or chasing a marathon finish, we’ve rounded up her top tips for running stronger and smarter with fewer regrets. Spoiler alert: it’s so much more than an impressive PB.
1. Ready, get set, go!
- Set a goal – signing up for any running event keeps you accountable, do not rely on motivation alone. Jenny says: “The race is happening whether you train or not. Even if it’s just a 5k or 10k, if you’ve signed up, you have to show up. “Most people are only motivated 20–30% of the time, maybe even less. It’s about making running part of your routine.”
- Walking is okay – focus on covering the distance rather than speed. “Your pace doesn’t matter in the beginning. It is so subjective and personal. “My first marathon was in February 2024 in Seville. The race had a six-hour cut-off, so many back-of-the-pack runners, including myself, ended up running alone or walking at times. Overall, I felt well-prepared, I hit most of my training goals and race day went smoothly despite the warm weather.”
- Don’t compare yourself to others – everyone is at a different stage in their journey. “It’s easy to compare yourself to runners on social media doing four-minute kilometres, but they could’ve been running for years! “Don’t compare your chapter one to someone else’s chapter 30. Just go at your own pace and enjoy the process.”
- Be patient for the breakthrough moment – stay consistent and it will eventually click. Jenny added: “In the beginning, it feels hard, but everyone has that one run where it suddenly all comes together. For me, during my ultramarathon training, I had a half marathon training run where I felt really strong.
“That was the moment I realised my training was working. It can take months to get there, so staying consistent is key.”
2. Smash your training
- Follow a structured training plan – adapt it to fit your lifestyle. Jenny states: “When I first started, I ran four times a week and did two strength sessions, sometimes skipping the latter (which I wouldn’t recommend). Now, I do three runs and three strength sessions every week, and I’ve noticed a big improvement in my running.”
- 80% of your runs should be easy – you should be able to hold a conversation without getting out of breath. “Keep your heart rate low and pace comfortable,” she says. “If you need to walk, a good time to do it is at water stations. If you go out too fast, you’ll struggle later on.”
- Only push your speed in one session per week – to avoid burnout and injury. “I learned that managing stress, prioritising recovery and incorporating strength training are just as important as running itself, and I’ve applied those lessons to my current training.”
- Strength training is essential – incorporate single-leg exercises, split squats and hip thrusts. “My second marathon was the New York one in November, and it was a completely different experience. A common mistake in long-distance running is neglecting strength training, which I fell into after doing an ultra and a marathon back-to-back.”
- Increase mileage gradually – avoid sudden jumps to prevent common injuries like shin splints. “I’ve had shin splints twice, both times from increasing my mileage too quickly. If you get them, don’t keep pushing through; reduce your mileage and recover properly.”
- Take a deload week every month – a planned period of reduced training and intensity, to aid recovery. “A good rule is to increase mileage gradually and take a deload week every month.”
3. Prevent injuries, recover smart
- Fuel your body properly – protein, sleep and good nutrition aid muscle recovery. Jenny states: “I take pre-workout before some runs, even though some people disagree with raising your heart rate beforehand. But I like it – its good to do what works for you. Sleep, nutrition and rest all play a role in injury prevention.”
- Hydration is key – drink plenty of water and take electrolytes. “Hydration is also crucial, so I drink plenty of water and take electrolytes the night before and the morning of. I’m currently loving the Tri-Active clear whey and pre-workout.”
- Get a gait analysis – to understand how you run, make sure you’re wearing the right running shoes and consider sizing up
- Recovery is just as important as training – sleep, foam rolling and sports massages help prevent injuries. “For New York, I aimed for a faster time, but my stress levels were higher, my recovery suffered and I wasn’t strength training enough. I ended up injured during training, got cleared a month before the race, but the injury flared up mid-marathon,” she shares.
- Keep up with the supps and nutritious meals – incorporate things like protein shakes into your routine and look into the likes of vitamin D, magnesium and electrolytes. Jenny states: “Eating meals with enough protein or supplementing is a great way to aid recovery. Taking it after runs ensures your muscles rebuild properly.1-2 Sleep is also essential – if you’re not recovering, it’s harder to train and injuries can creep up. I personally take magnesium to help with tiredness and fatigue.3 Eating good food is key, too. Think of your body like a car – it needs fuel.”
4. Prep for race day
- Lay out everything the night before – race bib, gels, clothes and a hoodie for easy prep. “I lay out everything – clothes, race bib, gels and even a spare hoodie – so I don’t have to think about anything in the morning,” Jenny says.
“I try to be in bed early, with about nine hours before my alarm, since nerves can mess with sleep.” - Start slow – first-time marathoners should focus on finishing, not time. “First-time marathoners should forget about time goals – just focus on finishing.”
- Practice your target pace – work out your ideal pace per km for your dream PB and try it out ahead of time. “I’d start about 10 seconds slower per km than my usual pace (so if my comfortable pace is 7:20/km, I'd go at 7:30/km).
“Around halfway, assess how you feel. If you're still feeling strong at 25k, pick up the pace slightly, then reevaluate at 32k. In the final stretch, you're just running with your heart, holding your target pace, pushing through, and in the last 2k, giving it everything you've got.” - Carb load properly – have a solid pre-race meal and snacks at ready. “I always have a gluten-free pepperoni pizza the night before – it's become a bit of a tradition. Also, Trek bars for snacks and jam or peanut butter bagels for breakfast.”
- Pack toilet paper – marathon toilets can be grim, especially for slower runners who get to them last. "By the time you use them, everyone else already has!"
5. Go for it!
- Embrace the nerves – accept the ‘maranoia’ and enjoy your first marathon. Jenny adds: “This might sound a bit strange, but over time, the nerves do fade. However, for your first marathon, I think it's important to just embrace the emotions as there’s really nothing anyone can say that will completely erase the anxiety of running 42.2km. “I struggle with self-doubt and ‘maranoia’ before races because the distance feels so daunting. But I know I have the grit to push through.
“Marathon day itself is completely different from training. The energy, the crowds, the atmosphere – it all changes the experience. You’ll see people running in costumes, some even carrying fridges on their backs (especially in races like the London Marathon), and that perspective can help you realise that it’s not just about time or performance. It’s about enjoying the moment.”
- Trust the process – tapering feels tough, but your training will pay off. “If you were to go out and run 30km the week before the race, your body would still be fatigued on marathon day. So, tapering is crucial – it allows you to feel fresh when it matters most.
“But this phase can be mentally tough. For the last 16-20 weeks, marathon training has been your routine, almost your identity, and then suddenly, you’re running much less. That shift leaves you with more time to think – and doubt. You start to question everything. Have I done enough? What if I forget how to run?” - Run with your heart – push through doubt and let determination carry you. “In New York I remember thinking, I don’t know if I’ll finish this. But once I hit 32k, I told myself, I’m finishing this no matter what. If you can get to that point, you just run the rest with your heart.”
Jenny's marathon must-haves
The final say
Whether you're a total beginner or a seasoned marathoner, there’s something here to help you run smarter, stronger and, most importantly, enjoy the journey. Whether you get your period on race day or are worried about runner’s stomach – we've rounded up some bonus running advice for you to keep your cool for that photo finish.
“One key thing to remind yourself is that you've done the training and you've put in the work. At this point, the best thing you can do are rest, eat well and stay hydrated – there’s nothing else that will significantly impact your performance on race day,” Jenny adds.
“You only get one first marathon, so make the most of it.”
Some supplements or workouts might work for Jenny but not be right for you – it's all a personal journey.
This article provides informational advice and is not a substitute for medical care. Curated by experts for accuracy, we take great care to ensure the information is up-to-date and relevant. However, you should always consult your GP or healthcare professional before using supplements or alternative products, particularly if you have medical conditions or are under supervision.
- Van Vliet S, Beals J, Martinez I, Skinner S, Burd N. Achieving Optimal Post-Exercise Muscle Protein Remodeling in Physically Active Adults through Whole Food Consumption. Nutrients [Internet]. 2018 Feb 16;10(2):224. Available from: https://www.mdpi.com/2072-6643/10/2/224
- Schoenfeld BJ, Aragon A, Wilborn C, Urbina SL, Hayward SE, Krieger J. Pre- versus post-exercise protein intake has similar effects on muscular adaptations. PeerJ. 2017 Jan 3;5(5):e2825.
- National Institutes of Health. Magnesium [Internet]. National Institutes of Health. 2022. Available from: https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional/
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